Re: [drakelist] AGC Fault Drake 2-C

[Garey Barrell]

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Frank -

I haven't worked on that many 2-Cs, but it sure sounds like either your 
MUTE shorting plug "isn't" or possibly the contacts on S-3B aren't 
making contact!   What you're seeing is exactly what I'd expect to see 
if the MUTE shorting plug was left out.  The S meter can drift around 
with the AGC off, and often moves upscale. 

This must be the day for weird Drake problems with Rob's three 
apparently bad final tubes and your "non-shorting" MUTE plug!!


73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




francobevi francobevi wrote:


"francobevi francobevi" <[EMAIL PROTECTED]> made an utterance to 
the drakelist gang

--
Hi guys!

I am trying to repair the agc of a Drake 2-C.

First I notice that in standby the s-meter goes up S9+40, while 
setting the function switch to ON (or external muting with the muting 
plug) the s-meter goes to S1 but it moves up to about S5 with the AVC 
in OFF position when strong signal are heard (that's strange should it 
really move or stay fixed?? on strong signals distortion is heard). In 
AVC postion SLOW or FAST the S-Meter goes to S9+40 as in postion 
STANDBY and nothing is heard.


I measured the voltages at TP1: in position AVC OFF it is -1.35 Volts, 
and in position AVC SLOW or FAST it is something like between -15 Volts.


I was thinking that the wiring from the function switch to the AGC 
section could be wrong but before making any change I would like to 
know what you think it could be.


73, Frank

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Re: [drakelist] TR-4C transmitter troubleshooting

[Garey Barrell]

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Rob -

Certainly looks like tubes   Have you tried turning down the bias 
(towards 0 volts)?


I can't think of anything else to try.  Let us know what happens!

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Garey-

It's sure looking like the tubes, odd as that seems.  Here
are the readings I'm getting (measured at the tube socket):

  Pin 1 - 255VDC RX, 247VDC TX
  Pin 2 - -58 VDC
  Pin 3 - 155VDC RX, 0VDC TX
  Pin 4, 5 - Filaments (good - tubes light, get hot, RX works)
  Pin 6 - -58 VDC (Same as pin 2)
  Pin 7 - 255VDC RX, 247VDC TX  (Same as pin 1)
  Pin 8 - Ground
  Plate cap - 748VDC (+/- 1VDC, all 3)

Definately agree that all three tubes would have to be open to
draw no current, but there doesn't seem to be another explanation.
It sure seems odd.  Almost impossible, even.  You would think
that opening the meter shunt resistor would actually protect
the tubes -- they were obviously drawing plenty of current
when the resistor blew.  Not knowing the history of this rig
though, it's hard to say.

I pulled the tubes -- nothing obvious to be seen there.  The
above readings were taken after I put the tubes back in.  Wish
like heck I had a spare set to try, but I now have a set on
order.  (BTW -- I've never dealt with Antique Electronic
Supply - tubesandmore.com before, but if anyone's interested,
they have 6JB6A's on 'sale' for $14.60 apiece until 5/14 and
claim they'll match them for $1.25 apiece.)  A tube sale???

So... unless someone sees something wierd with the voltage
readings, I guess I'm waiting on tubes.  Oh... also
checked the meter switch on the load control -- it ohms
out fine.  The factory selected resistor (R13) in this
rig is 39 ohms.

Many thanks again!

73, Rob (KFØRT)




  

-Original Message-
From: Garey Barrell [mailto:[EMAIL PROTECTED]
Sent: Sunday, April 16, 2006 4:45 PM
To: R. Ton
Cc: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshooting


Rob -

I find it hard to believe that ALL three tubes are totally dead,
assuming the filaments are lit!

First, have you measured the screen voltage on the tubes?  Each tube
should have about 250VDC on the screen pin via a 68 ohm, 1W resistor.

Where are you measuring the plate voltage?  Measure at the plate cap of
each tube.

Again, if there is 750 VDC on the plate cap, 250 VDC on the screen, 0
VDC on the grid and 0 VDC at the cathode, each one of those tubes would
draw over an amp of cathode current.   To control this current, you
apply a negative voltage to the grid, and typically ~ -55 VDC should
limit that current to ~ 30 mA.  IF these conditions are met at the tube
pins, then the only remaining answer is three completely open tubes,
which I still find hard to comprehend.  The three tubes are in parallel,
so if any one of them is even slightly good, you should see plate current!

If the cathode PINS are at 0 VDC in transmit, then the RFC, meter shunt
and relay contact are OK.  There are two RF chokes in series between the
HV feedthrough under the chassis and the plate caps of all three tubes.

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:


Great idea, Garey...

With my meter set as low as it'll go, I'm showing about 0.3 mV across
the shunt resistor in transmit.  This thing isn't drawing any current
at all!  In receive, I'm getting a cathode voltage of about 155V and
a plate voltage of about 754V.  The 754V plate reading is the same
as my AC-4 under no load.  In transmit, there is no change in plate
voltage, but the cathode voltage goes to zero.

According to the schematic, the cathodes are grounded via the T/R relay,
the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
showing 0V on the cathode in transmit.

Wierd.  This would sure seem to indicate that the finals aren't
conducting at all.  Still, very weak on my tube theory here --
could a grid condition cause this?  I'm showing a good -60V on
pins 2 and 6.

I was also thinking that a 1 watt, 2 ohm resistor should be able
to handle about 700ma without cooking.  When I got the rig, this
resistor was burned in half.  Maybe it's time to pull the tubes
and see if anything is rattling around inside?  :(

Is my thinking halfway straight?  :)  Hoping like heck the plate
current meter isn't shot -- I have a feeling those are hard to
get.

Thanks again everyone!

73, Rob (KFØRT)



  

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
Sent: Sunday, April 16, 2006 9:57 AM
To: R. Ton
Cc: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshootin

Re: [drakelist] TR-4C transmitter troubleshooting

[Garey Barrell]

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Rob -

Certainly looks like tubes   Have you tried turning down the bias 
(towards 0 volts)?


I can't think of anything else to try.  Let us know what happens!

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Garey-

It's sure looking like the tubes, odd as that seems.  Here
are the readings I'm getting (measured at the tube socket):

  Pin 1 - 255VDC RX, 247VDC TX
  Pin 2 - -58 VDC
  Pin 3 - 155VDC RX, 0VDC TX
  Pin 4, 5 - Filaments (good - tubes light, get hot, RX works)
  Pin 6 - -58 VDC (Same as pin 2)
  Pin 7 - 255VDC RX, 247VDC TX  (Same as pin 1)
  Pin 8 - Ground
  Plate cap - 748VDC (+/- 1VDC, all 3)

Definately agree that all three tubes would have to be open to
draw no current, but there doesn't seem to be another explanation.
It sure seems odd.  Almost impossible, even.  You would think
that opening the meter shunt resistor would actually protect
the tubes -- they were obviously drawing plenty of current
when the resistor blew.  Not knowing the history of this rig
though, it's hard to say.

I pulled the tubes -- nothing obvious to be seen there.  The
above readings were taken after I put the tubes back in.  Wish
like heck I had a spare set to try, but I now have a set on
order.  (BTW -- I've never dealt with Antique Electronic
Supply - tubesandmore.com before, but if anyone's interested,
they have 6JB6A's on 'sale' for $14.60 apiece until 5/14 and
claim they'll match them for $1.25 apiece.)  A tube sale???

So... unless someone sees something wierd with the voltage
readings, I guess I'm waiting on tubes.  Oh... also
checked the meter switch on the load control -- it ohms
out fine.  The factory selected resistor (R13) in this
rig is 39 ohms.

Many thanks again!

73, Rob (KFØRT)




  

-Original Message-
From: Garey Barrell [mailto:[EMAIL PROTECTED]
Sent: Sunday, April 16, 2006 4:45 PM
To: R. Ton
Cc: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshooting


Rob -

I find it hard to believe that ALL three tubes are totally dead,
assuming the filaments are lit!

First, have you measured the screen voltage on the tubes?  Each tube
should have about 250VDC on the screen pin via a 68 ohm, 1W resistor.

Where are you measuring the plate voltage?  Measure at the plate cap of
each tube.

Again, if there is 750 VDC on the plate cap, 250 VDC on the screen, 0
VDC on the grid and 0 VDC at the cathode, each one of those tubes would
draw over an amp of cathode current.   To control this current, you
apply a negative voltage to the grid, and typically ~ -55 VDC should
limit that current to ~ 30 mA.  IF these conditions are met at the tube
pins, then the only remaining answer is three completely open tubes,
which I still find hard to comprehend.  The three tubes are in parallel,
so if any one of them is even slightly good, you should see plate current!

If the cathode PINS are at 0 VDC in transmit, then the RFC, meter shunt
and relay contact are OK.  There are two RF chokes in series between the
HV feedthrough under the chassis and the plate caps of all three tubes.

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:


Great idea, Garey...

With my meter set as low as it'll go, I'm showing about 0.3 mV across
the shunt resistor in transmit.  This thing isn't drawing any current
at all!  In receive, I'm getting a cathode voltage of about 155V and
a plate voltage of about 754V.  The 754V plate reading is the same
as my AC-4 under no load.  In transmit, there is no change in plate
voltage, but the cathode voltage goes to zero.

According to the schematic, the cathodes are grounded via the T/R relay,
the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
showing 0V on the cathode in transmit.

Wierd.  This would sure seem to indicate that the finals aren't
conducting at all.  Still, very weak on my tube theory here --
could a grid condition cause this?  I'm showing a good -60V on
pins 2 and 6.

I was also thinking that a 1 watt, 2 ohm resistor should be able
to handle about 700ma without cooking.  When I got the rig, this
resistor was burned in half.  Maybe it's time to pull the tubes
and see if anything is rattling around inside?  :(

Is my thinking halfway straight?  :)  Hoping like heck the plate
current meter isn't shot -- I have a feeling those are hard to
get.

Thanks again everyone!

73, Rob (KFØRT)



  

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
Sent: Sunday, April 16, 2006 9:57 AM
To: R. Ton
Cc: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshootin

[drakelist] AGC Fault Drake 2-C

[francobevi francobevi]

"francobevi francobevi" <[EMAIL PROTECTED]> made an utterance to the drakelist 
gang
--
Hi guys!

I am trying to repair the agc of a Drake 2-C.

First I notice that in standby the s-meter goes up S9+40, while setting the 
function switch to ON (or external muting with the muting plug) the s-meter 
goes to S1 but it moves up to about S5 with the AVC in OFF position when 
strong signal are heard (that's strange should it really move or stay 
fixed?? on strong signals distortion is heard). In AVC postion SLOW or FAST 
the S-Meter goes to S9+40 as in postion STANDBY and nothing is heard.


I measured the voltages at TP1: in position AVC OFF it is -1.35 Volts, and 
in position AVC SLOW or FAST it is something like between -15 Volts.


I was thinking that the wiring from the function switch to the AGC section 
could be wrong but before making any change I would like to know what you 
think it could be.


73, Frank

_
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Re: [drakelist] Experience with the L4 (not L4B) amplifier

"" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Karl,

Yes, I own one of L-4 amplifiers.  I will provide any information that I can.

73 - Doug N9XTF

Quoting "Karl Oyster, K1KO" <[EMAIL PROTECTED]>:

> 
> "Karl Oyster, K1KO" <[EMAIL PROTECTED]> made an utterance to the drakelist 
> gang
> --
> Good morning to all:
> 
> I have not previously posted to this list, but discovered it in an 
> attempt to get some information about an amplifier I have recently 
> come into possession of.  If anyone is familiar with the Drake L4 
> amplifier, I would appreciate the opportunity to talk with you 
> about it.
> 
> Thanks, in advance,
> 
> Karl Oyster, K1KO
> Virginia Beach, VA 
> 
> --
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> body
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> 


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RE: [drakelist] TR-4C transmitter troubleshooting

[R. Ton]

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Garey-

It's sure looking like the tubes, odd as that seems.  Here
are the readings I'm getting (measured at the tube socket):

  Pin 1 - 255VDC RX, 247VDC TX
  Pin 2 - -58 VDC
  Pin 3 - 155VDC RX, 0VDC TX
  Pin 4, 5 - Filaments (good - tubes light, get hot, RX works)
  Pin 6 - -58 VDC (Same as pin 2)
  Pin 7 - 255VDC RX, 247VDC TX  (Same as pin 1)
  Pin 8 - Ground
  Plate cap - 748VDC (+/- 1VDC, all 3)

Definately agree that all three tubes would have to be open to
draw no current, but there doesn't seem to be another explanation.
It sure seems odd.  Almost impossible, even.  You would think
that opening the meter shunt resistor would actually protect
the tubes -- they were obviously drawing plenty of current
when the resistor blew.  Not knowing the history of this rig
though, it's hard to say.

I pulled the tubes -- nothing obvious to be seen there.  The
above readings were taken after I put the tubes back in.  Wish
like heck I had a spare set to try, but I now have a set on
order.  (BTW -- I've never dealt with Antique Electronic
Supply - tubesandmore.com before, but if anyone's interested,
they have 6JB6A's on 'sale' for $14.60 apiece until 5/14 and
claim they'll match them for $1.25 apiece.)  A tube sale???

So... unless someone sees something wierd with the voltage
readings, I guess I'm waiting on tubes.  Oh... also
checked the meter switch on the load control -- it ohms
out fine.  The factory selected resistor (R13) in this
rig is 39 ohms.

Many thanks again!

73, Rob (KFØRT)




> -Original Message-
> From: Garey Barrell [mailto:[EMAIL PROTECTED]
> Sent: Sunday, April 16, 2006 4:45 PM
> To: R. Ton
> Cc: Drakelist
> Subject: Re: [drakelist] TR-4C transmitter troubleshooting
>
>
> Rob -
>
> I find it hard to believe that ALL three tubes are totally dead,
> assuming the filaments are lit!
>
> First, have you measured the screen voltage on the tubes?  Each tube
> should have about 250VDC on the screen pin via a 68 ohm, 1W resistor.
>
> Where are you measuring the plate voltage?  Measure at the plate cap of
> each tube.
>
> Again, if there is 750 VDC on the plate cap, 250 VDC on the screen, 0
> VDC on the grid and 0 VDC at the cathode, each one of those tubes would
> draw over an amp of cathode current.   To control this current, you
> apply a negative voltage to the grid, and typically ~ -55 VDC should
> limit that current to ~ 30 mA.  IF these conditions are met at the tube
> pins, then the only remaining answer is three completely open tubes,
> which I still find hard to comprehend.  The three tubes are in parallel,
> so if any one of them is even slightly good, you should see plate current!
>
> If the cathode PINS are at 0 VDC in transmit, then the RFC, meter shunt
> and relay contact are OK.  There are two RF chokes in series between the
> HV feedthrough under the chassis and the plate caps of all three tubes.
>
> 73, Garey - K4OAH
> Atlanta
>
> Drake B & C-Line Service CDs
> 
>
>
>
> R. Ton wrote:
> > Great idea, Garey...
> >
> > With my meter set as low as it'll go, I'm showing about 0.3 mV across
> > the shunt resistor in transmit.  This thing isn't drawing any current
> > at all!  In receive, I'm getting a cathode voltage of about 155V and
> > a plate voltage of about 754V.  The 754V plate reading is the same
> > as my AC-4 under no load.  In transmit, there is no change in plate
> > voltage, but the cathode voltage goes to zero.
> >
> > According to the schematic, the cathodes are grounded via the T/R relay,
> > the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
> > ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
> > showing 0V on the cathode in transmit.
> >
> > Wierd.  This would sure seem to indicate that the finals aren't
> > conducting at all.  Still, very weak on my tube theory here --
> > could a grid condition cause this?  I'm showing a good -60V on
> > pins 2 and 6.
> >
> > I was also thinking that a 1 watt, 2 ohm resistor should be able
> > to handle about 700ma without cooking.  When I got the rig, this
> > resistor was burned in half.  Maybe it's time to pull the tubes
> > and see if anything is rattling around inside?  :(
> >
> > Is my thinking halfway straight?  :)  Hoping like heck the plate
> > current meter isn't shot -- I have a feeling those are hard to
> > get.
> >
> > Thanks again everyone!
> >
> > 73, Rob (KFØRT)
> >
> >
> >
> >> -Original Message-
> >> From: [EMAIL PROTECTED]
> >> [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> >> Sent: Sunday, April 16, 2006 9:57 AM
> >> To: R. Ton
> >> Cc: Drakelist
> >> Subject: Re: [drakelist] TR-4C transmitter troubleshooting
> >>
> >>
> >>
> >> Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> >> drakelist gang
> >> --
> >> Rob -
> >>
> >

RE: [drakelist] TR-4C transmitter troubleshooting

[R. Ton]

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Looks like it's good, Mark.  I sprayed it with Deoxit when I did the
other contacts and it ohms out good.

73, Rob (KFØRT)

> -Original Message-
> From: MNACE [mailto:[EMAIL PROTECTED]
> Sent: Sunday, April 16, 2006 5:17 PM
> To: R. Ton; [EMAIL PROTECTED]
> Cc: Drakelist
> Subject: Re: [drakelist] TR-4C transmitter troubleshooting
>
>
> I had a TR4-C that had a very dirty slide switch that Garey talks
> about (the
> one that switches between plate current and power out).  I actually (very
> very carefully) took it apart, cleaned the contacts, re-assembled, sprayed
> with deoxit, and all the meter problems went away.  The other option would
> be to replace with a new slide switch
> 73,
> Mark
> N5KAE
>
> - Original Message -
> From: "R. Ton" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Cc: "Drakelist" 
> Sent: Sunday, April 16, 2006 4:14 PM
> Subject: RE: [drakelist] TR-4C transmitter troubleshooting
>
>
> >
> > "R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
> > --
> > Great idea, Garey...
> >
> > With my meter set as low as it'll go, I'm showing about 0.3 mV across
> > the shunt resistor in transmit.  This thing isn't drawing any current
> > at all!  In receive, I'm getting a cathode voltage of about 155V and
> > a plate voltage of about 754V.  The 754V plate reading is the same
> > as my AC-4 under no load.  In transmit, there is no change in plate
> > voltage, but the cathode voltage goes to zero.
> >
> > According to the schematic, the cathodes are grounded via the T/R relay,
> > the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
> > ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
> > showing 0V on the cathode in transmit.
> >
> > Wierd.  This would sure seem to indicate that the finals aren't
> > conducting at all.  Still, very weak on my tube theory here --
> > could a grid condition cause this?  I'm showing a good -60V on
> > pins 2 and 6.
> >
> > I was also thinking that a 1 watt, 2 ohm resistor should be able
> > to handle about 700ma without cooking.  When I got the rig, this
> > resistor was burned in half.  Maybe it's time to pull the tubes
> > and see if anything is rattling around inside?  :(
> >
> > Is my thinking halfway straight?  :)  Hoping like heck the plate
> > current meter isn't shot -- I have a feeling those are hard to
> > get.
> >
> > Thanks again everyone!
> >
> > 73, Rob (KFØRT)
> >
> >
> > > -Original Message-
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> > > Sent: Sunday, April 16, 2006 9:57 AM
> > > To: R. Ton
> > > Cc: Drakelist
> > > Subject: Re: [drakelist] TR-4C transmitter troubleshooting
> > >
> > >
> > >
> > > Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> > > drakelist gang
> > > --
> > > Rob -
> > >
> > > OK, a little more information.
> > >
> > > When the 2 ohm meter shunt resistor opens up, the Final
> cathode current
> > > is routed through a "slide switch" mounted up on the LOAD capacitor
> > > shaft, (activated by pushing in the LOAD control,) a series resistor
> > > that is selected at test, (mounted on the slide switch terminals,) of
> > > typically ~200 ohms, and the plate meter.   It wouldn't take much
> > > current to damage that resistor and/or meter with the shunt resistor
> > > open.   Or if the slide switch contacts are not closing
> properly in the
> > > "out" position of the LOAD control.
> > >
> > > Perhaps your finals are drawing idle current, it's just not showing on
> > > the meter!?  Measure the voltage drop across the meter shunt resistor.
> > > 100 mA should read 200 mV.
> > >
> > > By the way, if you're not used to working on tube gear, keep in mind
> > > that 650V (OR 250v) BITES!   An AC-4 bleeds down pretty quickly when
> > > turned off, but only your meter knows for sure before you stick your
> > > fingers in there!
> > >
> > > 73, Garey - K4OAH
> > > Atlanta
> > >
> > > Drake B & C-Line Service CDs
> > > 
> > >
> > >
> > >
> > > R. Ton wrote:
> > > > Thanks to all (!!) -- more coming when I get a chance (life is
> > > getting in
> > > > the way of fun right now).
> > > >
> > > > So far, I've had the chance to change out the relay -- the ONE
> > > spare part
> > > > I had on hand.  No difference.  The rig does go into transmit
> > > when switched
> > > > to CW mode (no key plugged in).  Both relays respond and the
> > > receiver mutes.
> > > > I just noticed this AM that the .025 plate current reading I
> > > get is there
> > > > even with the power off.  Meter moves about a needle's width
> > > when put into
> > > > transmit and the S-meter reads about 7-8 in transmit -- may be
> > > another clue?
>

[drakelist] FS: R-4C instruction manual

[mike maghakian]

mike maghakian <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
I have an overall good condition R-4C original
instruction manual for sale. it is  comb bound and the
fold out schematic is quite nice.
accepting cash or trade offers

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[drakelist] Chirp on TR4Cw

[Dieter Horst]

Dieter Horst <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Hello Drake Enthusiasts,

I currently have my father's TR4Cw here for service. 
An earlier problem with the PA no longer exists. It looked like dead finals but 
after transport
the TX put out power as usual. Probably not enough in use...hi

A subtle detail can be noticed, however. 
When transmitting CW on 15 and 10 meters, a slight 'chirp' can be observed.  It 
does not exist on 40 and 80/20 meters.
Having looked at the block diagram, I decided to measure the frequency of the 
crystal oscillator using two turns of wire
around the oscillator tube being coupled to a frequeny counter or a spectrum 
analyzer.

Yes, it's the crystal oscillator that is slightly changes frequency under full 
output power. Order of magnitude: 30...40 Hz 
Sounds a bit like UB5 stations 15 years ago... 

Has anyone out there ever experienced a similar behaviour of the TR4? I wonder 
what is the reason for this. The oscillator 
runs off the 150 V regulated (with OA2). I have not yet measured this voltage 
but I guess this is the only thing to check.

I have followed the alignment procedure for the oscillator described in the 
handbook without success.

Any hints appreciated!

Best regards from Germany

Dieter DL5RDO




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Re: [drakelist] TR-4C transmitter troubleshooting

[MNACE]

"MNACE" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
I had a TR4-C that had a very dirty slide switch that Garey talks about (the
one that switches between plate current and power out).  I actually (very
very carefully) took it apart, cleaned the contacts, re-assembled, sprayed
with deoxit, and all the meter problems went away.  The other option would
be to replace with a new slide switch
73,
Mark
N5KAE

- Original Message - 
From: "R. Ton" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: "Drakelist" 
Sent: Sunday, April 16, 2006 4:14 PM
Subject: RE: [drakelist] TR-4C transmitter troubleshooting


>
> "R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
> --
> Great idea, Garey...
>
> With my meter set as low as it'll go, I'm showing about 0.3 mV across
> the shunt resistor in transmit.  This thing isn't drawing any current
> at all!  In receive, I'm getting a cathode voltage of about 155V and
> a plate voltage of about 754V.  The 754V plate reading is the same
> as my AC-4 under no load.  In transmit, there is no change in plate
> voltage, but the cathode voltage goes to zero.
>
> According to the schematic, the cathodes are grounded via the T/R relay,
> the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
> ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
> showing 0V on the cathode in transmit.
>
> Wierd.  This would sure seem to indicate that the finals aren't
> conducting at all.  Still, very weak on my tube theory here --
> could a grid condition cause this?  I'm showing a good -60V on
> pins 2 and 6.
>
> I was also thinking that a 1 watt, 2 ohm resistor should be able
> to handle about 700ma without cooking.  When I got the rig, this
> resistor was burned in half.  Maybe it's time to pull the tubes
> and see if anything is rattling around inside?  :(
>
> Is my thinking halfway straight?  :)  Hoping like heck the plate
> current meter isn't shot -- I have a feeling those are hard to
> get.
>
> Thanks again everyone!
>
> 73, Rob (KFØRT)
>
>
> > -Original Message-
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> > Sent: Sunday, April 16, 2006 9:57 AM
> > To: R. Ton
> > Cc: Drakelist
> > Subject: Re: [drakelist] TR-4C transmitter troubleshooting
> >
> >
> >
> > Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> > drakelist gang
> > --
> > Rob -
> >
> > OK, a little more information.
> >
> > When the 2 ohm meter shunt resistor opens up, the Final cathode current
> > is routed through a "slide switch" mounted up on the LOAD capacitor
> > shaft, (activated by pushing in the LOAD control,) a series resistor
> > that is selected at test, (mounted on the slide switch terminals,) of
> > typically ~200 ohms, and the plate meter.   It wouldn't take much
> > current to damage that resistor and/or meter with the shunt resistor
> > open.   Or if the slide switch contacts are not closing properly in the
> > "out" position of the LOAD control.
> >
> > Perhaps your finals are drawing idle current, it's just not showing on
> > the meter!?  Measure the voltage drop across the meter shunt resistor.
> > 100 mA should read 200 mV.
> >
> > By the way, if you're not used to working on tube gear, keep in mind
> > that 650V (OR 250v) BITES!   An AC-4 bleeds down pretty quickly when
> > turned off, but only your meter knows for sure before you stick your
> > fingers in there!
> >
> > 73, Garey - K4OAH
> > Atlanta
> >
> > Drake B & C-Line Service CDs
> > 
> >
> >
> >
> > R. Ton wrote:
> > > Thanks to all (!!) -- more coming when I get a chance (life is
> > getting in
> > > the way of fun right now).
> > >
> > > So far, I've had the chance to change out the relay -- the ONE
> > spare part
> > > I had on hand.  No difference.  The rig does go into transmit
> > when switched
> > > to CW mode (no key plugged in).  Both relays respond and the
> > receiver mutes.
> > > I just noticed this AM that the .025 plate current reading I
> > get is there
> > > even with the power off.  Meter moves about a needle's width
> > when put into
> > > transmit and the S-meter reads about 7-8 in transmit -- may be
> > another clue?
> > >
> > > And thanks for the hollow-state theory Garey.  It's been a
> > REALLY long time
> > > since I've worked on any tube gear, but it's slowly coming back
> > to me. :)
> > >
> > > I'll be digging some more in a bit here and will report back.  I'll
also
> > > see if I can catch the technical net this afternoon.  7.238 @
> > 2000Z, right?
> > >
> > > Thanks again everyone!
> > >
> > > 73, Rob (KFØRT)
> > >
> > >
> > >> -Original Message-
> > >> From: [EMAIL PROTECTED]
> > >> [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> > >> Sent: Sunday, April 16, 

Re: [drakelist] TR-4C transmitter troubleshooting

[Garey Barrell]

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Rob -

I find it hard to believe that ALL three tubes are totally dead, 
assuming the filaments are lit!


First, have you measured the screen voltage on the tubes?  Each tube 
should have about 250VDC on the screen pin via a 68 ohm, 1W resistor.


Where are you measuring the plate voltage?  Measure at the plate cap of 
each tube.


Again, if there is 750 VDC on the plate cap, 250 VDC on the screen, 0 
VDC on the grid and 0 VDC at the cathode, each one of those tubes would 
draw over an amp of cathode current.   To control this current, you 
apply a negative voltage to the grid, and typically ~ -55 VDC should 
limit that current to ~ 30 mA.  IF these conditions are met at the tube 
pins, then the only remaining answer is three completely open tubes, 
which I still find hard to comprehend.  The three tubes are in parallel, 
so if any one of them is even slightly good, you should see plate current!


If the cathode PINS are at 0 VDC in transmit, then the RFC, meter shunt 
and relay contact are OK.  There are two RF chokes in series between the 
HV feedthrough under the chassis and the plate caps of all three tubes.


73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:

Great idea, Garey...

With my meter set as low as it'll go, I'm showing about 0.3 mV across
the shunt resistor in transmit.  This thing isn't drawing any current
at all!  In receive, I'm getting a cathode voltage of about 155V and
a plate voltage of about 754V.  The 754V plate reading is the same
as my AC-4 under no load.  In transmit, there is no change in plate
voltage, but the cathode voltage goes to zero.

According to the schematic, the cathodes are grounded via the T/R relay,
the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
showing 0V on the cathode in transmit.

Wierd.  This would sure seem to indicate that the finals aren't
conducting at all.  Still, very weak on my tube theory here --
could a grid condition cause this?  I'm showing a good -60V on
pins 2 and 6.

I was also thinking that a 1 watt, 2 ohm resistor should be able
to handle about 700ma without cooking.  When I got the rig, this
resistor was burned in half.  Maybe it's time to pull the tubes
and see if anything is rattling around inside?  :(

Is my thinking halfway straight?  :)  Hoping like heck the plate
current meter isn't shot -- I have a feeling those are hard to
get.

Thanks again everyone!

73, Rob (KFØRT)


  

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
Sent: Sunday, April 16, 2006 9:57 AM
To: R. Ton
Cc: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshooting



Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
--
Rob -

OK, a little more information.

When the 2 ohm meter shunt resistor opens up, the Final cathode current
is routed through a "slide switch" mounted up on the LOAD capacitor
shaft, (activated by pushing in the LOAD control,) a series resistor
that is selected at test, (mounted on the slide switch terminals,) of
typically ~200 ohms, and the plate meter.   It wouldn't take much
current to damage that resistor and/or meter with the shunt resistor
open.   Or if the slide switch contacts are not closing properly in the
"out" position of the LOAD control.

Perhaps your finals are drawing idle current, it's just not showing on
the meter!?  Measure the voltage drop across the meter shunt resistor.
100 mA should read 200 mV.

By the way, if you're not used to working on tube gear, keep in mind
that 650V (OR 250v) BITES!   An AC-4 bleeds down pretty quickly when
turned off, but only your meter knows for sure before you stick your
fingers in there!

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:


Thanks to all (!!) -- more coming when I get a chance (life is
  

getting in


the way of fun right now).

So far, I've had the chance to change out the relay -- the ONE
  

spare part


I had on hand.  No difference.  The rig does go into transmit
  

when switched


to CW mode (no key plugged in).  Both relays respond and the
  

receiver mutes.


I just noticed this AM that the .025 plate current reading I
  

get is there


even with the power off.  Meter moves about a needle's width
  

when put into


transmit and the S-meter reads about 7-8 in transmit -- may be
  

another clue?


And thanks for the hollow-state theory Garey.  It's been a
  

REALLY long time


since I've worked on any tube gear, but it's slowly coming back
  

to me. :)


I'll be digging some more in a bit here and will report back.  

RE: [drakelist] TR-4C transmitter troubleshooting

[R. Ton]

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Great idea, Garey...

With my meter set as low as it'll go, I'm showing about 0.3 mV across
the shunt resistor in transmit.  This thing isn't drawing any current
at all!  In receive, I'm getting a cathode voltage of about 155V and
a plate voltage of about 754V.  The 754V plate reading is the same
as my AC-4 under no load.  In transmit, there is no change in plate
voltage, but the cathode voltage goes to zero.

According to the schematic, the cathodes are grounded via the T/R relay,
the 2 ohm shunt resistor, an RF choke and a 15 ohm resistor (one 15
ohm resistor for each tube).  Even through the 15 ohm resistor, I'm
showing 0V on the cathode in transmit.

Wierd.  This would sure seem to indicate that the finals aren't
conducting at all.  Still, very weak on my tube theory here --
could a grid condition cause this?  I'm showing a good -60V on
pins 2 and 6.

I was also thinking that a 1 watt, 2 ohm resistor should be able
to handle about 700ma without cooking.  When I got the rig, this
resistor was burned in half.  Maybe it's time to pull the tubes
and see if anything is rattling around inside?  :(

Is my thinking halfway straight?  :)  Hoping like heck the plate
current meter isn't shot -- I have a feeling those are hard to
get.

Thanks again everyone!

73, Rob (KFØRT)


> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> Sent: Sunday, April 16, 2006 9:57 AM
> To: R. Ton
> Cc: Drakelist
> Subject: Re: [drakelist] TR-4C transmitter troubleshooting
>
>
>
> Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> drakelist gang
> --
> Rob -
>
> OK, a little more information.
>
> When the 2 ohm meter shunt resistor opens up, the Final cathode current
> is routed through a "slide switch" mounted up on the LOAD capacitor
> shaft, (activated by pushing in the LOAD control,) a series resistor
> that is selected at test, (mounted on the slide switch terminals,) of
> typically ~200 ohms, and the plate meter.   It wouldn't take much
> current to damage that resistor and/or meter with the shunt resistor
> open.   Or if the slide switch contacts are not closing properly in the
> "out" position of the LOAD control.
>
> Perhaps your finals are drawing idle current, it's just not showing on
> the meter!?  Measure the voltage drop across the meter shunt resistor.
> 100 mA should read 200 mV.
>
> By the way, if you're not used to working on tube gear, keep in mind
> that 650V (OR 250v) BITES!   An AC-4 bleeds down pretty quickly when
> turned off, but only your meter knows for sure before you stick your
> fingers in there!
>
> 73, Garey - K4OAH
> Atlanta
>
> Drake B & C-Line Service CDs
> 
>
>
>
> R. Ton wrote:
> > Thanks to all (!!) -- more coming when I get a chance (life is
> getting in
> > the way of fun right now).
> >
> > So far, I've had the chance to change out the relay -- the ONE
> spare part
> > I had on hand.  No difference.  The rig does go into transmit
> when switched
> > to CW mode (no key plugged in).  Both relays respond and the
> receiver mutes.
> > I just noticed this AM that the .025 plate current reading I
> get is there
> > even with the power off.  Meter moves about a needle's width
> when put into
> > transmit and the S-meter reads about 7-8 in transmit -- may be
> another clue?
> >
> > And thanks for the hollow-state theory Garey.  It's been a
> REALLY long time
> > since I've worked on any tube gear, but it's slowly coming back
> to me. :)
> >
> > I'll be digging some more in a bit here and will report back.  I'll also
> > see if I can catch the technical net this afternoon.  7.238 @
> 2000Z, right?
> >
> > Thanks again everyone!
> >
> > 73, Rob (KFØRT)
> >
> >
> >> -Original Message-
> >> From: [EMAIL PROTECTED]
> >> [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> >> Sent: Sunday, April 16, 2006 8:41 AM
> >> To: Drakelist
> >> Subject: Re: [drakelist] TR-4C transmitter troubleshooting
> >>
> >>
> >>
> >> Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> >> drakelist gang
> >> --
> >> Hi Kevin -
> >>
> >> Expertise is just experience clouded by memory!  :-)
> >>
> >> I don't think I've ever come across a PAIR of finals that "lit up", but
> >> wouldn't draw at least a couple hundred mA if they had the DC
> potentials
> >> applied to them.  In fact, I can only remember one tube that
> was "open",
> >> but lit.  I still think it had a broken weld inside it!!  :-)
> >>
> >> But then I've been wrong before.  A favorite med school phrase, "when
> >> you hear hoof beats, think horses, not zebras" comes to mind!
> >>
> >> Hopefully Rob will get it fixed in spite of my help and let us know the
> >> truth!!
> >>
> >> 73, Garey - 

Re: [drakelist] TR-4C transmitter troubleshooting

[Don and Diana Cunningham]

"Don and Diana Cunningham" <[EMAIL PROTECTED]> made an utterance to the 
drakelist gang
--
Rob,
Mr. Simpleton here, I must confess, but it was always MUCH easier for me to 
set bias with the Drake gear, assuming that the meter worked, (Garey's post 
covers that though) by using either a microphone in the SSB mode and pushing 
PTT with no audio or keying the rig up with a clip lead in the SSB mode. 
That's the only way I learned to do it (again, other than getting inside 
like Garey suggests).  I haven't seen that suggested. Like I say, probably 
too simple but always worked for me.

73,
Don, WB5HAK
- Original Message - 
From: "R. Ton" <[EMAIL PROTECTED]>

To: <[EMAIL PROTECTED]>; "Drakelist" 
Sent: Sunday, April 16, 2006 10:38 AM
Subject: RE: [drakelist] TR-4C transmitter troubleshooting




"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Thanks to all (!!) -- more coming when I get a chance (life is getting in
the way of fun right now).

So far, I've had the chance to change out the relay -- the ONE spare part
I had on hand.  No difference.  The rig does go into transmit when 
switched
to CW mode (no key plugged in).  Both relays respond and the receiver 
mutes.

I just noticed this AM that the .025 plate current reading I get is there
even with the power off.  Meter moves about a needle's width when put into
transmit and the S-meter reads about 7-8 in transmit -- may be another 
clue?


And thanks for the hollow-state theory Garey.  It's been a REALLY long 
time

since I've worked on any tube gear, but it's slowly coming back to me. :)

I'll be digging some more in a bit here and will report back.  I'll also
see if I can catch the technical net this afternoon.  7.238 @ 2000Z, 
right?


Thanks again everyone!

73, Rob (KFØRT)


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
Sent: Sunday, April 16, 2006 8:41 AM
To: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshooting



Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
--
Hi Kevin -

Expertise is just experience clouded by memory!  :-)

I don't think I've ever come across a PAIR of finals that "lit up", but
wouldn't draw at least a couple hundred mA if they had the DC potentials
applied to them.  In fact, I can only remember one tube that was "open",
but lit.  I still think it had a broken weld inside it!!  :-)

But then I've been wrong before.  A favorite med school phrase, "when
you hear hoof beats, think horses, not zebras" comes to mind!

Hopefully Rob will get it fixed in spite of my help and let us know the
truth!!

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




kbgluxford wrote:
>
> kbgluxford <[EMAIL PROTECTED]> made an utterance to the drakelist
> gang
> --
> I certainly don't have Garey's expertise or long experience, but I did
> have a similar problem on one of my TX4 transmitters recently.  I
> changed out the PA tubes and the problem disappeared.
>
> 73
> Kevin
> VK3DAP / ZL2DAP
>
> Garey Barrell wrote:
>>
>> Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
>> drakelist gang
>> --
>> Rob -
>>
>> You don't mention anything about "keying" the transmitter.  You have
>> to "key" the Push-To-Talk (PTT) of the microphone to switch it to
>> transmit to see the idling plate current.  You should hear the relay
>> click when it closes.
>>
>> If the final tubes have plate voltage, screen voltage and filament
>> voltage, and the cathodes are returned to the negative pole of those
>> supplies, they WILL draw plate current!   The grid voltage is the
>> only thing that keeps them from drawing AMPS of current in the
>> presence of the other voltages.
>>
>> There are two RF chokes in series between the +650VDC supply and the
>> plate caps of the tubes.   There is a 15 ohm, 1W resistor in series
>> with each of the final tube cathodes to another RF choke, through the
>> meter shunt resistor, and then through a relay contact to ground.
>>
>> 73, Garey - K4OAH
>> Atlanta
>>
>> Drake B & C-Line Service CDs
>> 
>>
>>
>>
>> R. Ton wrote:
>>> "R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
>>> --
>>> I'm finally digging into a TR-4C I bought used some time ago.  It
>>> "worked
>>> fine" when it was shipped here, but I haven't been able to get any
>>> power out
>>> of the transmitter.  It at least oscillates -- I can hear it on a
>>> receiver
>>> in the same room.
>>>
>>> Starting at the beginning...
>>>
>>> The manual says to adjust the bias on the AC-4 s

[drakelist] Just trolling for now.. looking for a r4c

[Mike Bryce]

HolaKinda of looking for a drake R4c... does not need to be collector perfect or have any extra crystals...But no real junk eitherand don't really want to pay ebay prices eitherAny one have a spare they want to part with?Mike...Mike Bryce, WB8VGE the heathkit shopSunLight energy systemsJ e e po|||o 

Re: [drakelist] TR-4C transmitter troubleshooting

[Garey Barrell]

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Rob -

OK, a little more information.

When the 2 ohm meter shunt resistor opens up, the Final cathode current 
is routed through a "slide switch" mounted up on the LOAD capacitor 
shaft, (activated by pushing in the LOAD control,) a series resistor 
that is selected at test, (mounted on the slide switch terminals,) of 
typically ~200 ohms, and the plate meter.   It wouldn't take much 
current to damage that resistor and/or meter with the shunt resistor 
open.   Or if the slide switch contacts are not closing properly in the 
"out" position of the LOAD control.


Perhaps your finals are drawing idle current, it's just not showing on 
the meter!?  Measure the voltage drop across the meter shunt resistor.  
100 mA should read 200 mV.


By the way, if you're not used to working on tube gear, keep in mind 
that 650V (OR 250v) BITES!   An AC-4 bleeds down pretty quickly when 
turned off, but only your meter knows for sure before you stick your 
fingers in there!


73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:

Thanks to all (!!) -- more coming when I get a chance (life is getting in
the way of fun right now).

So far, I've had the chance to change out the relay -- the ONE spare part
I had on hand.  No difference.  The rig does go into transmit when switched
to CW mode (no key plugged in).  Both relays respond and the receiver mutes.
I just noticed this AM that the .025 plate current reading I get is there
even with the power off.  Meter moves about a needle's width when put into
transmit and the S-meter reads about 7-8 in transmit -- may be another clue?

And thanks for the hollow-state theory Garey.  It's been a REALLY long time
since I've worked on any tube gear, but it's slowly coming back to me. :)

I'll be digging some more in a bit here and will report back.  I'll also
see if I can catch the technical net this afternoon.  7.238 @ 2000Z, right?

Thanks again everyone!

73, Rob (KFØRT)

  

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
Sent: Sunday, April 16, 2006 8:41 AM
To: Drakelist
Subject: Re: [drakelist] TR-4C transmitter troubleshooting



Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
--
Hi Kevin -

Expertise is just experience clouded by memory!  :-)

I don't think I've ever come across a PAIR of finals that "lit up", but
wouldn't draw at least a couple hundred mA if they had the DC potentials
applied to them.  In fact, I can only remember one tube that was "open",
but lit.  I still think it had a broken weld inside it!!  :-)

But then I've been wrong before.  A favorite med school phrase, "when
you hear hoof beats, think horses, not zebras" comes to mind!

Hopefully Rob will get it fixed in spite of my help and let us know the
truth!!

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




kbgluxford wrote:


kbgluxford <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
--
I certainly don't have Garey's expertise or long experience, but I did
have a similar problem on one of my TX4 transmitters recently.  I
changed out the PA tubes and the problem disappeared.

73
Kevin
VK3DAP / ZL2DAP

Garey Barrell wrote:
  

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
drakelist gang
--
Rob -

You don't mention anything about "keying" the transmitter.  You have
to "key" the Push-To-Talk (PTT) of the microphone to switch it to
transmit to see the idling plate current.  You should hear the relay
click when it closes.

If the final tubes have plate voltage, screen voltage and filament
voltage, and the cathodes are returned to the negative pole of those
supplies, they WILL draw plate current!   The grid voltage is the
only thing that keeps them from drawing AMPS of current in the
presence of the other voltages.

There are two RF chokes in series between the +650VDC supply and the
plate caps of the tubes.   There is a 15 ohm, 1W resistor in series
with each of the final tube cathodes to another RF choke, through the
meter shunt resistor, and then through a relay contact to ground.

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:


"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
I'm finally digging into a TR-4C I bought used some time ago.  It
"worked
fine" when it was shipped here, but I haven't been able to get any
power out
of the transmitter.  It at least oscillates -- I can hear it on a
receiver
in the same room.

Starting at the be

RE: [drakelist] TR-4C transmitter troubleshooting

[R. Ton]

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Thanks to all (!!) -- more coming when I get a chance (life is getting in
the way of fun right now).

So far, I've had the chance to change out the relay -- the ONE spare part
I had on hand.  No difference.  The rig does go into transmit when switched
to CW mode (no key plugged in).  Both relays respond and the receiver mutes.
I just noticed this AM that the .025 plate current reading I get is there
even with the power off.  Meter moves about a needle's width when put into
transmit and the S-meter reads about 7-8 in transmit -- may be another clue?

And thanks for the hollow-state theory Garey.  It's been a REALLY long time
since I've worked on any tube gear, but it's slowly coming back to me. :)

I'll be digging some more in a bit here and will report back.  I'll also
see if I can catch the technical net this afternoon.  7.238 @ 2000Z, right?

Thanks again everyone!

73, Rob (KFØRT)

> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Behalf Of Garey Barrell
> Sent: Sunday, April 16, 2006 8:41 AM
> To: Drakelist
> Subject: Re: [drakelist] TR-4C transmitter troubleshooting
>
>
>
> Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> drakelist gang
> --
> Hi Kevin -
>
> Expertise is just experience clouded by memory!  :-)
>
> I don't think I've ever come across a PAIR of finals that "lit up", but
> wouldn't draw at least a couple hundred mA if they had the DC potentials
> applied to them.  In fact, I can only remember one tube that was "open",
> but lit.  I still think it had a broken weld inside it!!  :-)
>
> But then I've been wrong before.  A favorite med school phrase, "when
> you hear hoof beats, think horses, not zebras" comes to mind!
>
> Hopefully Rob will get it fixed in spite of my help and let us know the
> truth!!
>
> 73, Garey - K4OAH
> Atlanta
>
> Drake B & C-Line Service CDs
> 
>
>
>
> kbgluxford wrote:
> >
> > kbgluxford <[EMAIL PROTECTED]> made an utterance to the drakelist
> > gang
> > --
> > I certainly don't have Garey's expertise or long experience, but I did
> > have a similar problem on one of my TX4 transmitters recently.  I
> > changed out the PA tubes and the problem disappeared.
> >
> > 73
> > Kevin
> > VK3DAP / ZL2DAP
> >
> > Garey Barrell wrote:
> >>
> >> Garey Barrell <[EMAIL PROTECTED]> made an utterance to the
> >> drakelist gang
> >> --
> >> Rob -
> >>
> >> You don't mention anything about "keying" the transmitter.  You have
> >> to "key" the Push-To-Talk (PTT) of the microphone to switch it to
> >> transmit to see the idling plate current.  You should hear the relay
> >> click when it closes.
> >>
> >> If the final tubes have plate voltage, screen voltage and filament
> >> voltage, and the cathodes are returned to the negative pole of those
> >> supplies, they WILL draw plate current!   The grid voltage is the
> >> only thing that keeps them from drawing AMPS of current in the
> >> presence of the other voltages.
> >>
> >> There are two RF chokes in series between the +650VDC supply and the
> >> plate caps of the tubes.   There is a 15 ohm, 1W resistor in series
> >> with each of the final tube cathodes to another RF choke, through the
> >> meter shunt resistor, and then through a relay contact to ground.
> >>
> >> 73, Garey - K4OAH
> >> Atlanta
> >>
> >> Drake B & C-Line Service CDs
> >> 
> >>
> >>
> >>
> >> R. Ton wrote:
> >>> "R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
> >>> --
> >>> I'm finally digging into a TR-4C I bought used some time ago.  It
> >>> "worked
> >>> fine" when it was shipped here, but I haven't been able to get any
> >>> power out
> >>> of the transmitter.  It at least oscillates -- I can hear it on a
> >>> receiver
> >>> in the same room.
> >>>
> >>> Starting at the beginning...
> >>>
> >>> The manual says to adjust the bias on the AC-4 so that the plate
> >>> meter reads
> >>> .1 amp.  This is with the sideband switch counter-clockwise and the
> >>> xmtr
> >>> gain all the way down.  The meter seems to read about .025 in
> >>> receive and
> >>> goes up just a little when the rig is switched to CW.  Adjusting the
> >>> bias
> >>> has no effect on the plate meter, but it does indeed adjust the bias
> >>> voltage.  Setting it to -60 volts is no problem, but I'm unable to
> >>> get any
> >>> "real" plate current no matter what I do.  Any ideas?
> >>>
> >>> I haven't done anything to the radio since I got it except spray the
> >>> switches with Deoxit D5 and replace R45 (2 ohms -- plate meter shunt
> >>> resistor!!).  This resistor was fried in

[drakelist] Experience with the L4 (not L4B) amplifier

[Karl Oyster, K1KO]

"Karl Oyster, K1KO" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Good morning to all:

I have not previously posted to this list, but discovered it in an 
attempt to get some information about an amplifier I have recently 
come into possession of.  If anyone is familiar with the Drake L4 
amplifier, I would appreciate the opportunity to talk with you 
about it.


Thanks, in advance,

Karl Oyster, K1KO
Virginia Beach, VA 


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Re: [drakelist] TR-4C transmitter troubleshooting

[Garey Barrell]

Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Hi Kevin -

Expertise is just experience clouded by memory!  :-)

I don't think I've ever come across a PAIR of finals that "lit up", but 
wouldn't draw at least a couple hundred mA if they had the DC potentials 
applied to them.  In fact, I can only remember one tube that was "open", 
but lit.  I still think it had a broken weld inside it!!  :-)


But then I've been wrong before.  A favorite med school phrase, "when 
you hear hoof beats, think horses, not zebras" comes to mind!


Hopefully Rob will get it fixed in spite of my help and let us know the 
truth!!


73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




kbgluxford wrote:


kbgluxford <[EMAIL PROTECTED]> made an utterance to the drakelist 
gang

--
I certainly don't have Garey's expertise or long experience, but I did 
have a similar problem on one of my TX4 transmitters recently.  I 
changed out the PA tubes and the problem disappeared.


73
Kevin
VK3DAP / ZL2DAP

Garey Barrell wrote:


Garey Barrell <[EMAIL PROTECTED]> made an utterance to the 
drakelist gang

--
Rob -

You don't mention anything about "keying" the transmitter.  You have 
to "key" the Push-To-Talk (PTT) of the microphone to switch it to 
transmit to see the idling plate current.  You should hear the relay 
click when it closes.


If the final tubes have plate voltage, screen voltage and filament 
voltage, and the cathodes are returned to the negative pole of those 
supplies, they WILL draw plate current!   The grid voltage is the 
only thing that keeps them from drawing AMPS of current in the 
presence of the other voltages.


There are two RF chokes in series between the +650VDC supply and the 
plate caps of the tubes.   There is a 15 ohm, 1W resistor in series 
with each of the final tube cathodes to another RF choke, through the 
meter shunt resistor, and then through a relay contact to ground.


73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs




R. Ton wrote:

"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
I'm finally digging into a TR-4C I bought used some time ago.  It 
"worked
fine" when it was shipped here, but I haven't been able to get any 
power out
of the transmitter.  It at least oscillates -- I can hear it on a 
receiver

in the same room.

Starting at the beginning...

The manual says to adjust the bias on the AC-4 so that the plate 
meter reads
.1 amp.  This is with the sideband switch counter-clockwise and the 
xmtr
gain all the way down.  The meter seems to read about .025 in 
receive and
goes up just a little when the rig is switched to CW.  Adjusting the 
bias

has no effect on the plate meter, but it does indeed adjust the bias
voltage.  Setting it to -60 volts is no problem, but I'm unable to 
get any

"real" plate current no matter what I do.  Any ideas?

I haven't done anything to the radio since I got it except spray the
switches with Deoxit D5 and replace R45 (2 ohms -- plate meter shunt
resistor!!).  This resistor was fried in half.

What am I in for?

Many thanks in advance!

73, Rob (KFØRT)

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Re: [drakelist] MIKE ELLIOTT, W8KRR, SILENT KEY

[Jim Shorney]

"Jim Shorney" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
On Sat, 15 Apr 2006 16:41:05 -0500, Don and Diana Cunningham wrote:

>Mike was a true gentleman that answered several of my "dumb" questions with 
>wisdom and patience.  He will be missed.


Mike was very cordial and patient in my email correspondances with him, as
Don says, a true gentleman. He will be missed. I own both of the "cousins",
TR7 and SB104A, and they will never leave my shack. Mike's contributions to
ham radio will not be forgotten.

-Jim


--
TR7/RV7, TR6/RV6, T4XC/R4C, L4B, NCL2000, SB104A, R390A, GT550A/RV550A - all 
vintage, all the time!


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