Re: [Drakelist] Help in identify a "Mod" in my R-4C

[Scpmiller]

The C6050G IC is an MC 1496.  I used it myself for a product detector  way 
back in the late 70's.  I was going to make a little direct conversion  
receiver with it but never finished the project.  Later, when I got my R4C  I 
put the TL 442 based product detector in it and in an R4B.  They worked  great 
and the one in the R4B is still there.  I completely redid the R4C  with 
all new Sherwood mods about 5 years ago.  It's still a great  receiver.
 
Steve 
KD2ED
 
 
In a message dated 3/11/2012 7:53:10 P.M. Eastern Daylight Time,  
w1es1...@earthlink.net writes:

Sounds like an early mod.
 
I've seen them and mods to the C-Line were quite  common back in the late 
'70s and early '80's.  I'm thinking that it's  actually harder to find an 
R-4C that doesn't have any changes.   The folks who bought Drakes were 
generally more willing to go inside and soup  them up.
 
73,
 
Steve Wedge, W1ES/4
 
Live free or die: Death is not the worst of  evils.
John Stark.
 
All my computers have my signature with various pearls  of wisdom appended 
thereto.





From: _Robb Urie_ (mailto:ru...@mywdo.com)  
Sent: Saturday, March 10, 2012 11:52 PM
To: _drakelist@zerobeat.net_ (mailto:drakelist@zerobeat.net)  
Subject: [Drakelist] Help in identify a "Mod" in my  R-4C





 
Howdy,
 
While installing 4 of the Sherwood mods in my R-4C, I came across a  
pre-existing circuit board that turned-out to be a replacement product  
detector.
I removed it to make way for the new PD-4, but am curious is this could  be 
one of the early Sherwood ones or maybe a Santori version.  It is on a  
small perf board and uses a Motorola HEP C6050G IC.  I don’t have  any of 
the HR magazines that described the DIY mods, maybe it’s time to get  the
CDs.
 
I’m just wondering what it is...I’ve had this set since 1995 and have  
only installed the Inrad GUF-1 up to now.  I've also done the LED lamp  kits
and they look great.  For those who maybe considering doing any  mods, be 
aware that wayward soldering irons love s-meter pots.
 
For the folks who despise any Mods, sorry for the offense. 
 
Thanks for any info.
 
73,
 
Robb N0RU
Woodland Park, CO


 

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Re: [Drakelist] AC-3 Ver AC-4

[Ron]

Do you have a small 12 Volt transformer?  Hook it up on the two 120 volt AC 
power plug leads with a 100 ohm resistor on series.  That should allow you to 
do a few voltage measurements w/o blowing the fuse.  everything should be 
1/10th give or take what the 100ohm resistor drops.

Otherwise take a ohm meter and make sure you have at lease some resistance on 
the primary (across the power plug).  Just to make sure that the primary is not 
connected wrong.  It should not have moved, but.  easy enough to get the 
120/240 sire crossed if you did disconnect them.

After that, if you have not found anything, it is time to disconnect all 
secondaries and see if you still blow fuses.  I prefer testing w/o desoldering 
first if possible.

One last thing, look at the caps, make sure they are installed in the correct 
polarity.  

73,
Ron WD8SBB

--- On Sun, 3/11/12, John Gartman  wrote:

From: John Gartman 
Subject: [Drakelist] AC-3 Ver AC-4
To: Drakelist@zerobeat.net
Date: Sunday, March 11, 2012, 11:36 AM




 
 








Well I installed a heath kit in my AC-4 and all mine does
is blow the fuse when the jumper is between pins 1 and 2. I have gone over it
many times. 

Wire for wire reds to reds yellows to yellows blues to
blues etc. but it blows the 5 amp and a 6.5 amp slow blow and it blows that
also. 

What I don't know is what capacitors to leave on the
bottom there are 2 that go to ground. One from the fuse holder and one from L2
Are these needed?  

I did not assemble the new circuit board I bought it
assembled. I know it is hard to guess without seeing and who knows what kind of
goof ups a yahoo makes  

in wiring but anyone have an idea on where to look next ? 
It did not blow the fuse before the board was installed. 

   

Thanks 

   

John AG6GL 

   

   






-Inline Attachment Follows-

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Re: [Drakelist] Help in identify a "Mod" in my R-4C

[Steve Wedge]

Sounds like an early mod.

I've seen them and mods to the C-Line were quite common back in the late '70s 
and early '80's.  I'm thinking that it's actually harder to find an R-4C that 
doesn't have any changes.  The folks who bought Drakes were generally more 
willing to go inside and soup them up.

73,

Steve Wedge, W1ES/4

Live free or die: Death is not the worst of evils.
John Stark.

All my computers have my signature with various pearls of wisdom appended 
thereto.



From: Robb Urie 
Sent: Saturday, March 10, 2012 11:52 PM
To: drakelist@zerobeat.net 
Subject: [Drakelist] Help in identify a "Mod" in my R-4C


Howdy,

While installing 4 of the Sherwood mods in my R-4C, I came across a 
pre-existing circuit board that turned-out to be a replacement product detector.
I removed it to make way for the new PD-4, but am curious is this could be one 
of the early Sherwood ones or maybe a Santori version.  It is on a 
small perf board and uses a Motorola HEP C6050G IC.  I don’t have any of the HR 
magazines that described the DIY mods, maybe it’s time to get the
CDs.

I’m just wondering what it is...I’ve had this set since 1995 and have only 
installed the Inrad GUF-1 up to now.  I've also done the LED lamp kits
and they look great.  For those who maybe considering doing any mods, be aware 
that wayward soldering irons love s-meter pots.

For the folks who despise any Mods, sorry for the offense. 

Thanks for any info.

73,

Robb N0RU
Woodland Park, CO





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Re: [Drakelist] R4B Audio Distortion

[Steve Wedge]

Yep - wound up being lucky this time - didn't even have to buy another tube!

Someone else had mentioned the Sherwood audio amp, and this particular R-4C 
has that mod.  Overall, it sounds good now.



Steve Wedge, W1ES/4

Live free or die: Death is not the worst of evils.
John Stark.

All my computers have my signature with various pearls of wisdom appended 
thereto.



--
From: "Garey Barrell" 
Sent: Saturday, March 10, 2012 11:20 AM
To: "Steve Wedge" 
Cc: "Mike Bryce" ; "Randy WB4SPB" 
; 

Subject: Re: [Drakelist] R4B Audio Distortion


Steve -

Yes, the tube noise only seems to be a problem in the 3rd Mixer, and 
'noisy' tubes can often be used in the IF with no problem.  I guess it has 
something to do with the way the stages are biased, but I've never really 
investigated it.  I'm lazy, I'll just select a good tube, and it usually 
outlasts the radio.


I've had a couple (three?) guys who doubted me on this, and all three 
replaced every component in the AF Output stage.   All three 
eventually ended up selecting a 6EH5!  :-)   It's a tough sell, cause 'I 
put in a NEW tube'..  :-)


It's kinda like the IDLE current in a PA.  If the supply voltages are 
there, the PA tubes WILL draw current.  The only question is how much, and 
there you have an adjustable bias to take care of minor differences.


Except in this case you don't have 'easily' adjustable bias.  If you have 
the right cathode resistor, and the voltages are present, the tube WILL 
draw ~30 mA.  However, (there's always a however',) when the tube gets 
_hot_  if the grid starts emitting electrons, or there are gas particles 
in the 'vacuum', the 'natural order of things' is screwed up and the tube 
starts drawing a little more current.  Which gets a little more grid 
current, which gets the tube a little hotter, which 


73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Steve Wedge wrote:
I just wound up fixing an R-4C - and one of the things I did was to swap 
V4 and V6.


That single exchange did more to reduce the noise in the receiver than 
anyting else I could have done.  I did go on and convert the third mixer 
to cathode-feed, and that improved things a bit more, but you're on to 
something with respect to the audio output.


OTOH, I still sit here and wonder.  At audio frequencies, is everything 
as designed by Drake really that critical?  It might be a good time to 
replace components to find out...


Yeah - I'm a troublemaker...

Steve Wedge, W1ES/4

"I can't complain, but sometimes I still do."
- Joe Walsh

If the above message appears, it came from Steve's Son of Laptop!
- Original Message - From: "Garey Barrell" 
To: "Mike Bryce" 
Cc: "Randy WB4SPB" ; 
Sent: Friday, March 09, 2012 10:21 PM
Subject: Re: [Drakelist] R4B Audio Distortion



Mike -

I think the problem is that 'new' tubes are 50 years old..  Even a few 
molecules of air a day adds up after that long.  When Drake assembled 
the radios, the tubes were _really_ new!!   The 6EH5 gets 'really' hot 
in normal operation, and perhaps the heat/cool cycles are harder on the 
metal/glass seals at the pins.  Some tubes definitely are more prone to 
'gas' (grid emission), the 12BA6 comes to mind.  That one shows as a 
'drifting' S-Meter as the tubes heat up.  The 6EJ7 is prone to noise in 
3rd Mixer service, probably for a similar reason.  The only answer I 
have come up with is to keep trying tubes until you get a 'good' one.


73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Mike Bryce wrote:

I wonder.

when drake assembled the radios, did they go through three or fours 
tubes per radio to get one that worked correctly?


dosen't seem logical. And although you can't argue with the fact that 
the subing out the tube fixed the problem, I wonder if there is 
something hidden down someplace in the design that causes the problem


just a thought

Mike, wb8vge


On Mar 9, 2012, at 4:25 PM, Randy WB4SPB wrote:

Altogether, I bought two 6EH5s and one 6CA5.  I already had a spare 
6EH5, so, considering those alone, I had to try three to get one.  If 
I count the 6CA5 that I bought, I had to try four to get one.
The 6CA5 IS very similar.  Some sources do not even have the 6EH5 and 
refer you to 6CA5.  The tube that originally manifested the problem 
was a 6CA5 that had been in the radio for many years before these 
symptoms appeared.
Whether the difference in 6EH5 and 6CA5 is important here, I cannot 
say. I'll stick with 6EH5s in the future, while I can get them.  For 
sources I've seen that have both, the price is the same.

73,
Randy WB4SPB

- Original Message -
*From:*Al Al 

Out of curiosity, how many 6EH5 tubes did you have to go through 
to find a good one?


Al, n7ioh
Payson, Arizona, USA



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[Drakelist] FS: Unique Drake Service Supplement CDs

[Garey Barrell]

Here is the information that Drake left out of their manuals!

Unique supplemental service information CDs available for the Drake TR-4, TR-4C/Cw/CwRIT, A, B and C 
Lines, 2-C / 2-NT and the 2-B receiver.


High resolution color photos of the under chassis and individual PC boards of each unit, with all 
parts identified and keyed to a parts list make it easy to locate any component.  No more trying to 
trace wires through bundles, etc.  This information is not available elsewhere and really makes a 
difference in servicing these units.


These CDs are NOT just scans of the original manuals that were included with the equipment when new. 
 High resolution scans of the original manuals ARE on the CDs, along with scans of manuals for 
associated equipment such as the C-4, FS-4, MN2000, L-4B, W-4, etc.


Samples of these pages (at reduced resolution) and purchase information are at 
.

--
73, Garey - K4OAH
Glen Allen, VA



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Re: [Drakelist] Help in identify a "Mod" in my R-4C

[Garey Barrell]

Robb -

I don't recognize the HEP6050, and can't find any data on it. It's a Motorola 'replacement' (like 
NTE) and 'may' be an MC1496. If so, there may be a PD in Ham Radio. The original 'Sartori' PD, that 
I think became the Sherwood used a TL-422 originally, and later subbed with a '1496.


73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Robb Urie wrote:

Howdy,
While installing 4 of the Sherwood mods in my R-4C, I came across a 
pre-existing circuit board
that turned-out to be a replacement product detector.
I removed it to make way for the new PD-4, but am curious is this could be one 
of the early
Sherwood ones or maybe a Santori version. It is on a
small perf board and uses a Motorola HEP C6050G IC. I don’t have any of the HR 
magazines that
described the DIY mods, maybe it’s time to get the
CDs.
I’m just wondering what it is...I’ve had this set since 1995 and have only 
installed the Inrad
GUF-1 up to now. I've also done the LED lamp kits
and they look great. For those who maybe considering doing any mods, be aware 
that wayward
soldering irons love s-meter pots.


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Re: [Drakelist] AC-3 Ver AC-4

[Mike Bryce]

john,

divide and conquer!

First thing to do is disconnect the secondary from the transformer to the pcb.

Unsolder the wires from the 'red' wires from the transformer to the diodes. 
then, the 'yellow' wire that goes to the diodes. Finally,  disconnect the blue 
wire that go from the transformer to D7

this separates the transformer from the pcb assemble. 

Now, check to make sure you don't have one of the loose wire contacting the 
chassis and when you're happy, plug in the supply and turn it on. (via shorting 
pins 1 and 2 together)

if the fuse holds, then power down and then re-connect just one of the of the 
sections at a time. If you find that when you, let's say the yellow wires, blow 
the fuse, then you have a wiring problem on the output side, most likely a 
short 


if the fuse blows with the secondaries removed from the pcb, then you have a 
short someplace in the wiring that you did when connecting the wires from the 
transformer to the pcb

this should help you,

mike, wb8vge


On Mar 11, 2012, at 11:36 AM, John Gartman wrote:

> Well I installed a heath kit in my AC-4 and all mine does is blow the fuse 
> when the jumper is between pins 1 and 2. I have gone over it many times.
> Wire for wire reds to reds yellows to yellows blues to blues etc. but it 
> blows the 5 amp and a 6.5 amp slow blow and it blows that also.
> What I don't know is what capacitors to leave on the bottom there are 2 that 
> go to ground. One from the fuse holder and one from L2 Are these needed?
> I did not assemble the new circuit board I bought it assembled. I know it is 
> hard to guess without seeing and who knows what kind of goof ups a yahoo makes
> in wiring but anyone have an idea on where to look next ?  It did not blow 
> the fuse before the board was installed.
>  
> Thanks
>  
> John AG6GL
>  
>  
> ___
> Drakelist mailing list
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[Drakelist] AC-3 Ver AC-4

[John Gartman]

Well I installed a heath kit in my AC-4 and all mine does is blow the fuse
when the jumper is between pins 1 and 2. I have gone over it many times.

Wire for wire reds to reds yellows to yellows blues to blues etc. but it
blows the 5 amp and a 6.5 amp slow blow and it blows that also.

What I don't know is what capacitors to leave on the bottom there are 2 that
go to ground. One from the fuse holder and one from L2 Are these needed? 

I did not assemble the new circuit board I bought it assembled. I know it is
hard to guess without seeing and who knows what kind of goof ups a yahoo
makes 

in wiring but anyone have an idea on where to look next ?  It did not blow
the fuse before the board was installed.

 

Thanks

 

John AG6GL

 

 

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