Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Tony King - W4ZT]

The 5V I  had in 1969 was FM.
73,
Tony W4ZT

At 02:07 PM 6/11/2004, John wrote:
>Was it a 5V?  (I think they did make AM 5V's - Neil do you know this bit of
>history??)





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  Thanks Mike, 

  Neil 


Mike WA6ILQ wrote:
> 
> The web page at  might
> help answer this question.
> 
> At 01:07 PM 6/11/04 -0500, you wrote:
> 
> >Was it a 5V?  (I think they did make AM 5V's - Neil do you know this bit of
> >history??)
> >
> >Don <[EMAIL PROTECTED]> wrote:
> >
> > > At 12:16 AM 6/11/04 -0500, you wrote:
> > > >Since Moto never made AM twin V's (that I am aware of), was this a exotic
> >mod
> > > >or a typo?
> > >
> > >
> > > Probably  a senior Moment , Stupidity  or To long ago , But it was 
> > > Motorola
> >
> > > and it was AM .
> > >
> > > Don KA9QJG
> > >
> > >
> > > >Don <[EMAIL PROTECTED]> wrote:
> > > >SNIP
> > > > > The first Dynamotor
> > > > > I saw was when I gave a Ham a jump start , He was using a Motorola
> > > > > twin v , on 6 Meter AM .
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> 
> 
> Yahoo! Groups Links
> 
> 
> 
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  I certainly remember the 5V ... but never saw one on AM. 

  Neil 


JOHN MACKEY wrote:
> 
> Was it a 5V?  (I think they did make AM 5V's - Neil do you know 
> this bit of history??)
> 
> Don <[EMAIL PROTECTED]> wrote:
> 
> > At 12:16 AM 6/11/04 -0500, you wrote:
> > >Since Moto never made AM twin V's (that I am aware of), was this a exotic
> mod
> > >or a typo?
> >
> >
> > Probably  a senior Moment , Stupidity  or To long ago , But it was Motorola
> 
> > and it was AM .
> >
> > Don KA9QJG
> >
> >
> > >Don <[EMAIL PROTECTED]> wrote:
> > >SNIP
> > > > The first Dynamotor
> > > > I saw was when I gave a Ham a jump start , He was using a Motorola
> > > > twin v , on 6 Meter AM .
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> 
> 
> Yahoo! Groups Links
> 
> 
> 
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Mike WA6ILQ]

The web page at  might
help answer this question.

At 01:07 PM 6/11/04 -0500, you wrote:

>Was it a 5V?  (I think they did make AM 5V's - Neil do you know this bit of
>history??)
>
>Don <[EMAIL PROTECTED]> wrote:
>
> > At 12:16 AM 6/11/04 -0500, you wrote:
> > >Since Moto never made AM twin V's (that I am aware of), was this a exotic
>mod
> > >or a typo?
> >
> >
> > Probably  a senior Moment , Stupidity  or To long ago , But it was Motorola
>
> > and it was AM .
> >
> > Don KA9QJG
> >
> >
> > >Don <[EMAIL PROTECTED]> wrote:
> > >SNIP
> > > > The first Dynamotor
> > > > I saw was when I gave a Ham a jump start , He was using a Motorola
> > > > twin v , on 6 Meter AM .
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
>
>
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[JOHN MACKEY]

Was it a 5V?  (I think they did make AM 5V's - Neil do you know this bit of
history??)

Don <[EMAIL PROTECTED]> wrote:

> At 12:16 AM 6/11/04 -0500, you wrote:
> >Since Moto never made AM twin V's (that I am aware of), was this a exotic
mod
> >or a typo?
> 
> 
> Probably  a senior Moment , Stupidity  or To long ago , But it was Motorola

> and it was AM .
> 
> Don KA9QJG
> 
> 
> >Don <[EMAIL PROTECTED]> wrote:
> >SNIP
> > > The first Dynamotor
> > > I saw was when I gave a Ham a jump start , He was using a Motorola
> > > twin v , on 6 Meter AM .
> >
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> 
> 
> 
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 







 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  At one time Motorola did make an AM receiver strip - came in two 
 sub-bands as I remember: 1600 - 2400 kHz and 2400 - 3200 kHz.  

  The physical dimensions were exactly that of the early Unichannel 
 or later Sensicon G series of receivers - but shorter in length.  It 
 also had a Permakay IF filter. 

  I have the result of a photocopy of the schematic in my collection 
 in the garage. 

  Neil 


Don wrote:
> 
> At 12:16 AM 6/11/04 -0500, you wrote:
> >Since Moto never made AM twin V's (that I am aware of), was this 
> >a exotic mod or a typo?
> 
> Probably  a senior Moment , Stupidity  or To long ago , But it was 
> Motorola and it was AM . 
> 
> Don KA9QJG
> 
> >Don <[EMAIL PROTECTED]> wrote:
> >SNIP
> > > The first Dynamotor
> > > I saw was when I gave a Ham a jump start , He was using a 
> > > Motorola twin v , on 6 Meter AM .
> >
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  Or one hell of a 'slight' modification ... 

  Neil 

JOHN MACKEY wrote:
> 
> Since Moto never made AM twin V's (that I am aware of), was this 
> a exotic mod or a typo? 
> 
> Don <[EMAIL PROTECTED]> wrote:
> SNIP
> > The first Dynamotor
> > I saw was when I gave a Ham a jump start , He was using a Motorola
> > twin v , on 6 Meter AM .
> 
> 
> Yahoo! Groups Links
> 
> 
> 
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Don]

At 12:16 AM 6/11/04 -0500, you wrote:
>Since Moto never made AM twin V's (that I am aware of), was this a exotic mod
>or a typo?


Probably  a senior Moment , Stupidity  or To long ago , But it was Motorola 
and it was AM .

Don KA9QJG


>Don <[EMAIL PROTECTED]> wrote:
>SNIP
> > The first Dynamotor
> > I saw was when I gave a Ham a jump start , He was using a Motorola
> > twin v , on 6 Meter AM .
>
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>






 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[JOHN MACKEY]

Since Moto never made AM twin V's (that I am aware of), was this a exotic mod
or a typo?


Don <[EMAIL PROTECTED]> wrote:
SNIP
> The first Dynamotor 
> I saw was when I gave a Ham a jump start , He was using a Motorola
> twin v , on 6 Meter AM .






 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Don]

At 02:05 PM 6/10/04 -0700, you wrote:

>   I used to attend the classes too.  But that was way back when ...
>
>   Neil - WA6KLA
  Neil , That was when We use to Fix Dynamotors and Vibrators. Cops use to 
not worry about the bad Guys stealing Squads,  They had to keep the running 
So the Radio Equipment would not run the battery down. The first Dynamotor 
I saw was when I gave a Ham a jump start , He was using a Motorola twin v , 
on 6 Meter AM .

Ha Ha Don KA9QJG 






 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Jim B.]

Neil McKie wrote:

>   I used to attend the classes too.  But that was way back when ... 
> 
>   Neil - WA6KLA 
> 
> 

*lol*

-- 
Jim Barbour
WD8CHL





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  I used to attend the classes too.  But that was way back when ... 

  Neil - WA6KLA 


"Jim B." wrote:
> 
> Neil McKie wrote:
> 
> >   From my experience and my opinion, the Motorola owned shps are
> >  better financed and can afford more of the very expensive electronic
> >  test equipmenmt that the privately financed shops can't.
> >
> >   Neil - WA6KLA
> >
> 
> Also they actually send the techs to training classes on a regular
> basis. Plus they can afford to pay the techs in the first place, which
> attracts the better ones...
> 
> --
> Jim Barbour
> WD8CHL
> 
> 
> Yahoo! Groups Links
> 
> 
> 
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Jim B.]

Neil McKie wrote:

>   From my experience and my opinion, the Motorola owned shps are 
>  better financed and can afford more of the very expensive electronic 
>  test equipmenmt that the privately financed shops can't. 
> 
>   Neil - WA6KLA 
> 

Also they actually send the techs to training classes on a regular 
basis. Plus they can afford to pay the techs in the first place, which 
attracts the better ones...

-- 
Jim Barbour
WD8CHL





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  From my experience and my opinion, the Motorola owned shps are 
 better financed and can afford more of the very expensive electronic 
 test equipmenmt that the privately financed shops can't. 

  Neil - WA6KLA 


wd8chl wrote:
> 
> --- In Repeater-Builder@yahoogroups.com, "Chris Peterson" <[EMAIL PROTECTED]>
> wrote:
> 
> >
> > The director of emergency management insists on a Motorola shop
> doing the
> > work, and there is only one in town.  He is willing to send it out
> of town
> > if it would be cheaper, or more effective.
> >
> 
> One thing people forget (or maybe don't know), just because a shop has
> a set of batwings on their door doesn't mean they are a Motorola shop.
> Most "Motorola" shops are MSS's, which are privately owned and
> operated. And they frequently are NOT of the same caliber as a genuine
> Motorola-owned shop.
> 
> Jim Barbour
> 
> 
> Yahoo! Groups Links
> 
> 
> 
>





 
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[Repeater-Builder] Re: MSR-2000 parts/repair needed

[wd8chl]

--- In Repeater-Builder@yahoogroups.com, "Chris Peterson" <[EMAIL PROTECTED]>
wrote:

> 
> The director of emergency management insists on a Motorola shop
doing the
> work, and there is only one in town.  He is willing to send it out
of town
> if it would be cheaper, or more effective.
> 

One thing people forget (or maybe don't know), just because a shop has
a set of batwings on their door doesn't mean they are a Motorola shop.
Most "Motorola" shops are MSS's, which are privately owned and
operated. And they frequently are NOT of the same caliber as a genuine
Motorola-owned shop.

Jim Barbour






 
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[Repeater-Builder] Re: MSR-2000 parts/repair needed

[[EMAIL PROTECTED]]

I'd like to find a continuous-duty MSR-2000 450-470 MHz PA Deck (any level,
but 20-40 watts would be more than enough). I'm trusting that they would
directly swap out with the one that I'm using now - I have a 100-watt
intermittent duty MSR-2000 Repeater on a UHF Ham channel, but don't want to
cook the PA deck. Most people I know that have used these in Ham
(continuous-duty) service have fried the intermittent-duty PA deck numerous
times, even with fans blowing continuously on the heat sinks. When we had
these in service with the local Police Dept., we always had to keep plenty
of the PA Deck repair kits in stock ($450+ for each one!)

Larry




To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

 Hello ...

skipp025 wrote:

> 
> A round of sales person BS was what you received.
> Lower power versions were available.
> I have a number of ~30 watt rated output MSR UHF
> PA's.  Ordered that way new from the Big M. 



mail2web - Check your email from the web at
http://mail2web.com/ .






 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  Hello ...

skipp025 wrote:
> 
> > Neil McKie <[EMAIL PROTECTED]> wrote:
> >   Hello ...
> >   Back in the ... er ... ah ... late eighties:
> 
> When the MSR-2000 was in its prime time. 

  Mid - late eighties? 

 
> >   Ordered a new 450 MHz MSR2000 from the big M
> > ... was shipped as expected - had the 12 VDC
> > only option - was going to a 12 volt only site
> > that used a thermo-electric generator for power.
> 
> Wasn't for Cobb Mtn was it?  For a location known
> as the Geysers? 

  Nope ... much closer to the west coast.  :) 


> >  The license for this station said 20 watts
> > output maximum.  The only way it was orderable
> > was the full power model at 75 watts output.
> 
> A round of sales person BS was what you received.
> Lower power versions were available.
> I have a number of ~30 watt rated output MSR UHF
> PA's.  Ordered that way new from the Big M. 

  Well, I didn't know that.  Wish I had though, would have saved 
 me a bunch of time. 

 
> The TEG I put in at the Geysers ate propane like
> crazy, but it put out a healty 22 amps.  

  Ours charged a pair of 8D 'cat' batteries.  We used the radios 
 off them.  Somewhere around here I have a video tape of that 
 installation. 

  I think it is the same video tape of another friendly commenter 
 on this remailer ... showing in great detail his grand radio 
 installation in his 80's Chevy Camaro.  

  For a short period of time, FEMA Gettysburg borrowed that video 
 to show what they thought was an interesting installation of 
 several radio sites. 


> > After careful study of the transmitter and
> > the associated schematic diagrams, I noticed
> > the PA driver stage was identical to the PA
> > final stage execpt the driver stage comprised
> > of one module and the final had three of the
> > same modules.
> 
> Motorhead PA designers were smart along one line,
> making most of the stages 50 ohms in and out. One
> could route around a stage for lower power
> operation.  

  Was very handy for trouble-shooting the T34 / 44 MST Motrans 
 when they had a problem.  

  The first time I ever saw one, I called the Motorola factory 
 Service people asking how do we service these radios - since there 
 were no clues in the Instruction Manual.  The Motorola reply was 
 'We're hoping you will tell us.' 

  Fortunately, I had some non 2 way radio lab experience with 50 ohm 
 RF circuitry so we had it figured out pretty soon.  Also owning a 
 one watt 200-500 MHz Bird Slug helped too.  


> > After some careful thought, I slightly modified
> > the PA deck by bypassing the three module PA
> > Amplifier and connect the driver stage (1 module)
> > to the output.  Got 16 watts out of the deal
> > discovering it was very stable and lowered the
> > DC power drain a lot.
> 
> a big lot... 

  True ... 


> > Since this was a licensed link radio, the
> > distance was 9.1 miles, I figured the 16
> > watts would be way overkill.
> 
> It was, it would take less than 2 watts with
> decent 8db yagi antennas.

  Never tried that - just wanted to be sure we had sufficient 
 overkill to ensure would not fail. 

 
> > My testing from the shop using a ground
> > plane for an antenna, I could bring up
> > one of the systems with the service monitor.
> >   Neil - WA6KLA
> 
> The Service Monitor test with a dial tone
> can really freak out the system users. Everyone
> starts looking for a place to hang up the phone.  

  Sounds like the users could have a real hang-up with that 
 one ...  ;) 

 
> cheers Neil
> 
> skipp
> www.radiowrench.com
> skipp025  at yahoo.com 

  73, 

  Neil - WA6KLA





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Chris Peterson]

Hi all,

I'm sorry if my explanation of this problem is incomplete.

The RC-850 was connected through a modification to the squelch gate card.  I
didn't do the mod, but I believe it was done using instructions for
modifying a Micor station on repeater-builder.com.

As for how it got on that frequency, I don't know.  The repeater was
purchased, on that frequency, from a ham club in Iowa, I believe.

I don't know what resources the Motorola shop has.  The director of
emergency management has been doing all of the communication with them so
what I get is from him.  From the sound of things, though, they're not to
helpful.

I have someone I trust work on my own machines, but it isn't politically
correct for him to work on the MSR.

The director of emergency management insists on a Motorola shop doing the
work, and there is only one in town.  He is willing to send it out of town
if it would be cheaper, or more effective.

Anyone know of anyone in southeast MN or southwest WI that would fit the
bill?

Thank you all for the responses thus far.  I'll try to get answers to your
questions and see if we can figure this out.

Thanks and 73,
Chris Peterson, KG0BP



- Original Message -
From: "skipp025" <[EMAIL PROTECTED]>
To: 
Sent: Tuesday, June 08, 2004 10:45 AM
Subject: [Repeater-Builder] Re: MSR-2000 parts/repair needed


> > "Chris Peterson" <[EMAIL PROTECTED]> wrote:
> > All,
> > Our local EOC has an MSR-2000 repeater, converted
> > to 146.745- Mhz.
>
> How was it converted?
>
> > It has always had a flaky PA.  The local Motorola
> > shop says there is a crack in the board that broke
> > a trace.  This has failed about every 6 months and
> > the Motorola shop has simply soldered across the
> > trace and temperarily solved the problem.
>
> "temporarily solved the problem" ..?
>
> > Now, though, we're having a different problem.
> > When it gets hot, the repeater TX drops out
> > completely, sometimes for a couple minutes.
> > This, to me, sounds like an exciter problem,
> > or possibly a bad connection between the
> > exciter and PA,
>
> I would not make that assumption. You can use
> the metering points to help find the problem.
>
> > but the Motorola shop has tried to blame
> > the RC-850 that is connected to the repeater.
>
> Consider a different repair shop for your next
> job.
>
> > We've disconnected the RC-850 and still have
> > the problem using the internal controller,
>
> See my comment just above.
>
> > so we believe we've mostly ruled out the
> > modification as being the problem.
>
> What was the modification?
>
> > I'm looking for replacement PAs, exciters, or
> > any other MSR-2000 parts.
>
> Contact me off the group, I can probably help
> you solve your problem.
>
> > I'd also be interested to know if any other
> > Motorola parts will directly
> > drop in.  I.E. Mitrek parts?
>
> Some, not all.  Depending on what band and
> model you have, some Micor and Consolette
> units have some similar parts.
>
> > It's storm season now, so we'd like to get
> > the repeater functioning properly
> > as soon as possible.
> > Thanks and 73,
> > Chris Peterson, KG0BP
>
> cheers
>
> skipp
> www.radiowrench.com
>
> also skipp025 @ yahoo.com
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>





 
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Re: [Repeater-Builder] Re: MSR-2000 parts/repair needed

[Neil McKie]

  Hello ... 

  Back in the ... er ... ah ... late eighties: 

  Ordered a new 450 MHz MSR2000 from the big M ... was shipped as 
 expected - had the 12 VDC only option - was going to a 12 volt 
 only site that used a thermo-electric generator for power.  

  The license for this station said 20 watts output maximum.  The 
 only way it was orderable was the full power model at 75 watts 
 output. 

  After careful study of the transmitter and the associated 
 schematic diagrams, I noticed the PA driver stage was identical 
 to the PA final stage execpt the driver stage comprised of one 
 module and the final had three of the same modules. 

  After some careful thought, I slightly modified the PA deck by 
 bypassing the three module PA Amplifier and connect the driver 
 stage (1 module) to the output.  Got 16 watts out of the deal 
 discovering it was very stable and lowered the DC power drain a 
 lot. 

  Since this was a licensed link radio, the distance was 9.1 miles, 
 I figured the 16 watts would be way overkill.  

  My testing from the shop using a ground plane for an antenna, I 
 could bring up one of the systems with the service monitor. 

  Neil - WA6KLA 



skipp025 wrote:
> 
> There are at least three or four MSR 2000 PA
> units available.
> 
> Yes, the versions with the ceramic substrate
> are very touchy to repair, hacks are not able
> to fudge the proper job.  Walk away from
> any shop that doesn't appear to have first
> hand knowledge of methods used for repairing
> this type of pa stage.
> 
> It's nice to have the hot gas bonder (or
> similar) method for repairs, although I know
> a limited number of people who can do it with
> special soldering systems.
> 
> Any strong stress on the substrate will cause it
> to fail with hairline cracks.  If your PA suffers
> from hairline cracks, no fix except new substrates
> will (properly) solve the problem long term.
> 
> As a general rule...
> The mid split high band pa will fail when run
> continous at >65% power in the low range. You
> derate derate the mid split (range) PA when
> using it in the Amateur Band.
> 
> The problem is running the PA at reduced
> ratings.  As a rule of thumb, rf power amplifiers
> are best operated within 5% of their rated
> values.  Running class C rf power amplifiers
> at reduced values is not the best option.
> 
> >  "N9WYS" <[EMAIL PROTECTED]> wrote:
> > Chris,
> > You say your Motorola shop "soldered across
> > the trace"...  I guess I need to know HOW
> > they did this.  We have an MSR2000 UHF machine,
> > and our PA has failed twice in about 6 months also.
> 
> You need to put two fans in the factory MSR cab,
> sucking air from the bottom up and out. Turn the
> the UHF PA down to 65 watts output.
> 
> > The local tech tried to do the "I'll solder
> > across the trace" fix, and it also failed.  To have the
> > PA repaired properly, we sent it to the Motorola shop (Chicago
> > Communications).  They have a "hot air" solder system, which is
> > apparently needed for this type of repair.  I'm told
> > the failure was on a board that has a ceramic substrate,
> > and if not repaired PROPERLY, it will continue to fail,
> > as ours did.  Improper heating and/or pressure
> > during repair can >>crack the substrate<< and ruin the
> > circuit board.
> 
> A big time yep...  and the power amplifier modules are
> not cheap.
> 
> > I just got the PA back, and haven't even had a chance
> > to get it back on the air yet; nor do I know what
> > this repair has cost us.
> > Just something you might want to look into.
> > Mark - N9WYS
> 
> Set the power level down to 75 watts max output and
> put at least one fan in place to move the air around.
> 
> If you have high duty cycle operation, turn the PA
> down even more to 65 watts max output.
> 
> cheers
> skipp
> www.radiowrench.com
> 
> skipp025 at yahoo.com
> 
>





 
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[Repeater-Builder] Re: MSR-2000 parts/repair needed

[skipp025]

There are at least three or four MSR 2000 PA 
units available. 

Yes, the versions with the ceramic substrate 
are very touchy to repair, hacks are not able 
to fudge the proper job.  Walk away from 
any shop that doesn't appear to have first 
hand knowledge of methods used for repairing 
this type of pa stage. 

It's nice to have the hot gas bonder (or 
similar) method for repairs, although I know 
a limited number of people who can do it with 
special soldering systems. 

Any strong stress on the substrate will cause it 
to fail with hairline cracks.  If your PA suffers 
from hairline cracks, no fix except new substrates 
will (properly) solve the problem long term.

As a general rule... 
The mid split high band pa will fail when run 
continous at >65% power in the low range. You 
derate derate the mid split (range) PA when 
using it in the Amateur Band.  

The problem is running the PA at reduced 
ratings.  As a rule of thumb, rf power amplifiers 
are best operated within 5% of their rated 
values.  Running class C rf power amplifiers
at reduced values is not the best option. 


>  "N9WYS" <[EMAIL PROTECTED]> wrote:
> Chris, 
> You say your Motorola shop "soldered across 
> the trace"...  I guess I need to know HOW 
> they did this.  We have an MSR2000 UHF machine, 
> and our PA has failed twice in about 6 months also. 

You need to put two fans in the factory MSR cab, 
sucking air from the bottom up and out. Turn the 
the UHF PA down to 65 watts output. 

> The local tech tried to do the "I'll solder 
> across the trace" fix, and it also failed.  To have the
> PA repaired properly, we sent it to the Motorola shop (Chicago
> Communications).  They have a "hot air" solder system, which is
> apparently needed for this type of repair.  I'm told 
> the failure was on a board that has a ceramic substrate, 
> and if not repaired PROPERLY, it will continue to fail, 
> as ours did.  Improper heating and/or pressure
> during repair can >>crack the substrate<< and ruin the 
> circuit board.

A big time yep...  and the power amplifier modules are 
not cheap. 

> I just got the PA back, and haven't even had a chance 
> to get it back on the air yet; nor do I know what 
> this repair has cost us.
> Just something you might want to look into.
> Mark - N9WYS 

Set the power level down to 75 watts max output and 
put at least one fan in place to move the air around. 

If you have high duty cycle operation, turn the PA 
down even more to 65 watts max output. 

cheers
skipp 
www.radiowrench.com 

skipp025 at yahoo.com 





 
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[Repeater-Builder] Re: MSR-2000 parts/repair needed

[skipp025]

> "Chris Peterson" <[EMAIL PROTECTED]> wrote:
> All, 
> Our local EOC has an MSR-2000 repeater, converted 
> to 146.745- Mhz.

How was it converted?  

> It has always had a flaky PA.  The local Motorola 
> shop says there is a crack in the board that broke 
> a trace.  This has failed about every 6 months and
> the Motorola shop has simply soldered across the 
> trace and temperarily solved the problem.

"temporarily solved the problem" ..?  

> Now, though, we're having a different problem.  
> When it gets hot, the repeater TX drops out 
> completely, sometimes for a couple minutes.  
> This, to me, sounds like an exciter problem, 
> or possibly a bad connection between the
> exciter and PA, 

I would not make that assumption. You can use 
the metering points to help find the problem.

> but the Motorola shop has tried to blame 
> the RC-850 that is connected to the repeater.

Consider a different repair shop for your next 
job. 

> We've disconnected the RC-850 and still have 
> the problem using the internal controller, 

See my comment just above. 

> so we believe we've mostly ruled out the 
> modification as being the problem.

What was the modification? 

> I'm looking for replacement PAs, exciters, or 
> any other MSR-2000 parts.

Contact me off the group, I can probably help 
you solve your problem. 

> I'd also be interested to know if any other 
> Motorola parts will directly
> drop in.  I.E. Mitrek parts?

Some, not all.  Depending on what band and 
model you have, some Micor and Consolette 
units have some similar parts.

> It's storm season now, so we'd like to get 
> the repeater functioning properly
> as soon as possible.
> Thanks and 73,
> Chris Peterson, KG0BP 

cheers

skipp 
www.radiowrench.com 

also skipp025 @ yahoo.com 





 
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