Hello Eric, Skipp, and the Group!
I concur with rtc's PA fix scenario..... That is real accurate on the
procedure and results that I experienced in the many PA repair issues I
have resolved in the majority of Mama Mo's Maxtracs, Gm300, and 1225
mobiles in use as-is or repeaters. A seasoned tech like you Skipp, IMHO,
is not going to need a "road-map" to fix the obvious.
I have encountered many Comm Sales People REPLACE repeaters and mobiles
with these types of PA failures. I guess that keeps us techs with
something to do and more refurbished product to sell.
Have Fun doing what we do best, Fixing Stuff!
I love my job {hobby}!
Charlie
"It is not the class of license the Amateur holds, but the class of the
Amateur that holds the license."
Charles Mumphrey
Amateur Radio Station Kc5ozh
Kc5ozh Rowlett Repeater: 441.325 MHz + 162.2
Kc5ozh Dallas Repeater: 441.950 MHz + 162.2
Kc5ozh Rowlett Repeater II: 441.950 MHz + 110.9
Rowlett R.A.C.E.S. Unit 823
http://www.CharliesElectronics.com
http://www.hello-radio.org
http://www.emergency-radio.org
> -------- Original Message --------
> Subject: [Repeater-Builder] Re: Motorola R1225 versus Kenwood TKR-750
> From: "rtc_0001" <[EMAIL PROTECTED]>
> Date: Sat, July 14, 2007 11:03 pm
> To: [email protected]
>
> It's not so much a defect as it is asking the rptr to do more than it
> was designed for. It may be a 45 watt PA but in rptr use, medium to HD
> rptr use, drop it down to about 25 to 30 watts out of the PA. Enjoy
> what you get thru the duplexer. Asking for more will melt the PA.
>
> The earlier units had a temp controlled fan that only came on when the
> PA was about to melt. The next generation of power supplies came with a
> switch to turn the fan on permanently.
>
> You will probably be able to fix them without the manual. Most of the
> time the PA transistor collector got hot, melted the solder & the chip
> caps moved (slid down the pcb due to gravity).
>
> I repaired these on a regular basis without needing new parts unless the
> damage literaly burnt the pcb around the collector lead. I removed the
> chip caps, removed the solder on the collector tab & trace & resoldered
> it all back in with silver solder. This, along with turning the factory
> output down, made them last a long time even under HD casino use.
>
> I think it took me maybe 45-60 mins to get it all apart, fix it,
> reassemble, reinstall. Lots of times I did it in place at the customer's
> premises. rtc
>
>
> > -----Original Message-----
> > From: [email protected]
> <mailto:[email protected]>
> > Sent: Friday, July 13, 2007 11:08 AM
> > To: [email protected]
> > Subject: [Repeater-Builder] Re: Motorola R1225 versus Kenwood TKR-750
> >
> > Hi Eric,
> >
> > <SNIP>
> >
> > I just pulled three 1225 uhf repeaters from two different locations
> > and they all have the same failed tx pa problems. Wonder if there's
> > a minor pa defect problem (like there was in early version one tkr
> > repeaters) or it's just bad customer karma time. I've got to find
> > a service manual before we open them up...
> >
> > cheers,
> > skipp
