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got a 939 for repair. it is modified for "TX audio direct injection"
on the back of the radio, and had a "golden screwdriver" turning
this and that. :oops:
It worked but ran so hot I was told they had to
put a fan in place of the speaker to keep it cool. :mad::mad:
so yes, the "520's" bias...
I got this old Galaxy Saturn radio to bring back to life.
Working on the RF output. It had several watts of carrier for AM,
and SSB was "rough" "scratchy" sounding bad I was told.
did the usual RF output transistor bias level check at first.
at driver transistor TR44 the bias would barely...
I have this old 2970 (with the -013 board) that had many problems. it was worked on by others,
sometimes making things worse. (solder blob shorts across circuit traces., etc)
But the last thing I was trying to repair was while in SSB receive, with even a moderate
strength signal, the audio was...
.
I wanted a little amp, with a bias circuit already in it,
and to be driven by my Cobra 148.
I checked my pile of broken amps that were given to me.
(I got that RM Italy amp working, but no bias, sucks in SSB!)
Took a look at that DYNAMO amp, and recognized the board
as the same as a PALOMAR...
from the infineon.com post - "Pre-sale Counterfeit Verification"
"Additionally, we do not support the sale of Infineon products via eBay
or similar auction houses or any other below market source."
https://www.infineon.com/cms/en/product/promopages/counterfeit-products/
"Infineon products...
I have a few of these 250's here. This RF key circuit has been messed with
in both amps. One is keyed up all the time. I traced the diagram out
and it makes little sense. So did this circuit ever work? AM and SSB?
These amps seem to be OK. The transistors are biased, unlike many
of these...
Connex 3300HP Galaxy DX55HP circuit EPT360015C
- I got my hands on a Connex 3300HP to repair.
I see that many have problems with this radio, and all those other
IRF520 MOSFET RF output section radios in general.
- I only have worked on a few of these radios, to get them to work in SSB...
any techs out there that are real familiar, or have a radio on their bench now.
I have been trying to get another radio in town here to compare with,
to save time and effort.
I have been working on this, my first 2970N2 main board EPT695015BR
that another tech was working on and gave up. not...
While working on my first 2970N2, from another techs hands,
found the main transceiver unit was getting hot. low output. the
IRF520 bias settings were way to high, and one was acting squirrelly,
eventually damaging IRF520 Q62. With the shorting board and Q62 removed
from the board, I...
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