| Author |
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Pc751
| | Posted on Wednesday, May 15, 2002 - 11:50 pm: | 
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The 2950 I have is fairly new, but I have checked all solder joints. Problem is this: Radio keys on all modes, no AM modulation present. Has FM modulation, and SSB modulation.
Also, the RF output control on front does nothing to vary the AM/FM power, but does control the SSB output power. Radio is keying 35 watts on AM and FM, and is doing about 40 watts PEP on SSB.
I read somewhere that if this radio is reversed polarity, it will cause the AM regulator to go bad. This radio has never been hooked up backwards either. I tested Q51, and two leads check open. I cant determine whether this (open circuit on Q51) would cause mod/rf problems. Seems like an open circuit would cause the radio to have no output at all. Im getting frustrated. And I hate to burn the circuit board up by soldering alot of components that arent bad. Any clues? |
Pc751
| | Posted on Saturday, May 18, 2002 - 10:36 am: |
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Update: I have fixed the rig. Q54 Seemed to be OPEN from Base to Collector. The whole time I was checking parts with a ohm meter, I was only looking for shorted transistors and diodes in the AM Mod amp section. I then decided to start pulling transistors and checking them out of circuit, cause you will not get a reading that indicates open circuit while still in the circuit. The first one I pulled, just happened to be open. I replaced it, checked all connections, and fired it up. AM modulation is back.
Hope this may help someone with the same problem. |
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