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Transistor replacement needed

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Ken1

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Hi, I have a GE Superadio I portable AM FM radio that probably needs a replacement transistor for the AM RF amp stage. The FM band works perfectly but the AM band is very lacking in sensitivity. I tried aligning the AM section according to the procedure in the service manual but there is very little improvement. All voltages on the RF transistor and the IC are correct. I would like suggestions for suitable part numbers for a replacement for this transistor as the original GE part is no longer available. I have attached a copy of the schematic and parts list.
 

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If the voltages are correct, ie. ~.6-.7 VBE, VC ~1.9, then chances are your transistor is working properly, so changing it will most likely not help. You say you aligned per the manual, can I assume you had the AM signal source suggested in the tuning guide (if not you will have a tough time getting back in tune) ? Have you tried an external AM antenna? If anything, I would suspect poor solder joints on the AM ant L6. If I recall, those old antennas had funky wire. My dad had one of those old GE radios in his garage to listen to the games, his also had the shortwave bands.
 
I aligned the radio by simply tuning in over the air AM stations. Around here there are enough stations across the AM band to do this and I have aligned many AM tuners over the years this way and it always worked for me. An external antenna would probably help however the tuner is lacking on sensitivity and performs the same as any AM tuner without an RF amp in it. All the weaker AM stations are missing and there is no background noise on unused frequencies anymore. This radio employs an 8 inch ferrite rod antenna.
 
Here is what the manual says (and getting a signal source at this frequency with AM is pretty cheap on EBAY). I have also tried tuning radios, by your method and messed them up. I would try to follow the manual before replacing parts. Also look for old solder joints that may have cracked over time. Then again after reading more of the manual, maybe your method might work for most of the procedure except the parts that say closed dial setting, not sure what that means?

GEradioTune.PNG

Link to full manual. https://earmark.net/gesr/sr1_manual.htm
 
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