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sx-1250 Tuner out and indicator lamps

Aiden T

Aiden T

Member
Hi everyone im working on restoring a sx-1250 and am having issues with the tuner being out and indicator lamps. so far i have read some other diagnosis on ak but most are dealing with the lack of voltage on the power stabilizer board. I know there should be 23 volts on pin 7 but i only have about 2 volts so i figured there was an issue with the initial power supply board, but couldn't find any bad components. I did change out the caps already on both boards so we can rule that out and checked for bad solder joints. what should i look for next? can a bad component on the stabilizer board cause the lack of the 23 volts at pin 7? The 23 volts leaves pin 8 on the initial power supply board. so just wondering which board to focus on. thanks
 
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Aiden T said:
Hi everyone im working on restoring a sx-1250 and am having issues with the tuner being out and indicator lamps. so far i have read some other diagnosis on ak but most are dealing with the lack of voltage on the power stabilizer board. I know there should be 23 volts on pin 7 but i only have about 2 volts so i figured there was an issue with the initial power supply board, but couldn't find any bad components. I did change out the caps already on both boards so we can rule that out and checked for bad solder joints. what should i look for next? can a bad component on the stabilizer board cause the lack of the 23 volts at pin 7? The 23 volts leaves pin 8 on the initial power supply board. so just wondering which board to focus on. thanks
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That board needs every transistor replaced, and for every resistor rated above 1W I replace with the next size up (1 -> 2W).
Do this and report back.
 
If the 23v IS coming off of the AWR-107 pin 8, yet the AWR-106 pin 7 has only 2 volts,
first be SURE that the 23v is on pin 8, then check the wire between pin 8 out and pin 7 in.

IF the 23v isn't at pin 8, then check the two fuses FU3 and FU4, as well as D5 and D6.

You can check the current draw of the sections of the AWR-106 by measuring the voltage across R17(3.9 ohms the +13.5v supply)
and R18 (100 ohms +5.4v supply)
 
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FYI: I had the same issue with my SX 1250 (no indicator lights and and no tuner functions) and found R17 3.9 ohms to be open (AWR-106 pcb). Replacing it got everything back. Thanks to Markthefixer for pointing me in the right direction!
 
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Just restored an SX-1250.
Indicator lights were out after rebuilding stabilizer board.
Went back and found I'd missed replacing a transistor. Yeah, the one that powers the lights.
 
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