My newly acquired "Dead-fender"

TheDrewster

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Donor 2012
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I brought home a Defender from Paul (pcolson) and started working on it today. It powered up, made the startup chime, then nothing. First, I replaced a fuse for the -5v. No change. Then, I reflowed all the header pins on the ROM and CPU board as well as reseated all the ROMs. But now, when I turn it on, I get a low buzz (not a chime) and all 4 LEDs on the ROM board are lit. Then, silence.

Did I just kill it somehow?
 
Nope, that didnt work. However, I did also reseat the CPU and video encoders on the CPU board and found that I didnt plug the CPU in all the way. Could I have fried it by powering it on without plugging it in fully?
 
When you power up, do the LEDs blink off then on or just on?

If they blink, then you are probably getting CPU action as it goes through the internal power on self test.

ken
 
I brought home a Defender from Paul (pcolson) and started working on it today. It powered up, made the startup chime, then nothing. First, I replaced a fuse for the -5v. No change. Then, I reflowed all the header pins on the ROM and CPU board as well as reseated all the ROMs. But now, when I turn it on, I get a low buzz (not a chime) and all 4 LEDs on the ROM board are lit. Then, silence.

Did I just kill it somehow?

I've got a tested working Defender MPU/ROM pair, I would trade for you non working pair + $$.

Satbreez
 
UPDATE: Now the machine chimes up and the board blinks all 4 twice, indicating passing the tests, but I am only getting 3.8 on the +5. Time for a PS rebuild?
 
UPDATE: Now the machine chimes up and the board blinks all 4 twice, indicating passing the tests, but I am only getting 3.8 on the +5. Time for a PS rebuild?

Definitely. Test the voltages coming off BR1 and going to the voltage regulator. IIRC, the PS schematic has nominal voltages at several points in the circuit. These will help pinpoint defective components that need replacing.

<shameless plug>
Or I can ship you a tested and working rebuilt one. Send me a PM if interested.
</shameless plug>

ken
 
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