Data East Desert Assault repair

tonyarbisi

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Donor 2023
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Hello All.

Hoping someone can help me with a few questions on this repair of Desert Assault I am working on. First, what is this black rectangular component in the picture? It looks to be short to ground and I need to find a replacement. It is right by the jamma connector. It is the first thing in the path from the blue video pad. Thinking a resistor array of some sort. Schematics label it as FB2. So maybe thinking a ferrite bead or maybe a filter or fuse of some sort? But it has 3 legs.

Second question. I removed the component, and it appears to allow the board to boot now (figured it would just not have blue), but I now get a "sub cpu sleeping" error. I have never seen a tired cpu. Any thoughts on what to check.

Repairs on board so far: deep cleaning, removed and polished up all removable chip legs, removed damaged amp (waiting for part to replace), fixed two trace runs ( guessing from shorts - one to amp and one to blue), replaced all electrolytic caps (several had bad esr, so did all), replaced a burned resistor, replaced 3 video transistors (think only blue was bad, but the others had inconsistent measurements so replaced).

Made some progress from it not doing anything.

Thanks for any advice on what to check next.
 

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EMI filter. Schematics don't really help beyond that. One pin, probably center, will be connected to ground. One pin will be connected to a card edge signal and one will go somewhere else. You can connect the two that are not grounded and it will bypass the part.

Without more info/markings its hard to say with any confidence what a replacement would be. Something like an EMI222T-RC would be a reasonable guess, though its discontinued too.
 
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