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Brezzasoft Crystal System - Trying to repair it...

TheDeath

TheDeath

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Hey guys, i'm trying to repair a Brezzasoft Crystal System
The mobo is powering on but the only thing i can see it's a white/dot-ish vertical line to te right of the screen.

20200512-182541.jpg


I've read some LED status inside a wiki, D1 led blink then turns off, D2 blink then turn off, then both blinks and turn off, and repeat in loop.

It was mentioned that this could be releated to the Sdrams so i have ordered a new set anche changed them, result was the same.


After that i made sure myself that the vrender zero was properly soldered and i reflowed all the pins and checked them with a scope. Same result.


Then i went to check the 278R33 mosfet, the output was a little bit higher from what srams tend to work good based on their datasheets, so i've used a buck converter, set it to 3,3 and feed the Vout to the srams. Again, same result.


I've cleaned the socketed bios, the GAL and few moisture here and there. I don't know what to do else. Maybe change the 256ram near the bios but other than that... drives me crazy.


20200512-182536.jpg


Any suggestions?

Thanks
 
I’d work back from the JAMMA edge for video out with a multimeter and see if it’s carrying signal all the way properly. If you’ve already done all that work there aren’t many chips left on the board lol. I’m always impressed that’s basically a “we jammed everything on a single chip” pcb.
 
I think i've just found the VrenderZero nos on alibaba, lucky for me it's the normal one, not the plus version. I might just grab a pack but they won't be cheap.
Thats a DC DC converter in place of the 278RR33 as i wrote. Carries exact 3.3V needed by srams and other components that won't run by standard 5v ttl
 
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