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Post by simonecolombo on Apr 20, 2020 11:06:28 GMT
Hello, i have a problem with my VA9 PAL Saturn, sometimes ( 10% of times) it starts and the other time no, green led is powerd, the power supply is ok, i have looked inside and think the issue is on IC9, when it doesn't starts the reset to scu etc is low. i checked the IC35 and it look ok but i found only the VA0 version of schematics and is not similar because the button in my version is going in pin 35 of IC9 not in IC35. anyway if you have a schematics of VA9 should helpful for me.
thanks!
Simone
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Post by zyrobs on Apr 20, 2020 12:46:49 GMT
VA9 units suffer from dead caps that affect the PLL chip. I'd try recapping the board.
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Post by simonecolombo on Apr 20, 2020 13:18:41 GMT
Thanks,
i have already recapped but the behaviour is the same, the problem came from 315-5744, i'd like to have the schematics.
when it starts "wrong" and i manually reset on pin 15 the IC9 restarts "good", i'm starting to think the problem is on IC35 but with oscilloscope everything is working well...
i'm looking inside again, but without a schematic i have to follow the tracks to understand... i'm workin with VA0 schematics but is different..
thanks again
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Post by zyrobs on Apr 20, 2020 14:32:04 GMT
The only other schematic available is the VA13 one, but the VA9 boards are actually closer to the VA0 inasmuch that it mostly uses the same chips while the VA13 has many parts replaced with cost reduced ones (and we only have the electronic drawings for those, not the chip pinouts).
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