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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: 8bitplus on June 11, 2017, 07:13:47 AM
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Hello. I'm trying to fix a black PC engine duo. The sound is working correctly for the HU card games, but very faint for the CD background music.
I have done a complete re-cap, and initially everything worked. Then the next day NO SOUND at all.
After days of poking around I fixed a couple of traces and replaced the 2 op-amps under the board, and the one at the AV jack.
I reassembled and found the CD volume is very low on both the AV and headphone jack.
Can someone tell me which caps and amps are for the CD drive?
Thanks
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After more reading it sounds like the problem may be related to the M51131L. I have a second fully working Duo and its getting 5v to pin 8 of the M51131L when playing CD music, but this Duo is getting less than 1v.
I'll take the board out of the case again and inspect that area closely...
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Fixed.
Turned out the OP-Amp at IC521 wasn't getting correct voltage. I linked it to a 5v line on pin3 and the cd music is nice and high again.
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Sorry to necro but I had this EXACT problem and there was a hairline break in a trace going to pin 3 of IC521, also voltage drop on the same pin
I never would have found that without this thread, a million thanks 8bitplus!!