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Rom1

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Some info:
- OE is a pin on M1 ROM on the cart (also on SM1 ROM on the slot).
- Reset, Halt, M1, IRQ are pins on Z80.
- High, low, pulse are the status your logic probe shows.
- U13 is the ref of the components, model 74hc32.
 

HornheaDD

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OK, thanks Rom1, I'll see what I can figure out after work today.
 

HornheaDD

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So I blew up this board. :(

After some research it looks like the YM2610 sound chip is a common point of failure. So I ordered a new one for $9 to install it. I'm not a solderer, I wouldn't even consider myself an amateur solderer.

I was able to remove the chip using a hot air station and it worked great. Cleaned up the remaining solder with some wick and flux - but trying to get the solder out of the pin holes, even with an electric solder sucker proved difficult. I got like 15 of them cleaned out super pretty. But I guess while doing one of them that was proving troublesome, I nicked a trace. And it's way too small for me to repair.

Oh well, at least this board was only $40.
 

Rom1

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If I earned a dollar each time I heard this kind of story, I would be rich today.

At least you learned some things in the processing.
 

HornheaDD

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you can jump the trace from 2 endpoints
Oh yeah, I'm aware but I would probably do more damage than good at that point. Its much too small for me to do it properly. I might have a friend try and fix it for me, but my skill is nowhere near the level needed to do a trace repair, especially when next to 2 or 3 other traces.
 

Rom1

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You take the right decision by stopping there if you estimate your skills are not high enough.
Don't throw it in the bin and wait for someone to fix this. Arcade community is full of skilled people that can repair it.
 

dos

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Several years ago I got a Battle Garegga PCB for a steal because it had some graphical issues. When I received it I saw immediately that there was some cold joints on U30, a very fine pitch QFP. At the time I had no micro pencil or microscope, but I thought I'd fix it myself, since I'd never really run into issues repairing my own stuff before. I immediately bridged it and then bent some pins trying to remove the bridge with my gigantic 1.2mm tip. I immediately stopped and got in touch with someone on IRC who was known for repairs (totally forget who this was now unfortunately). Anyway dude fixed my screw-up and brought the board back from the dead. Moral of the story is to know your limits and equipment, know when to stop, and that your screw-up probably isn't as bad as it looks, the board can probably be saved in the right hands.
 

channelmaniac

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Small update, I tested the digital audio like the test from ArcadeComponents and it seems that the digital audio is functioning as designed. I got a logic probe today from Amazon and tested it, and I am getting the steady beeping and static like in the video. So that's a little progress there. I finally have some time to get my vision visor on and see if I can find any messed up traces.

Hey, I know that asshole in that video! :) (Me!)

If you get the beeping and scratchy sounds then you have digital data making it to the DAC. You either have a bad DAC (unlikely) or a bad cap (VERY likely) in the audio section.

RJ
 

channelmaniac

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Look into getting a small spool of 30ga Kynar wire for doing the patches. Easy Peasy.
 

HornheaDD

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Hey, I know that asshole in that video! :) (Me!)

If you get the beeping and scratchy sounds then you have digital data making it to the DAC. You either have a bad DAC (unlikely) or a bad cap (VERY likely) in the audio section.

RJ
I'll have to take a look at the caps, but I still need to clean up the rest of the solder from the 2610 chip I removed (and am waiting for a new one in the mail).

I'll check out the wire, but I honestly think I wont be able to fix it at this point. I need quite a bit more practice.
 
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