While I'm still working monitor issues, one consistent issue is that my Pacman has a loud hum coming from the speaker. I haven't been able to hear any other game sounds yet at all. I've been doing some searching but haven't really found any solid suggestions.

I have replaced a couple of sound-related ic's on the pcb (and will probably replace the amp etc) and have a pcb recap kit on the way as well. Are there any go-to tests that I should focus on? Something specific I should look at first that's maybe more obvious to those more experienced with this issue?

Thanks!!!
Brian


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901 was blown but I've replaced x01 and the flyback. Would it be worth it to replace B+ filter cap (C904) though it's uncommon? It did discharge into my finger, , because 901 was blown.


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Where do I test to see if the monitor is receiving AC?


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Working a G07 CBO in a Pacman upright. The first chassis had half a screen (vertical deflection) despite replacing FR, flyback, vertical IC's and a full recap. Figured that it just had too many lifted solder pads or issues I am not experienced enough to repair.

Found a second used chassis. Recapped it. New flyback, HOT, X04, fused resistor 401, cement resistor, glass fuses, and horiz width coil. (Yes I made sure all my caps are in correctly at least 4 times and I've had successful recaps in the past). Pulled FR901 out of circuit and it's fine.

I started with the cap kit and got no neck glow. Did all the rest and still no neck glow and get ZERO B+. Not even getting a pop when discharging the anode.

I've got to be missing something. All I get is a black screen and a petty good hum from the speaker.

Can anyone suggest anything that I must have missed? Solder side looks decent and no cracks that I can see. From what I've read on forums, I think I've hit the high points and then some.

Thanks for any help!


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I got it off there.


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No, not the one under the control panel. The one above it in front of the bezel:


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Any tips for removing the old under-bezel instruction sticker from a donkey kong jr.?
It looks like the board that this thing is on might be laminated. (The top edge seems to be missing it's laminate molding too. Not sure if I can find a replacement or just sand and paint that).

Can I go after that sticker with a heat gun and a razor blade? Will it ruin the board? Or is there a better way? It looks like the only way that board comes out is if the cab sides come off. Otherwise, if there's a trick to getting that piece out, I'll just refinish it all.



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The Dk Jr. I recently picked up has this same problem. I never would have believed how loud these things can get! In my case, as Ian mentioned, the pot seems to be going bad. It's very touchy and will turn down a little bit, but it doesn't take much to set it back to jet aircraft decibel levels!

Bob Roberts sells the part if you want to replace it and it's cheap. I got the audio board kit with the cap kit for the 20EZ so I'm replacing everything anyway. Wanting to get that done this weekend and get playing! 

P-Feif,

I'm still working on this thing. So far I have replaced the ROMS so that they are back to Pacman. I'm sure you can find other resources as to how to change the speed back if you're just wanting to have standard Ms. Pacman. My guess is that it's just a replacement of one of the ROM's, but I can't say for sure. I just sleeved my old Ms. Pac turbo roms and put them away for now. I screwed up my 285 daughter board so am waiting on a new one. (I replaced the 28 pin sockets with dual-wipes but installed the 285 upside down and I think turned it into a belt buckle or paper weight).

I'm still working on the monitor. I just replaced the vertical IC's but have half a screen and the right half is collapsed (which is better than the total collapse I had). I'm looking at various parts of the chassis. I had some crappy pads so some of the caps I installed when I did the cap kit didn't solder properly and I'm having to fix those as I find them. Hoping that will eventually fix my screen issue. Some people complain about a few resistors in that area going bad (R522 pops up a lot in forums), but Bob Roberts doesn't carry any of them as of yesterday. He said that he doesn't know where to find them as they rarely go bad. I wanted to just replace the lot because of the heat that was apparent there at some point and I can't get continuity on every one.

I also have sound problems. I replaced the RAMs at 2L and 2K so far, and am waiting on a few parts that should come in today before I can try again once everything is put together. I have an IC for the sound amp, but am hoping not to have to replace that. Once I have the new 285 in, I should be able to see where things are.

If you want to email, my email is my username at yahoo. I'm basically just learning by doing. Yeah I'll screw up a lot, but by the time I get done, I will know a lot about this game and have increased skills to tackle the next game.

Brian

Thanks. I don't have a reader and getting new ROMs was cheaper at the moment than getting a reader/writer. I'll check in after I have a chance to install everything. No sound either so I'm likely to be replacing other ic's on the pcb.


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So L and M are the extras ?

Second one shows the 285.

These might be better:

Here's a pic. The 285 is off the board.

So after finally getting my monitor issues fixed, I found that my pacman is really a fast-speed Ms. Pacman.

I've been trying to do some research and it seems that often the Z80 socket contains a daughter board. Mine doesn't. It's just the Z80. Is it possible that only the ROMs are programmed for Ms. Pacman? Would just swapping those out for Pacman ROMs get it back to Pacman?