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There are 74LS161s in the motion object area.. check those.. they can cause lines in the sprites also

Thanks for writing them up.. I know it's a lot of work :)

Watching :)

I like the monitor box and power switch - nice work.

Adding the other 2 boards from this set.. Board #3 – Spare board for repair I used this one as a reference while trying to figure out how these worked in general. It had both of the large filter caps missing. I had to order them to get it back to working with AC correctly. The audio amplifiers...

Board #2 - Customer board for repair Board came in reported with no video.. After getting the minimal bench adapter set up and the power figured out.. plugged it in .. no video.. and no clock to speak of after probing around. Bad 7437@R9 - no clock - no video. Replaced it. That is what got...

*** Note: I formatted this on a PC. Not sure how it will show up on a phone *** A repair shop that I've done some work for asked me if I would take a look at Sprint 2. I've only worked on a few bronze age games. One thing about them is you can see how the golden age games evolved from the...

I like the phrase "Start at the power cord and work your way in.. " Validate and check each part on the way..

All of those sounds can get killed by a number of things.. I've had trouble with them in this area.. If you swapped the 51xx, 52x and 53xx from your other board and it made no difference - then poking through this part of the board is in order..

Sounds remarkably familiar to this... https://forums.arcade-museum.com/threads/pole-position-ii-high-score-initialized-repair-log.537953/#post-4826690

I've only worked on a handful of Nintendo so far.. Nice work on that... 👏

Nice - that you read to the end AND found out I forgot that little detail.. I updated the post.. LS373@3K. and thanks :)

Yea - that controller was the second one I ever made - I have a bunch of different ones now.. It's not meant to 'play' the game so much.. it's meant to test it.. I've considered redrilling a new aluminum plate and moving it all around.. but there is no to reason as far as testing goes. That...

Board #4 - Board in for repair This one got shipped directly from eBay by its new owner.. Known not working as described in the listing - accurate. 3 of the 4 Nintendo boards recently have had this same video issue.. Note: This video is not from this board.. just an example. It is caused...

Board #3 - 8 Ball Action - De-convert back to a Donkey Kong This one should have been simple, right? I didn't power the board up with 8 Ball Action but it had been running.. All of the EPROMs needed to be removed and reprogrammed and this is the kit that converts Donkey Kong to 8 Ball Action...

Board #2 - Donkey Kong Jr. - Board in for repair This one came in with reported missing sprites... I did board maintenance, chip cleaning and inspection.. First - the EPROM@3H was backwards (and ruined).. It is the sound ROM.. Burned a new one. While cleaning chip legs - I found a number of...

Colors are off because of inverter board adjustments.. I need to get my Sanyo running.. However.. this didn't last very long.. Up until this point the board had multiple chip failures.. This failure started as twitching and progressively got worse. I spent some time looking for it but the...

*** Note: I format this on a PC - not sure how it will look on a phone. *** *** It's been educational. Nintendo is a bit of a learning curve for sure.. If there are good clean schematic scans out there.. let me know! *** *** This is a cross post from my site *** I've always planned to do some...

Funny - I just tried this working on a Battlezone last night.. I could barely get the XBIP to adjust 'left' (I'm assuming that is neg voltage..) but it adjusted right just fine. I sorta narrowed it to the TL082 or the DAC.. Piggybacked the TL082 and there was no change.. I socketed the DAC - no...

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