*** Note I format these on a PC browser - not sure how they will come through on phones ***
Had a few of these lately - this one was sent in labeled "DEAD"

It visually had a number of issues - but the edge connectors were in reasonable condition. I removed all the socketed chips and verified all of the EPROMS on my tester. PP tests a handful of them on the CPU board - but none of them on the video board.


I few of the caps were busted or just completely missing - video C4 & C17, cpu C56. Replaced them. After cleaning chips, verifying ROMs and repairing the caps and a few other small items.
Once it was all back together - getting a board set to boot is the hardest part. Here we get through almost all of the boot process before it resets and starts over. There was no 'crash' sound which is standard on PP before the final screen.. That was part of the clue. On the CPU board there are 3 Namco customs, the 51xx, 52xx and 53xx. Each are involved with sounds and voice etc. I swapped some in from a known working board and determined the 51xx was bad. It had failed in such a way that it was preventing the completion of the boot sequence.
Once I got past that - there was plenty more to do. The game now booted into diag mode and reported the 6116 RAM@3F was bad. Replaced that..

Once the game is running, it is a matter of hunting down all of the glitches. Cars and signs had were messed up colors. Tracked this down to the PROM@12H (a known common failure point) to get them working properly again. While I was looking for the issue - I noticed a wrong RAM was used @10F. These are supposed to be high speed 2149 RAM. As some point someone replaced it with a 2114 RAM. The are pin compatible, but not as fast. Since they are part of the color outputs - I replaced it (which turns out caused an issue a bit later.. stay tuned)
Now that the cars and signs had proper colors.. Another graphics glitch revealed itself..

This interleaving showed itself on the logo and on the cars at certain points.. they would phase in and out depending on car rotation and position. It certainly had the look of a counter issue..

The 74S161@10H had been socketed and replaced in the past - but it seemed to be bad again. Replacing it corrected the graphics interleaving. While doing some testing, the boards showed RAM22 had died (on the video board..) except it was fine.. and the 3rd CPU would not boot.
On the CPU board

These 4 - 10xx customs often cause random errors to the video board. If you can remove, reseat or somehow get the game to boot and fail just by manipulating them - they need sockets. Visually the sockets looked fine, but this style of socket often has a crack in the leg where the pin meets the PCB. This PP set would randomly fail with video board errors.. Replacing the sockets made the game run overnight w/o crashing.
This last part was semi-self inflicted.
Look real close as you pass the yellow sign on the left - you get an interleaved version of it on the right.. This happened in a number of places and even at the end of one of the attract sequences there was an interleaved sign sitting in the middle of a field - where it would not be under normal circumstances.

It was just noticeable enough to be annoying and was just a brief flash.. Seeing that it was interleaved and it was a sign at least pointed me in the right direction.. Knowing that an interleave like this under normal conditions is RAM related..

My first thought is was that it was a chip that supported these 2149 color RAM. I pulled the RAM @9F and ran the attract mode and got regular road signs with missing lines as expected due to the missing ram.. The artifact signs still flashing in for an instant.. Next I put that RAM back and pulled the 2149@10F.. I got the signs with missing lines (as expected again) but NO artifact signs! Nice - the issue was on the 10F side of the circuit. Before I went too much further - I put the known working 9F RAM in the 10F socket.. no artifacts.. Bad RAM? yup.. I replaced the RAM that I had replaced earlier and corrected the issue. Maybe it was too slow? to fast? or just lazy.. But it was causing the interlaced sign artifacts in the wrong spot.
Board works!