Hi all -- I had the same problem on my High Speed, and I wanted to thank you all for the inspiration and for nudging me in the right direction to solve my particular problem.

My machine would lose all settings and flash "Adjust Failure" at every startup. I still had the original battery holder with lithium AAs installed. I replaced them with new batteries to no avail. Piecing together advice from this forum entry, (and having the schematic handy also helped a lot), I was able to determine that my battery holder, which looked to be in fine shape, was NFG. I took further inspiration from this YouTube video and decided to install a lithium coin battery socket, and baby, it feels good.

So here's how it went down for me (please refer to the photo for clarity):

I hung my meter's ground to the CPU ground post and tested for voltage at pin 24 on the RAM IC, (U25 on my High Speed), and also at the anode side of the diode at D2 (directly to the left of the battery holder on the board). There was no voltage at either point, but I noticed that if I wiggled the battery holder or held a little pressure on it, voltage would suddenly appear. The holder was fouled.

I cut out the old battery holder with wire cutters and, using a soldering iron, removed the legs and excess solder from the board. I ordered these 2032 sockets from Amazon (~$7 for a set of 5):

https://smile.amazon.com/gp/product/B00E0JRP8C/ref=ppx_yo_dt_b_asin_title_o00_s00

The legs of this new battery socket happen to line up perfectly with two of the six now open holes at the bottom left of the old AA section on the CPU. Although the socket does sit right up against the IC at U14, it solders in place perfectly.

I also had to run a jumper wire between the old AA battery holder ground connection at the top right over to the top left connector hole to get the negative side of the new battery socket grounded. A trace on the solder side of the CPU connects these two points.

The 2032 now provides a steady 3.1v at the anode side of D2, 2.8v at the cathode, (and the same at pin 24 of U25). This is less than the 4.5v prescribed by the three AAs, but is apparently more than enough for U25 to keep its shit together, and will never leak. My machine now holds all settings and high scores and starts up without error.

Diagram (resized).jpg

If say, a remote battery holder is used instead, it means any time the CPU needs to be removed from the machine for whatever reason, you're probably going to have to unplug this connection, and all settings and scores are lost. The onboard lithium socket eliminates this pitfall that might rub some owners/players the wrong way.

I hope this helps others make a quicker diagnosis of an "Adjust Failure" error. Thanks all!

Paul