I'll take a stab

I've seen this happen myself and also saw someone else mention that if the 5101 RAM is flaky you could get a lock-up in lamp test mode. Not saying that's what's happening in your case, but it's a possibility that it's related to the 5101 -- or the piggyback in some way.

Will it start a game?

Did you redo the grounds on the transformer.

Redo the grounds at the transformer assy and double up the +5V and GND connections between driverboard and CPU board. DON'T use the heatsink from the +5V power supply as a common for Ground. It is wrong, that heatsink is just barely isolated from the +5V; only by a very thin shim between the LM338 housing and the heatsink.......

The 5101 was a good bet.
You really need something like Ed's QuikScan80 to verify the RIOTs first.
After that, the addressing logic is where I'd start probing.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info

Or a test ROM like this one:

For the test rom images -> send me a PM with your email address. Ed's tester is or will be available at the site of Great Plains Electronics.

https://www.greatplainselectronics.com/products.asp?cat=41

Marco

I see the OP has ROM burning capabilities, so will likely go a DIY route, but I'll post this here just in case.. or for others.

I'll have Marco's test roms available soon along with fully assembled tester boards that plug into the TC1 socket (at the top center of the MPU) that make using Marco's (or Leon's) ROM a bit more plug-and-play @ http://www.pinitech.com/products/gottlieb_universaltester.php

You could also go the DIY route and order bare boards from OSHPARK (there's a link on that page) and source the components yourself. If anyone orders the assembled board + ROM through me.. I'll be sending Marco proceeds from the ROM sales after I cover cost of chip and a buck or two for time to burn/label. If you go fully the DIY route consider donating to Marco somehow if you like his ROM(s) and find them useful -- he's got lots of great test ROMs he gives away for free all the time & I think it's good to support people helping us make troubleshooting easier.

Ed's Quickscan80 is a great product too -- I've heard many great things, it's advanced in what it tests and has great read-out of error codes. Unfortunately I haven't had the chance to own one myself as he sold out of his first version. Looks like his new version is "Coming Soon" (still in testing) -- I'm sure I'm not the only one waiting to throw some money his way when that happens.

I've been shamed into actually building the board up that I got from "acebathounds" kind OshPark post over a year ago. It works! I programmed V31 of Marco's test ROM into a 2732 and tested it on a known good System 80 MPU. I received the proper number of flashes indicating all was well with the board. I'll have to try it on a suspect board, and compare the results with Ed's QS80 tester.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

Bax1 sorry to dig this thread up but did you ever resolve the problem with your MPU? I was working on a Tag Team last night with the same issue. Game would boot up OK. in test mode I could scroll through the audits but then it would hang on Lamp Test (lamp 2).

I was able to add credits but could not start a game.

BTW installed Freeplay ROMS from https://www.flipprojets.fr/Proms80B_EN.php using Piggydeux from acebathound

Cheers!

Well, I'm hoping it's not the freeplay ROMS that are the problem. Hopefully, we can figure this issue out Thanks for the link to your thread, I was going to start my own but may hold off for a while.

I just checked your new thread and it looks like you are now getting into switch test mode (previously it was stuck on lamp test)... do you remember what you did to resolve that issue?

Ok thanks, I'll go ahead and reflow the piggy back board.