History of pinball in the USA

Just put a new article online - the history of american pinball manufacturers.
The large, known brands of pinball machines were in control of only a handful of people.
Holding companies or subdivisions went bankrupt, were taken over, ..

Spent two evenings desoldering corroded parts on the Black Hole Sys80 cpu.

Used sandpaper to get rid of the corrosion (forgot to take a before picture).
Finally used vinegar (it's an acid you need to neutralize the base fluid that has leaked out of the battery), scrubbed everything well, rinsed the pcb, ..

Now it's ready to solder in new parts and check all traces. The thick trace at the bottom left corner is broken where it connects to the bottom left pin of the ic above it (of the 2 the most right IC).

Update: soldered all the new parts in place. Found two broken traces, fixed with jumper wires.

Now tested the cpu. It's dead :-( Will have to review all connections and parts to check they're soldered well and there are no shorts anywhere..

Black Hole repair part 4

Found the problem with the locked on popbumpers - like I posted at the end of the previous post, the +5v is indeed missing at the boards.

Traced continuity back to the cpu board (A1J6 iirc) so the wiring or connectors are not the problem.
Investigated the trace on the board and found the problem, battery acid ate a small trace right at the bottom corner of ic Z3 (or Z2, don't remember, the right one of the two).

Soldered a small jumper cable over the trace but only got about 2,5 volts.. so decided not to hack the cpu further but first repair all the damage completely. I still have a battery damage repair kit from GPE that I bought years ago.
Double checked all components are present, marked them on the paper sheet, so I know what parts I have to desolder.
Then I'll clean up and check continuity on all traces.

Also found a new problem - the voltages on the power board are much too high :-(
5v was 8, 64v was almost 100, 40v was 68, 8v was 18, ..
Soldered the input on both transformers from the 220v to 240v tap, but that did not change anything.
So I will also rebuild the powerboard.

Black Hole repair part 3

Worked for a few hours more on my Black Hole. My deadline to get it working by the end of August has passed :-(

Spent yesterday evening soldering on the driver board, did the optional ground modifications (about 10 jumper wires) like described on Clays repair guides (these are not online anymore).

Also played a bit with connectors, measures continuity, ..

The flippers suddenly work. Don't know exactly what did the trick.
Probably the ground modifications.. let's hope it keeps on working the next days :)
I did learn that you need to have 3 pinballs installed in the ballthrough for the flippers to work and Q to stay activated. Testing with the playfield in the up position (so you can see the relay) and then not having pinballs in the through, will make the relay not stay on. Doh.. so maybe this issue was solved before and I lost 2 days troubleshooting a non-issue..

Popbumpers still lock on immediately :(
Traced continuity in the ground and that's ok, from the green wire on each popbumper driver board, through the driver board, up to the large ground strip in the bottom of the cabinet.
There must be another short somewhere.. but I have no idea what to look for :(
Update: maybe missing +5 volts..