2716 is a 16K rom. 2532 is a 32K rom (with a slightly different pin out).

You can get new ROMs here.

http://www.thatpinballplace.com/eproms/index.htm

Beware the during the time of jungle lord and black knight, WMS mislabeled two of the rom IC## designations. So when replacing the ROM ICs, use the drawing the MPU from a sys 7 manual to place your new ROMs. The new replacement ROMs will be labeled properly and match the drawing in the manuals.

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Question for you Vid: the guy that runs the local electronics store tells me that 12,000 mfd capacitors are no longer available. I saw that in your example you swapped a 12,000 for a 15,000...will that still be ok for the 12,000 on a Williams System 6 sound board? Mine looks like it's about to burst out one end and it has to go! Do you think the sound quality will be affected?

Fair enough, I believe you! However, would a 15k work just as well or cause issues?

Thanks a bunch...I'll also remember to make sure that I don't buy into his BS next time.

Vid, it appears that the kit from Great Plains contains all the upgrades that you suggested for the high-voltage section. Can you confirm? I'd like to purchase the kit, as it is far easier than hunting down everything individually.

https://www.greatplainselectronics.com/Downloads/W3-11_HV_Kit.pdf

Just started replacing the caps on my Firepower soundboard. Also checked the fuses, and someone installed 6 amp ones when they should be 4 amp. Just like Vid has said before, don't assume anything about who has done what previously!

So I replaced all the caps on my sound board. It appears to work just fine. I had a question though: Capacitor C12's orientation on the Firepower.com soundboard schematic from Phil Butcher lists the polarity as being from negative at top to positive at bottom. My board, however, has the positive side plus symbol printed on the top mounting hole. I mounted the capacitor as per what the board listed, not the schematic. The cap that was there was quite small and old, and I could not decipher which end of it was which. Does anyone (or Vid) know why this discrepancy exists? Is it an error in the schematic or the board itself? Which is correct?
Recapped board (minus zip tie!)

Interesting. I looked at my prints as well and the negative side is up. I also looked at the pictures of my sound board (Blackout, same board) and I have the negative up. I'm sure i soldered them in according to the markings on the board.

I'll have to get a good quality, up close shot tonight.

The first versions of the sound board have the polarity marked wrong on the PCB for that cap.

You can tell if you have the first version because there is a 1uF bypass cap tacked down across the 5v rail on the top left area of the sound board. The later version (with the correct polarity mark) has through holes for this cap.

Looks like mine is one of those (check my photo above, I just replaced that one...and wondered why the heck there were no holes!). In that case, I assume I should then remove the cap C12 and orient it according to the schematic, not based on what is on the board. What does that cap do, anyhow? The board currently works with it backward!

The cap still does its job when installed backwards but will have a much shortened life.

Well it is getting swapped around regardless. I was under the impression that electrolytic would only work in one direction...I must have been misinformed. Thank you for the help.

replace it with a new one. It may be damaged. 1uF is cheap enuogh cap not to gamble on.

in many circuits, a backwards polarity cap will heat up and explode.

It's brand new, turned on for about 10 minutes once...still no good in your opinion?

If the cap still tests OK and shows no visible signs of puffing up it will probably be OK, but I would still use a new one for peace of mind knowing that I won't have to screw with it again.

That's a very good point. I'll pick one up on the way home. Thank you for the help!

Vid, for the two diodes D7 and D8 that you suggest to replace, I don't have 6A4s on hand, but I do have some 3 amp, 400PIV diodes in my spares box. Are these worth it to upgrade, or is the amperage not enough to be a good replacement? It appears that the MR500s were 3 amp, but I would assume you chose 6 amp ones on purpose. Would it not make any sense?

So I finished upgrading my high-voltage supply area with the Great Plains kit (minus replacing the transistors), and it works great: displays are dimmer slightly, as advertised, but it's not a big deal for keeping them alive for much longer. However, I now notice a "twitch" or flicker in the first digit of my 4th player display, as well as a not-as-often flicker in the second digit of the same display. All the others are in perfect order. My question is: does this flicker represent a problem with the display that I didn't notice before simply because it was brighter? Is it possibly a flaky connection somewhere, or does it represent the beginning of the end for that display?

Turned out to be loose wire to terminal contacts on the 4th player harness. All fixed! I'll also get some before and after pics of the display brightness. As you said, it is minimal. I hope to keep my originals and not upgrade to LED, so this is a much welcome upgrade. Thank you for all of your work and help on these forums.

Installed some 6A4s last night...those suckers are huge!

Great post , Thanks again for the guides. I will be fireproofing and bulletproofing my Alien Poker in a few days and im thrilled to getting running proper again.

I installed some 6A4s last night & was thinking how huge they are compared to the originals.

IMG_6699 (resized).JPG

Success on my fireproofing and bulletproofing of the power supply. on to the next task

I'm currently working on a Space Shuttle.
I've done all the recommendations in this thread, except the diode 6A4.
Should I swap out the diodes for the beefy 6A4? If so which ones D3 & D4?
Thanks

Hi Vid. I've followed most of the recommendations in this thread for my Firepower. I added a remote battery holder this afternoon. and suddenly my score displays don't work at all. I re-seated the connectors on the CPU board with no change. They are original displays and prior to not working they looked flawless.

Do you have any hints as to where to start the debug on this? Any help will be appreciated.

Thanks!

Scratch that. its a CPU problem. Both LED 1 and LED 2 are solid. I'm going to re-seat the new 40 pin and see if that fixes it.

Thanks

argh nothing...what have I done?? Broke one of my cardinal rules "if it ain't broke...don't fix it"...stupid stupid stupid...

guess I can turn this into an excuse to buy a scope .

So I sat down with the board and realized I missed changing one of the IC sockets. pulled it out put in a couple of SIPs. Chip back in and voila...working firepower. I really thought I'd screwed the pooch on that one.

I've just split the GI on Blackout.
I have one string with a 10A fuse for the playfield lights, because you can't split those easy.
And two 5A fuses for the backbox insert panel.
The 39 lamps can be split in two strings of 19 and 20 lamps.
The fourth string is the coin door and with 2 lamps it can do with 2A fuse.

Splitting the GI up so as to fuse individual strings is a good idea - it gives better protection and is easier to fault find. You can just run a 5A fuse in each string or if I run leds in a pin I downsize the fuse rating too. A led draws about 20 mA, compared to 250 mA for a type 44 and 125 mA for a type 47 incandescent.

Measuring true load is a pretty good plan as it takes care of different loads due to differing numbers of globes in each string - Inkochnito mention a few post back thata coin door is one string with only a few globes.

Another approach is just to say a led is 20 mA and the 250 mA for a type 44, so just ratio it as 20/250 x 5 A = 400 mA and round up a bit, say 1 A. That's the approach I take with mpu controlled lamps in these games which just originally have one 8 A fuse for all, so I go about 2A for leds.

Fuse tolerances are pretty sloppy so it's not an exact science and in the case of a non controlled ie GI lamp string the most likely scenario is a direct short. In mpu controlled matrix there's chance of a row or col being stuck on.

In general if you underfuse the only consequence is blowing more fuses than necessary, so a few cents wasted. Overfusing can cause far more problems

Many thanks, vid1900 et al. Was experiencing resets on my Alien Poker when firing both flippers simultaneously. Took a little chasing but found the problem and now have a more reliable power supply and eliminated a fire hazard I didn't even know existed.

After re-seating all power connections with no luck, started researching and found this thread. Replaced three Suspect MPU molex connectors, both bridge rectifiers (including fuse install), both big beefy diodes, the 12v capacitor and the 5v regulator. Still no go. Found a rusted/corroded fuse holder on the 12v circuit and replaced it.

Still no go. Only thing left was flipper coil diodes. Clipped one end on each and all tested ok. Went ahead and replaced them since I had to solder on them anyway. Low and behold, new diodes solved it! Can't say if it was a bad diode or a bad joint as the culprit but who cares at this point?

Separate issue - any idea if the double flippers on the right are supposed to be able to flip separately? Mine fire together. Can't press the button half way and get one to fire alone. Is this normal?

Are there two switches on that button? No schematic on ipdb to confirm, but I'd assume so; every other williams game I've played from that era has had stageable flippers

Look at the switch. If it has 2 sets of contacts you can bend/adjust to get them to fire together or apart depending on when the contacts close.