Thank you, appreciate all the help so far.

Well the game boards appear to be dead (which isn't a surprise) - and fault finding there isn't going to happen with my level of expertise lol.. still waiting for new working set to arrive.

Thanks for the reply - it's connected to 115.

Hope I'm not irritating anyone asking so many questions - but yeah.. I have another.

Today I used the Kit Bob Roberts supplies to rebuild the 90411 PSU board.. and two "trimmer pots" were part replaced in the process (not sure why the third wasn't included. I tested the PSU and was pleased to say that not only did it fail to blow-up but it also seemed to yield the approximate correct voltages.

Readings I'm getting from the PSU (that would go to game boards) are:

On the -5 I'm getting -5.73
On the +12 I'm getting +12.23
On the +5 I'm getting +4.95
On the other +5 I'm getting +4.95

Q1. How close to -5, +5 and +12 should I be.. is slightly over better than under or dead on?
Q2. Also there is a yellow ground cable coming from the AC filter.. it's going nowhere but looks like it's supposed to be attached to something - I can't find any info on what though (maybe the game board cage?)



From the manual it looks like that GND cable attaches somewhere behind the game cage (to the right) - likely?

Uh-oh, a couple more questions.. before I replace caps etc. on the PSU PCB - and risk a known working gameboard set

I'm wondering if one of the transformers needs replacing (the one leading to the game boards - the "MT87").

As you can see in the following picture the posts are rated at (my readings to the right):

14.5 - reads at ~15.0
9 - reads at ~10.5
0
14.5 - reads at ~11.63
0
12 -reads at ~12.96

Q1: Are these readings reasonable/okay? (using a cheap multimeter atm -Innova 3320).
Q2: Are the two 0 posts interchangeable when taking readings?.. I'm guessing not
Q3: In the last picture down below you can see what it looks like, would this be considered in bad shape - or does visual appearance mean little with these?



The schematic shows:



Top view of the MT87 (looks a little rough - what do you think?):



Thanks for your patience

Yup, no big issue.

Awaiting parts now

Thanks for your reply but isn't there something to be said for the long-term reliability of a modern switching PSU?  I mean I have a set of replacement cards coming shortly (just incase) for the game logic - but obviously I can't keep replacing these boards

Or do I just need to go about replacing the caps on the PSU every few years (I'm assuming these are the cause of the unstable power readings)?

Hi, I have bought a Wizard of Wor upright (my first) cabinet that was sold as not working and would really like to restore this (having played the C64 conversion to death in the early 80's).

The voltages coming from the PSU PCB seem to be fluctuating wildly and the large 20000 mF cap appears to be leaking, I appreciate that the game boards and other parts may have been damaged (I will deal with this later).

My first question of what will probably be many is what is the opinion of people here - should I buy a repair kit to restore the original PSU board, or go via a modern Switching PSU and Midway adapter?  And which would be less likely to damage future game boards? - which is my main concern.