Repairing the Globetrotters Power Board - stage 1

The Globetrotters power board is in bad shape. Scorch marks, burned components, missing pieces, etc.

However, the good news is that I can easily buy a replacement, so..... that makes it a perfect candidate for my first board reconstruction!

If you recall from the last entry, this is how the unit started.

Separating the board meant unsoldering each one of the wires:

But at last, I had it separated!

Unfortunately, my soldering skills are still not quite as good as they should be. But in my defense, removing the big Bridge Rectifiers (essentially big square boxes soldered to the board) is hard. All 4 contacts have to be heated simultaneously while the board is held in the second hand and the rectifier is extracted with the 3rd hand.

Anyway, as you can see, I managed to remove the little metal slots and pads where the solder wen through the board:

I still have the big connectors to remove and I need to check the resistors and diodes to see how they look, but I can't do that while they are under a layer of dirt and grime......so, into the bath they went!

After 1/2 hour in concentrated soap and with a light scrubbing from a delicate paint brush, the board looks much better:

Next step, remove the rest of the components I plan to replace (multi-pin connector and the fuse holders) then brush with a tougher brush (toothbrush)

Pulling the Globetrotters Rectifier Board

After my failure to get any power on the Harlem Globetrotters pinball, it was time to pull the power board out and take a look at it.

Step 1 was trying to get the large connector off. It had 40 years of accumulated rust and grit in it, took quite a bit of finesse to get it off without breaking anything.

I then started trying to pull the board off the nylon spacers but it would not budge.

That's when I noticed the the screws on the board went all the way through and out the back of the mounting plate

So there was nothing to do but pull the whole transformer and board off all in one piece. First the transformer shield came off - making me nervous - isn't there lethal voltage in those things?

I VERY carefully unscrewed and removed the unit, taking care not to touch the transformer at all

Then finally i was able to see the rectifier board up close. It definitely shows scorch marks. Looks like it is time to purchase some electronic parts!

First work on Harlem Globetrotters

After the move of the pinball tables, when I discovered that I was missing a circuit board in my Harlem Globetrotters table. I decided to purchase a replacement. The nice folks at Alltek make a replacement board, so I ordered one. It arrived today!

But - before installing it.....I read the manual!   and it said to make sure that the 5v power was correct so that I did not burn out my brand new board.

So I plugged the table in, turned it on and connected up my trusty multi-meter:

I got nothing... no voltage, no lights, no hum, no nothing.

At first I thought I had a blown fuse, but after looking at them, the fuses are all ok.

However, while looking closer at the fuses, I noticed my power board does not look too good:

There are a couple of burned looking spots. One big on up near the top that looks like something might be missing and another one down by the connector.

I unplugged everything, looks like it is time to do some power board checking!