I replaced a very grotty looking rectifier board on my Bally Star Trek because after replacing most molex connectors at J1 - J3, I could not get Playfield GI to work consistently. I took great care to hook all wires up correctly. I'm getting 177 volts at Test Point 2, 12,6 v at TP3, 7,4 AC at TP4 and 43V at TP 5, but ZERO V at TP 1. The fuses are good.

I took the transformer out of the game and checked continuity from all wires I'd soldered [E1 to E12] to the transformer lugs from the front of the board. All tested good.

I stared a game: it boots fine and plays ok. In fact everything works except the controlled lamps on the playfield. (Which worked find before I installed the repro board).

Where should I look?

All hints appreciated.

Thanks so much. I’ll try that.

First, I cut the zip ties on the wire bundles and really checked that the wires are going to the correct transformer lugs as stated in the schematics. They do.

I have three questions:

1. With ONLY J2 plugged in and game on I tested AC voltage at E9. This was only 4.6v. Is that within reasonable limits?

2. I also tested DV voltage at E10. Here I got 3.3 V. Again this seems to be very low. Too low?

3. I'm testing voltage at the test points with ONLY J2 connected. Do I need to connect J1 or J3 to get a reading at Test Point 1

All hints / advice / help appreciated.

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I only reconnected wiring to the rectifier board.

Is it conceivable that this board is not compatible with this game?

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I am indeed not an expert at soldering. I have done some Google research and I see I have probably created some cold solder joints.

Should I disconnect wires and then resolder them correctly or heat up each soldered point and add a little more solder?

If I disconnect the wire at lug 13 and measure from lug 13 to ground, Will that tell me if I’m getting the correct AC voltage from that lug?

Thanks.

From lug 13 to 14 I get about 8v AC.

From Test Point 1 to ground I get no reading.

Perhaps the new rectifier board is the problem.

What should I test next?

Thanks!

I Put red probe on + leg of BR and black probe on - . Got 6 VDC.

Got 8.2 VAC across the other two legs.

Transformer assembly is not screwed in.

The ground braid on the head is firmly connected to the head.

The mystery is: why no DC at Test Point 1...???

Thanks.

„you will have to physically trace from the rectifier positive output to TP1.“

This I am trying to do. It‘s very difficult as you can‘t see most of the traces on this board. The circuit isn‘t interrupted from + of the BR to R2. I can‘t work out where it goes from the other end of R2.

TP1 is definitely the 5v test point. I have no schematic, but a fellow pinhead took a good look at a photo of the board on the vendor‘s website. There are also traces going from the + leg of the BR to J1 and Test Point 1 on the front side of the board, so he recommended desoldering and then resoldering that leg, which I will do.

Yay! Problem solved.

A smarter man than I suggested the break in continuity was between the + of BR1 and the traces on the top of the board. I reflowed the solder there (also on the back) and I got 6VDC at TP1. I hooked up J1 and J3 and the playfield lamps work. In fact everything works Many thanks for all the useful hints.

My learnings:

Completely remove the transformer from the cab head to connect a new rectifier board.
Buy a proper board holder.
Label the wires. Some of those shades of green and blue look awfully similar.
Although this generation of pins is very well documented, I have to accept my limitations. I'm not an electrician and sometimes you should ask for help sooner.
Don't rule out an unlikely solution: in this case that a new repro-board had a break in continuity.

And the final learning: as there are no local pin-technicians where I live, I am going to only buy Bally EEs in future in order to build up my own expertise and not get on your nerves so much.

Thanks again

That‘s a good idea. Will do.