I've done a quick search, and could not find anything about testing outside of the machine. I want to take a spare transformer/rectifier assembly and hook it to an SDB to verify/repair the power supply sections. (I already have a tester for the solenoids and flippers, and have repaired those sections.) My proposal is to feed the power supply with 115VAC at pins A2J2 6 & 7, run a special built cable from A2J3 5, 8, 16, & 17 to SDB A3J3 3, 6, 10 & 12, and run a jumper from the chassis of the transformer/rectifier assembly (A2) to the ground test point on the SDB (A3).
A2J3 - 8 to A3J3 - 12
A2J3 - 16 to A3J3 - 10
A2J3 - 5 to A3J3 - 6
A2J3 - 17 to A3J3 - 3

Once completed, I should be able to test for the 5 VDC and the 190 VDC. Since I have nearly a dozen SDBs to test/repair, I am thinking this would be a lot easier than leaning into a machine. Thoughts?

Jim

The main reason is I want to see if this will work, hence the question in case somebody has already tried this and found out it would not work, or what they had to do to make it work.

As far as the outputs from the transistors and the flipper relay circuit, that has already been done. I built a tester based on Leone B’s article, and added on it so I could completely check out the flipper circuitry.

I do the jumpers as outlined, so the ground and 5 volts are robust.

Since I have so many, to me it’s easier to sit at my work bench instead of hunkering over a machine, and having to awkwardly reach in to do voltage checks. Besides, I have more room at my bench than I do around all the machines. They always seem to get heavier each time I need to move them.

UPDATE: It Works!!

Here's my write up - hopefully, its clear to everyone. If not, please ask for clarification.

First thing was to verify the voltages from the transformer/rectifier assembly was correct. One interesting find was there was a difference of potential between ground on the rectifier board the chassis of about 30 VAC, with very minimal DC. (Brought back memories of discovering the difference between common and ground when working on TVs.) I used a jumper from transformer lug 18 to the chassis. (Another way would be to go from rectifier board E8 or ground to the chassis.) I am using a Rottendog board.

I decided to use a display and a #47 bulbs as a load - I was worried about the power supplies not giving true readings due to no load conditions. For the display, all I was looking for was a glow. The bulb was hooked to the regulated 5 volts.

For the display, I ran a jumper from A3J3 - 8 to Pin 1 on the display, and the return was from display pin 13 to A3J3 - 20.

For the 5 volt load - I ran from A3J3 - 13 to the center of the bulb, and the return side of the bulb went to A3J3 - 19.

For power to the transformer/rectifier assembly - Hot wire to A2J2 - 6, Neutral wire to A2J2 - 7, and ground to A2J2 - 10.

For power to the SDB from the rectifier/transformer assembly:
A2J3 - 8 to A3J3 - 12
A2J3 - 16 to A3J3 - 10
A2J3 - 5 to A3J3 - 6
A2J3 - 17 to A3J3 - 3

I tried this using a known good SDB and I'm looking forward to trying it out on failed boards. I should also add that I used a remote AC on/off switch, hooked to a GFCI. I'm not ashamed to admit I stood back first time I powered it on.

Here's some pics.

DSCN3845 (resized).JPG

DSCN3847 (resized).JPG

DSCN3852 (resized).JPG

Wiz - thanks for the kind words. I made a tester for the rest of the board earlier (See post #249 in Show and Tell Your DIY tools). My next step is to integrate the SDB power so I can test the transistors without using an external power supply, although I doubt I will spend a lot of time on it.

Do you test the complete board with that setup, including powering up the LEDs on the indicator board?