Yep, measure between tp1 & tp3 and between tp2 & tp3. You may have a blown fuse if either voltages are missing. If fuse continues blowing, may need to rebuild or repair high voltage section on power supply.

A helpful tip: never ever plug or unplug a display with the game turned on! It will do lots of damage to the display and mpu. Also, *be careful*--the displays use high voltage! Proceed with caution and you'll be fine. If you have any questions, ask away. There's lots of helpful folks here

Sounds like it. Have you checked voltages at the power supply board? That's the board in the lower right region of the backbox.

If you haven't already, i would highly recommend checking every fuse installed in the game. Not just to be sure they're good, but more importantly to make sure they're the correct *rating* and *type* (slow or fast blow). It's very common for the incorrect fuses to be installed and you likely won't know until it's too late. Take a few minutes to verify all that stuff for your safety and proper protection for the game's circuitry as well. If all fuses are correctly rated and check good, verify voltages on the power supply board, there are usually test points on there as well. I might be telling you stuff you already know, but safety is key when working on these games.

I gotcha. I'll look over the schematic and see where you can test voltages. Do you have a copy of the schematic? If not you can download a copy here: https://www.ipdb.org/files/789/Bally_1988_Escape_from_the_Lost_World_Operating_Parts_Manual.pdf

Ok, so for the ac tests, there's two ac test points at 6 & 7 and another pair at 8 & 9. I don't think either of those are for the high voltage though. Either way, I'm pretty sure you can set your meter to ac and put a probe on either pair to check them. For now though, what voltages are you getting from the test points at the high voltage section of the power supply board?

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Yeah, i actually cropped that pic i posted from the same power supply pic you just posted

I just zoomed in on that section to focus on the high voltage test points, but we're talking about the same board.

I believe you should be able to test ac volts between those 2 pairs of test points. (2 at lower left, 2 at upper right)

Actually, my method is probably incorrect then--it's probably adding the 2 11vac circuits making 22

Try one probe on the ground test point, one probe on either ac test point with meter set to ac volts and see what it reads.

Ok, cool--do you have the correct dc voltages at those 2 test points in the high voltage section i posted the pic of above? 230 + 180vdc?

If voltages are good there, but not at the display then i would imagine it could be a connector issue. The link for the manual in one of my above posts should have all the schematics, the connector info and pin outs should be somewhere in there.

That's what i would do next. Connector J4, pin 9 on the power supply board should have 190 vdc. Red probe on connector pin, black lead on ground strap.

Yeah, looks like you're closer to the problem now. Have you tried reflowing the solder for the header pins at J4?

Yep, should be 190 solid as far as i know. Def reflow the solder on the headers for j4 on the power supply if they haven't already been done...with any luck that might be where the problem is. Does the voltage fluctuate even with the display unplugged?

Nice!!! Good work! Glad to be of assistance