I would check the 2 blue capacitors on the display board first. Looks like they have some smoke damage on them.

The speaker frame is grounded (see green wire in the upper right side of your picture). A metal flashlight body seems most likely to short between the frame of that speaker and the exposed leads on C1 or C2 on that board.

Touching the lead on C2 near the fuse holder would have caused a large amount of current to flow through D4, almost certainly damaging it. The same is true with the lead on C1 damaging D3. I would start with checking those two diodes. Your meter should allow you to test them easily in diode mode. They should measure somewhere around 0.7V forward voltage in one direction, and "open" in the opposite direction. They are also cheap to replace (1N4004 through 1N4007 will work fine).

The troubling thing about high voltage circuits is that once one thing goes bad, it can take out other components. If you find a bad component, either look downstream of that and continue testing, or ask for further guidance. There really aren't many components in the regulated section for the high voltage, so you can probably quickly test everything, or just shotgun components if necessary.

Finally, if you add you location, somebody local might be able to assist. If you are in the bay area of California, I can give you a hand.

Hmm. Some of this sounds suspicious. A reading of "1" might be fine, since some meters use that to indicate an open circuit. This would be the case when testing a reverse biased diode. The forward bias voltages seem wrong, though. A 1N4004 diode should likely have a forward voltage of somewhere between 0.6V and 0.7V. Your "6.4" reading just seems really wrong. The "644" reading may make sense if you didn't notice a "." before the number (so 0.644), or if your meter is showing the voltage in units of millivolts (mV).

The diodes are *really* cheap parts. I would just replace both of them with 1N4007 diodes and see where that gets you. This type of diode is used all over the machine, including on all of the lights and switches in the matrix, so you might as well grab a small pack of them to have on hand.

Ok. Those diode measurements seem reasonable. As I mentioned before, though, "The troubling thing about high voltage circuits is that once one thing goes bad, it can take out other components".

By any chance, can you point out where you believe the flashlight may have touched? Or any better idea of where the smoke came from?

Can you measure the resistance across R52 and R53? Similarly, measure resistance across C1 and C2. That will hopefully narrow down if the issue is on the +100V or -100V side.

There really aren't many components in the high voltage circuit. You should be able to quickly measure most of them in circuit and see if there is anything strange (either open or shorted). I doubt that you meter will be able to correctly measure the zener voltage on D5 and D6, but if either one measures as a dead short, you know that it is bad.
pasted_image (resized).png

Hopefully you didn't kill the UDN6118 or UDN7180. The UDN6118 is still obtainable at a fairly reasonable price, but the UDN7180 is not.