Have had this item for years and finally figured out what it is good for. Repair Log: Shadow Dancer Sega System 18 PCB Problem 1: Bad sprites in player and other screen objects Reseated Rom board: No change Checked all roms: Matched mame Probed around with logic probe and didn't see anything odd. Saw a clutch hitter on ebay for cheap so picked it up to do some comparisons with as I didn't have any System 18 in my stocks. Tried rom board on CH board. No sprite problems. Went back to original board and still had corruption. Started looking at the board closer, and found a nick in the traces. jumped 4 traces with Kynar wire. Problem solved Problem 2: No sound No sounds at all, but the CPU seemed to be running. Sounds fine if putting the rom board on the CH main. Verified the CPU to be good and the Sound PAL was also good. Started probing around the 74LS244 & 245 and found pin 5 on IC276 ('244) was looking bad. Grabbed my HP Logic comparator and clipped it on. Hit test and Pin 5 bad. As there are no schematics for the System 18 I did some continuity checking to try to figure out where that pin goes, found it goes to pin 2 on the sound PAL. And up to the interconnect for the Rom board. But due to a slipped probe I noticed something else. I was also getting continuity at GND (about 175ohm). And at the +5 rail (3 ohms). Bad 244, shorted internally so I clipped pin 5 and checked continuity again for GND and +5. Same thing. BUGGER. With the trace damage I had seen I thought there was probably a pin touching a trace somewhere. But after more than an hour with a tiny screwdriver and a magnifier I wasn't any better. Did some YouTube research on tracking down shorts. Really didn't like the idea of dropping a few amps down the +5 rail grounded through the pal pin to try and find something warm. I don't have a milliohm meter and they run a couple hundred $. I do have an ESR meter which is a small resistance meter but it wasn't high enough resolution to find it by probing around the board. Found a video on the HP 547A current tracer and using it to track down shorts: https://www.youtube.com/watch?v=Verow5aGL0w I just so happen to have one of these I bought off ebay years ago thinking it might be useful in tracking down vector board problems. But I have never taken it out of the box to date. Ran my logic pulsar output into the +5 rail with the ground of it tied to the sound pal pin 2. Then I was able to adjust the light on the 547A to just showing when touching that pin. Started tracing around the board and picked up the signal near the connector to the rom board. Ran along that area until I found a trace it was running up and followed it a couple inches then BOOM no more signal. There was a chip pin leg right the spot it vanished. Used my little screw driver to lift the pin and no more signal on the trace I was following and nothing at the pal pin 2. Put the rom board back on and sound fixed. Total cost of repair: < $.50 in kynar wire (not counting the Clutch Hitter PCB which I will keep as a ref board for the future) Total time spent: about 4 hours _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/