Well, not that I need one very often - the Fluke 9010A finds 99% of the problems - but right now I have a headache with a Williams F-14 pinball MPU that refuses to produce speech. According to the 9010A everything seems just fine, I can access the PIA, ROM signatures are correct (paged ROM, but pages seem to work correctly). There really is very little hardware - two Eproms, a 6802, 2106 RAM, some logic glue, and a 6821 PIA, but it won't run the speech data. Using my audio probe I don't even get the sounds on D0 so I know the problem is actually before the 6821. Audio probes are fun to use for troubleshooting digital audio as you can even hear the sounds on the logic data bus - weak and fuzzy, but clearly the sounds you are looking for. So, I figure I'd dig up one of my ancient logic analyzers that I bought around 2002 figuring I'd use them some day. Two Arium ML4100s (one deader) and an Arium ML4400. However, can I find them? No. We moved the shop after 35 years last May and my helpful staff buried two of the three Ariums somewhere in the 6,000 sq ft shop...the only one I could find was a dead ML4100. So, now I figure I'd see what was online for modern LAs and there are some interesting 16 bit units including a few from China that should work on the SIGROK software. http://www.qdkingst.com/en The point of this ramble? A question - anyone here using one of these modern inexpensive LAs (or another brand) and cares to tell us your experiences? I guess the other point is, has anyone troubleshot a Williams sound/speech section and can tell me what I have overlooked? I do know (substitution) that RAM/ROM/CPU/PIAs are all good, have replaced the glue chips, but really, they changed state correctly for the Fluke as well as my logic comparator. There is some corrosion on the board, but suspect sockets replaced and while I did have a short from R/W to another line, I did track that down and fix it. All sounds EXCEPT speech work just fine. Gah! Frigging FM. Thanks, John :-#)# -- How to subscribe or unsubscribe from TTL http://seven.pairlist.net/mailman/listinfo/techtoolslist _______________________________________________ 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/