Thanks Clay, Much appreciated (you coming to the show in 2 weeks?) Barry

Been working on the units and I am finally getting somewhere. - I blew U1 on the Display board.  Anyone know what chip this is?  (its the large 40-pin chip)  Marking: P8041A 1210 8423 535419 Intel '77 I confirmed that this was the issue by swapping it out between the displays.

Intel 8041 microcontroller... It's a mask ROM part, IIRC (I think the 8741 was an EPROM version). It's similar to the 8048, both of which were predecessors to the ubiquitous 8051... (MCS-51 family vs. the MCS-48 family) Unless someone has managed to extract the code and you can locate an 8741 to program it on to, you're probably stuck with just swapping in one from another unit. (At some point, maybe getting that particular MCU decapped to preserve the ROM would be a good idea...)

Display 2: - 10th character sometimes disappears, sometimes is faded, sometimes is fine.  I traced that this is controlled by U4 (pin 11) and U8 (pins 2 & 17).  I can replace both, but which is the most likely problem?  Anyone know where I can get U8 (UDN6118A) chips?

Allegro and Sprague used to make those... You could steal some off of an old Williams pinball VFD driver board, or just type "UDN6118" in on eBay and there will be some there. -Clay _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist FTP site is: ftp://ftp.flippers.com/TTL/TestEquipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/ _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist FTP site is: ftp://ftp.flippers.com/TTL/TestEquipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/