Is this a crowbar scr on the 15 volt supply? If so, you might read the first note at this site. http://www.ko4bb.com/manuals/index.php?dir=HP_Agilent/HP_1980A_B The 100 volt part should be fine. Regards, Tom ----- Original Message ----- From: "Andrew Welburn" <andy@andysarcade.net> To: "Technical Tools Mail List" <techtoolslist@flippers.com> Sent: Tuesday, June 04, 2013 2:18 PM Subject: [Techtoolslist] HP 1980b replacement thyristor... hi all.. I have a HP 1980b oscilloscope that has a shorted thyristor, marked 1884-0217.. after looking online and getting two quotes for a replacement ($777.77 and $600 each!) i decided to hunt a replacement. I managed to pick up a service manual for this thing, and helpfully HP lists the 1884-0217 with a manufacturer number of MAC10-2 I can't find any of those either just yet, but wondered if a replacement MAC10-3 might be ok as i can get one of those.. http://www.datasheetarchive.com/MAC10-2-datasheet.html The MAC10-2 has a maximum repetitve peak voltage of 50v, the MAC10-3 is 100v... Its used in the LVPS (pcb A1 refdes A1Q2), would having a higher maximum repetitve peak voltage cause problems when replacing a Triac/Thyristor? any advice appreciated! -- Andrew Welburn http://www.andys-arcade.com _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com http://seven.pairlist.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment 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://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/