Christian, I tried to track down details of the 1820-0183 and the manuals appear to say it's an RCA item, part number 80170 but I cant find anything with that number anywhere - you are probably on the right track with a CA3082A or similar. My experience in fixing similar faults on the memory boards of the 2116A was that the transistors were often leaky which created stuck bits. Sometimes I had to swap parts around between working and non-working bits to isolate the faulty items and it turned out exact replacements for the bad transistors were still available for purchase. If you're prepared to swap components around on your boards to troubleshoot, you might by lucky and find that the ICs are OK. David Collins -----Original Message----- From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Christian Corti via cctalk Sent: Friday, 27 July 2018 9:14 PM To: cctalk at classiccmp.org Subject: Troubleshooting HP 2116B Ok, so I've got the computer almost running now. I now need to fix both sense amplifier cards. One (0..4k) sometimes reads a one for bit 3 after the machine has warmed up. The other (4..8k) has a stuck one for bit 7. Swapping these cards make the errors move to the other core bank respectively. I have the newer cards, 02116-6298, not the older 02115-6001 The latter has CA3028A used as sense amplifiers. My card uses HP 1820-0183 (metal can IC from RCA). I guess that it is also a CA3028A or maybe a CA3053. Can anyone confirm this? Next, the manual on bitsavers (02116-9153_2116B_Vol2_Oct70, and the same as found on the hpmuseum site) not only contains some errors (see my other post about the front panel lamps). It has also some badly scanned pages with parts missing, notably page 5-50 (PDF page 350) lacks the right part of the page. Is there a better scan available? My 1968 copy does not list the 02116-6298. Christian