Troubleshooting HP 2116B

Christian Corti cc at
Fri Jul 27 06:14:26 CDT 2018

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 

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.


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