|Early HP-41C PCA picture as well as memory problem... |
Message #1 Posted by Geoff Quickfall on 3 Aug 2009, 8:06 p.m.
HP-41C 7931Axxxxx tall keys with ac contact balls and all the bugs! Just one problem:
Setting size equals zero results in program memory totalling 47 instead of 63. Obviously one of the D/S chips is shot as each chip is 16 56-bit registers. Which one though? All programs function in the allotted memory. The machine acts normally except 47 registers instead of 63. Since the curtain moves between program memory-registers and machine memory could it be the last D/S chip that is unserviceable?
Here is a shot of the PCA with the defunct D/S chip. Since I do not have a service module (anyone out there willing to throw one at me for free ;-) am I correct in my assumptions that:
a. it is the last 16 bit D/S chip (63-47=16)that is shot and
b. it is chip marked E in the figure below.
Note the hex nuts that hold this in place!
Here are some off topic pictures of the card reader internals going into the manual. Just trying to pique your interest.
By the way, what is the correct term for the wire connectors pictured in the second and third pictures below, I think the term starts with a Z (zygat)?
Edited: 3 Aug 2009, 8:13 p.m.