|HP 19C continuing saga...pictures!!!|
Message #1 Posted by Geoff Quickfall on 27 July 2011, 8:05 p.m.
One simple question.
I spent an hour working on this calculator mechanically removing the cemented blue corrosion. I used a dental pick and fiberglass brush. Ethanol and a natural bristled paint brush to rinse with.
What can I soak this in to dissolve the blue corrosion.
Now to the calculator. I purchased this one for parts for the ACT chip and swap to the 19C from this post:
The other 19C
The calculator was missing the LED red plastic lens and the calc was described as non-working, with original battery pack. So I had no illusions that it would function. Wasn't cheap (100USd) but I can justify as it is for the book.
Here is a top view with the missing lens:
For the heck of it, I removed the battery pack (not bad) and cleaned the minor dusting of white powder off the contacts. Then attached an alternate battery pack with clips to the appropriate contacts.
It not only lit up but PRX printed the display. All 98 program registers and functions were perfect!! So now the "Other calculator" is to be the donor.
Started to disassemble and was met by this internal label:
Investigating further; HOLY COW look at the before pictures and you tell me if it should have lit up!!!!
Even the two capacitors at the battery contact PCA were delaminated and rotting. I actually thought there were three caps on this board:
So time to clean up.
On these two photos most of the contaminant was removed and unfortunately a trace was missing a section after cleaning. Corroded through for a 1cm section. This was bridged by a black wire seen below.
I used the donor with two good caps to replace the two bad caps (but functioning):
So now here it is with the donor lens in place and back to the first question. What does one use to dissolve the blue (vinegar bath?).
THE CL is AWESOME! it is the only calculator I use now! Unsolicited advertising for the CL.
Edited: 27 July 2011, 8:06 p.m.