HP-55
Message #1 Posted by Howard on 18 Aug 2003, 8:28 a.m.
A couple of months ago I wrote to this forum about the problems I am having with my HP-55.
It works OK in Timer and Run modes but will not programme. It gives " -15" for every key that is pressed except for when "GTO 0, 1, 2, 3, or 4".
The general consensus of opinion was that the main memory chip is shot.
Anyway I've got hold of another HP-55 for parts and I am looking to see if it is feasible to take out the main memory chip from it. I thought of changing over the whole board but it does not appear be working.
My first problem is that there are eight chips.
Can anybody point me to the right chip?
Or better still, Does anybody fix these calculators?
Thank you in advance.
| 
Go back to the main exhibit hall