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HP41CV freezes after a couple of seconds - Printable Version

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HP41CV freezes after a couple of seconds - Adalin - 04-23-2017 09:13 PM


I have a HP41CV that shows some strange error, after I press ON the calculator boots and shows memory lost, then it works for a few seconds before the display freezes and it stops responding to keystrokes

I need to remove the battery and short the terminals for it to boot again but it does the same after that.

The CPU board is of this design, I borrowed the picture from an old thread here at the forum
[Image: hp41cv1981.jpg]

When I got the calculator it did not boot at all and it was drawing a lot of current.
I suspected that the big capacitor was the problem and it was indeed shorted.
I replaced both the silver capacitors and then the calculator at least booted, but now has the problem I wrote about in the beginning.

has anyone had a freezing HP41 before? and what was/is the problem?

My suspicion is that its a memory chip problem