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HP48SX LCD problem... - Printable Version

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HP48SX LCD problem... - Geoff Quickfall - 08-15-2009

I picked up a completely non functional 48SX about 5 months ago hoping it would be the deteriorated contact foam under the keyboard flex ribbon. That is the foam which holds the the keyboard flex ribbon agains the logic PCA contacts.

It was, and after disassembly, a thorough cleaning of all contacts, including the LCD zebra connectors and a new foam inser the calculator worked perfectly. In fact I removed the connectors, cleaned them, ensured no dust on the PCA contacts or connectors, and then reassembled the calculator.

I put the calculator away without batteries for 4 months. Today I picked it up, installed the batteries (using this example for Chapter 13, Stretch Pioneers) and it now powers up with a vertical line to the extreme right of the display.

Today in an effort to remove the line I have:

1  disassembled and cleaned all contacts again!
2 reset with the reset under the foot.
3 reset with batteries out and reset under the foot.
3 tried all the diagnostics, it passes!

The line is still there! Any ideas?

I found the following link which may explain the problem, alas, not fixable:

HP48SX display problem

My serial number is 3147Sxxxxx

Cheers, Geoff

Edited: 15 Aug 2009, 5:20 p.m.

Re: HP48SX LCD problem... - Quan - 08-15-2009

Since it was OK before you stored it, I would suggest taking a closer look at the contacts on the connector and the display under a magnifier.

Or the display becomes defective?

Re: HP48SX LCD problem... - NACHO - 08-15-2009

Have you tested it with another 48LCD?

I replaced a faulty LCD in a 48S with a 49G LCD and it works perfect. (Black LCD ).

I installed the faulty LCD in the 49G and it still is faulty.


Thanks Quan and nacho - Geoff Quickfall - 08-15-2009

Yes, have checked the connector strips, LCD panel and contact points on the logic PCA. I actually cleaned them again!

Every thing looks good.

The idea of swapping with a good LCD panel on the 49G never ocurred to me so thanks for that.

At the moment the location of the line is not affecting the display but it is annoying.

So I will look out for a bad 49G (as is not working) for a spare LCD replacement.

Cheers, Geoff

Re: Thanks Quan and nacho - NACHO - 08-16-2009

moment when I swaped 2 displays.