HP 71b repair advice - won't power on with batteries or on AC adaptor

[KimH]

If you had been in Germany, I would have said "come on over and let's look at it" - but that's obviously not an option...

You can find the repair manual with the link below, that should help you with how to open and peek inside. Some electronics experience is required if you want to repair!

AND a Torx 6, don't try without!!

Documentation

I have repaired a few of these after corrosion - Battery-Leak - and it can be very tricky.

You can have anything from Copper traces being corroded to oblivion or the ZEBRA which connect top and bottom on the Plastic-Back model - and many more, peeking should give you some hints.

The ZEBRA can be replaced with soldering short wires from top to bottom "clam", if you are good with an iron and have the kit to solder "thin" wires on small pads.

If you like you can drop a photo of what you find here on HPMUSEUM and there will surely be some commentary from the 71B experts on this forum

(06-07-2021 06:19 AM)dmh Wrote:  I have 2 plastic backed 71b units with battery terminal corrosion and breakage, one bad and one worse. They won't power on with batteries and I was hoping they would work on the AC adaptor but no go with that either (I tested a working 71b without batteries on the same adaptor so the adaptor is fine).

Other than the battery terminal corrosion they look in reasonable condition and keyboards feel ok.

I haven't been able to locate much information on what to look for or try in this situation (I found some reset articles but the problem unit in these was powering up but freezing and mine don't power up at all).

How hard is it to take the 71b (plastic back) apart and then are there any easy test/fix points?

Could it just be the AC adaptor connection is corroded too or is it more likely to have damaged something else first?

Has anyone had much luck repairing the 71b?

TIA, dmh