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HP 21 not powering on - repair/troubleshooting advice
01-27-2021, 07:31 AM
Post: #6
RE: HP 21 not powering on - repair/troubleshooting advice
(01-26-2021 10:13 PM)dmh Wrote:  Hi,
I received a collection of HP calculators recently including 3 x HP 21.....

I received some HP 25 in the same lot which all work

lucky man.... Smile

Have you verified that the circuit and the components are not dirty, I mean traces of acid leakage from batteries? The problem could be due to the presence of bad/wrong contacts due to dirt, Usually the first thing I do with a sleeping woodstock is a bath in a solution of water and vinegar, then letting dry well several hours, often it helps. Try this this, please if you haven't already done it!
Regards
Aurelio
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RE: HP 21 not powering on - repair/troubleshooting advice - aurelio - 01-27-2021 07:31 AM



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