HP-67 wall charger

[Wytnucls]

I am looking for parts to fix a HP-67 charger.
There is conflicting information on the rating of the Zener diode inside the charger. I have seen 4.7V and 5.1V mentioned. Does anybody know which one is correct?

Also, transistors were made by HP and are now difficult to obtain. Are there modern equivalent parts to PNP1853-0015,PNP1853-0338 and NPN1854-0581?

[Ignazio Cara (Italy)]

Hi,
for more info about the HP classic charger HP-82002A, take a look at this link.

HTH

Ignazio

[Dan W]

That is a very good page on the charger. We decided after some experimentation a 5.1V works best. Some of the discussion is here:

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