82002A Battery Charger voltages - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: 82002A Battery Charger voltages (/thread-70108.html) |
82002A Battery Charger voltages - Pyerre - 03-05-2005 Hello,
My Battery Charger AC Adapter has following output voltages
The HP35 calculator works just fine in standalone with its battery pack. Re: 82002A Battery Charger voltages - Tony Duell - 03-07-2005 I am pretty sure you can download an ascii-art schematic for The 35 should run off the charger even without a battery pack (the 2 outputs from the charger are a constant-voltage supply, supposidly 4.2V, for the logic, and a constant current supply to charge the battery. The battery is disconnected from the logic when you connect the charger).
Most likely the output from your charger has excessive ripple. The voltage looks fine, but you'd not see ripple on a voltmeter. Again most likely the 400uF electrolytic capacitor on the charger PCB has dried up. Try replacing it (a 470uF is fine).
Re: 82002A Battery Charger voltages - Pyerre - 03-07-2005 Many thanks for your advices. Re: 82002A Battery Charger voltages - Tony Duell - 03-08-2005 Have you checked the output voltage and ripple when it's connected to the calculator (turned of, of course)?
Have you got the schematics yet?
Re: 82002A Battery Charger voltages - Pyerre - 03-08-2005 With the adapter connected, the output voltages at the battery contacts are about +5.0vdc, ripple ~6.0mVac anh remains unchanged even turn the calculator on.
I've got your (HP82011) schematics here : and beleive it's the same for the 82002A.
Many Thanks,
Re: 82002A Battery Charger voltages - Tony Duell - 03-09-2005 Does it behave in the same way if you plug the charger into the calculator _without a battery pack installed_ (it is quite safe to do this on a 35, I have read the schematics..)
Have you checked the various voltages inside the calculator when the charger is connected? At least Vbsw at the logic-to-keyboard connector and the Vss and Vgg lines on the testpoints?
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