HP82002A replacement capacitor

[teenix]

(05-15-2020 11:36 PM)EricBlair Wrote:  I'm attempting to repair my original HP8002A charger that came with my HP45. From what I read, it is very likely that the 400uF/15V capacitor has failed. Can anyone point me to where I can buy a replacement capacitor? The size of the replacement is critical since there's very limited space on the circuit board. Also, I'm concerned that the area of circuit board under the four parallel 1/4 resistors/diodes/capacitors shows evidence of heating. That is, the circuit board is darkened. Any idea if other components need to be replaced in addition to the electrolytic?

Look for a 470uF 25V RB electrolytic capacitor. It will almost certainly fit, but most larger component suppliers have data sheets for a lot of their component inventories so you can check this for certainty.

Try replacing the capacitor and charge the battery, with the case top in place but not fastened with the screws.

After half an hour or so, make sure you remove the mains plug, take off the cover and check how hot the components are. In general terms, I would expect to feel some warmth on the transformer and components, and maybe even a bit warmer than you think is ok, but this is reasonable. As long as they are not overly hot to the touch, they should be fine. I don't have a charger, but from memory I think the case got quite warm during charging. Over many years of use, the circuit board could have discoloured.

If the charger has a mains 110V and 230V switch it could have accidently been in the 230V position when connected to a 110V mains supply which would have caused a higher current than normal and excessive heat.

cheers

Tony