[time-nuts] HP 105B Battery the saga continues

Scott McGrath scmcgrath at gmail.com
Sun Sep 18 07:33:58 EDT 2016

That NiCad pack is part of the power supply and as Jeremy points out is part of the filter system.    And so one needs to restore it as part of the instrument as even the 28V external power supply floats these cells and trips power interruption indicator if lost

Power supply is not terribly hard to fix and the small signal transistors can be replaced with  2N 2222,3904 and 3906'es depending on rating.  You don't even need a extender a Huntron tracker or similar current limited lissajous bridge will identify failed or leaky caps and semiconductors 

Remember HP did nothing without a good engineering reason and that plate is there for RF shielding to prevent stray sources coupling with the outputs

If a proper rebuild is too expensive I'd suggest selling it on the well known auction site rather than hacking it up as 105's have been selling in the hundreds regardless of condition 

> On Sep 17, 2016, at 10:16 PM, Jeremy Nichols <jn6wfo at gmail.com> wrote:
> How did you come up with the 33,000 uF number, Perry, and is it one big capacitor or lots of little ones tied together? The big cap will also filter out some of the remaining ripple in the power supply that may have been managed by the ni-cad battery.
> Jeremy
>> On 9/17/2016 3:50 PM, Perry Sandeen via time-nuts wrote:
>> <snip>
>>  Where the nicad pack was located one can put in 33,000 uF of Nichicon 105C caps for $20 for a buffer hold over. <snip>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list