[time-nuts] HP-105B Battery

[Brooke Clarke]

Hi Joe:

I got a good deal on a Gibbs  rack mount frequency standard because the oven was not working.  This was a double oven 
system and used a Bliley 5 MHz glass tube crystal.
It turns out that having a lead acid battery anywhere near heat (like a crystal oven) is a very bad idea since the acid 
fumes will literally eat the traces off printed circuit boards.
This is probably a potential problem for any battery chemistry that can vent acid fumes.

You might want to remote locate those SLA (Gell cell or whatever name) batteries, i.e get them out of the same box that 
contains the crystal oven.
https://prc68.com/I/office_equip.html#Gibbs

-- 
Have Fun,

Brooke Clarke
https://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.

-------- Original Message --------
> Hello Roy,
>
> I replaced the original batteries with two 12 Volt 3.3 Ah SLA batteries and a
> string of diodes between the batteries to compensate for the different battery
> voltages.
>
> This is not perfect, but it works for about 3 years before the batteries need
> replacing.  I used 7 1N4004 diodes in series to prevent overcharge and a
> MBRF1045 diode across the diode string to allow discharge.  The SLA batteries
> float at 13.7 volts each.
>
> Be careful to not let the metal battery box touch and short the meter terminals.
>   I used some of the original battery box plastic strips between the now loose
> battery box and the meter.
>
> Best,
> Joe, W7LUX
>
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