[time-nuts] HP 5275A

paul swed paulswedb at gmail.com
Sun Nov 6 17:15:39 EST 2016

Don't know what to say on the transistor. It may have been actually made
that way. They did lots of things back then. Yes familiar with the bcd
decoder its used in the 5245 class counters also. I think someone was doing
some funny stuff at lunch time to come up with that. It was the 60's after
How about some pix of a 9815 calc. That would be pretty neat.
On really old stuff if you can't find the part needed its pretty easy to
replace the whole function with modern answers. I know it sort of breaks
the original mode but for me at least its a case of getting it going.

On Sun, Nov 6, 2016 at 1:59 PM, Adrian Godwin <artgodwin at gmail.com> wrote:

> Slightly off-topic, as this is a general repair question. But it's a TIC.
> I'm repairing a 5275A timer (all-discreet count logic to 100MHz, neon bulb
> display, a most amazing bcd to decimal decoder made from neons and LDRs,
> 1-2-2-4 decade counters ..) and the current problem is a 2n1038-2 germanium
> T05 transistor in the power supply.
> It's mounted in an aluminium bush which is then isolated from the chassis.
> I don't think the bush is also a collet but I can't see how to remove the
> transistor. It resists ungentle pushing .. should I push it with a hammer ?
> Or is there a kinder way ?
> (I'm hoping to eventually put this into a system with a 101A oscillator and
> a 9815A calculator to measure the ADEV of a Boule electric pendulum clock).
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