Just homemade opto-isolators. Used in choppers, too. The transistor was
indeed bonded to the heatsink. Just replace the whole thing with a
3-legged regulator? or simply a modern PNP t0-220 with a little heat
sink on it.
73, Don
On 2016-11-06 15:15, paul swed wrote:
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
all.
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.
Regards
Paul
WB8TSL
On Sun, Nov 6, 2016 at 1:59 PM, Adrian Godwin <[email protected]>
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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--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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