Re: Help restoring a 547 scope


felix_cantor@...
 

On Tue, Jan 30, 2018 at 02:42 pm, Albert Otten wrote:


Hi Felix,
What is the state of the holf-off multivibrator V145A/B? When the
multivibrator hangs in the hold-off state then the top of D85 is pulled down
and D85 doesn't get enough bias current to have it triggered by a switch of
D45 (to D45's high state). So what is the cathode voltage of V145A, about +2 V
or about -20 V (= hold-off state)?
Albert
Hi Albert,

ok, here are the measurements:


V145A

Plate (pin1): 85V
Grid (2): 0.4V
Cathode (3): 1.3V

V145B

Plate (6): 103V
Grid (7): -18V
Cathode (8): 0.76V

Thanks!

F.

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