Re: 577 D2 question(s)


Andy tubes are really available for the 577 d2 they can be salvaged from
one of the 5000 series scopes. If I remember correctly the 5220 is the one
you want to find. It is a direct drop in replacement I can confirm the
scope later today of need be.


On Wed, May 5, 2021, 11:05 AM Andy Warner <> wrote:

Thanks all,
I was hoping it would not be the tube, I have been lucky enough to
avoid that on my other Tek gear.
I'll take a pass at the HV board first, but it sounds like I likely have a
poisoned cathode.

Any reason I should not try a full rejuvenation - including applying some
current limited HT between cathode and grid, or is there a reason you
suggested just overdriving the heater, Bob ?

From the serial #, my unit has the 154-0633-10 tube, which appears to be
unobtainium - sigh.

On Tue, May 4, 2021 at 10:33 AM <> wrote:

The symptom is known as "double peaking" and indicates the CRT has
interface, AKA cathode poisoning. The CRT is near the end of its life.
Applying 12 volts for 10 or 15 minutes to the filament (with the
power off, since, in operation, the filament is at -3400 volts), may
a temporary repair. Access to the filament is easy via a two-pin
on the HV/deflection board.

Bob Haas


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