Re: Tek 464 CRT tube presenting "double-peaking" - Is rejuvenation recommended
Thanks for your valuable input so far.
For now, I`m mostly standing by, or doing some cosmetic cleaning here and
there, while the new transformer doesn't arrive from Canada.
See my replies next to your last answers...
2016-10-09 2:58 GMT-03:00 David @DWH [TekScopes] <
If doubling peaking is a problem, then it is usually prettyThat the trace bloom is there is sure, as well as many other symptoms
here and there on the net as being associated to cathode poisoning and/or
Since the trace is not that much dim and I can still get decent focus
some struggle and having to retouch it when I change Intensity), I have
the damage is still recoverable to some good degree. We shall see.
Do not forget to do the storage calibrations.I will, as soon as the transformer is installed and I can put it back
I didn't go through the procedure yet and I hope it doesn't involve exotic
as I don't have them.
The second one is what I was thinking of.I`m glad that you're actually thinking of the second option!
It gives me hopes that I will be able to improve matters without having to
to more radical approaches. I fear hurting the CRT.
I tried to measure the heater voltage with my DMM (in AC) to no avail.
It can't measure AC to 50KHz... It's not True RMS.
I can still try to obtain a good reading indirectly, by rectifying it with
a signal diode
and a small cap (no load) and compensate the reading for the diode drop and
Value vs RMS value.
But apart from measuring, just looking at the schematics, I conclude that
Up to serial number B129999 the heater voltage was DC, shunt regulated by
CR1514, C1514 and VR1514 (a 6.2V Zener) and mine doesn't have them (it's
Since there are no other parts change coincident to that S.N129999
it means that units just prior to S.N. 129999 shared the same
and everything else that matters like mine but still, they had the 6.2V DC
to the heater and mine doesn't, which means that my CRT must also be 6.3V.
That is a great idea. Make sure you include the connection betweenAbsolutely, I know of the danger of arcing between the cathode and heater
that could cause the heater to blow, being why the heater is "elevated" to
the cathode's potential.
Maybe you can open W1514 and connect the battery there. The batteryThat's a perfect spot to connect it. I will insulate the whole thing and
it using some H.V. wiring (TV Flyback wiring...).
Watch myself... here's a good one!
Once when I was 15 years old, I did my first mains voltage doubler using 2
old aluminum can capacitors
scrapped from an old tube amplifier, 2 diodes and 1 mains wire.
It was meant to be the power supply to my first Xenon strobe light (to
boost my Disco parties).
It was all "air-mounted" in the best "Jim William's" style... and the two
capacitors were in series.
So, the the cans had about 170V between them...
At some point I needed to make some room in the table and had the
"brilliant" idea to move
the whole thing aside...one hand in each can :-) :-) ... My hands closed
the cans i was stuck to the thing (it was still connected to the mains!!!).
I only got free because I got desperate and ran away... the mains wire
finally the capacitors discharged (on me) and I was free....
I was home alone that day and I could have got myself killed! I never told
Lesson learned... I was never so stupid again!
Still, throughout the years I had many electrical shocks (who doesn't?) but
between my two hands, never on the inside of the hands... Always one hand
in the back pocket!