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Hallicrafters T-54
This is the Hallicrafters T-54s mentioned in the grneral TV thread.
How do you remove the HV box? Its looks to be a really stupid design, requiring wire unsoldering. Is there another way? |
#2
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If nobody answers, send a PM to UberVacTuber, that's Dan Jones (of Predicta fame). He just restored one not long ago.....
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia." |
#3
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Yes, you must unsolder several (4 or 5) wires under the chassis to remove the assemly.
jr edit add: actually 6 wires, counting the HV output. Last edited by jr_tech; 05-11-2018 at 08:57 PM. Reason: add correction |
#4
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I hate that crap. I bet the cat that designed it later worked for GE.
No reason not to make things physically seviceable, Maybe a few bucks at most on $200+++ Its a pet peeve....... 73 Zeno LFOD ! |
#5
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Last night I got a raster. Easy recap job. I got the HV box recapped by undoing only 4
wires, the B+, B- (it has a -100v or so B- supply), ground, and HV. The filaments can remain connected. I did this by unscrewing the bakelite (?) plate and the box itself. Then you can lift the box and unscrew the aluminum plate on the bottom. Then the plate comes off, and you wiggle the bakelite loose and remove the box. Its then easy to service. Getting two screws back in the aluminum plate is finicky. The HV wire was toast so I replaced it. I got 4.7kV HV. Next job is getting reliable contact from the pushbuttons. The buttons often fly off. What do you do about the looseness problem ... I don't want to use strong glue. |
Audiokarma |
#6
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Maybe put a paper towel between the shaft and the button then insert. Something to make it a slightly tighter fit like that could keep the buttons on without glue.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#7
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I got it working properly. It needed just the recap and a full careful alignment, as
it was badly out. Of course it didn't work well at first ... hum in the picture. Arggggh ... it was a ground loop in my modulator setup. Looks good now, nice sharp picture, though still retrace lines in dark low contrast pictures. Only one problem: the brightness control could not turn down far enough. A zener diode in the grid lead pulled down to the -120 supply with 1 megohm did the trick. One could of course pull the cathode up more, but that would get it fairly close to the heater-cathode rating of the CRT. |
#8
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Is the HV stable or does it drop considerably after the set has been on for a few hours?
jr |
#9
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For glue, perhaps a dab of rubber cement? May have to re-do it every now and then, but at least it'll come off when required.
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#10
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Quote:
exactly as speced in Rider's, 4.7 kV. |
Audiokarma |
#11
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Oh yes, I forgot ... the original purpose of the whole thread!
The plate cap of the HV rectifier is awfully close to the lid of its box. Is that safe? Should I install insulation? Should I go to a perforated metal lid for cooling? Or, I could install standoffs so the lid had 1/4 inch of clearance both for HV purposes and ventilation. |
#12
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They look right, but these shafts are the push-on fluted ones. If I recall
correctly, those don't use setscrews. And 5 of them would be $50! Doug McDonald |
#13
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The front and rear knobs on my t-54 look like this:
The front knobs are 29 mm in diameter, and the rear knobs are 29.5 mm dia. at the skirt. The front knobs are very dark brown. IIRC, the metal version of the set uses front knobs similar to those on the SW radios. "The plate cap of the HV rectifier is awfully close to the lid of its box" Do you have any shorter 1B3s? considerable variation in height can be found... also SS diode? jr |
#14
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Well, you said 'need', not 'want'...
(Sorry man, just kiddin'.) |
#15
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Since this is a hot chassis set you do need to have something insulating on those control shafts. Well unless you always have it on an isolation transformer.
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Audiokarma |
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