Author Topic: Trying to save a 576  (Read 383 times)

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Offline Zenwizard

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Trying to save a 576
« on: December 05, 2019, 04:37:52 am »
Got a 576 that was supposed to be in working order but it seems it is no even close. After rebuilding the collector supply, I managed to get sweep again on the tube but the tube is VERY dim The picture shows the tube with the intensity turned all the way up. I have a strong high voltage power supply and it is exactly where it should be. given how faded the graticule lines are I have a suspicion the former owner stored it in the sun and it baked the tube. Is there any way I can safely drive the tube a little harder to try and get some brightness back. I also probed the 225V intensify pulse and it seemed it was stuck high it was not pulsing like it should. Any way to bring this on back or do I have a parts unit?  The odd thing is the tube is uniformly dim it is but burned just not bright.
 

Offline andy3055

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Offline Zenwizard

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Re: Trying to save a 576
« Reply #2 on: December 06, 2019, 01:12:06 am »
voltages as measured from the rear CRT pins.

1) -3815 Vdc
2) -3841 Vdc
3) -3840 Vdc
4) -2667 Vdc
5) NC
6) NC
7) 100 Vdc
8) 100 Vdc
9) 100 Vdc
10) 109 Vdc
11) 52 Vdc
12) NC
13) -3814 Vdc
14) - 3814 Vdc


Heater voltage ping 1-14) 5.9Vac
 

Offline andy3055

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Re: Trying to save a 576
« Reply #3 on: December 06, 2019, 02:01:34 am »
Check page 65 of the service manual where there is a good explanation of the CRT HV supply.

I do not see the CRT screen voltage on the diagram bu there is a mention of -4kV in the section mentioned above.
 


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