Topics

Trying to save a 576


Mlynch001
 

That is my guess as to the problem. Mine did exactly the same thing. I have a very old one and a very late model one as well. The old one had the Brown transformer, the new unit has the Black one. I found the power in wire to the HV transformer and put an ammeter in-line to read the current draw. I will look at the schematic and tell you which wire I used. What mine did was started out at a low current draw , the unit worked fine, and as it heated up, the draw slowly increased until the power supply finally tripped. I don’t remember the exact current draw numbers. BTW, I have a prototype transformer in the works to replace the brown transformers. I will put you down on my list as potentially needing a replacement for yours.

--
Michael Lynch
Dardanelle, AR


Mlynch001
 

Eric,

I’m not saying that I am 100% correct about this, it just sounds exactly like what my unit did as well.

--
Michael Lynch
Dardanelle, AR


Mlynch001
 

On the HV board, find Pin G, disconnect the wire and put your ammeter in-line. You should get a baseline reading when you first turn it on. As the unit warms up you should see the current draw slowly increase (if the HV transformer is shorted). This is the 100V Supply, but it affects the entire system when it overloads the main transformer.
--
Michael Lynch
Dardanelle, AR


Martin Whybrow
 

Ryan, has that CRT been taken? If not, I would be interested, does the screen appear burned? My 576 works, but has a completely dead spot where the intensity was left too high with a static spot displayed.


Eric
 

Martin,

    Unfortunatly I can answer that. I have the tube in question it is weak. It is doing a double ramp but this one is slightly weak. I have a second tube as well that is VERY weak. I have not looked in to rejuvination of these or rebuild yet let me know if you are interested They came to me at cost of shipping and I am more then happy to pass them on for cost of shipping.

Eric

On 5/28/2020 5:35 AM, Martin Whybrow wrote:
Ryan, has that CRT been taken? If not, I would be interested, does the screen appear burned? My 576 works, but has a completely dead spot where the intensity was left too high with a static spot displayed.


Martin Whybrow
 

One of the things being added to my workshop is a vacuum system that would be suitable to pump down a CRT, but I wouldn't entrust myself to a CRT as rare as the one in the 576 as a test candidate! I can live with the burned spot for now, but thanks for the offer.