I have a relative that has a problem with this device in that the blue screen goes out of phaze drasticly after warm up. I have done some research and realize that this is a relatively common problem and the convergence ICs STK-394-250 are suspect. I did check their solder connection(s) to the main PCB w/o effect. The Horzontal (IC8C01 - ID from purchased svcManual) seems to be at fault from my estimate. To add to this, the heat sing is shared with IC8C02 of the same type and the area the suspect IC occupies has a much greater temperature than 02.
My question is; If I replace IC8C01 what are the odds that the problem will be solved?
If you replace BOTH IC's at once and check F9A04 and F9A05 in the main power supply, you should be set. BUT DO NOT find one of the fuse bad and replace it WITHOUT first replacing the convergence IC's as a pair or you will cause more damage to the power supply and the odds of you fixing the set then are 20?80, with the 80% being the bad side. Good Luck
Thank you Larry, I will order the parts and tear into the project.
Great! Let us know how it turns out for you.
OK, I ordered parts and was very disappointed in Bluestar due the fact that I received unmatched obviously used parts (unannounced to me).
I am afraid that the product I have will not be effective.
Please know that I have checked the fuses and they seem to be fine.
Received new ICs, installed and result is the same.
How are the fuses now? Let me see a picture(s) of the soldering around the IC's please.
Both F9A04 and F9A05 are good as before the pics you requested are below.
Thanks for your help
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Yep, they look OK to me. What type of voltage measurments do you get on L8C01 and L8C01
My patience finally paid off. I was trouble shooting several connections in the powersupply as well as other solder connections when I happened to tap on the front of the set during a trial run.
I viewed lines in the pic with the taps and narrowed down the source which was a connector on the convergence board that leads to the blue CRT. (see attached from manual) The connector is easily accessable from the front of the device labeled as VU.
I hope this will help others that have a similar equipment.
By the way I have a perfectly good NEW matched set of STK 394-250s that I will not need. Let me know and I will make arrangements for whoever is interested.
Thank you Larry for your help I may need you again as I have another big screen to diagnose for my Mother in Law.
Have a good one
Was the connector loose in the plug/socket or on the boards solder connections?
The solder connection on two pins had failed. A quick touch up solved that.
Probably happened when pulling out the chassis to replace the IC's.