|
|
Post by gregstv on Jun 13, 2016 7:57:06 GMT -5
Been fixing some HV boards from a Barco 909. They all have 2 HV diodes shorted. There is also a 1ohm resistor in series with one of them that was burnt as well. I have replaced all these parts and all the caps on the boards. I have run them for 3-4 hours each and they seem fine. Do you guys think it would be the caps or the quads that would cause this?.
Also rebuilding a power supply that went bang. I have it running after repairing both switch mode sections and Q61 on the std by board. I have also repaired blown tracks and recapped it. The problem now is that the picture is smearing with the 17 volt rail set at 17.3. To get a reasonable picture I need to set the 17 volt tail to 18.2 volts. Any idears? |
|
|
|
Post by Casethecorvetteman on Jun 13, 2016 8:07:54 GMT -5
Have you tested 17v at another location other than the test point?
Does it have a reported voltages page in the menu? Look there and see what its reading. My meter reads a higher voltage than is actually present when the battery is low.
Id say it would be quad causing the HV board issue, as per something i read in the SEOS info you sent me.
|
|
|
|
Post by gregstv on Jun 14, 2016 4:33:05 GMT -5
Thanks Casey,
According to Curt the 9 series will work with old or new quad. I am a little concerned that the old style 808 quads are causing the HV boards to fail when run for long periods of time. Looks like the quad fails at the same time.
The power supply is a strange one. If I use a different power supply it works as it should. Time to put the oscilloscope on the rails to see what is happening. There maybe some oscillation coming from the supply.
|
|
|
|
Post by Casethecorvetteman on Jun 14, 2016 5:53:50 GMT -5
The old quads work fine, no issues there. They wont cause this issue, ive done 2,000 hours on old quads and never had anything other than a quad fail. Id not buy used quads from there if i were you, will tell you over the phone why if you like.
|
|
|
|
Post by gregstv on Jun 15, 2016 2:51:16 GMT -5
Thanks Casey, I need to find out what is making the noise. Its bugging me. I have changed all the boards and no change. I don't think the splitter would cause the noise at the quad end of the projector. It maybe the p16 tubes running in the 909 chassis. I need to find out if there is any differance between the 909 and the 908.
|
|
|
|
Post by Casethecorvetteman on Jun 15, 2016 3:48:51 GMT -5
Yeah ive got no idea on the 908, i was under the impression its got all the same parts except for tubes and related harware.
The splitter can cause noise if its arcing internally, ive had one do that before. Its usually the quad though more so than the splitter, those caps inside the quad arc and cause noise as you know, but the splitter can do simular things.
|
|
|
|
Post by Casethecorvetteman on Jun 15, 2016 3:52:07 GMT -5
If Jenum can rebuild those quads successfully we'll be laughin, its the only item that is really hard to repair!
You have proven the point with the boards being reliable after replacing capacitors, the rest of the set really is very good so far, just that bloody HV section that causes issues.
|
|
