CurtPalme.com Home Theater Forum

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Just for reference.

http://www.curtpalme.com/docs/BarcoServiceBulletin_R762716_New_EHT.pdf

wingnut2001 · Posted: Wed Sep 15, 2010 10:40 pm Post subject:

Mike, check on R762833 for me as well...very late 1208/e quadrupler

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

HI Tom,

Thanks for the bulletin. Interesting it says the second LED - D14- is to tell if the EHT voltage is too high or overvoltage protection. That doesn't sound like a quad failure, hmmm I'm not sure what to make of that, anyone.

**Curt Palme** · Posted: Wed Sep 15, 2010 11:28 pm Post subject:

Either light lit on the EHT board is USUALLY the quad, the splitter second and the EHT a distant third..

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Okay I'll take your word for it as you no doubt have more experience replacing these things and their causes of failure. I think it's just the way they worded the bulletin that makes me think otherwise at first read.

wingnut2001 · Posted: Thu Sep 16, 2010 1:21 am Post subject:

I have a rice crispy quad that actually works sometimes and doesn't shutdown, the outsides of the image start shaking violently and HV pops start after 15 mins of being on, I am also hearing popping at the splitter area, is this normal for a bad quad or are both bad? or could it just be the splitter?

thanks Curt

**Curt Palme** · Posted: Thu Sep 16, 2010 1:24 am Post subject:

It could be either. I had a bad HV splitter today as well.

**kal** · Posted: Thu Sep 16, 2010 1:37 am Post subject:

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Damn, would you look at that, somebody put all the part numbers in a nice orderly fashion to make easy for us to find. Good work Kal, thanks.

Hey who had that 1200 that had problems and wasn't he trying to dump the parts?

wingnut2001 · Posted: Thu Sep 16, 2010 2:46 am Post subject:

Curt, anyway to diagnose?

thanks for the help

**kal** · Posted: Thu Sep 16, 2010 3:05 am Post subject:

wingnut2001 · Posted: Thu Sep 16, 2010 3:17 am Post subject:

found this info from a barco repair guy:

If you are getting a red LED on the EHT Generator, this indicates an "EHT Hold down". This indicates an EHT failure of some kind. It could be the Quadrupler, the EHT board, the Splitter(unlikely), or a failing crt. Visibly inspect the Quad for any bulges or pregnant spots. This would indicate a bad quad. To check the CRTs, disconnect the CRTs high voltage lead to/from the Splitter, and disconnect its Endstage or RGB Output Amplifier also. Do this for 1 crt at a time, and if the HV or EHT stays up without that crt, then that crt is bad. Be careful that the unit is never powered up without the quad plugged into the Splitter input. Before and After the unit has shut down into EHT hold down, measure the feedback on the Splitter. There is a small coaxial cable that is soldered to the Splitters small sub board. There is a Divide by 1000 circuit on this, and so instead of reading 34,700V DC, we should read about 33 - 35V DC. This is measured at the solder point of this coaxial cables center conductor. If it reads below 33V at startup, the quad is probably at fault. If the quad is not pregnant, it is probably good, but this is not for sure, just likely. If the quad looks okay, and the crts prove not to be the cause, then I would look at the EHT Generator.

mp20748 · Posted: Thu Sep 16, 2010 1:03 pm Post subject: