CurtPalme.com Home Theater Forum

timf · Posted: Mon Mar 31, 2008 12:00 pm Post subject: Barco SMPS

Hi,

I was wondering if it is possible for a SMPS to lose voltage output or wear out if that is the correct terminology or does it just stop working if a fault develops?

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

You might want to read this...

http://www.curtpalme.com/Barco500_Layout6.shtm

timf · Posted: Mon Mar 31, 2008 12:30 pm Post subject:

Yep I already looked at that on the Barco 808 section and thats what caused me to ask the question, I recall seeing somewhere else that a low faulty ps could cause a dim image to be projected.

Looked at Curts 808 layout pages and saw the 17v trimpot and wondered if this can go off key at times affecting the power provided to the tubes.

**Curt Palme** · Posted: Mon Mar 31, 2008 12:32 pm Post subject:

There's only one trimpot on the unit that will adjust the 17 volt output (and all others), but generally no, the supply will not drop output if it's working properly. Failures usually show themselves with the SMPS pulsing or not coming on at all. Actually, they can also pulse very weakly.

timf · Posted: Mon Mar 31, 2008 1:01 pm Post subject:

Thanks all, that answered my question.

**Curt Palme** · Posted: Mon Mar 31, 2008 1:56 pm Post subject:

What's the problem with the set?

timf · Posted: Mon Mar 31, 2008 2:24 pm Post subject:

The problem I have is a low light level coming out of my BD808s, the pic seems really dark and the brightness is turned almost to max , I've tried adjusting G2 but while I can get a slightly brighter pic by doing that again the G2 settings are amlost maxxed out.

A bit perturbed on what could be causing the dark pic.

I thought that maybe a drop in voltage from the SMPS might be causing the tubes not to light up correctly, a bit like a dimmer switch on a normal house light

**Curt Palme** · Posted: Mon Mar 31, 2008 2:31 pm Post subject:

Check the filament voltage. The Sony tubes take more draw from the SMPS than the MEC tubes (that's my guess anyways), and check that the SMPS is hte correct one. THe right one is the 7621706. A 7621705 will work, but with low filament voltage which results in dim tubes.

If the filament voltage sits at anything over 6.0 volts, then your tubes are shot. That's very common on sets that have >10K hours on the chassis, I've had to trash more than one perfect looking BG808s... with the exception of dead tubes with very low output.

Sad

timf · Posted: Mon Mar 31, 2008 2:50 pm Post subject:

Thanks Curt, I've checked the PS and I've definitely got the right one, the tubes would probably have no more than 3k on the clock and the problem hasnt always been there.

It only seemed to occur once i had it calibrated around 18 months ago, the output was fine before that so I dont know what was adjusted that would cause it to do that. The brightness seems to improve after about an hour or so after it is switched on, so a bit stumped atm.

**Curt Palme** · Posted: Mon Mar 31, 2008 3:37 pm Post subject:

Well it's either the SMPS or the G2 board is bad. Since it affects all tubes, that's all I can see it being.

timf · Posted: Mon Mar 31, 2008 11:47 pm Post subject:

Thanks for your help Curt,

I'm far from being an expert but thats pretty much what I was thinking, if you have an SMPS and G2 board could you please PM with a price to buy and ship to Australia?

Thanks mate

**Curt Palme** · Posted: Tue Apr 01, 2008 12:55 am Post subject:

Email me at curtpalme@shaw.ca please.

Cheers!

timf · Posted: Tue Apr 01, 2008 7:13 am Post subject:

Done

Thanks Curt