CurtPalme.com Home Theater Forum

pm · Joined: 23 Aug 2010 Posts: 85 Location: Hants UK

Hi guys,

My 1209s has been with me for one year and performed faultlessly until recently.

The quad went, but that was quickly sorted because with amazing (for me) foresight, I'd bought a spare quad!

All was back to normal for about a week when I started to lose the picture from my HTPC.

It deteriorated to the point where the warm up screen flickers and clicks away. When I exit the warm up to input a picture, the tubes turn off completely.

There should be a short wideo attached and a picture of the fail lights.

Apologies for the quality of the video! If you turn the sound up, you'll be able to hear the clicking noise that accompanies the flickering.

My repair attempts have stopped at simply pulling the cards and re-seating them, to no effect.

My gut feeling was a PS problem forcing the cards into a fail mode..... with absolutely no evidence to back up my insinct!

I'd appreciate your thoughts chaps!

I'd also be interested in any UK users with knowledge of repair shops/individuals in the UK who'll take on this kind of work.

Thanks for looking,

PM

http://homepage.ntlworld.com/p.mew/barco%20screen%20clip.mpg

barclay66 · Posted: Fri Oct 07, 2011 5:52 pm Post subject:

Hi,

You might have a problem with the SMPS board (power supply). If you look closely at the G2/Diagnostic board (the one with the many LEDs) You will see that one green LEDs is off. This indicates that one required voltage is missing. You might check out the fuses on the SMPS first if Your abilities and measurement equipment allow for that. Otherwise You could get a good SMPS from Curt...

Regards,
barclay66

Addition: I might be wrong with my assumption because I based my assumption on the LED layout of a G2/Diagnostic board of a Barco Graphics 808. The 1209's board could be different and indicate different things. You better check if there's anything written next to the LED that's off. Then report back here...

pm · Joined: 23 Aug 2010 Posts: 85 Location: Hants UK

Thanks for that.

I can wield a multimeter, no problem, so I'll have a prod around. I'd feel far more comfortable with a circuit diagram so I know what I'm looking for though....

If it is a PS problem, is there any compatability between different Barco models?

Cheers,

PM

barclay66 · Posted: Fri Oct 07, 2011 10:48 pm Post subject:

**Curt Palme** · Posted: Sat Oct 08, 2011 2:22 am Post subject:

I don't think it's the SMPS.. yet.

MY guess is that the H board is bad. Any indication that the pix is narrow on the startup screen? Also try tweaking the master H width pot on the sub SMPS board.

pm · Joined: 23 Aug 2010 Posts: 85 Location: Hants UK

I managed to buy a copy of the service manual and I'm scouring it for things I can easily check without resorting to HV stuff and oscilloscopes.....

On the SMPS there is a test point and a pot that can be adjusted for Vout @17.5V

Mine was reading 17.1V.

I've tweaked the pot back up to 17.5V and guess what.... It seems to be working fine again! Very Happy

Can it really be that simple or is it just a fluke?

Many thanks for the inputs so far!

PM

barclay66 · Posted: Tue Oct 11, 2011 6:29 am Post subject: Re: Update......

pm · Joined: 23 Aug 2010 Posts: 85 Location: Hants UK

Thanks for the reply,

Everything appears mechanically sound on the board and all the fuses are fine.

Flush with the previous success, I thought I'd see what else I could check/tweak....

The service manual states that you can adjust potentiometer P2 on the SMPS to measure 48V on the collector of Q3 on the Horiz Defl Module.

As stated in the manual, I dialled up the brightness/contrast to mid range. Used a genlocked test pattern and adjusted the Horiz Size to maximum..... and measured 161V !!

It was possible to wind the voltage back to 48V but the tubes turned off and the fail light came on.

Fortunately, I was able to re-establish the previous setting with no harm seemingly done.

Any ideas as to what am I doing wrong please?

Cheers,

PM

barclay66 · Posted: Tue Oct 11, 2011 10:38 am Post subject:

Hi,

Sorry that I have to say that first (no offense intended): Please don't try to "tweak" anything that You don't fully understand. Most of the variable resistors are factory pre-adjusted. Re-alignment should only be done by qualified personell using suitable equipment. In this regard I even consider myself being an amateur and I wouldn't touch those.
If You read the Service manual section of the SMPS completely You would have seen that the HTHD voltage is variable and directly coupled to the Horizontal deflection frequency. So if You didn't prepare the Barco correctly (no input signal, test pattern in STD resolution selected) I wouldn't be surprised if You measured different voltages from those expected.
Additionally, for this measurement it is important that the meter's negative probe (mostly the black lead) is connected closely to the H-boards ground.
Right now I would leave the set as it is and simply use it. If Your adjustment of the 17.5V did the trick, then fine. If not, the defect will reappear and additional diagnosis will lead to its solution...

Regards,
barclay66

pm · Joined: 23 Aug 2010 Posts: 85 Location: Hants UK

Hi,

Absolutely no offence taken! Thumbs Up

I believed I had set it up exactly as the service manual explained.

I find the manual to be very clear compared to some, so felt comfortable having a go . I think I have enough knowledge/understanding to recognise those adjustments which are beyond my abilities and will leave well alone.

The tweaky geek in me is always looking for something though!

I do realise the importance of the age old maxim of "if it isn't broke, don't try and fix it!"

barclay66 · Posted: Tue Oct 11, 2011 12:26 pm Post subject: Re: Continuing......

Great!
I really hope that You still will have a lot of good viewing experiences with Your machine!
Just to give You the complete picture and what the (minor) difference in setup might have been: