CurtPalme.com Home Theater Forum

cd1melton · Joined: 01 Mar 2011 Posts: 9

I know the usual fault in a scan fail is the vertical or horz. boards. But my problem is different..... I have a #1 Barco 809 that I am getting the scan fail on the G2 and Vertical boards. I have an identicle #2 Barco 809 that I can put all the boards from the # 1 809 into the # 2 including the EHT and Quad and they will work just fine. Reverse it and put all boards back into the # 1 809 and I get the scan fail......... Any ideas as to what is dragging it down?

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

possibly bad tube or bad deflection coil.

cd1melton · Joined: 01 Mar 2011 Posts: 9

yeah im about to swap tubes now and see what it does from there....although i thought I had tried that before with no luck. Ill know in the next hours as to what it does

**Curt Palme** · Posted: Tue Mar 01, 2011 1:39 am Post subject:

Did this just die by itself, or did you just buy these sets? In other words, was the set working for a while, then went into SF mode? If so, I'd check the motherboard, check for loose yoke wire connections (I think this is the same as the 909 chassis without the deflection switches under the H and V boards, bad solder joints on the motherboard.

Keep in mind that the video boards or the controller board can also cause the SF light to come on, even though those boards appear unrelated to deflection.

cd1melton · Joined: 01 Mar 2011 Posts: 9

No these are running units, not just bought units. This is what I have. A total of 5 809 projectors on a flight simulation dome. The packs are mounted separately from the tubes. Unit was working fine up until vertical board was pulled to ohm out deflection switches. Placed vertical board back in and got a scan fail. Pulled that exact V board out and placed in separate split pack. Works fine. Removed every last board there is in the pack that had the scan fail including the controller board and put in another pack. All works fine. Put all boards from a working pack in and it will go to scan fail. Hooked up a working 809 split pack to the tubes on the unit that is giving the scan fail and they will fire right up. Eliminating the tubes and related components. Here is the real kicker.....out of the 5 projectors 4 of them have the exact same fault doing the exact same problem. All tubes work fine all boards check good. I think its the mother board myself but 4 at one time? I guess anything can happen. One other thing the others than have gone out all happened when the V board was removed and put back in. Yet put those exact boards into a known working 809 and they will fire up with no scan fail every time. This really has me stumped

**Curt Palme** · Posted: Tue Mar 01, 2011 2:47 am Post subject:

Can you post a pix of the guts of the 809? I think it's just a BG808s, or is it based on the 909 chassis? I've never seen an 809..

cd1melton · Joined: 01 Mar 2011 Posts: 9

looks identical to the 808. just tubes, tube amps and HV splitter are housed in separate chassis. I have a 808 also and the boards swap over between the two in the exact same locations

**Curt Palme** · Posted: Tue Mar 01, 2011 3:02 am Post subject:

OK, not having seen a split back like that, nor having the s/manual.. I'm guessing a bit here.

One thing I've found with electronics is that the fault will end up being completely logical once you find it, and all symptoms you see will indeed relate back to the problem once you find it. That sounds a bit obvious, but many a time I've been sitting here in the shop working on some problem that makes no sense, and I do things like put in three replacement boards, figuring maybe I've got a bad one in stock, blah, blah.

So from what you're saying:

-it's not a module
-it's not the tube pack

-what about the interconnect wiring harness/connectors?

Is the spring broken on the V deflection switch, or popped out of place? That happens all the time. Normally when that happens, I simply pull the switch out all the way or push it all the way in, depending on what your setup needs, but I've had one V switch that gave a SF if it was pushed out or in all the way. Slightly short of all the way out or in cured the SF. (I ended up changing out that switch).

cd1melton · Joined: 01 Mar 2011 Posts: 9

Basically a modified 808. Where the tubes are in separate chassis. Ill give the V switch a look again. Although they were never touched except for one of the packs. Just V board pulled and reseated. Ever looking for boards to rob parts off of or to repair let me know I have plenty of all sorts for the 808.

Thanks for the insight

**Curt Palme** · Posted: Tue Mar 01, 2011 3:26 am Post subject:

Oh, I've got a zillion 808 boards, but thanks! Smile

About all you can do is scope the V output section to see if the sawtooth pulses from the V amplifier are getting to the yokes. There are independent V amplifiers, one for each yoke. If one connection is broken, or the V switch isn't engaging, then you'll see the lack of drive to the yoke, triggering the SF.

cd1melton · Joined: 01 Mar 2011 Posts: 9

Thanks for the info you gave me. It did lead me in the right direction. We never use the V deflection switch for anything. Its really never touched. So on that note I powered up the units and took a screw driver and slowly engaged/disengaged the switch. Eventually seeing the scan fail light go out at about the halfway position of the switch. Wow how weird to have 4 projectors with the same problem in a switch that is never touched. All within a couple of days. Anyway I ended up cycling through the switch rapidly while spraying down with blue shower. Springs were ok...just dirty contacts I guess. All are up and running now. THANKS AGAIN!!!!!

**Curt Palme** · Posted: Tue Mar 01, 2011 4:01 pm Post subject:

Nice! BTW, grab a can of Caig cleaner (www.caig.com). I know of Blue Shower back from my TV repair days, but Caig is probably longer lasting.

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

that's impressive curt. i've been to the MArquee school of hard knocks but can't imagine going to Barco, sony, NEC and ampro schools as well. Great place to learn though. Surprised

at 15 years old now average age, anyone who is attempting to run or operate any CRT at this point should own a bottle of De-oxit of some kind. Only thing I don't like about Caig is the price, $10. for a teeny little bottle size of my thumb. Confused

**Curt Palme** · Posted: Tue Mar 01, 2011 4:32 pm Post subject:

Well, this adventure into me repairing laptops is like someone diving into a CRT for the first time. As my g/f said as she loaded the custom drivers from the Dell website into the 6400 laptop that I'd installed Windows into which worked fine save for the internet connection: 'I do this like you fix video projectors. The thing is, do you have the time to learn laptops like you know video projectors?'

Sage words of advice that I'm still stewing over. Very Happy