CurtPalme.com Home Theater Forum

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

Hi,

Still setting up my 'new' Barco data 701 and after fully converging the unit to my satisfaction, I went to bed at 3am. Next night, switch the unit on and Crying or Very sad

... the red and blue using the same test pattern has moved up about 1/3 inch (on my 96" screen)! How annoying. So I go to the convergence menu, raster move and start to move red back down... As I was doing it, I noticed the test pattern screen started to flicker and the red and blue was jumping in and out of alignment. I waited for 1/2 hour and the pj seemed to settle and I re-did the convergence. I then started flicking channels on the STB. About 1/2 hour later again, the screen flickered again and the fricking red and blue jumped out of alignment again... the whole red and blue raster seems to have shifted up about 1/3 inch (either that or the green moved down 1/3 an inch).

Any ideas what the issue is?

Thanks.

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

Sounds like perhaps a loose connector or card. Never owned a 701 but check this first. You said it's new so I assume you just had it shipped and things can come loose.

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

Sounds like a cold (bad) solder joint to me. I would pull the boards out one at a time and inspect all the solder connections on the boards, start it up after putting each one back in to see if the problem goes away.

rpruen · Posted: Mon Apr 28, 2008 3:59 pm Post subject:

I had several issues like you are posting here. Most where quite easy to fix.

Check all the connectors as suggested above, and give the unit a good clean while you are inside. Remove all the dust and gunk you can. Chaces are the HT leads, and tube necks will be covered in hard to remove black stuff, I used PCB cleaning solvent (it's supposed to be for removing flux after soldering) on a microfibre cloth to wipe the HT parts. Don't get the solvent on plastic parts (it could melt). For the top of the splitter and Focus block, I used a brush with the same solvent, to clean the area. I used a warm air gun (hairdrier) to evaporate the solvent, so as not to leave the solvent there too long.

Remove the neck boards, and clean the CRT socket, and pin area of the CRT. I didn't do this, and the focus voltage flashed over, and killed a neck board, toasted the tube and caused grief in general. Anything you can do to prevent a flashover is time well spent, as the thing is so compact, then any high voltage leaking may well kill something. Cleaning also gives the chance to inspect everything for damage.

The issue is quite possibly (this worked for me) the conv board, it's the one under the top lid with chips (SMT type). The chips had poor soldering, and also caused random I2C errors when adjusting the convergance settings. The SMT chips legs are hard to see, as they are tiny. So I reflowed the lot of them, and every other solder joint in the set. The SMPS also had some iffy looking solder joints, so I would re-do all of those as well.

While working on the SMPS check all the capacitors, the electrolytic ones particularly. Any that have leaked, or look 'a bit bowed out (from internal pressure)' need changing. I swapped all of them as I found two slightly unhappy ones, plus one that had been melted with a soldering iron at some point.

If you are not happy soldering, then find someone nearby who can re-flow the boards for you. You can try a local TV repair shop (if such a thing exists anymore). I guess you could ship the boards to Curt for repair/exchange as well.

Hope you solve the problem

Richard

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

Also read this.

http://www.curtpalme.com/Barco701_Layout1.shtm

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

Thanks Rpruen. Very comprehensive. Here is a little more information that I've come up with after a little playing.
The flickering/jumping out seems only to happen on the green tube. As the rear socket/neckboard of the tube is the same for all three tubes, I swapped the red for the green socket to see if I can isolate it to the socket. Unfortunately, the green tube still flickers/jumps, so that means there is no problem with the socket.

I vacuumed the insides but did not clean the black stuff of the HT leads etc, yet. The sockets and pin area seem pretty clean already.

Knowing that the issue is with the green tube, I guess I'll try to work out which of the chips control the green tube and re-flow them at a minimum.

Thanks!

rpruen · Posted: Tue Apr 29, 2008 9:36 pm Post subject:

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

You could try cleaning the Green raster shift pots with a touch of contact cleaner to see if it helps. Sounds like a bad solder join but maybe Curt will have some better ideas...

rpruen · Posted: Wed Apr 30, 2008 7:19 am Post subject:

I agree that Curt, or someone who has worked on these sets a lot will maybe have a better idea, if it's a common problem.

If you look at the deflection module, in the middle of the boards on the top flap, has 3 bigish adjustable coils on it. Check IC 394 for a start, that is the digital potentiometer for raster shift. Also look over that board for poor soldering, or conections.

Another thing that sometimes help to narrow things down, is to use a plastic trim tool of some sort to press various components, wobble wires, and apply pressure to the board. You would need to do this with the set running, so be careful not to come into contact with any metal parts, or lethal voltages. If you are not happy working on live equipment safely, then don't.

Hope that helps

Richard