Sony CDP E200 monitor help

Peter C · Guest

Sorry about the multiple posts, I accidentally put this in the wrong forum.

Hi,
I hope there is a knowledgeable and experienced tech out there who can help me track down the cause of an intermittent fault with my Sony CDP E200 computer monitor, chassis No SCC-L31A-A. The problem manifests itself in the screen randomly dimming to black from normal brightness. It takes about 5 or 6 seconds to dim to complete black. Most of the time the problem can be (temporarily) fixed by powering off, waiting 10 or 20 seconds then switching back on. A quick switch off and back on usually doesn't help. Occasionally the screen doesn't dim to complete black but dims a little then returns to normal brightness after a few seconds. Sometimes the problem doesn't happen for days and sometimes it happens every ten minutes - very frustrating.

I've replaced c625 (2200uf 16V) which was a posted fix on the Techassist website (several years ago) for what seems to be an identical fault but alas, no good. (Actually, the recommendation was to change c825 (220uf 16V) but there is no c825 and after much scouring of the service manual I reckon c625 is what he meant.)

If anyone can offer any advice I'd really appreciate hearing from you.

Cheers everyone,

Peter

14 Jan 06

eko · Joined: 14 Jan 2006 Posts: 3

that problem is replace (??tda48xx??) autosync deflection
IC controller check 5v and 12v! voltage correction.

Guest · Posted: Sun Jan 15, 2006 1:45 am Post subject:

Are the heaters still glowing when the screen goes black?

Peter C · Guest

No, the heaters go off when it the screen is black.

Peter

Guest · Posted: Thu Jan 19, 2006 8:05 pm Post subject:

I am not familiar with your monitor but I would check the heater supply rails. Check the CRT socket and follow the tracks back, checking all components and solderjoints as you go. There may be two lines or one could be earthed. Check the flexible lead(s), mainboard connection(s) and follow the tracks back to the transformer.
Have you checked the 'autosync deflection IC controller' voltages as Eko suggested?

Let us know how you go. Smile

Peter C · Guest

I appreciate you guy's help. I'm sorry to say the way things are at home I don't have all that much time to dedicate to the monitor right now. But when I do get the time to do it justice I'll let you know how I go and probably ask for further guidance. (I'm surviving nicely with a Mitsubishi 1770f. Nowhere near the quality of the Sony but at least it's reliable.) Thanks again.

Eko, are you saying you feel the deflection control IC (CXA8071CP) itself may be faulty?

Peter

Guest · Posted: Thu Jan 26, 2006 8:23 pm Post subject:

Hello Peter,
No, I am saying I do not know your monitor. Heater supplies are generally sourced from the line transformer. A monitor has different resolutions/frequencies and could have these sourced differently.
Maybe the 'autosync deflection IC controller' turns off a transformer when it changes frequency and this transformer also supplies the heaters? You won't know until you trace it. Have you resoldered all big connections on your CRT board? Sometimes they 'look' O.K.
The heaters going out, account for your dimming picture, I guess your OSD darkens too. If you can trace them yourself you may be able to find your problem. It shouldn't take long. To me, it sounds like a loose connection/dry joint. Try wiggling the components whilst looking at the solder through a magnifier, or very bright light (sunlight).
If you use this monitor for detailed work, I would also replace all filter capacitors with high temp(105) Low ESR capacitors. (the ones after the diodes, after the transformers) for longevity.
Maybe you could send us a schematic? Or maybe EKO could enlighten us both?

Let us all know how it goes. Smile

Peter C · Guest

G'day again,

Yep happy to send schematics, etc. How do I get them to you? Can I send attachments via this forum?

Cheers,

Peter

PS: How's the weather? Stinking hot down here.

PC