4900 issue

prOk

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So, after a recap of a 4900 what could cause the screen to be compressed toward the top vertically and stretched toward the bottom? I triple checked the cap job, don't see any obvious solder issues.. anyone got any advice?
 
Was this issue there before the cap kit?

Did you try tweeking the vertical linearity pot.....and the vertical dampening pot (if your version has one)?

Edward
 
HI, yes the problem was there before although I think it's a touch more pronounced post cap kit. This particular 4900 is the later version with the damping adjustment, can't seem to adjust it out at all, no matter what I do the funny stretch/compress thing is there :(
 
i dont think keystoning is the culprit at the moment but tried to take a couple pix.

it's hard to notice unless you're looking but it's obvious when playing. In the pic, you can see how the letters and such to the right side of the screen the lines are farther apart making letters 'longer' where on the left side they are very tight together making them shorter (width wise).

I've adjusted the crap out of the damper and such but nothing really does squat here :(
 

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So while the right side looks like this (pic is much clearer of the issue on the 'sinistar' screen), the left side (which is the physical vertical top of the monitor) has tearing that I believe is foldover but I can't adjust it out no matter what. Replaced every cap on the monitor, reflowed tons.
 

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Sure have.. pretty much reflowed every solder point.. checked and reflowed again.
 
What about the sync header pins on the chassis & on the CPU board @ 1J3?

Also, does the video change if you wiggle the video harness at either end?
 
I'll try that. Someone else suggested the IC on the chassis might be the culprit but I can't find that chip anywhere :(
 
Ok, reflowed on the cpu and no change. Although now I have a new symptom I hadn't noticed before. There's apparently some arcing from the tube, just a sparky sounding tick coming from the anode cup. I pulled and reseated the cup a couple times, it's on there good but the electrical tick is still there. Does that mean anything? I dunno :(
 
Anode is not seated in the cup or the cup is dried out and the tube is dirty. Remove the anode and clean the tube and cup, make sure anode is seated all the way back into the cup and re-install.
 
Does adjusting the Vdamp pot do anything at all?

You may have a resistor or cap in that circuit out of value changing your adjustment range...
 
the vdamp pot does change it, seems full range and it makes the wrap/tear effect worse if I turn it down.

For the anode, I did clean the tube and the anode cup really well.. it's very pliable, no signs of cracking or anything like that. Both wires from the anode are firmly in there, it's pretty snug.
 
I'd swap it from another chassis if you have one handy. No sense ordering one until you know if it is the cause...
 
brian, i say bring the monitor over here, and we can beat it up with a hammer :p

you can stop off at paul's and get the ic chip too on your way..
 
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