Dell (sony) P991 trinitron troubles

[Starlite528]

Picked two of these big suckers up at a garage sale on the cheap. Unfortunately, they both don't work the way they're supposed to.

Symptoms: the screen is washed out in blue, and you can see diagonal scanlines. When I run the 'color refresh' feature, the blue and diagonal lines go away, but only while that's running.

I don't know if the problem is tin whiskers in the gun, or bad caps, or what! On a side note, someone said something about 'special sony software' they use to configure the monitors. What's the deal with that?

[PlainBill]

Re: Dell (sony) P991 trinitron troubles

Picked two of these big suckers up at a garage sale on the cheap. Unfortunately, they both don't work the way they're supposed to.

Symptoms: the screen is washed out in blue, and you can see diagonal scanlines. When I run the 'color refresh' feature, the blue and diagonal lines go away, but only while that's running.

I don't know if the problem is tin whiskers in the gun, or bad caps, or what! On a side note, someone said something about 'special sony software' they use to configure the monitors. What's the deal with that?

As an old TV guy, I'd say it's time to adjust cutoff and drive controls for the crt. Possibly touching up the screen voltage adjustment (usually on the flyback) will help.

PlainBill

[Starlite528]

Re: Dell (sony) P991 trinitron troubles

As an old TV guy, I'd say it's time to adjust cutoff and drive controls for the crt. Possibly touching up the screen voltage adjustment (usually on the flyback) will help.

PlainBill

Note that this is the same on /both/ monitors. In fact, I remember seeing one at work that was beginning to show the same symptoms!

[RJARRRPCGP]

Re: Dell (sony) P991 trinitron troubles

A good chance that the VGA cable or one of the VGA connectors are bad.

[PlainBill]

Re: Dell (sony) P991 trinitron troubles

Note that this is the same on /both/ monitors. In fact, I remember seeing one at work that was beginning to show the same symptoms!

It's a fact of life - often you will find identical problems occurring in a sizable portion of a particular model. This happens whether it be airplanes, cars, or monitors.

FACT: There is too much blue on the screen. Either the video card you used is defective, the video cable is defective, or the monitors all have the same problem. I doubt it is the video cable because most monitors go to a black screen if the video cable disconnected.

FACT: There are obvious retrace lines on the screen. That means the video signal is not being blanked for the horizontal retrace; that is often caused by a misadjusted screen control. Both focus and screen settings tend to drift as a monitor ages. Heck, many monitors have holes in the back / side so you can adjust them without even opening the case.

NOW, if you have any other ideas, I would be willing to give them all due consideration.

PlainBill

[Starlite528]

Re: Dell (sony) P991 trinitron troubles

FACT: There is too much blue on the screen. Either the video card you used is defective, the video cable is defective, or the monitors all have the same problem. I doubt it is the video cable because most monitors go to a black screen if the video cable disconnected.

This shows up regardless of what computer it's used on, and it's still visible after the cable is pulled loose, before it shuts down.

Heck, many monitors have holes in the back / side so you can adjust them without even opening the case.

Not these monitors. They shielded the hell out of these things. Once you take the cover off, and you have to go through a layer of sheet steel surrounding the whole setup! There are, I believe, focus controls on the flyback, but I don't know what else, if anything. If I can't fix these by adjusting those, I'll probably just toss them in a dumpster...unless I can find a place to repair them for me on the cheap.

[PlainBill]

Re: Dell (sony) P991 trinitron troubles

One of the controls on the flyback should be the screen control (it may be marked screen); the other one is the focus.

Apparently this monitor was also sold as a Dell. Here's something I found that doesn't even require a screwdriver.

Just read your question and I too had a brightness issue with my Dell Model P991 (as well as very faint vertical lines running across the screen). To fix this I went to the monitor's "Menu" and picked "Options". In "Options" I chose "Color Return".. after your monitor has had time to warm up press it. It resets the grey scale balance and should restore your Dell Trinitron model P991 to it's original factory setting.

PlainBill

[PlainBill]

Re: Dell (sony) P991 trinitron troubles

And further information. It appears the Sony P991 uses DAS to set parameters. Apparently the problem you are seeing is often caused by using the 'Color return' feature.

And here's the skinny on how to do it.

PlainBill

[gdement]

Re: Dell (sony) P991 trinitron troubles

This looks just like what happened to my old Trinitron G400. Except mine was just really bright (bad contrast), maybe pinkish but not blue. Developed the same barber pole lines when I gave up on it a few years ago.
Looking it up on Google, it also appears to be the same age and has same specs as the G400. I wonder if these are the same monitor internally.

Like you, I tried the color restore feature, and it worked for a while. But the problem quickly came back and color restore was no longer effective.
Eventually it began shutting off when cold. When this happened it would flash red for a moment. It was like trying to start an old car in the winter.

Don't know if yours is destined to do the same or not, but if these monitors are related then maybe that gives somebody another clue of what's going on.

[Wizard]

Re: Dell (sony) P991 trinitron troubles

Check for small bad caps on the CRT circuit. There are many, but ONLY One will be the problem.

Cheers, Wizard

[PCBONEZ]

Re: Dell (sony) P991 trinitron troubles

I had a board with an on-board VGA connector that they'd gotten some damned glue or something in the holes.
I eventually got it cleaned out with small drill bits by hand but along the way I probably had a dozen different combinations of 'only some' contacts 'making' the connection.
I was using a CRT.
Some times the screen was black (nothing), but often too blue, too red/pink, too green once I think, too yellow was popular.
The normally white text in the start-up flash screen would be the color that was going to be too much of when it got into windows.
-
I'm convinced that one or a few bad pins in connector, or wires in cable, or solder traces [at either end] can result about any of the 'off color' conditions that occationally show up.

So: Yes, it could be the cable, video card, or connectors at least insofar as the 'too blue' part of the problem.
And, if one pin or wire is damaged or degraded why can't two be?,,, possibly causing those lines.
Especially if they are shorted together...
.

[Starlite528]

Re: Dell (sony) P991 trinitron troubles

And further information. It appears the Sony P991 uses DAS to set parameters. Apparently the problem you are seeing is often caused by using the 'Color return' feature.

And here's the skinny on how to do it.

PlainBill

That's absolutely beautiful! I was afraid these screens would be a terrible waste but now I have hope. I also didn't realize that the 'color return' feature was actually a /cause/ of the problem! I didn't even know the feature existed until today, when I found the manual for a similar Trinitron (dell P990 (*1)), and used it to no good effect. I was also afraid the software might be totally unavailable. I found the service manual for the monitor, and it shows two adjustments on the flyback; H-focus and V-focus. Before I start fiddling with that stuff, I'm going to try the software first, but I need to build the interface. FORTUNATELY I just recently picked up a MAX232 chip for a recent project. The little sucker cost me $8, and an hour drive!

*1: On Saturday while garage sale-ing, I drove by a box on the side of the road, it was a Dell monitor box, and the word "GOOD" spray painted on the side. Stopped and picked it up, and it works perfectly. It's the P990. The only noticeable difference between the two P991's I have is that it's a curved screen instead of flat.

[jdimpas]

Re: Dell (sony) P991 trinitron troubles

Dude try this one.

Open up your monitor casing. And please do discharge for safety reasons.

Remove the Socket board in the tube and find R459 its actually a 10M ohms resistor.Then go to the market and grab some 4.7M~5M resistors, removed the 10M ohms (R459) then replaced it with 4.7M~5M. Solder it and return back the socket board in tube, just be sure that all cables are plug back. Then turn on you monitor! It should work.



Regards,
jdimpas

[gdement]

Re: Dell (sony) P991 trinitron troubles

From what I found on Google I'm fairly convinced this is the same monitor I had (in Sony branded version).
I wish I'd known about all this stuff when I had that monitor. It was a great display when it worked.
Excellent info.

[jdimpas]

Re: Dell (sony) P991 trinitron troubles

and by the way. Last few months ago my friend gave 15units of scrap monitor same with yours likewise with the problem (retrace lines and washed out color). As mentioned above I just changed the R459... Fortunately, all 15 was like pristine working.

Please don't forget to update us here.

[gdement]

Re: Dell (sony) P991 trinitron troubles

What's the wattage rating of that resistor?

[jdimpas]

Re: Dell (sony) P991 trinitron troubles

just try some 1/2 watt

[Starlite528]

Re: Dell (sony) P991 trinitron troubles

I used the method suggested by PlainBill to use the windas software and interface, and it worked! Finally I have some success with something! I still need to tweak it more, but I would rather edit numbers in a file than soldering resistors on a board engineered by engineers at Sony.

Drinkin Time!

[Oklahoma Wolf]

Re: Dell (sony) P991 trinitron troubles

This is a common problem with these - I got a free P1110 because of this issue. Used the resistor hack on mine, and I'm using it as I type this.

[PlainBill]

Re: Dell (sony) P991 trinitron troubles

I used the method suggested by PlainBill to use the windas software and interface, and it worked! Finally I have some success with something! I still need to tweak it more, but I would rather edit numbers in a file than soldering resistors on a board engineered by engineers at Sony.

Drinkin Time!

Great job!!!

PlainBill