Dell P1110 21" CRT repair thread

[Th3_uN1Qu3]

An engineer friend of mine called me a couple weeks back and asked me if i was still interested in his Dell P1110 21" monitor, he said he doesn't bother with it anymore. I wasn't in town then, i went and picked it up now. I paid him $24 for the beast.

It has the classic overbrightness problem common to this series, in this case it's as bad as it gets, retrace lines visible at zero brightness. In these monitors, there is no G2 (screen) adjust knob on the flyback, it's all MCU controlled. All you get is two focus knobs. Fortunately the fix is known, these monitors have a TTL port at the back, and a serial port (RS232) to TTL cable together with the WinDAS software can be used to adjust ALL parameters of the monitor, G2 voltage included. I have already built the cable using a MAX232 converter IC and i've had the software around for several years.

The guy didn't have a spare VGA cable and neither have i, so it'll have to wait until tomorrow. In the meantime, i'll give it a good cleaning. I'll be giving away my good ole' Nokia 920C (19") to a friend of mine who still runs a 15". The Nokia is a great monitor, i only paid like $12 for it 4 years ago, and all it needed was a good calibration, but the curved screen and ABL issues (contrast limiting when transitioning from dark to bright) have kinda gotten on my nerves. The Dell P1130 is 21" worth of flat, anti-glare goodness.

[yyonline]

Re: Dell P1110 21" CRT repair thread

Did you try the monitor's "color return" feature (accessible via the normal menu)? That brought most of the Dell Trinitrons at work back to normal color, even some of those that were showing the retrace lines.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Well, since i don't have a VGA cable atm that means i can't get into the menu either. I own another similar monitor, an IBM P275, and as far as i remember that very function is responsible for the increasing brightness. And since i have already built the service cable and have the software, why not do it the right way.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Alright, that software almost made me have a heart attack. But, eventually, it is solved. I also posted this in the relevant thread on Icrontic, which is 24 pages and several years long... Here's what i had to battle:

1. Sometimes WinDAS will not connect to the monitor unless you try to connect immediately after you switch the monitor on.
2. I have found that my monitor loses the 5v standby rail at a certain point, making WinDAS unable to save the file completely. The solution was to draw a wire from my power supply's 5v line and wire it up to the 5v of the TTL cable.
3. My P1110 will not load the file immediately after save - i need to turn it off then back on. Otherwise the WinDAS software would hang after the 2nd bar and the monitor would be DEAD. Still, after the WinDAS hang, ending the process, unplugging the power then plugging it back in, and opening it up and selecting Load File again would write the file properly and the monitor would wake up. Phew. I almost thought i bricked it.

Can't wait to pick up that VGA cable tomorrow. Btw, i used a XP virtual machine inside VMWare.

[Sparkey55]

Re: Dell P1110 21" CRT repair thread

I have that same Dell model with the over brightness problem ( now fixed). I fixed mine by parallelling a string of seven 10 meg ohm resistors across a feedback resistor near the G2 takeoff. Now setting the brightness near halfway is fine.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

I steered clear of that method because i read it messes up the colors and sometimes even the brightness control. If it is MCU controlled let's do it the right way.

Btw, i also got WinDAS working on my Win98 laptop, i had to copy the OCX file in the activex folder to the main WinDAS folder to get it to open the model list. The monitor still wants 5v supplied externally like i said, but that laptop does also have an USB port so i can get it from there.

[Krankshaft]

Re: Dell P1110 21" CRT repair thread

Was the screen voltage adjusted improperly at the factory or is it the result of corrupted data in the EEPROM?

Man this is a lot of effort for eliminating a screen pot. What we're they thinking? If they had to over complicate the matter why didn't they just have a hidden service mode where it can be adjusted on screen like 99% of all other CRTs factory settings?

Engineers they're always finding a way to make something simple more complicated .

So how does the MCU regulate the voltage to G2? PWM?

I'd think they'd have to take the boosted line voltage from the flyback and pass it through some type of external voltage regulating circuit.

Doesn't seem to me like it would save the manufacturer any money in component costs. It's baffling why they went with this setup.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Was the screen voltage adjusted improperly at the factory or is it the result of corrupted data in the EEPROM?

Corrupted data.

So how does the MCU regulate the voltage to G2? PWM?

As far as i've read, yes.

Doesn't seem to me like it would save the manufacturer any money in component costs. It's baffling why they went with this setup.

It's not for saving money. It's for having that nifty "color return" function, which supposedly compensates for the aging of the tube and brings the monitor to like-new condition. Unfortunately, that function has the habit of turning the G2 up, up, and up, till the issue described takes place.

Btw, the guy told me it isn't scratched. I think he meant, it isn't scratched a lot. It has quite a few vertical scratches. They didn't pierce thru the anti-glare coating all the way so they're not extremely annoying (on the IBM i have a horizontal scratch all the way thru the film at the top right), but there's a number of them. I'll probably take the anti-glare coating off. My Nokia doesn't even have it and there's been no problem with reflections.

I got the VGA cable now. It's going to require a bit of adjustment but overall it's looking good. Picture is nice and stable, focus is decent, convergence needs to be done but that's available from the menu, and even with no adjustment it's perfectly readable at 1600x1200. Btw, i dropped the G2 even lower, to 76, and the brightness still has enough range.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Alright, fiddled with it a bit more. I did the "color return" thing and it's funny - it got a bit brighter again (albeit the G2 value stayed the same, i checked), but the greenish tint did not go away. Fortunately it has an "expert" color menu, where you can set bias and gain of each individual gun. I lowered the green bias and that took care of it. I then used this page to calibrate the colors: http://www.photoscientia.co.uk/Gamma.htm I went for 2.2 gamma.

I found the service manual and tweaked the convergence pots on the back of the deflection a little, and it's looking really good. I figured it's good enough to go on my desk as my main monitor.

First impression? Mixed emotions at best. I knew my Nokia 920C was a good monitor (i also put quite a bit of work in calibrating it), but only now i realize it isn't a good monitor - it's an AWESOME monitor. The P1110 Trinitron is bigger? Yes. Brighter? Yes. But can i call it better? No... In fact, put head to head, the Nokia wins, hands down.

First of all, let's start with power up. From a cold start, the Nokia has some slight convergence issues, which normalize in the first 15 minutes. Nothing else. The Dell P1110 is $&@#!^* bright for like the first half hour, geometry, size and position also being slightly off. I'm used to it from the IBM i have at my grandparents' place - first half hour is basically tweaking the brightness and contrast till it settles. Any normal tube gets darker as it ages - a Trinitron gets brighter.

Next up, contrast. I like to run my monitors really dim at night. If i turn the contrast on my Nokia to minimum, i can't see $*!#. At night i run it at 20 or maybe 15. This one, contrast is too high even at 0. Not as bad as the IBM i have, but it's certainly going to require more tweaking...

Focus. On Trinitron tubes, focus gets softer as refresh rate increases. 75Hz at 1600x1200 is significantly better than 85Hz, but the Nokia can do 1600x1200 @ 75Hz just fine as well, it's just that my eyes can't take it. Even the custom 1440x1080 @ 85Hz that i had on the Nokia looks slightly blurrier on the Dell. Now, i'm sure this can be improved and i'll take my time, but again, good ol' Nokia wins.

And finally, there's that god-awful antiglare film. Not only is it scratched, but when cleaning it with regular household cleaning products they all leave a blue hue... and you have to rub it with the cloth over and over till it goes away. I'll have to take it off.

Don't get me wrong, this is not a bad monitor and i like it... It's just "not quite there".

[lti]

Re: Dell P1110 21" CRT repair thread

The Dell P1110 is $&@#!^* bright for like the first half hour, geometry, size and position also being slightly off.

My Sony Trinitron monitor does the same thing, but it didn't when it was given to me.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

It's just the nature of the beast, that's what the tube does when it ages. Now the really funny bit. I've spent my past couple hours setting up various resolutions. What looks best is - hold on to your seat - 1856x1392. At 84Hz.

It's unofficial, unsupported, and probably even unsafe. But it looks f'n awesome. The downside is that you can almost see every little circuit of this monitor at work - the edges wiggle ever so slightly, every little step in the geometry menu affects the picture a lot, and it even got a bit of the contour on the right side of stuff thing my IBM has... fortunately nowhere as bad as that one. Well, it's the same platform, so it's kinda obvious it'll have the same quirks. Looks like there will be work to do on the signal board.

I'll probably move back to a more sane resolution now.

Alright. Let's have some upsides now. Colors are more vivid and better defined than on the Nokia. And at the same 1440x1080 @ 85Hz that i ran on the Nokia the Dell does indeed look crisper. But, it probably does so simply because it's larger. I'll keep tweaking... maybe something good will come out of it.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Nooooo... It has the very same white shadow on the right of dark stuff that the IBM has... Like i said, it isn't as bad, but enough to make stuff appear that isn't there. It's impossible to do any graphics editing on this thing.

Speaking of which, the 19" Eizo in the living room isn't used anymore due to exactly the same problem... And that one isn't even a Trinitron. They've gotta have something in common and i believe messing around on the signal board can provide some answers. I'll practice on the Eizo and see what i get.

[momaka]

Re: Dell P1110 21" CRT repair thread

A Sony Trinitron monitor thread without me - that can't be!

Alright, that software almost made me have a heart attack. But, eventually, it is solved. I also posted this in the relevant thread on Icrontic, which is 24 pages and several years long...

Call me stupid but I can't find a link to that thread. Any chance you can post it here? I have quite a few Sony monitors, so it would be nice to have. All I have is this:
http://www.piclist.com/images/com/ge...ndas/index.htm
Any idea if this article/web page is any good?

Did you try the monitor's "color return" feature (accessible via the normal menu)? That brought most of the Dell Trinitrons at work back to normal color, even some of those that were showing the retrace lines.

I don't know how accurate this is, but I read that if this trick doesn't work, you can also turn up the brightness all the way up, then run the color return and it will supposedly turn down the G2. But again, this may be false information. I just remember reading it on some forum when I was looking at random articles for my broken GDM-FW900. The GDM-FW900 also has MCU-controlled G2. In fact, I think most (if not all) Sony CRT monitors do.

Alright, fiddled with it a bit more. I did the "color return" thing and it's funny - it got a bit brighter again (albeit the G2 value stayed the same, i checked), but the greenish tint did not go away. Fortunately it has an "expert" color menu, where you can set bias and gain of each individual gun. I lowered the green bias and that took care of it. I then used this page to calibrate the colors: http://www.photoscientia.co.uk/Gamma.htm I went for 2.2 gamma.

Looks like a good article. I'll definitely read it when I have time.
I had the same green-tint problem with the working GDM-FW900. It took a bit of playing around with the color biases and gains while viewing some pictures that I've viewed over 100 times on many different monitors. Ended up doing the same as you - just turn down the green bias and gain. I've only played with that monitor for about 1 hour, though, and I believe there was still a trace of green tint when I was done. Right now it's summer and it's just too hot to be running that monitor, so I'm using different monitors. But as soon as we get cooler weather, I'll be putting it on my desk .

By the way, I remember my GDM-FW900 had funky convergence when either the bias or the gain (I don't remember which) was set above 90%. Might be worthwhile to check on yours. My 21" Dell D1626HT doesn't have those problems, though.

Next up, contrast. I like to run my monitors really dim at night. If i turn the contrast on my Nokia to minimum, i can't see $*!#. At night i run it at 20 or maybe 15. This one, contrast is too high even at 0. Not as bad as the IBM i have, but it's certainly going to require more tweaking...

Why not turn down the brightness instead? On all of my Sony Trinitrons, I have them set so that the contrast is at or near 100%. I then adjust the brightness to the point where I can't tell if the monitor is on when displaying a full black screen.
If needed, go further down in brightness, and turn up the gamma a bit.

And finally, there's that god-awful antiglare film. Not only is it scratched, but when cleaning it with regular household cleaning products they all leave a blue hue... and you have to rub it with the cloth over and over till it goes away. I'll have to take it off.

I think all monitors with anti-glare coating have this problem. My Samsung SyncMaster 955DF is probably the worst I've seen - no matter how much I clean it and rub it and polish the screen, it still looks like it has finger prints on it (and it doesn't, it's just the anti-glare that looks spotty).
If you end up removing the anti-glare on yours, let me know how it goes. There's a Sony Trinitron E540 at my the workplace I volunteer that has a really deep tear in the anti-glare coating. No one is using that monitor and I'm pretty sure they will throw it away eventually (they already threw out one E540). I just want to know in case I salvage it .

Nooooo... It has the very same white shadow on the right of dark stuff that the IBM has... Like i said, it isn't as bad, but enough to make stuff appear that isn't there. It's impossible to do any graphics editing on this thing.

Can you post some pictures of that? I have an old HP A4032A (Sony Trinitron tube) that has 2 thick bright bars in the vertical direction - not sure if that's the same problem as yours, but I'm curious anyways.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Call me stupid but I can't find a link to that thread. Any chance you can post it here? I have quite a few Sony monitors, so it would be nice to have. All I have is this:
http://www.piclist.com/images/com/ge...ndas/index.htm
Any idea if this article/web page is any good?

That's what i have too. As for that thread, if you looked for "dell p1110" it would have been among the first 5 results... http://icrontic.com/forum/showthread.php?t=19549

Can you post some pictures of that? I have an old HP A4032A (Sony Trinitron tube) that has 2 thick bright bars in the vertical direction - not sure if that's the same problem as yours, but I'm curious anyways.

I don't think it's the same issue. Here's the white shadow i am talking about, albeit on a different monitor, a 19" Eizo which isn't a Trinitron. I took that one apart and cleaned it, we'll see if it's still there when i put it back together. Next step is changing all the caps, but they're all Rubycon and United Chemicon... The severity of the shadow depends on the horizontal scan rate (that means both higher resolution and higher refresh rate make it worse, but high refresh rates at low resolutions are fine).
http://www.imgurl.ro/di-NB2I.jpg

[momaka]

Re: Dell P1110 21" CRT repair thread

That's what i have too. As for that thread, if you looked for "dell p1110" it would have been among the first 5 results... http://icrontic.com/forum/showthread.php?t=19549

Thanks.
After using my Dell D1626HT yesterday, I feel that I might have to turn down the G2 on it sometime soon. Right now I have to set the brightness to 10% or less in order to get a completely invisible black screen at night. I guess it's okay for now, but if it gets brighter, I'll do it.
Contrast is also rather unimpressive, but still better than any LCD.

I don't think it's the same issue. Here's the white shadow i am talking about, albeit on a different monitor, a 19" Eizo which isn't a Trinitron.

Yeah, that looks much more different from what I have.

Next step is changing all the caps, but they're all Rubycon and United Chemicon...

I don't know if that will help, but I guess it's worth a try.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Some said it could be the tube, but that's something i'm not willing to accept, especially since i scoped the signals going to the tube and there is some ringing on them (which indicates some type of signal issue somewhere). There are a ton of small caps on the signal board. I wish i had two monitors with identical tubes, so i could swap boards around and see if the issue moves from one another.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Well, my wish has been granted. I'll be picking up yet ANOTHER 21" Trinitron, it's an IBM. Probably the P275 like i have at my grandparents'. So i can tinker away at one of them while still having a nice main monitor. And when i'm done, i'll just swap 'em around and fix the other one.

Btw, can't beat the price. F-R-E-E. And the guy giving it away also happens to live 15 minutes from my place.

[momaka]

Re: Dell P1110 21" CRT repair thread

Well, my wish has been granted. I'll be picking up yet ANOTHER 21" Trinitron, it's an IBM.

Awesome!
Good to see yet another nice CRT monitor saved from the trash.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Well, since here everybody jumps on free stuff, someone else picked it up before me. Looks like i'll use that 19" LCD i have sitting around as my main monitor, while i tear down and fix the Dell.

[deathamatend]

Re: Dell P1110 21" CRT repair thread

I was wondering if anyone could give me some pointers on a no power condition on a P1130 Dell monitor I have had since new? It had a great picture until it went out in July. Thanks!