My beloved display went bad

[Behemot]

My wonderfull 22'' Trinitron Philips Briliance 202P4 just went useless

It's been continuosly shifting image from left to right or back last two weeks, I first thougt maybe VGA was getting bad due to the 100% load 16 hours a day (bitcoin mining) or maybe it's the heat. Now geometry went to hell, the image was like being compressed to center.

Fortunatelly I have a spare HP P1110 but the image quality is not anywhere close and it's also physically larger. It also can do only 1856x1392 top at 85 Hz. Worst-case scenario is second-spare 21'' Dell but it has some scratch on the glass.

Unfortunatelly I don't even have time now to have a look on that but I will in next weeks for sure. Any CRT expert here I can count on?

[goontron]

Re: My beloved display went bad

sounds like a horizontal/vertical sync issue. im not sure what controls the yoke coil, but i know that a problem with it can cause that problem.

[lexwalker]

Re: My beloved display went bad

My wonderfull 22'' Trinitron Philips Briliance 202P4 just went useless

It's been continuosly shifting image from left to right or back last two weeks, I first thougt maybe VGA was getting bad due to the 100% load 16 hours a day (bitcoin mining) or maybe it's the heat. Now geometry went to hell, the image was like being compressed to center.

Fortunatelly I have a spare HP P1110 but the image quality is not anywhere close and it's also physically larger. It also can do only 1856x1392 top at 85 Hz. Worst-case scenario is second-spare 21'' Dell but it has some scratch on the glass.

Unfortunatelly I don't even have time now to have a look on that but I will in next weeks for sure. Any CRT expert here I can count on?

Sounds like the pincushion has gone nutz. When it started to shift left and right, the horizontal position control section was already problematic due to possibly dry solder joint or some failing component. Would be easier to troubleshoot if have the schematic or the service manual.

[Behemot]

Re: My beloved display went bad

I'll open it as soon as possible…

The HP died as well Some troubles with width, probably in the SW (I use PowerStrip to make resolutions which are not in EDID but the display can handle them, sometimes it gets messy). I tried to fix it with setting width on the monitor directly and, well, it didn't handle 100 %. One would ask why the hell they offer settings which will blow transistor in the display…

Anyway, I won't be reapiring this one, the image quality is not good, it's bigger than other displays of this size and also it has even more scratches than the Dell. It is P1130, can handle 1920x1440 just fine with better image so I will stick with it for now. Hopefully it won't die again…

[ben7]

Re: My beloved display went bad

Open your trinitron up, and look for bad capacitors, cracked solder joints, and/or overheated parts. Some pictures will help us too

[Behemot]

Re: My beloved display went bad

Open your trinitron up, and look for bad capacitors, cracked solder joints, and/or overheated parts. Some pictures will help us too

As I said, I don't have time right now - doing some reviews and stuff and than I have to run home and visit my dentist So this was more like information post for now. Images and other stuff will be as soon as posible

[shovenose]

Re: My beloved display went bad

People still use CRTs? Just get a good IPS LED-LCD monitor and be done with it! Just don't get a Dell S2440L no matter how cheap, it's a piece of shit.

[ben7]

Re: My beloved display went bad

People still use CRTs? Just get a good IPS LED-LCD monitor and be done with it! Just don't get a Dell S2440L no matter how cheap, it's a piece of shit.

I still use a dell trinitron CRT with my desktop, it works like a champ!

Besides, I'm actually not a big fan of giant and/or high resolution displays ... every person has different likings...

[Sparkey55]

Re: My beloved display went bad

People still use CRTs? Just get a good IPS LED-LCD monitor and be done with it! Just don't get a Dell S2440L no matter how cheap, it's a piece of shit.

I have 12 CRT monitors.

[Pentium4]

Re: My beloved display went bad

CRT's have such crisp colors. What's that famous Sony one, the FW900?

[Behemot]

Re: My beloved display went bad

Wide display?

[Behemot]

Re: My beloved display went bad

Oh bloody hell, now even the Dell P1130 died. I smelled something, than the image shrunk into the middle and went black. From than I only got LED.

I got it opened right here, all I can see with naked eye are some darkened spark gaps. What should I look after? Probably some transistors went bad? It's quite hot now. And can I remove that HV sucking-disk electrode from the electron tube?

[goontron]

Re: My beloved display went bad

from what i gather: when the arc-gaps are cooked the flyback is dead.
soooo, back to triniton (as in weight)?

[stj]

Re: My beloved display went bad

get a schematic.

there are 2 halves to crt based kit.
we want to split them and test them seperatly.

the psu supply's between 70 and 160v to the main section - it's called B+

you can isolate this by removing an inductor usually or with philips kit, buy pulling the scancoil plug because it has a B+ loopthrough.

so anyway, you want to isolate B+ and connect it to a 60w house lampbulb.
then power the unit up.
if it lights and is stable, we move on to the fun section.
otherwise it's a psu repair.

you may also want to pull and test the line-output transistor.
that's the big heatsinked bastard that connects he high voltage transformer to ground.

probably should post a safety dislaimer here so :

if you kill yourself - it's your problem.
it's not the voltage or current that kills you - it's the thing you smash your head against as you fly backwards!!!

right - got that out of the way.

the anode cap is usually a pair of spring-wires going left and right relative to the cap.
you shove the cap to one side till it pops out of the tube, then slide it the other way.
DONT TOUCH THE TUBE OR ANYTHING EARTHED WHILE YOU DO THIS - RUBBER GLOVE MAY BE A GOOD IDEA.

and dont touch thw hole it hooks into afterwards either - it can hold over 20,000v for atleast a month.
trust me on this - it's a giant capacitor!!!

[rievax_60]

Re: My beloved display went bad

Some CRT monitor designs have a small transformer just for the Horizontal Raster Shift function.
This transformer can develop shorted windings causing the whole monitor to not work.
The monitor would usually work again when the faulty transformer is removed.

[kc8adu]

Re: My beloved display went bad

careful removing the hv lead.besides the possible zap trinitrons have the h-stat line coaxial to 2nd anode.
bend that pin and the tube leaks.as in goes to air.

[Behemot]

Re: My beloved display went bad

get a schematic.

there are 2 halves to crt based kit.
we want to split them and test them seperatly.

the psu supply's between 70 and 160v to the main section - it's called B+

you can isolate this by removing an inductor usually or with philips kit, buy pulling the scancoil plug because it has a B+ loopthrough.

so anyway, you want to isolate B+ and connect it to a 60w house lampbulb.
then power the unit up.
if it lights and is stable, we move on to the fun section.
otherwise it's a psu repair.

you may also want to pull and test the line-output transistor.
that's the big heatsinked bastard that connects he high voltage transformer to ground.

probably should post a safety dislaimer here so :



right - got that out of the way.

the anode cap is usually a pair of spring-wires going left and right relative to the cap.
you shove the cap to one side till it pops out of the tube, then slide it the other way.
DONT TOUCH THE TUBE OR ANYTHING EARTHED WHILE YOU DO THIS - RUBBER GLOVE MAY BE A GOOD IDEA.

and dont touch thw hole it hooks into afterwards either - it can hold over 20,000v for atleast a month.
trust me on this - it's a giant capacitor!!!

OK I'll try but will need some help on this I guess.

As for holding charge, can I discharge that with e. g. 100k resistor to ground? I have already removed most of the housing, just the HV thingy is there and I cannot fully remove the board because it is connected to HV transformer.

Whaddaya mean kc8adu?

[stj]

Re: My beloved display went bad

100k?? if you want to see a resistor explode!!

you can do it with a bunch of 1meg or 4meg7 resistors.

best is to get high-voltage ones, put 2 or 4 in series.
solder them together in a string and slide some plastic tubing like a bic pen body over them.

put one wire on the earth-strap of the tube, then slip the other wire under the cap and leave it for an hour.


there are 3 ways people used to deal with this.

old timers used to use a pair of screwdrivers or a screwdriver with wire wraped round it to short the tube - DONT DO THIS EVER it will damage cmos chips nearby.
and has been known to damage diodes in the line-output transformer.

people who gave a shit used to discharge them with a high-voltage meter probe.

hardcore people like me dont give a fuck and just dont bother discharging them.

[Behemot]

Re: My beloved display went bad

Well what capacity does it hold? With 100k resistor it is 0,3 A at 30 kV. So better 500k that's 0,06 A ;-)

So just do a resistor net (can isolate them with double heatshrink) and stick it between ground of the tube and the electrode, that's all? The ground is not grounded when everything is disconnected though.

And I can remove the sucking cap? Cause I got one 17'' trinitron which has this cap bad, it looses the underpressure every time and falls off. Than the electric field is not strong enough to accelerate the electrons and image is everything from bad to none. I tried lubricating the rubber under the disk, hell I even tried superglue, nothign helped. That's why I am afraid of removing this thing…btw been touching this one with no problem. It gets discharged if the tube looses power while (like turning it off) in operation, no?

Here is the schematic.

[stj]

Re: My beloved display went bad

it's not a "sucking" cap, it's just like that to keep dust and moistue away from the contact so it wont arc across.

and the reason you want to discharge it slowly is because the voltage is so high that you dont want to damage the resistor(s)
that's also the reason for puting it in a tube.
it's all about the voltage.

some transformers contain a bleed resistor that will slowly discharge the tube when the tv is off, MOST DONT.

i'll say it again, THE TUBE IS A HIGH-VOLTAGE CAPACITOR!

i'll go find a foto or 2 of an anode cap for you.