Sony Trinitron CRT Monitor Wavy lines/distortion

[nick3092]

Not sure if this is something you guys usually discuss/troubleshoot here, but I'm running out of options.  So I figured I would ask.  I have nice 21" Sony Trintron CRT that I keep around for a specific use, and a while back it started failing on me.  I powered it up one day, and was greeted to a rather distorted image.  The OSD with nothing connected is also distorted, so it's not the PC or the input.  I tried to find anyone local who still works on these, and couldn't.  So Self repair seems to be my only option.

First thing I did was pull the power board and try to bench test it.  However, I found the board does not like being run outside the chassis for some reason.  I was getting some inaccurate voltages, and I had to trick it into powering up due to the standby mode.  So I put it back in the chassis, and the readings look very good while the board is in the chassis:

-15v rail (measured -14.5v)
+15 rail (measured 14.5v)
+80 rail (measured 78.2v)
+200 rail (measured 199.3v)

I showed the picture to a few people, and pretty much people either said it was the deflection board or the power board.  And it was most likely a bad electrolytic cap.  Unfortunately, I have found that not to be the case.  Or any e-cap at all.  Board by board I recapped the entire monitor (except the H board with the user controls on the front).  After each board, I reinstalled it and checked the monitor.  I saw no change either way, good or bad.

I looked over the deflection board for any broken/cracked solder joints, I couldn't find any.  To be safe, I reflowed a bunch of joints on the board, focusing on anything attached to a heatsink.  Nothing helped.

I did notice that the ripples running up and down the left and right sides of the screen change slightly if you mess with the geometry settings.  Except in one spot on the screen.  This spot on the screen never changes.  Its always the static plateau, valley, plateau, valley while adjusting it.  Not sure if that means anything.

Its possible whatever this is, is a defect across all similar Sony chassis.  Someone else found an eBay listing of a Sun monitor with a Sony chassis exhibiting the same thing.  Although, it looks worse than mine.  And according to the service manual for that monitor, the deflection board is about 99% identical to mine.  So my money is on a common issue with this design  The million dollar question though, is what?
https://www.ebay.com/c/13014969428

This is about as far as my CRT troubleshooting knowledge goes.  I'm looking for someone to help guide me to find the defective part.  I have a Rigol 1054z and can post screen caps.  But I'm not great with using a scope, and as I mentioned, not good at trying to figure out what to look at on a CRT.  So the more explicit the directions, the better.  The deflection board can be a bit of a challenge to try and get some readings off of it.  It's mounted to a metal cage that covers up the bulk of the solder side of the board.  It hangs vertically on the side, so its pretty much impossible to run the board without being attached to the cage.  So, I have to try and get most from the component side.

Here is a link to the service manual:
https://www.manualslib.com/manual/990031/Silicon-Graphics-Gdm-5011p.html

Again, sorry if this isn't something normally worked on here.  TIA for any help or advice.

-Nick

[MosherIV]

Hi
Welcome to the forum.
First note about safety! CRT screens hae 32,000V driving the electrons from the gun at the back to the front, so be very careful!

From the picture of your screen and distortion, it looks like everthing is working just the start of horizontal scan is irregular.
Star by looking around at the various silicone chips on the boards, download the data sheets for them.
You are looking for devices that control the electron beam horizontal beam (it will also  do the vertical at the same time).
Them visually trace the horizontal signals through the tv.
Check carefully for dry joints or loose cables.
The problem could be a capacitor going bad but start by checking the signal path.

Try not to do any work on it while powered on unless you have to.

I fix an old tv many years ago using this technique. Found it had dry joint in vertical scan.

Good luck. Stay safe. Do not do it if you feel you do not know what you are doing!

[CaptDon]

A couple of thoughts. The horizontal processor I.C. circuit. Either the
I.C. itself or a small bypass capacitor like .001uf / .01uf size is open.
If he crazy horizontal distortion is all randomized I have seen arcing
in the flyback / high voltage section cause a picture looking exactly
like this. The arcing interferes with the horizontal sync so the start
of the horizontal sweep gets all crazy and displaced. Listen, Look and
also sniff for the ozone scent of corona/arcing.

[nick3092]

Thank you for the advice.  I do know very basic electrical theory and what not to do/touch in a CRT.  I've taken several measurements, but never quite knew what I was looking for or at, so never got far.

Using your advice, I checked the wave forms at the horizontal yoke.  They have some sample waves for the deflection (D) board shown on page 27 in the service manual.  So I figured I'd start at the yoke and work my way back.  I took snapshots of waves 4 (H DY H) and 5 (H DY C).  I basically put the probe into the connector where the wire goes into the connector on the deflection board, pressed auto on the scope, and then increased the horizontal sweep to see more than one wave.  Not sure if that is the best way to do that.

Wave 4 looks pretty good against the manual.  But wave 5 almost looks like like there is a second offset wave interfering.  The peak to peak voltage is also off from what my scope is calculating compared to the manual on both waves.  Wave 4 says it should be 600v p-p, but I'm getting just over 1kv.  And wave 5 should be 120v p-p, but I'm only getting 39v p-p.  Not sure if that just has to do with things like resolution and what is on the screen at the time, or if it's also an indication of the issue.  The manual doesn't really give any parameters for what the monitor should be displaying when looking at these waves.

Given the 2nd overlapping wave in print 5, would that mean I want to focus on following the H DY C circuit back now?  What would be the next logical point to look at?  I don't really know anything about video circuits, so I wouldn't even be able to guess what to look at next, and what it should look like.  The other set of sample waves in the manual would be 2 and 3, which go back to Q504/505 base and Q506 base.  All 3 are labeled H drive.  Q506 is a through hole transistor, but impossible to get at from the component side.  Q504 and 505 look to be SMD parts on the solder side.  Luckily, the metal shield is perforated where they attach to the board.  I should be able to clip a short wire to my probe clip and thread it through the holes to check them, if it would be helpful to narrow down the issue.

I hear some buzzing/crackling.,  but its not super loud.  I assume that is just normal CRT static noise.  Although its been a long time since I was around CRTs on a regular basis to recall what they sound like normally when running.  I can't say I smell any ozone though, or hear any real loud pops/crackling.

Thanks!

[T3sl4co1l]

Definitely deflection.  Possibly pincushion.

Anything vary with mechanical movement?  Vibration, pressure?

Tim

[MosherIV]

I doubt it is the horizontal drive circuitry is bad because you are getting a good picture. If the coil drive circuit was bad, you would not get a complete screen.
More likely some wrong with the low voltage control and waveform  generation circuit.

Maybe check out what Captdon says. See if you can track down where the buzzing/crackling sound is coming from. CRTs should not make crackling noises after they have started up.

Something is disturbing the horizontal timing, it should be very regular but you should find that the blanking period (when the beam sweep off edge of screen back to other side/beginning) has become irregular.

Have a look around the chip that generates these waveforms.

[nick3092]

I think the buzzing noise I'm hearing is coming from the flyback transformer.  I noticed just now it seemed to be loudest when I had my head near that back corner of the chassis where the FB is.  I opened the chassis/cage "wings" which moves the deflection board out of the normal area to get a better listen, and the buzzing definitely seems to be coming from there.  I thought the FB just provides the high voltage.  It couldn't cause this kind of issue, can it?

When tapping on or shaking the bezel around the screen, nothing seems to affect the picture.  So it doesn't see m to be caused by a loose component/bad solder joint.  I had the monitor shaking pretty good, and didn't see anything.

As far as probing with a scope, I'm not really sure where to probe, or what to look at.  So I tired to probe the bases of Q504 and Q506, since they are shown on page 27 of the manual.  Q504 was a bit hard to get to and see, as I had to probe through the vent holes on the cage using a short piece of wire with my fingers.  I think I hit the base, but not 100% sure.

The Q504 wave form over all looks like #2 in the manual, with a bit of some noise at the top of the wave?  And the Q506 wave looks kind of ugly.  Not sure if it's exhibiting a ghost wave that is slightly offset from the original wave.  Plus some noise maybe?  I'm not really sure how to interpret these, so I've attached them if they are helpful.

As far as where to look next, I'm afraid I'm kind of lost.  If you can look at the schematic and tell me exactly what component or IC pins to look at, I can try and grab some waves if I can.  I'll need help looking at them though as I don't really know what they should look like.

[james_s]

That is a really bizarre symptom, I worked on a lot of CRT monitors back in the day and I never saw a fault quite like that.

I think I would look at the circuitry that handles geometry correction, particularly the power rails. These big Sony workstation monitors were the pinnacle of CRT display technology, they are very complex devices but it looks like yours is *mostly* working. Does the symptom change at all as it warms up? Do all of the geometry controls in the user menu do something?

[nick3092]

I can't say that I've had it on for more than 10 minutes since the fault occurred, but nothing really changes within that time frame.

When adjusting geometry controls, it seems like the screen is adjusting per the setting being changed.  Sometimes its hard to tell though with how distorted the screen is.  The power rails *should* be clean, every electrolytic cap in the monitor has been replaced, except for the two on the user control board in the front of the monitor.  But I'm glad to probe with the scope if you have any specific locations I should look at.

However, I just found new symptom.  Not sure how it correlates the display issue (or if it does at all).  It could very well be a totally unrelated fault.  When using the down arrow on the control panel, sometimes when you press it, I hear a relay click, the monitor goes blank for a second, and comes back.  But when it comes back, whatever is on the OSD is gone.  It happened while navigating the 9x9 OSD menu, while scrolling down in the geometry submenu, and while just pressing it with the OSD menu off to adjust brightness.  But it's sporadic.  Sometimes it took probably 20 clicks, other times 4, and other times it would do it back to back button presses.  I find it hard to link this to a horizontal sync issue, but I figure its worth noting.  Even when the monitor was working normally, I couldn't tell you the last time I even used any of those functions.  So its possible it predates the current issue.  Never seemed to happen with the left, right or up buttons.  Just the down button.

Edit:

I just had the idea to disconnect the connector from the deflection board that goes to the control panel on the front.  When I powered up the monitor, it came on and it looked like the brightness (up/down) and contrast (left/right) menu was on the screen.  This is the menu that pops up if you press up/down/left/right with the OSD menu off.  And the brightness number was going down, and that arrow was constantly flashing.  After it got to 0, the arrow kept flashing.  Then after ,maybe 10s of sitting at zero with the down arrow still flashing, the monitor did its clicking/blanking routine a few times.  I unplugged it shortly after.  So, something is screwy here.

[vk6zgo]

If the perturbations of your display are stationary, or drift up or down very slowly, that points to a relationship to the ac line frequrncy.

In any case, go back to where you were looking at the H yoke connections.

Now, instead of trying to look at the signal at horizontal rate, try setting the 'scope to around 5ms/div.

Oscilloscopes often have a position on their "triggering" switch called "line" -----this does not mean "TV line rate" but triggering from the "ac line" (50 or 60Hz).
If your 'scope has such a position, switch to it.

If as mentioned above, the problem is related to the mains frequency, you should see many cycles of the horizontal scanning frequency, riding upon an unwanted Mains frequency waveform, or one at a multiple of Mains frequency.

If the interfering signal is not locked to Mains, switch to "normal" triggering, as you can still find interesting information from this test.

Now, look at the DC supplies you already measured with your DMM.

A multimeter may read close to correct, even though there is a lot of hum & crud on the DC.

[nick3092]

I rechecked the horizontal yoke connector, and this time set to 5ms.  My scope doesn't seen to have a line option for trigger.  Just edge, pulse, slope, video, pattern, and a bunch of other specialty triggers that I don't think would apply.  Also, this time I noticed the H DY C wave looked clean compared to the one i took earlier today.  no ghost images, and now looks like the sample in the manual.  I also attached a picture of that clean wave as well.

I scoped the power rails at the connector on the power board.  I don't see any major AC ripple, unless I'm missing something.  I've attached them as well.

[SeanB]

Likely high voltage arcing. Either the series resistor from the LOPT to the CRT, in the lead, is open circuit and arcing over the resistor, or the LOPT or some part of it, like the screen or focus pots, are arcing over.

Frst try is to resolder every joint on the LOPT transformer, the LOPT driver transistor and every part associated with the drive of that transistor, along with every component attached to the heatsink, and any power resistors and large capacitors there. Clean the board afterwards, and check for any other dry joints. Most common failure points are cracked joins, and they then send off the expensive parts.

[MosherIV]

Why do you keep probing the high voltage coil drive circuits?
A few people here have told you that those look to be working correctly, since you get a complete screen but distorted.

You need to look at the low voltage circuit that generate the saw tooth ramps that drive the high voltage circuits. These are probably hard to get to when the monitor is powered, it is likely the large circuit board on the bottom.

Not sure if the lopt is arcing or not, sometimes they do buzz.
If you can hear clicking, then it is definitly arcing.
The fact that you get a complete picture means that the lopt is working, well at least to generate all the high voltages needed to drive the electron beam accelerator and the deflection circuits.

I am not sure if your new tests and symptoms are a problem or just lack of input board causing the controller to think that brightness decrement is being selected all the time.
It may point to a poor 0V connection somewhere which may also be causing the distortion.
Check all the leads and connectors - loose or broken wire, oxidation on connector pins or crimps.
Unplug both ends of cables and check continuity to be sure.

As well as the service manual, have you downloaded the data sheets for all the chip devices in the monitor?

[Labrat101]

Have you checked the degaussing circuit there is a small square thyristor if it goes short it will also cause
a horizontal problem .
From the pictures Its does look more like a degaussing problem . this section is often over looked .
Had similar problem on another CRT.
Also check there are a few high voltage ceramic caps that go leaky hard to spot
also it could be your flyback transformer with a shorted turn .
But usually its a failing cap near the flyback stage . If the flyback is out it will reduce the voltages
But Check the obvious first  ""Above""

If you must use your scope try the TV section or you will get just the  unexpected . Frame sinc ,Glitch ,
the flyback transformer also supplies voltages out for the grid etc.
Also remember the chassis is HOT to the scope .
BTW you screen shots   Q506 Base Wave 3.png   might be correct if ur scope was set to the correct setting .
The other pictures  all but 1 were meaning less . sorry
.

[nick3092]

SeanB: I have visually inspected the deflection board solder joints twice, and have re-soldered probably 80-85% of the through hole parts already, just to be safe.  I started with anything on a heat sink, and moved on to other parts from there.  Plus all the electrolytic caps have been replaced,so those solder joints are all good.  Not saying that some joint isn't bad, but the likely hood is low. If it is a bad joint, I'm hoping to zero in on it rather than just blindly re-soldering everything.

MosherIV: I went back to the yoke coil because that is what I read vk6zgo's suggestion to be.  I have never worked on a video circuit, let alone a CRT before.  This is all very new to me.  Which is why I have hoped for/asked for some specific guidance on exactly what components to check and interpreting the results.  I have not downloaded the datasheets for everything on the deflection board, because at this point that would mean nothing to me as I am not familiar with video circuits.  I'm not an EE, I'm just a guy who tinkers with electronics as a hobby.  And I am self admittedly over my head with this.  I would have gladly turned this over to a professional to fix, except that there appear to be none around me.  So I'm stuck trying to fumble through this myself.

If you have suggestions on which parts/pins to look at, I will gladly do my best to to report back with findings.  The deflection board is not under the monitor like in may sets.  Rather it hangs vertically and can be swung out to a servicing position, which helps give access to a large portion of the board.  I'm just asking for some help and patience as I work through all this.  And please don't get me wrong.  I'm grateful for all advise and suggestions.  I just need a little more explicit directions that probably many of the other posters here.

As for the issue with the user controls, I'm leaning towards that being a different issue.  Mostly because if it's not, I think that means the entire IC001 CPU is bad and I don't want to consider that right now.  Looking at the schematic for that board, all the buttons tie back to a single pin that runs back to the CPU.  And there are various resistors in between each switch.  So it must determine what button was pressed based on the amount of voltage it gets back on that pin.  It also looks like there is a resistor that is always in circuit between the +5standby and that pin, so it must not like seeing no voltage on the pin.

Labrat101:  I have not really done anything with the degaussing circuit.  I'm not sure how that can cause any kind of issue when it's out of circuit.  from what I see in the schematic, when the circuit is engaged, a relay energizes the circuit, and the only two parts in play are a thermistor and a varister.  I don't see a thrystor.  Unless I'm not understanding you correctly.  If I want to verify the screen print for Q506, what should I have the scope set?  And when you say to use the "TV" section, do you mean set the trigger to "Video"?

[Labrat101]

Hi first the degaussing coils are in circuit all the time they are enerjised when the set is cold and operate for about
15 sec . they are usually controlled by a thyristor or maybe a relay if they stay energized it would but an ac field
on the tube causing a nasty ripple .
Try just dis connecting the wires to this coil  .. turn it off and back on again . and see what happens . don't panic if the picture goes a funny color in the corners . or rotates slightly.

The Horizontal scan on ur Monitor is properly ntfs  if you are in the USA .
This is the sinc pulse and its sets the frame rate . its a fast burst pulse . But you need a scope that can see it correctly
I don't think yours has a line scan for NTfs pulse .. I have always use a CRT scope with the tv,frame setting.
My digital will not see it ether   .
But just leave this alone  even if you do get to see it you don't have the equipment  .
Do not change any of the Pots in this section .

See what the results are when the degaussing coil is disconnected it maybe putting a AC on your tube.
Don't look for complicated problems . It usely something stupidly simple .
if that fails . then it a ceramic Non electrolytic   cap leaky or a resistor gone hi in the frame section (were it gets Hot )

Take it slow . step by set and forget the scope just use you meter . If you have an ESR meter will help with the ceramic caps . & there maybe some small brownish ones go for those first .
Unplug it when using the meter .
your Power voltage are probable all good as you have a picture .

[nick3092]

I disconnected the degaussing coil from the G/power board, nothing changed when I powered the monitor back on.  Someone else who was looking at this with me found an indication that these N3 Sony chassis may suffer from a common issue with IC007, the deflection chip.  Here are snippets from 4 different threads:

"A defective IC007 can give a range of geometry-related symptoms, and yours are among them. For instance, distorted/squashed display, scalloped sides, jitter, unstable raster or scrolling, and the adjustments often still function."

"This chassis suffers from failure of the deflection processor IC007 CXA2403Q, this is an expensive surface mount chip about 1" sq with about 25 pins on each side."

"The 5010PT is a Sony N3 chassis - the number one failure is IC007 CXA2043Q which results in many deflection related faults."

"The CXA2043Q deflection IC is a high failure part that causes all kinds of geometry and convergence problems on that monitor. In fact, it's the only thing I can remember ever replacing on those."

Given that I've replaced the electrolytics and the low failure rate of ceramics and film caps, this sort of makes sense in my case.  Not sure if scoping any of the pins on this chip can prove that out.

It seems you can still find NOS chips.  But the problem is I don't have the tools or skills to try and replace a SMD IC.  So I would need to find someone locally who can do it, or ship off my deflection board and chip off to someone to replace.

[Labrat101]

Hi ,
If it is the deflection chip it is an expensive replacement and 100 pins to solder  .
Depending how old this monitor is . to way up the cost of repair against replacement .

But before totally condemning the chip double check for Bad Ceramic Caps   And resistors that have gone High.
In the many years that I have repaired monitors I have also lost a lot of hair over.
And found that  a 10 cent part that has failed . 9 times out of 10.

Double check . Murphy's Law Stats it will be the least obvious part that will screw ur life.
 
With out actually see the monitor it is very hard to guide u to the exact part.

Good luck

[T3sl4co1l]

FYI, my old Trinitron had a deflection-drive issue that turned out to be a cracked chip resistor (or bad solder joint).  I couldn't see anything with a pocket loupe, but that doesn't mean much; a crack doesn't need to even be visible to block a few tens of volts.  I found the culprit by probing the deflection board with an insulating stick; this wasn't the easiest process as the board is designed into a metal shield, so I kind of just had it propped up on its side... not the greatest position for something with casual 1000V traces around.

That model had independent HV and sweep, so you won't see bloom or bad focus or whatever as a consequence of bad deflection, or bad deflection as a consequence of bad HV (low, or arcing or whatever).  It had dynamic focus (hence the 1000V supply), and active pincushion which means there's literally an analog power amp tweaking the horizontal sweep!

You could be having a problem in several of these systems; it's interesting that the left and right edges of the screen look different, i.e. the position and width are both changing in an erratic manner.  Position may suggest horizontal timing, so the suggestion to check for supply bypasses, or anything related to exact signal levels and timings (signal caps, reference voltages/currents?) is reasonable.

Width suggests timing or pincushion.

I guess it wouldn't be arcing, because you'd only expect horizontal to arc during flyback, and that would severely delay retrace, making the picture much worse (like, lines jumping right by half the screen width say, and far more erratically).

I don't know what would be generating those apparent square wave edges, unless it's something like supply ripple, and the frequency happens to be HV (if it's independent) or the PSU, and these are slower than the scan rate hence you're effectively getting an oscilloscope readout of the waveform.  (Hmm, I think this would still be quite a stretch even if horizontal sweep is 110kHz and HV is 30 or 15kHz; it looks like it's much lower than that, a few kHz?)  It might make sense for them to show up towards the middle of the scan, because power consumption varies during the scan (up or down as the case may be, I'm not sure, to be honest..); or perhaps the interfering noise is quieter in that portion (perhaps because of similar reasons).

And you recapped the power supply, right?  What kind of supply is it anyway, is it one of Sony's favorite weirdo saturable-reactor-controlled resonant designs?  (Easy way to tell: there's some weird 4-pronged ferrite core with two sets of coils at right angles.)

Ed: Ah yes, my (HP branded A4576) is also an N3 chassis, so it should be basically identical, cool.

Tim

[shakalnokturn]

Arcing can confuse (sometimes destroy) the low voltage electronics because of interference. A typical case of this is poor CRT grounding.
If there is arcing usually it can be seen in the dark or smelled.

On the other hand a random drive with fast transients into power electronics and coils will make strange noises that could be confused with small arcs.

I do not know about the Sony N3 chasis as it's been over 15 years since I poked at one, but some deflection yoke assembly's have a small PCB where solders can fail too, not the most obvious place to think of...

[andy2000]

If it happened suddenly, then it's unlikely to be a cap.  They generally fail gradually as the electrolyte dries out. 

[nick3092]

To wrap this up, it was in fact IC007, the deflection process.  The NOS one I ordered showed up today, and I had found someone local who does SMD rework.  He swapped out the IC, I brought the board back home, reinstalled it, and when the monitor turned on, I had a nice, clean picture again.  Not sure why these N3's had such a bad run with that IC.  But if the last one lasted 20 years, being powered on for who knows how many hours at an SGI workstation, hopefully it will last another 20+ years in the limited usage it gets out of me.  Especially now that it has a chassis full of fresh caps, there isn't much else to go wrong.

[james_s]

Hey that's awesome! Glad to hear it's working, I love those old Trinitron monitors and remember lusting over them when I was a geeky kid back in the 90s, they were WAY beyond my budget! They were the pinnacle of CRT technology and I'm happy to see someone keeping one going, not a lot of big CRT monitors left anymore. Thanks for following up to let us know how it went. 

[Labrat101]

Good Luck .
    Well Done Nice to here the success . 
 Enjoy .
 May we all last 20 more Years .