Cause for CRT Monitor Jittering?

[sideburn]

Does anyone know what might be causing this old CRT monitor to be jittering like it is in this video?

https://youtu.be/_FlFdDvYHpA

Bad capacitors maybe?

[Armadillo]

Suspect Internal Loose Connection - Check deflection yoke plugs into the main PCB or at the base of the flyback transformer. Check for poor soldering joints and bad connections near high wattage components. Examine the solder connections on the PCBs, particularly in the area of the deflection circuits and power supply. Look for hairline cracks between the solder and the component pins - mostly the fat pins of transformers, connectors, and high wattage resistors. Just re-solder anything that look suspicious.

[JFJ]

The jitter only appears to be in the horizontal direction, which suggests that there are fluctuations in the line sync. Have you tried a different monitor (to eliminate the video signal source as being the cause of the problem)?

[Rasz]

dont you mean TV?
I have pretty much zero TV knowledge, but this looks like tv(pll?) is unable to catch sync in shitty NTSC composite signal

try connecting something using proper signal -RGB with separate sync (Euro connector).

[sideburn]

Yes I tried another tv to rule out the signal.
It is a sony monitor. Not a tv. Has BNC composite video input on the back.

[Twoflower]

That could be even outside the monitor. I've seen similar influences on CRT caused by electric trains passing by in a distance of 300ft. Not just that, as this problem was known half of the monitors in the office were covered in passive shielding, the other half they tried some active shielding (worked less effective).

So see if you can run the monitor in a different orientation to see if it changes. And or check any nearby electric gadgets.

[Rasz]

does it have other inputs? even svideo could be better

[james_s]

That looks like a hum bar, if the screen background weren't black you would probably see a bar scrolling down the screen. It can be caused by a ground loop, bad connection, or tired capacitors in the monitor. What sort of input does the monitor take?

[martinator]

Is that an Apple II?

I had the same problem with a IIe PAL machine I had.  I think it's probably a timing issue. I can remember replacing caps and all sorts and it didn't make any difference. How modern is your crt?  Newer crt's are not as tolerant to out of spec signals I suppose? Try to find one without a digital tuner. If it is an old crt and doesn't have a digital tuner then it sounds like it's scope time. 

[james_s]

I see now where it was mentioned that this is a composite monitor. Try feeding it video from another source to rule out timing issues or other problems with the computer.

[Armadillo]

Yes I tried another tv to rule out the signal.

How about a signal source from another computer showing Window on the Sony Monitor.

The signal seems to be from old computer like 6502 or Z80? What signal source is that?

[sideburn]

I have the same issue when I connect it to my art 800xl as well so I don't think it is that Apple II.
I have relocated the monitor and tried different outlets and it doesn't make a difference either.

[sideburn]

It does but they all have the same issue.

[drewscruis]

Looks like failing caps to me.

Sent from my KFSUWI using Tapatalk

[sideburn]

I think it’s caps too. Just not sure which ones. I’ll have to find a schematic and seee if I can get the values.

[drewscruis]

I have rebuilt plenty of arcade crt's, you should Google to see if someone has a cap kit available to make life easier. I'd replace them all as there pushing their service life at this point.

Sent from my SM-N910V using Tapatalk

[drussell]

Unplug the degaussing coil to make sure it isn't intermittently getting a bit of power fed to it after the initial power-up when it should stay off.  If that isn't it, check all the supply voltages to be sure they are stable and you don't see any fluctuations of the voltages when the wiggle happens.

If those are all stable then, yeah, it is probably a bad capacitor somewhere with the same kind of fault that can cause sizzles and noises in things like audio amplifiers that are often one of those great times to use an old timey audible "signal tracer."

[PKTKS]

It looks like you have a SECOND SIGNAL superimposed over the sweep

By the speed of the symptom I would guess that the  SYNCH SEPARATOR
block is faulty and the Hsynch is mixed with some ammount of Vsynch

Easy to check w/SCOPE on the output of the HSynch separator
Should have **ONLY** the proper high freq part - not the low (vertical seep)

Block faulty is not filtering the synch properly

Wild guess without the scope probe attached

Paul

[Bashstreet]

My knowledge of CRT's is also limited but i would check all connections inside first to see if something has got a bit loose or look suspicious.
Sometimes solder joints etc can also break if you move crt's.
Like someone said it might be number of things maybe caps also .

Good luck ! 

[drussell]

It looks like you have a SECOND SIGNAL superimposed over the sweep

By the speed of the symptom I would guess that the  SYNCH SEPARATOR
block is faulty and the Hsynch is mixed with some ammount of Vsynch

Easy to check w/SCOPE on the output of the HSynch separator
Should have **ONLY** the proper high freq part - not the low (vertical seep)

Yeah, if it seems to repeat at a predicable rate then it is likely a rogue signal pathway somewhere rather than the typical power filtering issues, though I suppose it could be an interaction between the power line frequency and the video refresh rate. 

That is one of those times where having a variable frequency AC supply is handy to quickly determine whether something like that is the case by being able to observe any generated beat "note."

[Bashstreet]

It looks like you have a SECOND SIGNAL superimposed over the sweep

By the speed of the symptom I would guess that the  SYNCH SEPARATOR
block is faulty and the Hsynch is mixed with some ammount of Vsynch

Easy to check w/SCOPE on the output of the HSynch separator
Should have **ONLY** the proper high freq part - not the low (vertical seep)

Yeah, if it seems to repeat at a predicable rate then it is likely a rogue signal pathway somewhere rather than the typical power filtering issues, though I suppose it could be an interaction between the power line frequency and the video refresh rate. 

That is one of those times where having a variable frequency AC supply is handy to quickly determine whether something like that is the case by being able to observe any generated beat "note."

Maybe AC line is picking signal and filter caps are bust ?

[PKTKS]

Maybe AC line is picking signal and filter caps are bust ?

Yes quite possible as well

THAT DEPENDS a **LOT** on the MONITOR YEAR (technology used)

Some old mutisynch monitors used to have  separated V/H paths
but they do MIX internally on some blocks (PSU and/or video MCUs)

More recent better monitors started to use a dedicated MCU to handle the
external synch signals which they would just "resynch" as possible to pass
that to the video controller IC

2 FIGURES of these 2 different approach attached

Note that on the ancient one the PSU also uses the SYNCH signals
to synch itself  switching freq.

SCHEMATICS will be very handy to see how the 2 separate inputs
are used along the synch path..  they do got mixed some how
and may be the AC PSU noise as welll

On the recent one the MCU handles the synch and the PSU
is not using the external synch entries as interface..

Paul

[PKTKS]

in other words... the so called E/W signal (or cushion or east west correction)
is faulty messy with some low freq noise.

Question is where that noise is entering the chain

[Fred27]

It seems this is not a problem that is likely to be rectified in the future. I was watching The Expanse and all their high tech devices seem to have screens that do exactly this. Why? In what way does that make things seem futuristic?

Sorry - a bit off topic!

[Rasz]

It seems this is not a problem that is likely to be rectified in the future. I was watching The Expanse and all their high tech devices seem to have screens that do exactly this. Why? In what way does that make things seem futuristic?

Sorry - a bit off topic!

its probably just their retro futuristic design aesthetic, like Alien/Fallout CP/M terminals