The video and audio circuitry between the input sockets and the optocouplers must have a separate power supply. Check the components in that.
Times are 5.5s, 13.8s and 22.1s.
Shapes are also clearly sine.
So horizontal deflection is feeling an extra wave.
It also seems to have a high point every 8 seconds.
Can you demonstrate different picture formats?
Those regular times are merely a consequence of the slightly different frequencies of the AC mains supply and the vertical scan rate of the video source.
I’m not sure what you mean. Do you mean check the components on the separate video input board where the composite inputs are?
Times are 5.5s, 13.8s and 22.1s.
Shapes are also clearly sine.
So horizontal deflection is feeling an extra wave.
It also seems to have a high point every 8 seconds.
Can you demonstrate different picture formats?
What kind of picture formats?
Check the components of the separate, isolated power supply for the circuitry that is between the input sockets and the optocouplers.
Times are 5.5s, 13.8s and 22.1s.
Shapes are also clearly sine.
So horizontal deflection is feeling an extra wave.
It also seems to have a high point every 8 seconds.
Can you demonstrate different picture formats?
What kind of picture formats?
Different horizontal and/or vertical refresh rates.
Exotics would be nice but CGA can also be one and normal interlaced video with static picture another.
Idea is to have interference differences, or not.
That way you may get some new info of the situation.
Jitter is clearly gone but my guess is that it is still there somewhere.
Check the components of the separate, isolated power supply for the circuitry that is between the input sockets and the optocouplers.
There is no separate power supply.. am I confused?
Times are 5.5s, 13.8s and 22.1s.
Shapes are also clearly sine.
So horizontal deflection is feeling an extra wave.
It also seems to have a high point every 8 seconds.
Can you demonstrate different picture formats?
What kind of picture formats?
Different horizontal and/or vertical refresh rates.
Exotics would be nice but CGA can also be one and normal interlaced video with static picture another.
Idea is to have interference differences, or not.
That way you may get some new info of the situation.
Jitter is clearly gone but my guess is that it is still there somewhere.
But the only input is composite.
The video and audio circuitry between the input sockets and the optocouplers must have a separate power supply. Check the components in that.
Hmm on that main board? I see a transformer in there.
[...] I did see another isolated small power supply for the video board I think. T401 and C416, with regulator Q416 C422, C423. Check those caps. [...] The other 9VDC power regulator for the (hot) video is C241, C408, C410 with Q241.
It's hard to know just where the AC hum is getting into the monitor.
Assuming the hum is getting in at the video isolator, there are two small power sections to check:
The isolated input jack side "T401 and C416, with regulator Q416 C422, C423" and then the hot-chassis side "9VDC power regulator for the (hot) video is C241, C408, C410 with Q241."
Next I would see where the vertical deflection is powered from, see if a bad cap is there.
Ok. I’ll check that next when I jump back into it. So far I cannot find a bad cap ESR. And I’ve checked most of them.
Relying exclusively on ESR as a pass/fail for electrolytic capacitors, I don't think it works because the ESR table you are using, they are all over the place.
Just keep in mind that notion might not be working here and low values for capacitance are passing OK. The small parts like 10uF and 47uF have widely varying ESR numbers.
example: I have 47uF 16V Nichicon VZ (blue) 16 years old 3Ω ESR. Is that a pass? I measured capacitance at 28uF or -40%. 10uF measured ESR 2.1-3Ω
It isn't a bad cap anywhere related to vertical deflection. The disturbance to the horizontal deflection is not at vertical deflection frequency. That is why it moves vertically.
Times are 5.5s, 13.8s and 22.1s.
Shapes are also clearly sine.
So horizontal deflection is feeling an extra wave.
It also seems to have a high point every 8 seconds.
Can you demonstrate different picture formats?
What kind of picture formats?
Different horizontal and/or vertical refresh rates.
Exotics would be nice but CGA can also be one and normal interlaced video with static picture another.
Idea is to have interference differences, or not.
That way you may get some new info of the situation.
Jitter is clearly gone but my guess is that it is still there somewhere.
But the only input is composite.
You can still have different formats.
What kind of possible sources you may have?
Apple II and C64 are mentioned.
Have you tried grounding(to known earth) the input connector's frame when picture is on?
Don't connect it, just tap the connector with the wire.
Is the hum same with DVD menu?
The last video I did with the blue game game menu picture was one of those cheap handheld Nintendo knockoff multi game consoles you can get on Amazon for $20 bucks. I’ve tried apple ][, Atari 130 xe, Atari 800xl, commodore sx-64, NES emulator console. Multiple A/C outlets from different locations. All the same result. I could have tried dvd but I think I just gave my last one away. I’m not positive about grounding test but I confirmed that the video input is connected to the ground pin on the power cord.
Also the handheld game unit used in the most recent video I posted is running on battery power and has its own composite video output.
The last video I did with the blue game game menu picture was one of those cheap handheld Nintendo knockoff multi game consoles you can get on Amazon for $20 bucks. I’ve tried apple ][, Atari 130 xe, Atari 800xl, commodore sx-64, NES emulator console.
Both Atari models may have PAL capabilities.
NES emulator can have what ever.
Multiple A/C outlets from different locations. All the same result.
And you're certain that at least one had a proper grounding?
I’m not positive about grounding test
Why?
but I confirmed that the video input is connected to the ground pin on the power cord.
To the wall end?
@floobydust.
You've made references to component numbers which makes me think you have a schematic. Can you post it or a link to where it can be downloaded?
@floobydust.
You've made references to component numbers which makes me think you have a schematic. Can you post it or a link to where it can be downloaded?
I would not be an asshat and withhold a schematic/service manual from the thread. I could not find one and am just looking at the PC board photos OP posted to list components to test. I have been in TV's/monitors enough to know the building blocks and in the day no schematic or service manual was available so you'd have to dig. Each section is marked on the bottom silkscreen.
I know hum bars as they are called are usually due to heterodyning between mains and the vertical deflection frequency, causing ripple on the rail (+135VDC) for the horizontal deflection. The horiz. defl is modulated by this which is the tearing/bump that is seen rolling.
OP's replaced the usual suspects filter caps but I wonder if the cap testing is actually working with just the ESR meter or in-circuit readings are misleading. With an isolation transformer and scope you can quickly find the fault but have to instead guess here.
At this point I think it's either some other capacitors that failed low value, or IC601 STR30135 +135VDC Vreg is weak and has mains ripple coming out, we used to sell a lot of them back in the day. OP could measure ACV on that rail.
Right now the repair doesn't make sense, the 3-4 prime suspect caps have been changed but hum is still getting in somewhere. The isolator board might have a problem due to the high common-mode voltage between hot-chassis and the video input jack.
The last video I did with the blue game game menu picture was one of those cheap handheld Nintendo knockoff multi game consoles you can get on Amazon for $20 bucks. I’ve tried apple ][, Atari 130 xe, Atari 800xl, commodore sx-64, NES emulator console.
Both Atari models may have PAL capabilities.
NES emulator can have what ever.
Multiple A/C outlets from different locations. All the same result.
And you're certain that at least one had a proper grounding?
I’m not positive about grounding test
Why?
I didn't check earth ground on the video input. But the console is battery powered anyway.
but I confirmed that the video input is connected to the ground pin on the power cord.
To the wall end?
yes the video input daughter board is earth grounded.
I dont have anything that can do PAL.
[...] I did see another isolated small power supply for the video board I think. T401 and C416, with regulator Q416 C422, C423. Check those caps. [...] The other 9VDC power regulator for the (hot) video is C241, C408, C410 with Q241.
It's hard to know just where the AC hum is getting into the monitor.
Assuming the hum is getting in at the video isolator, there are two small power sections to check:
The isolated input jack side "T401 and C416, with regulator Q416 C422, C423" and then the hot-chassis side "9VDC power regulator for the (hot) video is C241, C408, C410 with Q241."
Next I would see where the vertical deflection is powered from, see if a bad cap is there.
ESR on all these caps and diode check on transistors check out ok. I was wondering about IC601... I could order one and swap it out.
i will swap out:
c422
c2421
C416
C241
C408
C410
I happen to have all of these values already in my box o' caps.
Yikes! I think I found it. C423 - 470uf 16V. I pulled it out and saw leakage on the bottom of the cap and on the PCB and out of circuit ESR is ridiculously low. like at 0.016 ohms.
Its also an ELNA cap and ive had them go bad before. I think they have a track record of being crappy.
NOPE: UHG..
swapped out c422,c423,c241,c408,c410, and c416 and no change!