What’s wrong with my V2000/G05 B&W vector monitor?

@andrewb wait for it.

The video is showing an oversized crosshatch that quickly grows while fading out.

Looks like HV starts too low and drops out even more. Possibly completely but you can't see that.
 
Ok, what am I missing here.

IMG_5602.mov is coming up for me as a 9.28MB, 6-second video of a CRT with nothing on it. I'm looking really close, and I don't see an image.

I'm using VLC to view it, and tried downloading it again. Same thing.
 
Ok, what am I missing here.

IMG_5602.mov is coming up for me as a 9.28MB, 6-second video of a CRT with nothing on it. I'm looking really close, and I don't see an image.

I'm using VLC to view it, and tried downloading it again. Same thing.

If it was a snake it would bite you! :ROFLMAO:

The first time opened it on my phone and it worked.
Now I just opened it on my pc and it worked.....clicked the link, saved to disk, opened with VLC 3.0.16, and played it. Using Windows 10.

Here are some snapshots from VLC at 0, 1, 2, 3, 4, 5, 6 seconds. If you put them all in the same folder and open the first one with MS Photos (or similar tool) you should be able to do stop motion animation with the left and right arrows.

Weird that you can't play the the video after saving.
 

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Play by play is the image fades in and then fades out while getting bigger. Two different HV cages give the same result. Yes, I have an HV probe, but I'm assuming I've got a bad transistor or diode on the deflection.
 
If it was a snake it would bite you! :ROFLMAO:

The first time opened it on my phone and it worked.
Now I just opened it on my pc and it worked.....clicked the link, saved to disk, opened with VLC 3.0.16, and played it. Using Windows 10.

Here are some snapshots from VLC at 0, 1, 2, 3, 4, 5, 6 seconds. If you put them all in the same folder and open the first one with MS Photos (or similar tool) you should be able to do stop motion animation with the left and right arrows.

Weird that you can't play the the video after saving.


I can play the video after saving. However I think my problem is my version of VLC is old, so it's showing me a static image (of a CRT with nothing on the screen, like it's a thumbnail image, or the first frame of video), while playing the actual audio, giving the impression that it's a video showing nothing on the CRT. When in reality it's not showing the actual video, just a static image of the first frame, but with the actual audio. I probably just need to update VLC.

Anyway, thanks for the pics. Blooming means the HV is dropping. Normally you'd suspect something in the cage, however that's obviously not the case here. Which means something on the deflection board must be bad, dragging the HV down with it.

I would suspect something in the Z section, which is powered by the 95V that runs back from the cage to the deflection board.

I'd also check the monitor harness connectors (plugs) for the deflection and HV. Take a flashlight and shine it into each connector, and make sure all of the contacts look identical, with none of them bent or pushed in. They can get mashed inside the connector housings sometimes, and not make solid contact with the pins.
 
This rare effect is brought to you by soldering in C504 backwards. In my defense, the + marker is somewhat hidden and at times I am as thick as a brick. Check your work, kids!

That would do it! Glad it was something simple (and in the area we were suspecting). :)

Everything is working fine with both cages now?
 
That would do it! Glad it was something simple (and in the area we were suspecting). :)

Everything is working fine with both cages now?
It isn't 100%, but I'm getting closer. Thanks for all your help.
 
There is now a much slower expansion of the screen over time. The focus pot doesn't seem to have any effect at all. I pulled it and tested it, and it works fine. Could the reversed cap have done some collateral damage?

Reading up, it looks like my diode still isn't clean enough.
 
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There is now a much slower expansion of the screen over time. The focus pot doesn't seem to have any effect at all. I pulled it and tested it, and it works fine. Could the reversed cap have done some collateral damage?

Reading up, it looks like my diode still isn't clean enough.

Yes to the diode. Especially if it's getting hot. Let it run for 5-10 minutes, power off, discharge the tube, and feel the diode with the back of your finger. If it's hot, the connections aren't clean enough (or the diode is bad, but I think you said yours was new).

Also, the focus pot doesn't really do anything on these. That's normal. They're all that way.
 
I found that D506 on the deflection board was the original cause of the screen fading to black. I used some dust-off to cool down this diode and it would come back to life for a few minutes and then fade away again. The schematics describe this as "Diode 250V HS". Would a GMA02 (D1050) be a suitable replacement? The webpage says U2000 and D506, but nothing about V2000.
 
I think I bought some of these to use in similar situations.

One trick in cases like these (where the schematics and parts list don't give enough info) is to consult the schematics and parts list for the G05-802, which is an extremely similar design to the v2000, and has analogous circuits and parts. That doc indicates:

1725421285588.png

So we need 1A, 600V (which it were just that could be replaced with a 1N1007). However we also need Fast Recovery here, which I've replaced with:

Mouser: BYV38-TR, 2 Amp 1000 Volt 50 Fast Recovery Diode

You might just want to check the physical size, to make sure they fit where you need one. (I think I originally bought these for use in 6100 cages, but all of these monitors have several places where Fast Recovery diodes are used.)
 
Thanks for the mouser reference, Andy. Why are replacements treated as unobtanium in this discussion?

I don't know where they were searching, or what for, in that thread. But the diode I referenced is technically overspeced for this application. So whatever they may have been searching for might not have caught it. (Actually, VectorCollector's comments are valid, regarding searching for alternates, as a suitable replacement is not unobtanium, there are plenty of Fast Recovery diodes out there. ATGW's information was not correct.)

The original BY-208-600 is 1A, 600V, Fast Recovery (<300ns). The BYV38-TR is 1000V, 2A, but still <300ns. So it's beefier in terms of voltage and current rating (which is fine for diodes), but is still Fast Recovery.

I'm curious if that diode is actually your problem. If something else downstream from it is causing it to draw too much current, it's going to heat up, and artificially cooling it might just be helping it, even if it's not the root cause of the issue. I'm not saying that's definitely the case, but I've never seen that diode fail this way. So don't be surprised if you replace it and it doesn't fix things.

If you have another deflection board (v2000 or 802) that you could borrow the same diode from, it might be worth swapping them as a test, before placing an order for a few diodes.
 
I don't know where they were searching, or what for, in that thread.

FYI...I was in that discussion. You, VectorCollector, and I are in agreement. The point was if the original is unobtainium (it pretty much is) you need to search for alternates that can meet the needs of the application. You'll probably never find an exact match. But "close enough" will do if you understand the needs of the circuit.

On the surface the BYV38-TR looks like it could work. And you've already done the legwork to validate it. (y)
 
Working on a 15V2000 for my brother, and I'm leaning towards abad tube, but figured I'd see if anybody else has seen this behavior...

Asteroids Deluxe cocktail - all was good up until recently, when it suddenly wasn't.
Tested with multiple known-good deflection and HV cages - these work fine with a 19V2000.
Chassis transistors all quadruple (or more) checked at this point, and those voltages seem fine.

On my B&K 470 Rejuvenator - when I attempt to set cut off (one notch up from 0), I can't. It's either at zero, or the needle pegs. No shorts detected. It shows emission as crazy high. Clean & Balance - no change, at BEST, we can make out a faint bit of a blurry white circle in the middle of the tube. Normal vector chatter, spot killer off - everything else seems fine, just no image. Really no changes adjusting brightness/contrast. Anybody else come across this, or have suggestions? Smells like a short of some sort?
 
Working on a 15V2000 for my brother, and I'm leaning towards abad tube, but figured I'd see if anybody else has seen this behavior...

Asteroids Deluxe cocktail - all was good up until recently, when it suddenly wasn't.
Tested with multiple known-good deflection and HV cages - these work fine with a 19V2000.
Chassis transistors all quadruple (or more) checked at this point, and those voltages seem fine.

On my B&K 470 Rejuvenator - when I attempt to set cut off (one notch up from 0), I can't. It's either at zero, or the needle pegs. No shorts detected. It shows emission as crazy high. Clean & Balance - no change, at BEST, we can make out a faint bit of a blurry white circle in the middle of the tube. Normal vector chatter, spot killer off - everything else seems fine, just no image. Really no changes adjusting brightness/contrast. Anybody else come across this, or have suggestions? Smells like a short of some sort?

Being a cocktail, there's always that increased chance of debris settling into the neck and causing shorts, because the tube faces up.

Have you checked for shorts with a DMM? I wouldn't trust the tester alone. Just a thought.

There's also always the 'put it on its face and tap the neck gently' technique. I'd use a wooden spoon, something heavy but not too hard.

Can't say I've seen or heard of that one before. But I'm not a tube guru.
 
I'm curious if that diode is actually your problem. If something else downstream from it is causing it to draw too much current, it's going to heat up, and artificially cooling it might just be helping it, even if it's not the root cause of the issue. I'm not saying that's definitely the case, but I've never seen that diode fail this way. So don't be surprised if you replace it and it doesn't fix things.

If you have another deflection board (v2000 or 802) that you could borrow the same diode from, it might be worth swapping them as a test, before placing an order for a few diodes.
Swapped it with a working v2000 and you're correct, something else is at fault. When you say downstream, does that include the HV cage? As I read it, it is just capacitors, resistors, and the neons downstream. Wouldn't it be a failing component upstream that is letting too much voltage go to the diode? Something like Q504?
 
Swapped it with a working v2000 and you're correct, something else is at fault. When you say downstream, does that include the HV cage? As I read it, it is just capacitors, resistors, and the neons downstream. Wouldn't it be a failing component upstream that is letting too much voltage go to the diode? Something like Q504?

You can measure the voltage on both sides of the diode. Per the schematics, you should have around 95V or so on the high side, and 94.5V on the other. Also, you should have 4.5V on the low side of Q504. If Q504 is bad, pulling and testing it out of circuit with a 2-diode test should catch that (though I've rarely seen that one fail, but nothing is impossible.)

Dumb question, but do we know this tube is good? I don't remember from your existing posts.


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