Help Grundig V2000 2x4 video problem

[NicolaIT]

Good morning, I apologize for the inconvenience, I'm Nicola,I live to Italy an enthusiast and collector of Grundig Video 2000 equipment.

Hope this forum could help me!

I tried to go around various forums and other enthusiasts but no one was able to help me, then I remembered that many years ago I had written about this topic, on this platform.

I have five devices between 2x4 2000, 2x4 2200 and 2x8 2080, I managed to restore most of them by replacing the buffer battery, cleaning the tracks corroded by the Ablaufsteuerung acid, replacing the belts and sometimes repairing the comb cards, if possible.

I'm writing because one of them is driving me crazy: everything would be fine if it weren't for an odious disturbing line located perfectly in the center of the image that refuses to disappear.

A month ago it was much wider, then a few hours of use significantly reduced it, but not eliminated it, furthermore, even more disturbing are the micro shots that are present in the image, very annoying to see

The rest of the image is good, the audio is perfect and linear even in the presence of music, so the plate underneath is well centered and the strap is good.

I tried to replace ALL the boards taking them from a working device to see if the problem lay in the capacitors of one of them but the problem remained exactly as with the boards already fitted.

I tried cleaning the heads but it didn't solve the problem.

Going to exclusion, what remains is the transplant of the drum heads coming from a makeshift device which certainly still has good ones. Could I solve it just with this attempt?

It is true that they are old devices, which already had problems at the time and that the tapes are not of great quality, I guarantee you that 4 models work decently in all their options, only the one has the problems of micro jerks and the central line of disturbance .


To explain better I link a video shot just yesterday. What do you think about it? What should I replace to eliminate those microshots and that streak of noise?

Thank you very much and I hope for your response, best regards

Nicola see the sample problem video https://www.youtube.com/watch?v=vwWmZ3bc2Pk

[Amtec123]

Hi and welcome to the forum,
I'm not very familiar with the V2000 format, but looking at your video several possible reasons spring to mind. There seems to be a partial loss of rf for several lines.

Check the graphite anti static brush is clean and making good contact with the top of the centre video head drum shaft.
Check half way around the fixed lower head drum for any build up of tape oxide particularly on the reference edge.
Worst case would be a fault within the rotary drum assembly.

Hope this gives you a few more things to check.
Good luck
Les

[peterpixel]

Hi Nicola, welcome back to the forum. I have no experience of this format but have knowledge of machines of various types since 1968. My first thing to check is the lower drum (fixed) about half way between the input and exit guides. The fault could be caused by low RF signal off tape which may be because of a build up of oxide at this position. It may also be caused by low tape tension making the heads lose contact briefly with the tape. No doubt more knowledgeable people will help in due course. Best regards, Peter. This took me so long to type that Les contributed a similar answer so maybe we're on the right track.

[Amtec123]

Hi Peter,
Yes we both seem to thinking along similar lines, I can visualise a sharp dip in the rf when looking on a scope. Lets hope it's not a fault within the drum assembly such as the rotary transformer.
Regards
Les

[NicolaIT]

I thank you both for your welcome and kindness. This afternoon I followed your advice, I cleaned the copper piezoelectric contacts, the head drum and everything else, but the problem was not eliminated. I fear that the fault is inside the head drum and the only solution is to find a replacement drum from a device that has stopped for other reasons. Thanks again everyone!

[samjmann]

There must be something that is affecting head to tape contact
when the video head tips are halfway round the scan of the tape. This equate to about 1/4 of the width of tape from it's bottom edge. By this I mean there might be a line on the tape surface, running the length of the recording.

This could be caused by a small build up of tape debris on the tape guides fixed or moving. DO NOT touch the video head tips for this problem. Very throughly clean all the tape guides and examine them with a magnifying glass for imperfections dirt etc on their surfaces.

I had a Philips VR2022 for 5 years and this type of thing did happen. It was never the electronics.

Be very careful around the head drum assembly. The head tips and actuators are very delicate.

Regards, SJM.

[its ur aerial]

Nicola, I did repair a few of these years ago and I would agree totally with the previous comments, I don't think its a electronic fault with lower Drum fault.
Give all the tape path a really good clean as suggested.
You could also try just very gently touching the Back Tension arm, to see if this makes a difference.
Ken, G6HZG.

[samjmann]

There are a few steps you can take to find this problem logically

Playback a tape for say 2mins of a known good recording, this will have been checked on another known good VCR.

Take the same tape and wind it back to the start of the same recording, and play it back again in the known good VCR.

If the previously known good recording has a line across the centre, then the suspect VCR has marked the tape (usually permanently).

As the suspect VCR displayed the line on its first-pass, therefore the tape-marking has occurred between the tape leaving the cassette and contact with the drum assembly itself.

Please confirm this by following the above exactly.

Don't take out the whole drum assembly. The fixed guides would need realignment possibly... Also Grundig 2X4 was fussy on head height and lead in alignment. So please don't touch the drum!!

Please post your findings. SJM.

[NicolaIT]

I would like to thank everyone again for their help and suggestions. I did everything you wrote to me. I thoroughly cleaned all the tape path rollers, the head drum, the heads themselves, removed the pinch roller and washed them well with soap and hot water. I let the device work for an hour. The interference strip has definitely become smaller and this is thanks to you. Now the image is more watchable even if not perfect. Samjmann all the tapes that have the central noise line, in the other devices they work perfectly, there is absolutely no that line. So the tapes were not damaged. I did the test you recommended and the problem ONLY occurs with that device and with all the tapes.

[NicolaIT]

New sample video https://youtu.be/HQ__w9196ZQ

[samjmann]

The horizontal line on the screen suggests no off-tape signal at about half way round the head-scan. Have you access to an oscilloscope? If so you should be able to see a dip in off-tape signal at half way between lead-in and lead-out points.

Dont forget that the head 'heights' are modulated by the signals going to the
actuators on the heads themselves. This an be as much as +60v or -60v. If this is wrong the the heads would mistrack and you would get 'snow' at one point. The problem is that this is a closed loop. In as much as the output effects the input and vice versa...

We're not sure of you're techncial knowledge at this stage of course.

One easy test is to make a 2min recording on the suspect VCR, then transfer it to the known good one. If the recording is OK it might point to a replay cicuitry fault.

Don't wish to labour the point: Have you checked with a magnifier all the tape guide surfaces for tiny bumps or stuck on bits of dirt?

Regards, SJM.

[TIMTAPE]

I'd inspect the uppermost section of the stationary drum about half way around the tape contact arc for a small piece of stubborn dirt, just enough to slightly lift the tape off the upper drum's video heads each time they reach that point. This could explain a dropout always in the same spot on the screen that did no permanent damage to the tape and recording.

[NicolaIT]

Originally Posted by samjmann

The horizontal line on the screen suggests no off-tape signal at about half way round the head-scan. Have you access to an oscilloscope? If so you should be able to see a dip in off-tape signal at half way between lead-in and lead-out points.

Don't forget that the head 'heights' are modulated by the signals going to the
actuators on the heads themselves. This an be as much as +60v or -60v. If this is wrong the heads would mis track and you would get 'snow' at one point. The problem is that this is a closed loop. In as much as the output effects the input and vice versa...

We're not sure of you're technical knowledge at this stage of course.

One easy test is to make a 2min recording on the suspect VCR, then transfer it to the known good one. If the recording is OK it might point to a replay circuitry fault.

Don't wish to labour the point: Have you checked with a magnifier all the tape guide surfaces for tiny bumps or stuck on bits of dirt?

Regards, SJM.

I tried to clean everything that was possible and reachable but like you I think there is something hidden somewhere. The problem arose in fact after the ribbon of a VCC had twisted and come out of the guide. That strip on the at the beginning it was much larger and more marked. Now it is definitely decreasing. Tomorrow I will continue cleaning more vigorously. The voltage in this device comes from the DTF servo board and is +150 and -150 (measured voltages are correct). For recording, the device has only one AV. RF channels have not been present in Italy for many years. I don't know how to connect it to a VHS to test record.

Originally Posted by TIMTAPE

I'd inspect the uppermost section of the stationary drum about half way around the tape contact arc for a small piece of stubborn dirt, just enough to slightly lift the tape off the upper drum's video heads each time they reach that point. This could explain a dropout always in the same spot on the screen that did no permanent damage to the tape and recording.

Thank you for your answer. It is consistent with those received previously. You explained very well and in my opinion that is the problem. During playback the hum changes every now and then but looking at the path of the tape everything seems fine. A noise occurs cyclically after about 30 seconds, I have to inspect this too.

[marceljack]

Originally Posted by NicolaIT

I don't know how to connect it to a VHS to test record.

Hi,
Don't you have a DTT or a satellite receiver with an AV or a SCART output ?
If yes you could just connect the video out (cinch) or the CVBS out of the SCART (pin 19) to the AV in of your V2000.

[NicolaIT]

Thanks to you friends I solved my problem. As you had said (practically everyone) there were traces of oxide on the fixed drum + two guides that were not visible because they were hidden. I cleaned everything vigorously and now the image is back to normal. The device is 40 years old and it's a miracle that it still works. MANY THANKS TO ALL!!!

sample video: https://youtu.be/8FyHTc-y9u0

[NicolaIT]

Originally Posted by marceljack

Hi,
Don't you have a DTT or a satellite receiver with an AV or a SCART output ?
If yes you could just connect the video out (cinch) or the CVBS out of the SCART (pin 19) to the AV in of your V2000.

I have these links:
smart TV -- dvd recorder HDMI to HDMI

The DVD recorder has two scarts: AV1 (TV) to v2000 grundig and AV2 (EXT) to VHS recorder. If I select AV channel on Grundig can I record VHS images on Grundig v2000?

[marceljack]

Originally Posted by NicolaIT

The DVD recorder has two scarts: AV1 (TV) to v2000 grundig and AV2 (EXT) to VHS recorder. If I select AV channel on Grundig can I record VHS images on Grundig v2000?

Yes, it should work if the Cvbs out of the AV1 SCART (pin 19) is connected to the Cvbs in (pin 20) of the V2000 SCART (which happens with a standard SCART cable).
Of course the audio in/out will also be connected by this cable.

[whaka54]

those grundig may not have scart, but a DIN kinda connector instead.
as far i know, only french variants were provided with scart, and they also were very first video recorder to come with.

[samjmann]

Great to read it's working again.

The V2000 was really the best of the domestic VCR formats. I often wondered what the picture quality would be like on the current formulations of video tape.

SJM.

[whaka54]

they can be impressive.
considering philips never "cheated" with any kind of video noise reduction as beta and "HQ" vhs did, without always letting choice to user to disable it, they did something great.

some tapes of the era were already very good, specially 3M/scotch come to my mind.
time can also reveal which are more robust to entropy.
and clearly, scotch had formulation who can resist moisture and mould.
they can get mouldy (i had to deal with...) but the binder integrity isn't affected, a manual cleaning bring everything as the first day

from personal digitization, here's an exemple of what can be achievied when everything was (mostly) right from the era
so this can give you an idea what you could expect with refilled tape.

https://odysee.com/@WhakArchives:d/T...p-par-whaka):2