Hello Perepandel,

there´s no way to repair the video head. The copper cable is very, very thin! You can hardly solder it, so the only way to repair would be to rewind the defectife head - no chance!

The missing color:
It is possible, that the service adjustments are not correct.

Have you tested a new recording?
Make a new recording on a empty tape (you can take the tuner or the DIN-AV input), and look for the result of this recording. Is it b/w, too? Or is the new recording in color?

How is your V-2000 connected to the tv set? With HF coaxial cable or with DIN-AV to Scart connector?
Is your tv set switched to PAL? Some tv sets switch to SECAM (or switch off the color) automatically if the colour and/or video signal is not strong enough.

I remember, that one service potentiometer on one module switches away the colour when not correct adjusted.
I don´t actually remember, which service poti it is. Please take a look into the service manual for this.

It is also possible, that the second head drum is also worn enough to get such a result without colour.

Best regards,
stego

P.S.: The washers on the head drum axle:
Take a very good look on the axle and on the head bearing!
It has also happened to me, that the washers were bonded (by some oil or grease) and they are REALLY thin, so you can overlook them very easy!

In normal situation, on every head drum are three washers between the rotating head drum and the stationary head bearing! They are important for the correct head drum height. This is also described in the service manual.

Offtopic :

If you only want to play a few cassettes, it´s not neccessary to adjust the machine to 100 %. The DTF would correct a lot of disadjust. The exact adjustment was neccessary in the years when the V-2000 have been in daily use. Because, if not adjusted exactly, the compatiblility between every V-2000 machine is no more guaranteed.

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[ Diese Nachricht wurde geändert von: stego am 31 Aug 2011  9:33 ]

Hiya, Stego!

Well, the machine is connected to the TV with a DIN-AV to composite video cable I made myself (and that I know it's working because is the one I use to connect my "snowy" video to the same TV :D). So at the same time I can confirm that yeah, the TV set is correctly configured in PAL

Have yet to try to make a new recording. Let's see if I can try it tonight!

About touching the pots... I'd left that option as the last resort! They are all still sealed in the machine... I'm a bit afraid of disadjusting the whole thing even more!

Made a new recording...

No color!

Some white sparks that tend to dissapear after some minutes playing...

More to come!

Update! UPDATEEEE!!

So I thought what would happen if I'd try to play without the "chroma" module...

Well, it plays! But black & white (as one would expect - althought maybe it would be that it shouldn't play at all if the machine detects the module is missing... but the fact is that it plays, b&w!)

So I had a suspect for the chroma module... Swapped it with the one from my other machine and...

BINGO!!!!!

Full colour with the recording made some minutes ago!!

The sparks seem to dissapear gradually, that is a good symptom... almost no noticeable ones at the end...

But the image is lacking some sharpness. It's a bit grainy, and it also has no sharp borders in the well-defined shapes, for instance, big numbers/letters in white over black (like "20% OFF", etc.). Also colors blend in big shapes with uniform colors (the above exemple is also valid, but better on letters a bit smaller of colors like blue or red over images).

So now it comes another interesting question... What else to do? I'm going to test what happens with the "video" and "DTF" modules of my 2nd machine, to see if there is any improvement.

Also, in case some adjustment or tuning of the tape path and the video heads should be made, I'd thank any suggestion in what kind of oscilloscope would I need, just not to spend more money of the one needed one. That is: I think I'd need to be able to be able to scan signals of orders of tens of microseconds, is it that? So what should be the minimum bandwith and sampling rate of the machine? Any hint?

Hello Perepandel,

now that´s a great success for you! Congratulation!

The sparks in the picture: They might result as a defect in the drop-out compensator.
Also clean the commutator and the sliding contacts of the head drum motor well, and after cleaning put a little bit of vaseline on the commutator.

The capstan motor might as well have a defect and cause interferences (= sparks in the picture), and also each of the reel motors can do so.

You can change for a test all of the modules and look if any improvement is present.

Please, after changing the modules, check the voltages from the power supply! Because the modules have their tolerances, the voltage can change as well!

Best regards,
stego

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Hi Stego! Again, this is a bittersweet success...

I exchanged also the video module and the lack of sharpness went off. I don't know if both, chroma and video modules, are wrong, or if they are simply misadjusted (someone could have mess with the pots previously...). Anyway, as I'm lacking the instrumental at this time to do such calibrations and also I have the leftovers of the other machine just as spare parts, I can simply swap parts until I am satisfied with the results :D.

As I said, this is bittersweet because I cannot get rid of the white sparks. Now I have two "semifunctional" machines: this 2x4 best Nr 2000 made out of two of them :P, and an Interfunk 2x8. Both suffer from almost the same symptoms: white sparks accross the image. I clean the video heads, the white sparks usually dissappear (even completely)... but after a while, even with good quality tapes, they come up again.

I guess this is due to worn/defective heads and that there is no chance to repair it...

But one thing that amazes me is that the tape I recorded yesterday, with some DTV channel on it, and so "perfect picture" there :P, was recorded with the "sparks" heads... but this tape has been played and I'VE SEEN IT **WITHOUT THE SPARKS** MORE THAN ONCE! Shouldn't the sparks be "recorded" there permanently if the heads where wrong? Are'nt the same videoheads used for playing and recording??? Both machines record perfectly, and now both machines give the same quality image, which I think is almost 100% (maybe I like a bit more the colors on the subject machine of this thread :D), excepting the white sparks...

Another thing that has driven me crazy: theory of CENTERING THE CAPSTAN???

I've read on this forum that the capstan should be as centered as it could be... Well, I tried different alignements just to see if some "side jumping" that I was noticing on the image would disappear... Well that wouldn't; maybe because the source wasn't on the video itself or whatever :P. I didn't notice any changes between different tries, but the funny thing is that I "uncentered" once or twice the capstan purposely just to see what would happen... Well, guess what... I only got Play mode to play jerckly with one of these configurations. But in all my other tryings I got AN IMPROVEMENT of the image in reverse and slow mode!!! In my grey 2x4, slow mode was almost unwatchable. Reverse would get distorted on top and on bottom. WITH THE HEAVY UNCENTERED MOUNTING OF THE CAPSTAN NOW I GOT PERFECT SLOW MODE, almost perfect reverse besides some ocasionally distortion on top and perfect play (again, appart from the white sparks). Also fast forward stills goes wrong, no matter the capstan centering: about 2 secs after playing, the motor ends sounding "continuosly", and a "acceleration-brake" continuous sequence is heard, and the image is bad.

To end this long post... I'm becoming tired of this "machines from hell" . They seem to have several vulnerabilities in its design/guts. This is so unproductive and time-consuming! I'm going to capture my tapes whatever I can which what I have, whatever the results...

Ok, again I'm answering myself...

About centering the capstan: OK; I just noticed the "flutering" in the audio

This is odd: if the capstan is not centered, music will sound really distorted... but slow mode will work fine! Anyway, good sound in play mode is my priority

A couple more thoughts!

My two (half)working machines also have another problem, exactly the same in both.

Today, a couple of venerable good-quality, Sony VCC480 tapes I use for testing where destroyed (tape cut in half) because the tape got "trapped" inside the mechanism. The behavious is always the same: it seems the mechanism doesn't have enough power to pull the tape (its weight) around the head when the tape is sooo long. This only has happened with the maximum length tapes, and when about only 1/5th of the tape was left for playing. That is, when 4/5 of the tape are wrapped around the right reel. A "dented", jigsaw sound can be heard after the tape is inserted, while "wrapping" (this also serves to detect when the disaster is about to happen, about 99% certainity :D, so you can press "stop" and abort it). Some "backward motion" or recoil can be seen in the tape, coming from one of the reels, that causes too much from the tape to go out from the cartridge and then gets trapped in some part of the mechanism, pinch roller or whatever, which causes the mess.

The "intertial movement" in the reel can be seen progressively growing as more tape is rolled in the right reel, until the "critical point" of about the 1/5.

Maybe I'll try to upload a more illustrative video.

Also in my 2x4 the tape gets stuck half the way sometimes when pushing the "cass" button, having to roll manually the big belt of the tape loading mechanism. A sound coming from the respective motor can be heard, as if it didn't have enough power to push the tape out (I have yet to confirm if it only happens with the lenghlest/heaviest tapes).

I guess both problems are motor related, maybe too old, maybe to the capacitors attached to them, which cause lack of power. Or maybe it's a "bug by design" and maybe those machines haven't had enough power for that from the day they were designed!

Finally, a comment on tape brands: we already know Agfa ara bad quality... I had an old one which wouldn't play in color in my Interfunk 2x8. Now I've got another test one (a bit newer, but also Agfa, same model)... It also won't play in colour in my Interfunk 2x8 but, surprisingly, will play full wright colours in the "recovered" 2x4 (the subject of this thread).

This with the AGFA tapes is a result of the tolerances or the abrasion of the video heads on both machines.

The thread-in mechanism:
Perhaps, the rubber belt is worn and has not enough grip to move the mechanism to its final position. It has also happened to me, that some parts of the mechanic inside the white ring was strong to move (the spring at the guide roller, right rear side). This may result in a stop of the threading operation.

Check the rubber belt (the thick one) and put a little drop of silicon oil on the guidance rail of the deflection roller.

Best regards,
stego

Offtopic :

I´m afraid, we´re coming to a dead end with your V-2000 machines. I hope, you still know, which module has been in the one or another machine originally.... you know, it´s because of the tolerances... every module has been calibrated in the Grundig factory according to the other modules and parts of the VCR. If any module is changed, all the service adjustments shown in the service manual should be done. But that´s a life´s work without an oscilloscope and the original service cassettes...

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Zitat :

Offtopic : I´m afraid, we´re coming to a dead end with your V-2000 machines. I hope, you still know, which module has been in the one or another machine originally.... you know, it´s because of the tolerances... every module has been calibrated in the Grundig factory according to the other modules and parts of the VCR. If any module is changed, all the service adjustments shown in the service manual should be done. But that´s a life´s work without an oscilloscope and the original service cassettes...

Hi Stego!

Unfortunately, you're true... I would get my hands in an oscilloscope, but... what for?? My two "working" machines have their heads damaged! (or at least that's what it seems). The other one has its head ruined... and there are no replacements! So why should I bother making those precise adjustments if I won't get rid of those annoying white sparks all over the screen?

What makes me angry is that the sparks appears and dissappear... there are times where I get perfect picture, but it only lasts for a few minutes, or even seconds! I thought that bad image should be constant if the heads were damaged!

And my 4th machine doesn't even threads!

Any suggestions? I'm even thinking on throwing them to the rubbish...

If the sparks appear and disappear, and sometimes the picture is perfect, the heads can´t be worn, i think.
Then the fault can be in the circuit of the drop-out compensator or in the dynamic track following circuit.
It is also possible, that the drop-outs don´t come from the heads, but from another motor (interference distortion).
(You wrote, that the reel motors have some fault, because the tapes get destroyed.)

In the time, the drop-outs are present, switch to "pause". Is any change of the picture noticeable? Do the drop-outs still appear or do they get less or more than in "play" mode?

It can be something very strange: Do both break pads get off the reel motors? Or do they sometimes fall back because the magnet does not hold on?
Does the capstan motor turn constant and smooth? Is the rubber belt already changed (the capstan belt)?

That´s what reminds me at the moment...

Best regards,
stego

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Hi Stego! The sparks appear in pause almost exactly like in the play mode: if the machine is in a "noisy" stage, then the still picture will show lots of sparks; if it is in a "low noise" or "picture perfect" phase, the still image will be perfectly clear, too!

I have tried many alternative centerings of the canvas in one (the grey, recovered 2x4) machine; the other hasn't been touched, at least by me. At this time I've stopped with one that makes the tapes sound OK; no flutering or distorted sound. And correct slow mode depending on the tape :P.

In one of these attemps I was almost sure that the centering of the canvas definitely had something to do with the amount of noise. Now I'm not that sure

It's remarcable that after the intensive trashing with the machines, they are still able to provide some minutes of picture perfect images sometimes.

If I clean the heads, usually the pattern is always the same: when I insert a tape, first 5-10 seconds of playing will show huge amounts of snow/sparks, almost 90% sparks that quickly drop until they disappear or are unnoticeable; then it starts growing again.

My replacement belts have not come yet, so I am using the ones that came with the machine. Maybe that's a lot of wear, yeah!

Oh, I also forgot something in my previous message... If I manage to get an oscilloscope, is there anything I could do with it without the original adjustment tape?? It's viable to use a color bar generator? Maybe a copy is still available?

The only thing you can test with an oscilloscope, is:

- the DTF voltage (linearity)
- the HF from the heads
But the HF from the heads... it´s a problem, because the oscilloscope pictures shown in the service manual show the osc. image from the original service tape!

You don´t manage to service a V-2000 today in a perfect way - no service parts are avilable now!
In the "great years" of V-2000, the service repair shops had:
- The Grundig/Philips service tape "Bandlauf-Kontrollcassette"
- a few extension cards for lifting up the modules and measuring on them.
- a centering bush (for the capstan shield)
- a lot of instruction documents, if any serial faults have been discovered.

All these things are no longer avilable today. And so, the repair of any V-2000 is something like < 90%, more is not possible.

I guess, that lots of my V-2000 I have repaired, were a lucky procedure!
Sometimes, I have given up the one and another machine, if the repair got very difficult or failed because of missing parts.

I guess, the fault is in the DTF module. What you describe, happens, if I pull off the plug on the "SERVO/DTF" module, going to the two contacts on the upper side of the head drum, delivering the DTF control voltage.
Take a look on the service manual, part "SERVO/DTF". Perhaps, a security resistor has blown. At least, the plug is broken or a cable is broken!
Without a oscilloscop do the following:
Take a multimeter (preferred analogue), and switch it between one contact of the DTF voltage (upper head contacts) and ground, you must get a slight changing voltage on the contacts of the DTF voltage in "play" mode. This voltage must increase if switched to "pause" or "picture search" (because the DTF must correct the wrong time-based tracking.

If no voltage can be measured on these contacts, the fault is inside the DTF circuit (perhaps dead transistor or bad fuse resistor).

Best regards,
stego

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