with Help two Grundig 2x4: drilling sound, machine aborts after starting playing

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Help with two Grundig 2x4: drilling sound, machine aborts after starting playing

    







BID = 787497

stego

Schreibmaschine

Beiträge: 2452
 

  


@onnanokodesu:
The only "Low cost" V-2000 was the last machine produced by Grundig in 1984/85. It was the 2x4, No. 1600, which had no "complete" DTF system, no real time counter, no auto tape lenght identification. It was a simple top loading machine.
The video heads in this machine indeed are fixed mounted. But, the signals for the compatibliity with DTF in other machines get recorded also in this machine. The 1600 reads only the sync signal, but no DTF signals, and so in picture search mode, this VCR has stripes in the picture, like every VHS and Beta VCR.

But, at least V-2000 came to a dead end...
VHS was cheaper and much more common than V-2000.
And, last but not least, the prohibition by Grundig for distributing any sex films and action films on V-2000, has killed the V-2000 system.

@Perepandel:
Every V-2000 has two video heads in an angle of 180°. Because, the tape has only contact with the head drum in an angle of 186° (180°+ 3° before and after head switchover).
Even for flicker-free picture search and still image, and also for longplay mode, the V-2000 only needs two heads - thanks to the dynamic track following system!
The better VHS machines have, for improved picture quality and for LP mode, at least 3 or 4 video heads - because these heads are mounted fixed, not on a piezo crystal, like V-2000 heads.

Best regards,
stego

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BID = 787778

Perepandel

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Beiträge: 82
Wohnort: Miramar (Platja)
Zur Homepage von Perepandel

 

  

Sorry, it was my fault! xDDDDD
I don't know if I dreamed it or whatever but I was sure once I got surprised of seeing only one head in my FM404 when I looked at it after receiving it (that was before summer or so)... I looked at it this morning before leaving home and, of course, thre were two heads

Maybe DIY v2000 repair is too mind stressing... or maybe I drank too much beer that day!

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BID = 788275

stego

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Beiträge: 2452

Hello Perepandel,

now this weekend i managed to pick up the 2x4 (No. 2000) on my garage loft. But, after opening the machine, a big surprise: There is NO head drum inside the tape drive!!!

I can´t remember, if it was me, who has taken out the head drum (because someone needed a 2x4 head drum), or if I once got the machine already without the head drum. The "Ablaufsteuerung" is as well not present in this VCR...

Now I can offer you only a 2x8 head drum.

Please tell me, if you want to have it and also write me your address (via PM).

Best regards,
stego

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BID = 788393

Perepandel

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Beiträge: 82
Wohnort: Miramar (Platja)
Zur Homepage von Perepandel

Hiya and thanks for replying!

So you finally managed to get through the unattainable loft!

it's a shame that he head is not there, thought... Could it had been the mice? Anyway, wherever the head is, I hope it is spinning happily inside a working unit, making the delights of a now happy v2000 enthusiast!

By the way, that spare 2x8 drum would do miracles for me, too

PS: you have a PM


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BID = 788482

stego

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Beiträge: 2452

Well, we have NO mice on our garage loft, because... there´s no ladder upstairs, so how would any mouse get up there???

But, the more I remember.... I think, that the head drum now REALLY spins inside a working 2x4 V-2000 machine!
It´s a couple of years ago, when I got the machine (a silver-black Grundig Nr. 2000), working not good, but still working! And someone had a problem with his V-2000 and I gave him the head drum from this machine with my note "I don´t really know, if this head drum is 100 % ok". And, obviusly, the head drum now is doing it´s job...

Best regards,
stego

P.S.: I have already written an answer at your PM. So, you have PM, too!



_________________


[ Diese Nachricht wurde geändert von: stego am 27 Sep 2011 10:38 ]

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BID = 794732

Perepandel

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Beiträge: 82
Wohnort: Miramar (Platja)
Zur Homepage von Perepandel

Well, time for a big update.

After taking some time to make further tests, the status of this thread is almost failure.

I got Stego's head drum, took the drum off from my 2x8 and put in Stego's one.

The result was very bad image, almost black the 1st half, recognizable on the half bottom, and no color, except one or two single color frames here and there.

It looked to my more like a head from a different machine than a broken one, since it didn't display the greyish image with "superimposed" vertical bars I obtained with a phisically broken 2x4 drum (it had one of the thin copper wires broken).

So today I took it off again and put the head into my 2x4. And oh, (bad) surprise. This time the picture was familiar to me:

Again the old grey image with vertical bars. This sounded like a definitive symptom. Took the head off again and examined the heads carefully... And, with no doubt, I found it again: one of them had, again, one of the fine wires broken!!!!

I made some macro pictures, it's difficult to notice it but definitely it can be seen pictured below.

Well, this is not the end of the story - I have yet to publish some reports of several tests and other attempts I've made... but now it's very late and I have to work tomorrow, so... More to come soon!

PS: BIG THANKS to Stego for his drum... I PROMISE I treated it with great care... Maybe it got broken during delivery?


[ Diese Nachricht wurde geändert von: Perepandel am 31 Okt 2011  0:15 ]

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stego

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Beiträge: 2452

Well, sad to hear this!

At my test in my 2x8 recorder, the head drum worked really well!
So, the break of the wire must have happened during shipment.

But, with great care, the fine wire really is to solder! Take a fine soldering needle (1 mm), and a good magnifying glass. With a very small drop of solder, the thin wires can get bonded again.
Yes, sure, a little luck is also neccessary...

Best regards,
stego

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Perepandel

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Beiträge: 82
Wohnort: Miramar (Platja)
Zur Homepage von Perepandel

Too sad I didn't read you earlier! Now that's impossible, Stego... I tried the HARD way!

Remember the original drum from my 2x4 grey machine had also this same defect? I mean... It had exactly the same cut wire! Well, now I had two broken drums... I didn't think it was possible to solder the wire again...

...it happened that one drum had the red-green-white dotted head broken, and the other had the red and yellow dotted one...

...so yeah, I know it was almost impossible to get anything usable from this, but... I had nothing to lose, so...

I replaced the broken head from one of the drums with the entire one from the other!

And believe it or not... It "worked"!

I mean... It worked kind of better than the two broken drums separately.

I got colour and far less sparkles than in any of my other drums.

Unfortunately, the image was jumping quickly - to be accurate, it's like one field was jumping. I bet the "manually adjusted" head wasn't reading the proper field, so that's why I got that effect.

Fortunately, I took a video of how it looked like:

http://www.youtube.com/watch?v=GH9St7nrl6Y

Unfortunately... Now it don't works anymore. I made four or five manual adjustments. Believe me, I got a better picture than the shown above, but I didn't capture it. It didn't had black sparks, almost no white ones, not any other noise and good colour. Just the jumping fields, which I never could get rid of it while trying. But at the fifth attempt or so, I again got the black&white picture with the vertical "washed" bars. I took it off from the machine several times, inspected it, and couldn't find any broken wire - but it justs acts as if it was broken. Maybe I broke the piezo internally while screwing and unscrewing it; I don't know for sure, and maybe some other day I'll try some more attempts or I'll pick up a hughe magnifier to try to detect any broken part.

I made some videos and took some pictures of the process, even before trying the head replacement, while testing your drum and trying to identify what happened with it. Here they go:

- First of all, I wanted to test a 2x4 head inside a 2x8 machine:

http://www.youtube.com/watch?v=E71Qae7PdfQ

I would say it looks exactly like it does in the 2x4 machine.

That is an SP recording, so there's not much magic there - I wanted to test how a 2x4 machine would cop with an LP recording. And, to my surprise, it did it quite well: I'd say it performs exactly like with my 2x8 head drum!

http://www.youtube.com/watch?v=fP2OEj6fotA

That is a scene from Crocodile Dundee (German version :D) which came (for free ) when I ordered the machine.

Yeah, I know it looks bad, lots of noise and white sparkles - but that's exactly how it looks whith the original 2x8 drum.

I also wanted the test how the 2x8 head drum would perform in a 2x4 machine (with an SP record, of course):

http://www.youtube.com/watch?v=9ExgVZlbdbk

Certainly worse than with its original 2x4 head and/or much more worse than the 2x4 head performs in the 2x8 machine and with the 2x8 material.

And finally, this is how your drum looked in the 2x4. I previously tested in the 2x8 machine (as it should had been done) and got a really horrible picture, but looked different than this. Unfortunately I didn't take a shoot of it, but, as I said in a previous message, it had almost totally black in the upper half of the screen and image, with noise, coming progressively from the half of the screen to the bottom and black & white, with some spontaneous colour flashings. As I said, this vid is when running inside my 2x4 machine. It looks exactly like its original, broken, head drum:

http://www.youtube.com/watch?v=5O8VwVxBRoQ

End of the road? Not at all :P. I still want to reasemble the newer 2x4 machine I own (without a head drum :(); maybe its mechanics are better than with my old, grey 2x4 machine, and also I'll put the new belts I ordered through this page on it. I already have fixed the thin plastic cilinder for the oktoppler and it looks fine to me. I also have a capacitor tester now, so I'll test almost EVERY one can. I'm sure minor tension differences are causing more or less disturbances and mechanical problems. And oh - I tested the ones I replaced from my old Siemens fm404 (which also don't works; just accepts the tape) and almost all of them were faultly. Some shorted, some open, some other with far less capacity than they should. So now I'm 100% sure it was a good idea to replace them. I bet tape jams and half-of-the-way tapes caught in the tape slot when inserting/removing tapes can be caused by bad capacitors, too.

I'll play with what I have and, in the end, I'll capture my videos with white sparks if I can't get anything more decent. At least I've found a filter for Avisynth which make a decent job when removing those spots, preserving detail. I've used very succesfully with VHS caps with far less amount of sparks, but let's see what can it do in a worse situation.

I'm not in a hurry; I'll still experiment :).

Stego, I also still owe you a good one!

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stego

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Hello Perepandel,

if you take a head from another drum, you MUST take the same type of the head (not the one on the opposite side!), because, the two heads have a very different azimuth angle!

So, a "Head_1" cannot read the tracks recorded with "Head_2" correctly!

The azimuth of the two heads is nearly 90° apart! This is for a minimum cross-talk between the tracks of "Head_1" and "Head_2".

I also believe, that a picture was present, even better than with a broken head... well, logical!

As far as I remember, the recording electric current of a 2x4 and a 2x8 head drum is different. It MAY be, that a 2x4 head drum works inside a 2x8 machine in SP mode. But as I remember, a 2x8 head drum inside a 2x4 machine has a bad picture because of the lower head current.

Hope you have a good patience!

Best regards,
stego



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