Hi Stego, and thanks for your quick reply!

Speaking about my Grundig 2x4 Super stereo (or Siemens FM 404), I already thought of the capacitors. Now I've taken with me the list of spare parts and I'll go for them today after work. By the way, I already had the service manual I found somewhere on the web before arriving here, and also some pages scanned by you that I found on this forum. There's only one capacitor in your spare parts list! Can this be possible? On mine, I have the full list...

I also took the time to measure some of the output levels of the power supply. I couldn't measure the "A" and nor the "R" tensions (the ones available while recording and while pressing buttons, respectively), since noone was available to help me at the moment. Also the machine doesn't respond to clicks except tape eject, so I don't know if I'll get anything when pressing Play, for instance.
The D and E tensions seem to be almost correct... No "perfect matching value with my multimeter but about +- 0.4 V difference. EXCEPT for pins 1, 4, 26 and 27. These ones should be, theorycally, +13, +15, +12 and +12 V. Well, I've measured the following: 1 and 3 give me about +15.4 and 14.6 respectively, measured with the plate OUT of the case. When I connect it to the rest of the video, I get "oscillating" values between about +12.30 and +14.35. They go "jumping" from less to more and then start again, and won't stabilize. Also I get similar results with pins 26 and 27 (which I only could measure with the supply "inserted" into the video since they are V "E", that is, only available with the "standy-by" button on), which should read both +12 V and they go quickly from 12.36 to about 15 V.

So definitely it seems there's something wrong with the power supply. Nevertheless, I don't know if this behaviour can be due to any faultly capacitors. I'm not a technician but it sounds a bit strange to me...

Now about the Intefunk/Grundig 2x4/2x8 stereo 2280 or 2280a: I got almost perfect picture when I cleaned the video heads but it only last for an hour... I was afraid of breaking them by repeatedly cleaning them... But now I've taken a look in the manual and there's a kind of "logic path" for isolating problems with the drum "motor"... With the help of Google translated I "deciphered" it and guess what? In the second option I get to my problem... It says something that, if after cleaning I got correct picture but after further testing I go back again to bad picture, it can be due to dirty tapes... it clearly says "clean again" and "change to newer tapes". So I guess it cannot hurt to try another clean. Unfortunately, I cannot get rid of my tapes since what I want is to transfer them to DVD!! But it could be possible they are so degradated that they are making them dirty. Anyway, it would be great to get the Siemens working at least to compare.

Ah, and I forget to say that I also cleared those metal contacts on the top of the drum the time it worked. I'll also persist on there.

I'll keep you informed at night of my progress. By the way, I'd love to get all my machines working, so I have a lot of work to do!

Thanks again and hope to read from you soon!

Hello Perepandel,

The Siemens FM-404:
yes, the power supply is faulty. This may come from dry capacitors, the voltages are not stabile enough. The switching power supply increases and decreases the voltages because of the dry capacitors (feedback from the secondary side of the transformer to the controller IC on the primary side).

I would change ALL electrolyitc capacitors in the power supply at first.
Next check the missing voltages.
If marked with (A), then the voltage is only present in "Record" (german = Aufnahme) mode.
With (W), the voltage is only at playback (german = Wiedergabe).
With (F), the voltage is for a special function.

Now the Interfunk Stereo 2x8:

The sparks in the picture can have different reasons:
1. The video heads are worn - no chance to repair.
2. the Dynamic Track Following system is not working correctly. Here, you must check at first the presence of the + and - 150 Volts from the power supply. Moreover, check ALL Voltages of this machine as well.
3. The pickup-shoes in the head drum motor are dirty or worn. For checking this, you must open the head drum motor:
- First remove the bottom cover (three screws)
- then also remove the upper cover and remove the metal cover from the tape drive.
- Now you must remove the hex nut (5,5 mm) from the head shaft. Hold the head drum carefully at its top side, so it cannot rotate.
- Next remove the black cam from the shaft.
- Now remove the two screws left and right to remove the bottom cover of the motor:
ATTENTION:
Please mark the positions of the cover with a felt pen, then you need not to calibrate the commutation after reassembly!

Now you get a look at the pickup shoes (4 fine brass stripes at each side), and also at the commutator of the motor.

Clean everything, and after this, put a little bit of vaseline on the commutator.

Reassemble in reverse order.

It is also possible, that your tapes are so worn, that the heads are soiled after already one hour (the magnetic coating of the tape is releasing from the plastic tape).
The best tapes ever have been: BASF Chromdioxid extra. Bad tapes today are AGFA, PDmagnetics, some 3M/Scotch, some Philips. But there were also very good Philips Cassettes, the earlier ones.

Best regards,
stego




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[ Diese Nachricht wurde geändert von: stego am 20 Jun 2011 16:32 ]

Here I go again! Sorry for the delay on my post, but I really lack of free time...

Well, it seems it will be a little difficult to get aaaaall the capacitors in the power supply. On monday I just got 5 or 6 and yesterday, on the 2nd store I know (the most reliable one), they only had 2 and a half more of them (a half because they've sold me one 5 V below the specs, so I don't know if I'd do better putting it on the circuit... other one is 5 above them; I don't think that will hurt, hopefully).

Almost all are electrolytic capacitors; only a couple of the ceramic ones.

I've taken a look at some online stores (I didn't really know were could I start) and it seems even there is impossible to find de big one (the 385 V, 150 uF). The closest I've found is 400 V, but again I'm afraid of using ones of the incorrect value...

Well, after changing those ones, nothing really have changed. I still can hear the veeery low, high-pitched, cyclical sound coming from the power supply. Behaviour is the same. Tape gets into the machine, but as soon as I insert it, the red "" led turns on, and then the only responsive button is "tape" to take it out.

With some assistance, I could measure the voltages when the keys are pressed and all seem good to me: +-150 lines show about +-148, +-22 is almost exact, as 12 V, and +15 V are showing about 14.6 / 14.7... EXCEPT for the 1, 26 and 27 pins (+13 and +12 V, respectively), which still keep oscillating between about 12.5 and 15.5 V, as I noted on my 1st message. This make me think that the problem could be elsewhere and not on the capacitors, because it seems also strange to me that those two tensions, which are marked as "D" (that's, always present) behave differently if the supply is "inserted" into the motherboard or connected to the plug as "stand-alone", not connected with any other component. This way the values won't oscillate, and show about 15.39 V for the +13, for instance.

By the way, the few changed old capacitors that I could measure showed correct values.

I think I'll try another clean at the Interfunk and will try to capture my videos letting the player rest between each tape. After that, I'll concentrate on improve its quality as much as I can maybe using your instructions for removing the head drum... I'm really afraid of doing it!! I have a tendency to break things, and I suspect the head drum is very very delicated and I'm not sure I'll be able to get it back again to a working state after unscrewing it!

Again, many thanks for helping! I'll came with news on my progress soon

Hello perepandel,

NO, you need not to remove the head drum!
Only the lower cover of the head drum motor is to dismount!
This is, as i have written in my last post.

The electrolyc caps: A lower voltage is not good, a higher voltage is better - if the mechanical dimensions are ok.

The electrolyc caps are ALL standard types, every good radio and tv store with repair service should have them in stock...

If one of the voltages in the power supply is not stabile (goes up and down), then there can be a short circuit in one of the modules. The power supply then tries to start and stops again because of the short circuit.
This cycle is repeated every few seconds.

Best regards,
stego

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Hi again, Stego!

Well, I'm sorry; I didn't read with enough detail what you said about the head motor. In fact I instantly got frightened when I read of "head drum"...

Anyway, yesterday I got rid of my fears and was ready to unmount the lower cover of the motor! I followed slowly your instructions and was about to do it when I discovered that I didn't have a 5.5 screw (I had 4, 5, 6, 7 and 9, but no 5.5!!). Maybe today I'll try to get one. But do you think that can be so dirty that it can effectively affect the image that way? I did another "regular" cleaning (in fact, a bit more "agressive", persevering on the heads). I discovered that in fact everything was dirty again! The tape path had "bands" of black, greasy "tracks"; even traces of dust, like little "sand" black small "grains" in no doubt coming from the tape! The shinny, otherwise new-looking drum head had also black dirt, too. So I'm almost sure they are like decomposing and getting stuck inside the player. I have no other chance than capturing them quickly and getting rid of them...

This time the cleaning only lasted for a few minutes, if not seconds. I was ready to capture the 1st tape but the result is full of white noisy band on the third lower part of the screen, which sometimes are more obvious than others.

That was done with the Interfunk 2x8 Stereo.

Now about the Siemens 404... Didn't have time left for nothing more thant a little experiment (I also didn't had any new components to replace). With the machine turned of, I rotated the whide belt, simulating tape insertion and then putting the mechanism in the position of tape Play. When I turned on the machine, the drum motor started spinning quickly, as did the tape path mechanism, doing the operation of going back to his "rest" position and simulating tape eject. This confirms that the motors are OK. Today I'll try to catch any faultly parts on the power supply (at least those 12/13 V lines still look suspicious) and, if I'm not lucky enough, I'll center my efforts at the "motor" or the "servo" plates.

Will keep you informed and, as usual, thanks again!!

Regarding the tape: this syndrome is known as "sticky shed" and sems to occure frequently with some brands of audio tape (reel-to-reel). As far as I know it's recommended to heat the tape to 50°C for an hour prior to transfering any recordings - this is supposed to "repair" the glue holding the magnetic coating to the tape.

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"Und dann kommen's zu ana Tür da steht oben "Eintritt verboten!" und da miaßn's eine!"

Hello Perepandel,

if the white sparks are only (or most)in the lower part of the picture, you must also check the rubber pinch roller!
Perhaps, the pinch roller is worn (or the roller lever is twisted), and so the tape is driven out of track!
And why the lower part of the picture? The pinch roller is behind the head drum, so the tape is transported correctly at the lead-in of the head drum, but not correctly at lead-out of the head drum.

Please check the whole tape run for any mechanical faults!
Are all blue seals on the adjustment screws (erase head and audio head) still unbroken???
Or has someone turned the screws? Then the the whole tape run must get alligned!

Remember, about 80 % of all VCR Faults are mechanical, only 20 % are electrical!

Best regards and have a nice weekend!
stego

Also thanks to our friend "Trumbaschl".
What he wrote, is absolutely right. Very often, the magnetic coating of the tape is loose. Not only with video tapes, but also reel audio tapes, audio cassette tapes, and so on...



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Hi Stego and Trumbaschl, and thank you for your replies!

Yesterday I could do nothing; it was St. John's night (time to soak your legs at midnight in the beach), so that and the fact that I have to travel 2 hours to get back home after work, didn't left me any free time to experiment.

Believe it or not, on the last days I was thinking about the "sticky shed" syndrome, which I too already had heard of. But again, I'm too afraid of putting my tapes in the oven! Also, I think I already did the mistake of not capturing them on the 1st time and then have already degradated noticeably since the 1st play... I shouldn't had put them into the player until I hadn't tuned it up and then transferred them, but I couldn't wait to watch me and my family 20 years ago... Probably it won't do any better but maybe when I transfer them on a first trial, I'll put them in the oven to see what happens

About the pinch rollers: YEAH! I already thought of it, too! I think it was after reading the many posts on this forums about miscellaneous video problemas and almost reading entirely the guides at http://www.repairfaq.org/REPAIR/F_vcrfaq.html. Both places mention misadjustments in the pinch rollers as a source of image noise, and it could be consistent with the fact the the image sometimes appears snowy and sometimes not.
Also, I can hear a not very loud "clack clack" about once a second inside the player when plaing; it duplicates or triplicates the period (and the loudness, too!) when playing fast-fordward and, on this mode, I can see the pinch roller doesn't roun exatly vertically respectly to its axis!

I'm referring al the time to this piece (sorry but I don't have a better image at this moment):

As I have the manual, I think I could exchange it following the instructions and maybe the piece it's interchangeable with the same one on my old 2x4 for spare parts...

I also have another question I forgot to ask before. This is related to tape degradation. One of my tapes is so deteriorated that colour is gone almost the entire time. It comes and leaves from time to time, but most of the time it is B/W. I read somewhere that there are pots that can be adjusted to uprise the B/W-color treshold, but it is not clear for me where in the manual to look at, nor if it is better to leave those controls alone if I don't want to misadjust forever the machine . If you know any other tips to get back color / get rid off of severe drops, etc., when capturing, it would be great!

Hope to make more testing and adjustments on this weekend!

Hello Perepandel,

the pinch roller itself is equal of the 2x4 (Siemens FM-404) and the Interfunk 2x8.
BUT the lever of the pinch roller is NOT the same!
So, you have to remove the upper part of the roller lever and change the pinch roller into the lever of the 2x8 Interfunk.

The problem with your recordings, that are most played in black-white, it is possible, that 1.) the video heads are worn or dirty or 2.) the tape run is not ok, or 3.) the tape is de-magnetized since the last 20 years - perhaps they were stored in a humid/wet space, then the magnetic coating can also be damaged.

DON´T TURN AROUND AT ANY SERVICE ADJUST CONTROLLERS!!!
The machine was adjusted at it´s best in the factory, any de-adjust will decrease the performance of the VCR!
Any allignment is only neccessary after changing parts of any module. And there, the adjustment points are shown in the service manual. Any service controllers, that are not shown in the service-manual for adjustment, MUST NOT GET ADJUSTED!!!

Best regards,
stego

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Hiya!

Well, it's been a very frustrating weekend

After spending it almost entirely replacing capacitors, I haven't improved anything. Not all the capacitors have been replaced, but just almost them. So I'll try to keep my nerves calm and I'll order the missing ones over the internet since the "best" shitty stores on the capital city don't have half of them.

I also replaced some diodes, transistors and almost every IC, some from spare, replacement new parts I had at home and some other from the power supply part of the 2x4 I'm using for spares. No way, and even the incorrect values have increased by some decimals (or that's my impression).

One of the components that I haven't exchanged is the biggest one, the blue rectangular box I don't know what it is (and that I also haven't been able to locate in the service manual). I've uploaded a picture here:

Bild eingefügt

There are two items, the one from the FM 404 Stereo and the one from the 2x4. I thought they were identical so I proceeded to exchange them just to discover that they are slightly different after desoldering them xD. If anyone can explain me what the hell is that and if they are interchangeably... (and easy to break).

Stego, I'm sure (some of my) tapes are heavily worn / demagnetized, but also something is happening with the head since most of the noise is most of time in the sema areas of the screen.

Also the seals on the adjustment pots/screws seem to be intact in both my Siemens FM 404 and the Interfunk 2x8.

Maybe I'll play I little with one of the chroma pots I've already located at the manual. Maybe I can decrease the color treshold a bit and, if I don't succeed, I always can go back to the previous state if I careful enough...

Hello Perepandel,

sad to hear, that your weekend was frustrating...

The blue parts you have photographed, are the power transformers inside the power supply modules.
There´s no need to replace them, only if one of the voltages coming from the transformer is missing -maybe a wire break inside the transformer- makes a replacement neccessary.
But, the power transformers of the Grundig V-2000´s are very stabile, I have not heard of any defective transformer in any VCR machine, since I am working on them. Missing voltages have their cause in any other parts of the power supply, but never in the power transformer.

If you try to allign anything on the chroma module, be careful to mark the position of the service adjustment as exact as possible!

Best regards,
stego

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Hi again!

It's been a long time without updates. Lack of spare time...

Yesterday finally I tried the motor commutator cleaning method that Stego recommended. I was vey worried that I would break it.

When I removed the bottom cover, taking of a couple the couple of screwas that keep a "plate" attached to it, I noticed those had been already manipulated! They had a cover of orange paint to "seal" them that was broken, and the wheren't being kept "joined", so I'm almost sure someone has alreade been keepeing thir hand on there! Inside the motor there was the commutator. It was covered by a kind of dark, dirty, greasy, kind of solid paste. The "shoes" had "painted" their shapes over the commmutator, so there were left like concentrical circles of the "paste" and the pins of the shoes seemed to be in contact with the commutator itself.

After cleaning it (this time I didn't used alcohol isopropyl but "circuit cleaned", not directly but applied with cotton stabs. I think that was ok. But I dubted about applying pure vaseline... I thought that MAYBE the black grease was conductive, graphite-based grease. Or if it wasn't, I supposed that an oily, non-conductive lubricant would avoid good contact with the commutator so a conductive one would be better. But after searching the net for info, I then was also worried that a conductive oil could enter (when in liquid state after some friction) delicate, non-expected parts of the circuitry and then make a short... So finally I trusted Stego's experience and thought that it at least deserved a try - I could always try later with a different lubricant...

Well, it was almost 2 am when I finished the operation and today I had to get up at 6.30 am to go working... So I only had a couple of minutes to test the results.

So, after putting a tape on it, the result was...

A TOTAL FLAWLESS IMAGE!!!!! No spots, no white-snowy dots/line on the entire screen!!

Of course, there was not enough time to conclude anything... I have to go work again, but tonight I will test it extensively... I have hope!!!

Will keep you informed; I'm in a hurry now!!!!!

Hello Perepandel,

nice to read from you again!
I have already thought, that you have given up the V-2000 now.

Very often, the dirt on the commutator of the motor causes failures like sparks in the picture. The Radio/TV-Services had to clean the commutator of the Grundig V-2000, because Grundig gave a technical information to them, that this must be done on every machine.

I hope your cleaning was successful - not only for a few minutes!

Best regards,
stego

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