Siemens VCR (Grundig) FM404 (2x4 super stereo 880) - Tape not loading

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VCR Siemens (Grundig) FM404 (2x4 super stereo 880) - Tape not loading

    







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Perepandel

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Beiträge: 82
Wohnort: Miramar (Platja)
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Geräteart : Videorecorder
Defekt :
Hersteller : Siemens (Grundig)FM404 (2x4 super stereo 880)
Gerätetyp : Video player / VCR / system 2000
Chassis : Plastic
Messgeräte : Multimeter
______________________

Hi all!

------------- INTRO:

I'm an old forum user who did his last post about 5 years ago!

First of all, sorry to all by writting in English - I'm Pere from Valencia and I don't know a word of German :(.
I found this forum back in 2011 when searching for help about repairing old Video 2000 machines as it proved to be the best resource in the topic. With lots of helps of Google Translate and patience I finally was able to use the forum somehow, and all my previous efforts are documented here:
https://forum.electronicwerkstatt.d.....um=21
Admins where so kind to let me write in English, and I hope this policy still applies. May I ask an interface translation to English? It would be very helpful for non-German speakers, and it could be made available to user preferencies, as a selectable option (as a previous phpBB moderator I know it can be done).

I want to give a big greeting to STEGO, who back in 2011 was of great help and very kind - he even provided me with a spare replacement piece that at the time was very hard to find (that, unfortunately, didn't work due to further problems :(). Hi STEGO!! I hope everything is great in your life and I still think that I'm doubt with you!

After some time with my machines boxed and without any modifications in the state I left them (more info in the link I provided above), I have decided to lose my nerves again. After some experience with this forum, I'm going to open an independent thread for every machine in question.

------------- Now for the technical details:

This is an FM404 / Best nr 880 that had modifications in its supply power due to not being able to power up. After some component replacements, it was able to power on and accept some interaction.

It also had a couple components (transistors) replaced that looked burned in another PCB but I think it's safe to assume I didn't broke anything as they were farily common components and easy to solder.

The main problem was that after all the tape wouldn't load, not reacting when putting one inside it.


After 5 years, when switching on the machine all the segments in the display look messed up, so I assume something else has broken.

I just got the mono counterpart of this machine some days ago (Best nr. ) - seomeone sold it to me after buying it in a flea market and not being able to make it work. That machine was opened but, as far as I know, not manipulated. Which I later confirmed it when I opened it. Also it was able to turn on, but all it did was display a "cass" message an the red arrow pointing up on the "Band" button.

Back to the original machine: as both shared the same power supply PCB, I tried it in the FM404. Chars didn't look messed up this time, so at least it seems the "new" broken part during its 5 year sleep was, again, the power supply. Anyway, nothing was functional: red arrow up on the Band, too, in this machine.

I inspected visually the replacement PCB and it was very clear that one of the two big capacitors had exploded, so I replaced it, and also an electrolitic one.

After doing this and without further measurements, the machine now is accepting tapes. Well, sort of. Tape loading mechanism goes down, but it won't roll over the head drum. Sometimes it undergoes an "infinite" loop of down - up - down again - and forever, so I have to disconnect it from power.

Something interesting does happen sometimes. When putting the tape it won't always reach the end of the "cartridge rail" (did I said it right?). Maybe a cm or less of space is left between the cartridge and the end of the tape loading mechanism. Then the cartridge goes down but as the holes in the tape won't fit into the ones for aligment nor the ones for the motors, the tape loading mechanism won't close at all. But then, magically - the tape motors start spinning! They start rolling but won't affect the tape as it's not well-fitted but the motors for moving the tape are spinning - strange.

I did another test with disappointing results. It's well known that you can recreate, manually, the full tape-loading process, including wrapping the tape around the head drum, by gently dragging with your finger (with the machine unplugged from the outlet) the wide belt that connects the motor to the dented mechanism of the cassette shaft. I've done it before to force the mechanism to move back to its initial position and so check if the motor works, as it will go back to its initial position (unwrapped) when turning on the machine. Well, wrapping the head drum with the tape with this "manual" process evidencies that there is some misalignment, as when the head starts to get wrapped, the tape becomes shrinked as it passes through some parts of the path. I have to stope and roll back in order to not destroy it.

Could it be that the cassette shaft was previously dismantled and then it was misplace by a dent (teeth) or two? I think it's explained in the service manual about how to correct mount this, but as it's in German I cannot fid where.

And hints/guidance on this will be greatly appreciated.

Thanks for your patience




[ Diese Nachricht wurde geändert von: Perepandel am 27 Nov 2016  2:22 ]

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Perepandel

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Some update!

I noticed something strange in the winding motors. Looks like as if some components where missing. In every other Grundig (/Siemens) video 2000 I've seen there is an extra capacitor + resistor in each motor that is missing here. Could it be that the previous owner had stripped them down for replacements or whatever? In fact there is solder where the missing pieces, and some evidence of cut metal, that could indicate manipulation.

Before embracing into diving into the service manual, I would be glad to hear some qualified opinions. What do you think? You can compare the picture with the one below of a 403, but also every Grundig 2x4 / 2x8, super or not, have those resistor + capacitance. It's worth noting, too, that this is the only machine I've seen with those plastic partial-covers in the motors, which could mean that the apparent missing components are inside that or whatever...





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Maou-Sama

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Zitat :
Could it be that the cassette shaft was previously dismantled and then it was misplace by a dent (teeth) or two? I think it's explained in the service manual about how to correct mount this, but as it's in German I cannot fid where.
That's possible. But through all that back and forth and tons of text I kinda fail to identify that chassis. Is it the 2280a with the switchmode supply oder the 2280 with the big heavy transformer?
Depending on that the service manual either in itself contains a detailed mechanical alignment procedure or mechanical alignment instructions are supplied as separate pamphlet called "Mechanischer Teil"
However, the paragraph you may look out for should be called "Wechsel des Cassettenschachtes". And particularly the drawing with the magnified view called "Ansicht X" does denote the alignment of the toothed slider on the cassette compartment versus its partly toothed transport gear.
However, it has been decades since I have had my fingers squashed by these machines, so your best bet is to wait for someone who has recently serviced one of these or at least has a V2000 at hand to give more insight on mechanical alignment.


Zitat :
Looks like as if some components where missing. In every other Grundig (/Siemens) video 2000 I've seen there is an extra capacitor + resistor in each motor that is missing here. Could it be that the previous owner had stripped them down for replacements or whatever?
Nope. Furthermore would it be unrelated to your problem.
The additional capacitor from the motor terminal to the motor chassis is for additional noise suppression and speed loop stabilisation. It is used in combination with the older type reel motor 27121-067.01, which in turn is used in combination with the older module "Ablaufsteuerung" part no 27504-017.17/05 on chassis 2280.
The newer reel motors 27121-066.01 associated with the later "Ablaufsteuerung" part no 27504-063.01 on chassis 2280a do only use that single cap straight across the motor terminals.
Furthermore and on a sidenote; the resistor in parallel with the capacitor to chassis on motors 27121-067.01, as it appears in your picture, is not present on my 2280 chassis schematic. Maybe that resistor was some off schematic addition. But even then, IMHO that resistor would not make a helluva diffence for your problem.
Whether or not cap and/or resistor are present, the machine should at least load the tape.


Zitat :
It's worth noting, too, that this is the only machine I've seen with those plastic partial-covers in the motors, which could mean that the apparent missing components are inside that or whatever...

Aaand strike two... That is just the fork type optical sensor for sensing the reel motor movement and speed via a slotted wheel on the motor axis.
For detailed info refer to the service manual, exploded mechanical view section, and compare item [73] "Optokoppler/Wickelmotor" on fig 2 for the 2280 chassis with item [73] on fig 2a for 2280a machines. Observe the change in mounting style and location of these sensors depending on the type of reel motor.

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Perepandel

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Wohnort: Miramar (Platja)
Zur Homepage von Perepandel

Thanks a lot for your reply, Maou-Sama! At least I can discard the missing-motor-components thing. I will search for the "Mechanischer Teil" once I have a bit of spare time, maybe this weekend. I barely remember having seen some kind of a "mechanical service manual" time ago - it even my be lying in somewhere in my hard disk!

About the model, it's an old, bulky, 880 stereo. The power supply is marked as "netzeil 27502-059.01".

Thanks again, I will keep you informed of my improvements!

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Perepandel

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I can't believe my eyes... this seems to be just ALMOST WORKING...

First of all, I searched the net for the "mechanical manual" without success. At the same time, I was compulsively reading all V2000-related threads in this forum, with some help of Google Translate. Finally I found this post where Stego posted the relevant pages for the manual (well, it's for Best nr.2000 but I suppossed this mechanical part is the same). Now I'm sure either I had the full manual or I already read that post in the past because I recall having read those pages. Anyway, I followed instructions and assured the mechanism is synchronized with the dents. Looked like it was right but I can't assure 100% it weren't misplaced by a dent or two. Anyway now it's right for sure.

After that, I looked for the tape loading switch. Since I commented in a previous post the tape loading mechanism seemed to "lack force" when downloading the tape, I wanted to test it without one. Well, when trying to touch it with the finger it quickly fell almost off of its placement, so it looks like it was misplaced or moved from its place. I definitly took it off and switched it manually by pressing both metal parts.

Then left motor started to rotate. Nothing else. After 15 s the machine swtiched off as usual. Turned on again and then the action of throwing out the tape took off. Repeated the movement and I don't know how exactly did it, but seems like if I keep making contact on the switch before 15 s and press play, the threading mechanism moves and the drum head starts spinning!

Now I'm in the part of the process where I start to break things. I'm sooo sleepy (it's veeery late) I'm afraid of touching anything. When I wake up (6-D is a holiday here) I'll take the test of putting a tape. I'm afraid it will jam out. Also I don't know if a head cleaning before any attempt would be a good idea. Also it seemed to me only the left winding motor was rotating, but not the right one - will check in the morning.

Will keep you informed. For those who follow my adventures (anyone?), this is a great improvement - this machine has been sleeping for 5 years since my last attemp! Hooray!!

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Perepandel

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Wohnort: Miramar (Platja)
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Well, after 6 months I still haven't put a test tape on this machine as I've been busy with the Philips machine that got into my hands. Now that I'm waiting for spares I can get back to this. I have yet to repair the plastic switch, but before that...

...If you read the history back, you'll see that I have two similar machines: a 404 and its stereo counterpart, 808. Switching parts between them has helped to discover that at least one power supply is faulty and the other one is working.

My plan is to get back the two machines in working state.

The 404, after having its power supply repaired, made some scratching noise, and finally a big "clack".

It wasn't loading any tape, but after that one big "clack" some movement from the "cassette lift" is present.

Well, after careful inspection, I've been able to find at least two problems:

- This machine has all its rubber parts (the ones which look like latex) rotten. The four washers that keep the tape "casing" with their corresponding screws have disappeared. That's not critical because no precission seems to be needed there.

- There is a metal piece covered by rubber at the bottom of the elevator lift which, by inspection in the other machine, I've determined it serves as a "brake". When it gets closer to the motor, they are used to stop them smoothly. They are released when you rewind, play and so.

Well, this rubber has become rotten, too. But, at the same time, it has become sticky, somehow like a gum, and has acted as a glue, keeping the tape mechanism and the piece stuck at the bottom of the video. Probably dried capacitors helped to permanently become attached as it didn't have enough power to take off.

The big "clack" noise I heard probably was the sound of it getting suddenly unstuck when I put the repaired supply on it.

I have disassembled the piece and cleaned it and the adjacent area.

This is how the good one looks in its place:




This is the dissassembled piece on its bare metals:




It would be good if some measurements where available for that piece, so that I don't have to disassemble the good one in order to make a cast of the rubber parts (to reproduce them), as I'm afraid of ruinning it.

The problem is that the Service Manual I have for the 404 is the ELECTRICAL one, not the mechanical. So no info about the piece (and we have yet to see if there would be any physical measurement, which I doubt).

Does anyone have the MECHANICAL service manual for these machines? Or can anyone help / give any recommendations on reproducing this piece? Surely it's not that much precission needed here, but I want to do it the right way...

More to come soon, as the problems with this machine don't end here...

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stego

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Hi Perepandel!

These rubber pads only have one job: Holding both reels in Stop-Mode more than 15 seconds after switching the tape drive off. Because, both reels get stopped by the two winding motors, wich rotate in opposite directions. The central processor calculates the right torque for both motors, for all operating conditions: Play = right wheel puts tape up, left wheel holds the correct tape tension. Fast forward = right wheel has much more torque than the left one, Fast rewind: left wheel gets more power than the right one. And, by switching to "stop", both motors get as much power to stop both reels.
These rubber pads don't stop the reels from operating mode, like in any VHS-tape drive. They are just a kind of "safeguard" after switching off the motor power supply after 15 seconds.

Perhaps I have the mechanical service manual for the V-2000 800/850/880-series. Let me take a look into my repair room on Friday or Saturday. I will tell you then.

Best regards,
stego



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Perepandel

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Hi Stego!

Well, that's a very valuable information. So if I haven't misunderstood, it means that rubber it's meant only for keeping the reels in its place while the machine is off and the lack of it isn't so important at all?

Anyway, now that I already dismantled the piece, and knowing that this machine has some other serious problems that need to be solved, I'd feel better if at least I try to restore the rubber in some way.

I'm afraid of furtherly putting my hands into these machines without the mechanical service manual. I have a tendency to break things every time I do it (I'll give you a great example next) and when I've had this guide I've felt much more comfortable. By the way, I'm missing the models every time, but this pair of machines are Siemens FM304 + FM404 (or Grundig 2x4 800 + 2x4 Super 880 if I'm right - the English Wikipedia seems to add some confusion here). So I'll wait patiently and hope you have some scans in your workshop. I've searched through the internet a lot but didn't find it. Thanks a lot again, Stego! Although I'm even thinking about trying on eBay, as it seems to be available there...

Now look at this. It's on the back of the machine. See the big piece of white plastic, with that little grip or hook in the end where the spring in tension is attached? The entire set is involved on making the tape lift work and maybe the tape threading.




Well, now look at this one. Don't you think something's missing?




Well, the "hook" part was missing. It took me a lot to realize. Even after that, the "cut" was so clean that I thought it must be attached there by some way, before realizing that only explanation could be that it had felt off. I bet the high tensions due to the lift being "soldered" to the bottom could have something to do. The spring was still hanging there. Then I started planning ideas on how to repair this piece.




Now I have the right materials for casting and cloning the original piece from my "good" machine, but, again, I'm afraid of dismantling it. And it would be overwhelming. I thought I could clone just the missing piece and somehow attach/glue it to the plastic. That's why you see the hole. It's made in diagonal, antagonic angle to the tension. With so bad luck that, although acting very careful with a tiny Dremel-like drill, later I noticed that I drilled even through the "rolling" part you see at the bottom. At least it don't seems to be fatal, but you know.




Well, I thought that even a little metal hook with a similar shape that could be screwed there would do the job. But I couldn't find any. So finally I cloned it in epoxy, which covered a "metal heart" in order to reinforce it and act as a "stake".

And it seemed to work. But, believe it or not, I HAVEN'T BEEN ABLE TO YET FIND A GLUE THAT WILL ATTACH OR "SOLD" IT PERMANENTLY TO THIS WHITE PLASTIC. And I've gone trough everyone I've found that seemed reasonable there. What the heck is that table?? Cyanocrylate (w/ or without baking soda), cristal 2-component epoxy, regular "for plastic" glue, two-component "ultra-hard, glues all plastics" glue... DON'T WORK. When dried, you can take it of by scratching with your nail... So when the tension is put in it finally comes off and keeps resting for a while just mechanically through the hole. Add to that that the cloned hook itself finally ends bent by tension (although I think I could solve this by adjusting the material) and we got a totally fail here...

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stego

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Hi Perepandel,

I don't know by now, how this mechanical part is mounted correct. But in the mechanical part of the service manual it is described. It is the part of the tape drive to move the cassette holder as well as the tape thread ring. As far as I know, the worm gear must get inserted in a special way. Wait until I have found the mechanical service manual!

Best regards,
stego

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Tom-Driver

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Hi Perepandel,

To glue this type of plastic material is nearly impossible!
It feels like nylon and the surface doesn't react with any known or unknown solvent that is in typical plastic glue!
If you can not get a spare part (even from another rotten similar machine) you only can reproduce it with a 3-D-Printer...

muchos saludos,

TOM.

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[x] <= Hier Nagel einschlagen für neuen Monitor!

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Perepandel

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Hi Stego,

I'll try to be patient
You know how these things go: one wants it just at the moment, then when it finally arrives there may pass weeks... or ever years until one really does the hard part...

So while waiting I will keep entertaining you with my disgrace stories
This time it's related to springs. Remember my tendency to break things?

Well, although the one attached to the broken plastic grip was still there, not much time after I took them from there this is what it happened:




That happend after accidentally putting a heavy weighted object over it. I never saw a spring breaking like that before!

But it didn't end there. When dismantling the tape lift in order to remove this piece

Bild eingefügt

this is what happened to the spring that's placed there:




What a disgrace! Now I got a simple spring-hook-tool in order to avoid making those disasters in the future :hammer, but now that the damage is done, I'd like to hear for some recommendations on how to overcome this.

1) Do you think these broken springs are still "usable"? I mean... just half a loop it's broken from the first one. Do you think that maybe with some little pliers I could just reconstruct its broken hook? Could I assume the difference in tension to be negligible?

The 2nd one isn't "broken" but soffering from heavy deformation. I managed to "fix" (at least reduce the deformation significantly) a very small one by patientelly "rolling" over itself for quite a time, then fixing the deformed "loops" with some wire and applying heat with a lighter. Again, do you think that reducing a bit the amount of deformation could be enough?

2) I got these ones from Leroy Merlin, which were cheap and looked "similar" to the naked eye. Of course, they are not equal to any of both neither in wire diameter nor in length or in loop diameter. Using these looks like a worse solution, but who knows...




3) Better totally avoid using non-matching replacements and malformed, broken originals and go find proper, exact replacements? In that case, any recommendations on where to start looking? Any online stores? How to get the proper sizes/measurements? Could there be any hope by visiting local hardware stores?

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Perepandel

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Wohnort: Miramar (Platja)
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Wait! I just found the Mechanischer Teil!!

I can believe my eyes... It was in the "holy grail" of service manuals, and I've searched for this on it for several times but maybe this time I just put the right words? Or someone has read my mind?

http://freeservicemanuals.info/en/s.....TEIL/

Well, I'm so happy that I think I'm going to dismantle some machine now

It seems EVERYTHING it's on the internet; you just need to search for it right!

PD: there really don't seem to be that much difference with the 2x4 / 2x8 2XXX series, for whom I already had the manual, but better keeping attached to the right path!

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stego

Schreibmaschine

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Hi Perepandel,

this is the exact right service manual! Only a few pages, about 20, but very good for servicing the tape drive. Some parts are different to the drive assembled in the 2000/2200-series machines (The reel-brakes are on top of the reel motors in the 800-series, in the 2000-series they are on the bottom side of the motors, or the videohead tacho sensor is inside the stationary tape drum in the 800-series and on top of the videohead drum in the 2000-series).

Take a look inside this service manual, you can see how the worm gear is adjusted correctly.

Best regards and have a nice weekend!
stego

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