Geräteart : Videorecorder
Defekt : Noisy picture
Hersteller : Grundig
Gerätetyp : 2280 a
Messgeräte : Multimeter, Oszilloskop
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Hi, guys!

Some days ago I've bought Grundig 2x4/2x8 2280a Video2000 recorder in excellent condition. I've replaced drive belt and cleaned this recorder from dust. I've cleaned heads and capstan with isopropyl alcohol, and copper top of videohead too. Seller sold me 16 VCC-480 cassettes (Philips Quality grade and Sony Dynamicron tapes). DTF works good (still frame, rewind and slow motion plays good), sound is good too. But I have a little trouble.

I've read, that Video2000 gives better picture quality, than VHS recorders. But I have too noisy picture (compared to my old Sony's VHS picture). I've uploaded videos to compare on YouTube. Both were recorded from DVD-player connected via AV-input. You can see, that on VHS picture is more sharp, than on V2000. I can't guess, is it a videohead trouble (maybe they are too old for getting sharp picture?) or hardware trouble (maybe, some capacitors in Y/C-modules are bad?). And also when videohead rotates, it makes strong noise (compared to VHS-videohead). Is it normal for V2000? I was afraid to disassembly head. Maybe, head motor needs oil?

Another trouble is that some tapes plays picture, which contains almost noise, some seconds noise, some seconds something like a picture. And record on this tapes gives bad results... Tapes are not crumpled and they seems to be in good condition... But awful picture... I can't guess, is it a recorder trouble, or tape trouble... Also on some tapes I get stable still frame, FF, but noisy REV.

Thanks for your answers. My English isn't good (my native lang is Russian), but I tried to write without mistakes. Thank you.

VHS test: http://www.youtube.com/watch?v=b0ZBrL8Y23k
V2000 test: http://www.youtube.com/watch?v=VKwvZa7CIWc
V200 trst (some seconds of already recordered film): http://www.youtube.com/watch?v=mLUtQv44D3w

Hello, thank you for your reply!

About capacitors: is there available for download complete Service Manual for this VCR? With complete schematics and oscillograms I could test signal path from videohead to video amplifiers and check, if any of components cause this mess on the screen...

About tapes: I don't know, what was original package. All the tapes came to me in a book-style cases (like cases from original license VHS tapes, or BetacamSP tape cases). I could see that both Sony and Philips tapes fails. Some Sony tapes give very good picture, some - almost only noise. The same thing with Philips tape. Today I've ordered one tape (VCC-240 Grundig) on auction, and will test it when it arrives to me :). All tapes which I have were previously recordered (old German TV channels: RTLPlus, ZDF, TV3 and others, I'll post their idents, ads and news from them on YouTube later). I'll post photos of VCR and tapes later.

The idea of using new VHS tape is very interesting! The only thing which I should do is to measure correct tape length... Do you know the length of VHS E-180 and E-240 tapes?

Tape path looks good. I've cleaned all guides with alcohol, and they shine as chromium-plated (as new :)). Tape doesn't slide on rollers - pinch roller seems to be good. Maybe, tapes are the main fail (and worn heads too).

And I have another question. This recorder is B/G standard. Our TV works at D/K standard. What should I do to make tuner receive D/K sound? Not to retune modulator (I connect VCR via AV-cable to TV and digitizer), but to change sub-carrier of tuner itself. Is there a schematic of the tuner module?

Thanks!
Best regards,
Alexander.

Hello Alexander,

1.) I don´t know a source where the service manual is to download.
Sometimes, the printed manual is sold on eBay. But it is in german language! I don´t know, if the manual is avilable in other languages.

2.) I guess, that the main problem is the tape material. All your cassettes are used condition, and over 20 years old. The original package is most of all papercard slipcase and shrink-wraped. Sometimes, the cassettes were sold in "book jacket" (Grundig, Scotch).

3.) The VHS tapes are not so long as the V-2000 types, because tape speed is VHS = 23,35 mm/sec. and V-2000 24,48 mm/sec. But, as far as I remember, in a VCC-480 Cassette there are 356 meters, and in a E-240 VHS cassette there are 352 meters of tape. The difference of 4 meters doesn´t mind at all! You can take a complete E-240 Cassette and wind it into a VCC-480 cassette shell. But, unfortunately, you must do it by hand, because the cassette tape hubs are very different, and so you cannot put the cassette into a video machine for winding the tape.

4.) The TV standard is not to change, because Grundig has sold the machines in several countries with a tuner of the compatible standard.
So, you must change the whole tuner.
The tuner itself is not described in the service manual, because Grundig has only offered the complete change of a defective tuner or sending it to the Grundig factory (Germany, Nürnberg)for repair, because of the complex allignment of a tuner after repair.

Best regards,
stego

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Hello, Stego,

In Hifi-Archive (wegavision.pytalhost.com) I've found technical docs for Grundig 2x4. They are in German, but I think translators will help me :).

I've carefully looked at the last tape guide (before cassette) and noticed, that tape really goes up and down when rewinding... But some tapes play well, another - with a great mess. And if I'll rewind this tape (from PLAY mode), DTF begins to work not correclty... Only stable vertical bars on the screen. Only when I insert good tape, DTF normalizes.

I've also noticed some trouble with tape tension. After 12 hours of playing and digitizing tapes, I've noticed some sync problems. I can't describe it (VirtualDub eats this sync good, but DScaler in TV mode shows garbled picture and my old 16cm b/w TV shows garbled picture too). If I make bigger tension on videohead (just pushing tape with fingers to first tape guide), picture stabilizes. But when I put my finger out from tape, garbled picture appears. And another trouble is with rewinding tape from STOP mode. At the both ends of some tapes motor can't rotate reels... It seems like motors lose their power... Maybe, low voltages or smth else, I didn't checked it yet....

Best regards,
Alexander.

Hi

Zitat :

This recorder is B/G standard. Our TV works at D/K standard. What should I do to make tuner receive D/K sound?

In my manual only the alterations for the United Kingdom (A/I 6,0 MHz Sound carrier) on the Tuner module 29502-021.03 and 29502-021.04 are shown.

They include changing the ceramic filter F2230 at pin 2 of IC2230 U829B to the desired carrier frequency: 5,5MHz B/G -> 6,0MHz A/I (-> 6,5MHz D/K), and replacing C2222 at pins 5 and 6 of IC2230 68p B/G -> 47p A/I (-> D/K ?25p?).

Now while this seems quite straightforward and F2230 ceramic filters are the same as modern ones used in your tv sets, there is the problem of the IF saw filter F2200.
The original OFW361D (B/G) has to be changed to adjust for the added IF signal bandwidth.
Also keep in mind, that the IF saw filter F2200 is designed to interact with the TUA2000 and TDA4400 chips. A saw filter from modern TV using different IF chips around it, may not adapt correctly to those old chips.

While the for the UK's A/I system modification, the OFW362G is used, according to
http://www.mikrocontroller.net/attachment/79809/OFW361.pdf
on D/K you should need a OFW368,366,367 or OFW K1950 to achieve the neccessary IF Bandwidth of 6,5MHz.

Good Luck.

Hi Alexander,

it is possible, that the reel motors don´t have their full "power" now.
First check two electrolyt caps on the module "Ablaufsteuerung" (behind the tape drive). They are located near the copper heat sinks with the output transistors BD898 (or TIP125) - these are the power supply for the two reel motors.
Perhaps, one (or both) electrolyt caps have got dry and have lost most of their capacity.

By the way: Does the display show the correct tape lenght? If inserted a VCC-480 tape, the display must show "C4" (left side). If the VCR does not indicate the correct tape lenght, the tape tension is not correct as well!

What you have noticed (tape goes up and down at the tape guide), is the cause of the bad reverse picture search. You can clean the pinch roller very well with acetone or high-purity alcohole (< 90%). No abrasion of the tape must be left on the pinch roller. If you still see a glittering shape of the 1/2-inch tape on the rubber, it´s better to change the pinch roller (still avilable).

And, as you have already noticed, the tapes are VERY different quality! Some cassettes can be wound light and smooth, others won´t do.
THESE are the tapes, which clog the video heads very fast and heavy...

Best regards,
stego

Oh, sorry: I forgot:
The two electrolyt caps have 10 µF and 35 or 50 Volts, as far as I remember.

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[ Diese Nachricht wurde geändert von: stego am  9 Dez 2011  9:00 ]

Hello!

About tuner: this is good news! I think, I will find correct filters. I have tons of old TV boards, from which I'll be able to desolder necessary filter.

About reels: Capacitors are good, and when I initiate a tape loading sequence without tape, reels spin very fast and it is really difficult to stop them with fingers. Tape length displays correctly (C4) and time from the beginning of the tape displays correctly too. I think, this is trouble of some cassettes... After full 4 hours playing from begin to end, these "bad" tapes rewind good for the first time. And then they rewind good only at the beginning of each side. To the end it seems like motors are difficult to spin... But they do! Slowly, but spin!

About pinch-roller: I unmounted it and saw, that it is not the correct "straight" form... It is like a pillow... Tape made a deepening in a rubber. Alcohol and acetone didn't help... I'll try to restore roller with sandpaper (in this way I've restored pinch-roller in my old Sony VCR). And I've noticed one thing: in PAUSE, when sync is unstable, if I move tape up or down by finger at the beginning of tape path (near erase-head), I get good picture even on "bad" tapes! It seems like tape goes through video-head not exactly straight, but at one end of videohead tape is above or below the usual lever, and if I make higher tension, it adjacents to the videohead better... (sorry, it was difficult for me to explain clearly)

Best regards,
Alexander.

Offtopic :

And some old videos, which I've captured, when sync was good. The sound quality is much better, than on VHS-tapes (not HiFi)! ZDF Heute 07.12.2011: http://www.youtube.com/watch?v=CkrHRWPkCy0 Sat.1 Werbung (1989): http://www.youtube.com/watch?v=qLoW-IUQ424

[ Diese Nachricht wurde geändert von: Byteman am  9 Dez 2011 23:19 ]

Hello Alexander,

you can adjust the back-tension of the tape in play/record mode:

If you take a look from above into the copper heat sinks (on the "Ablaufsteuerung"-module), you can see a trim-potentiomenter.
With this "poti", you can allign the back-tension. Turn this poti carefully with a very small screwdriver (better: a plastic allign tool), until the picture quality is better, but not too high! Because, if too high, the abrasion will get high, too! (Perhaps the trimpoti has a oxydation...???)

This allignment takes no effect for Fast forward and rewind spin. I guess, like you already did, that it´s the cause of the different tape qualities. Some tapes, however, get sticky, and cannot be wound so smooth like good tapes.

My tapes are most of all BASF chromdioxid extra quality, they are simply the best (and the last produced) V-2000 cassettes.

Best regards,
stego

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Hello, Stego!

I have a bad news..... This VCR will make me some years older than I am.... Yesterday I was adjusting tape mechanics, and found, from what reason I had troubles with tape path... That were, as we thought, bad qoualitu of some tapes (some are very-very abrasive, and they makes very great tension before videohead, when drum is rotating), and another one was bad pinch-roller. I've repaired it with sandpaper, and made greater pressure to capstan. All seemed to be good, BUT.... Suddenly, when I tried to light on the tape to see any chewed places of the tape, I touched processor-board with my watches... Display went dark...

Power are good, all voltages are normal. When I power-on VCR, it makes usual startup-sequence (big rotating ring rotates for some cm in one and other side), seems that processor is good... I now have no oscilloscope (today will bring one from my friend), but usual multimeter shows me, that there are activity on I2C bus. On display board voltage convertor works fine (all necessary voltages are present on TMS3763ANL), but no RQ signal from TMS.... Also i saw that there are no good signals on display. Heater is good, +33 is good too, but no output from TMS. I don't know how to check exactly, is it a TMS fault or something else... Maybe, there exists some methodology of checking? And, if it is a TMS fault, is it possible to find replacement?

Thank you for your help.

Best regards,
Alexander.

Hello Alexander,

now that´s really sad to hear!

This is, why I NEVER wear any watches or something else - not at work on my electronic equipment, and even not at all! I don´t like watches on my hand wrist! In nearly all places and rooms, I have clocks on the wall, on the electronic devices (VCR, clock-radio, and so on) - so I don´t need a watch.

Now, what module do you mean, you have touched with your watch?
The one behind the tape drive? Called "Ablaufsteuerung"?

It is possible, that the central processor has a damage now. I would change the module completely, if I had one.
Because changing the "big" IC would be very difficult.

Another cause (very often!) is the CMOS-RAM-IC (a small IC).

What happens, if you press any function buttons (Play/FF/REW on right side, channel numbers on left side)?
Does something appear on the display, does the tape drive start any function?

In this thread:
https://forum.electronicwerkstatt.d......html
you can download the service manual for the "Ablaufsteuerung" module.
I have uploaded it a few years ago for a user named "Nicola".

Best regards,
stego



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Hello, Stego.

That was my mistake... I'll never wear them if I repair some electronic equipment...

If I remember correctly, I've shortened something near B1 connector on "Ablaufsteuerung" board... I've downloaded all documents about 2280 and 2280a models that were available on this forum.

Sympthoms are: black display, no response on any buttons... Only when I turn VCR on (by big button 0/O) it makes startup-sequence (rotates big ring with tape guides half a centimeter forward, and then back). And it looks like processor is alive... I think that VFD-driver died. What should be on /RESET pin of B1? Should be any pulses on /RQ? I see with my multimeter that there are pulses on SDA and SCL.

And! I remembered! There were "click" sound when I touched solder pionts... Maybe there were arc between watch and points

Desoldering of big ICs is not a problem at all. I have all necessary equipment. Another problem is where to find replacement parts and to know exactly, is this part really broken Now I want to test VFD/Keyboard controller, but I don't know how to do it...

And I've noticed, that transistor T249 on VFD-board gets hot. But it is good (I've desoldered it and tested with mutlimeter). Diodes on VFD-board are good too...

Best regards,
Alexander.

Hello Alexander,

i guess, the best is to replace the complete module instead of re-soldering any of the ICs.
But, unfortunately, most of these modules "Ablaufsteuerung" today are completely defective, because of leak accus on these modules! The circuit paths on the module get destroyed by the electrolyt from the leak accu.

So, if your module is in good condition, first check all the "fuse-resistors" on the module. They are marked in the service manual with a triangle symbol with a "!" inside. Most of them have 1 Ohms.
Perhaps, only one of these security resistors has blown...

Next, I would try to get another module (from a broken machine), and replace one IC after the other, beginning with the CMOS-IC, and last the "big" processor IC.

Sometimes, bad machines are on eBay. But most of them are in Germany...

Best regards,
stego

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[ Diese Nachricht wurde geändert von: stego am 13 Dez 2011 13:30 ]

Hoooraaaah!!!!!!! T1521 was all of my troubles!!!!!!! Just replaced it with russian KT315B, soldered it with wires, and VCR made a light from screen!!!! Yahhooo!!!!!!

Stego, thank you for your help!!!! Now I'll make all works without watch. Now I need to adjust tape transfer. And, if there will be possibility, to replace pinch roller.... Now I'll digitize tapes with old German TV and upload them on YT.

Best regards,
Alexander