ITT Nokia S-VHS VR 3799 Video Recorder - Information Needed

[hillsrob]

Indeed there is a 100R resistor on board MC1 that I'll check.

[Sanbeta]

I would also get the PSU checked for bad caps. It looks to be the same style that Sanyo had on Their VHRD4980e and i had to change quite a few to both the ones i had,Especially as they were the ELNA make and two or three leaking badly.
Also on the issues with the reel braking.On one of mine this was mainly on E180 tapes near the end when you pressed stop, the spools were not being sufficiently braked to avoid a bit of tape sticking out before you ejected it.Not always but on the odd occasion,hence Sanyo's update to the P90 version and re designed brake slider plate.

[hillsrob]

Originally Posted by Sanbeta

I would also get the PSU checked for bad caps. It looks to be the same style that Sanyo had on Their VHRD4980e and i had to change quite a few to both the ones i had,Especially as they were the ELNA make and two or three leaking badly.
Also on the issues with the reel braking.On one of mine this was mainly on E180 tapes near the end when you pressed stop, the spools were not being sufficiently braked to avoid a bit of tape sticking out before you ejected it.Not always but on the odd occasion,hence Sanyo's update to the P90 version and re designed brake slider plate.

Thanks for this. I noticed the problem first on a couple of 3 hour S-VHS tapes. I don't know if it's my imagination but they seem heavier than VHS tapes of the same duration. I wonder if the S-VHS tape is a heavier grade? I'll take a look at the PSU caps. I was under the impression that my machine has the P90 mechanism? The P90 service manual seems to match it as far as I can tell. I'm also using the Sanyo VHRD4890 service manuals which seem to be a good match. Did you get the 8 and 9 reversed?

[vhs doctor]

Make the following test with a casstte at the start press PLAY and then REVIEW.

If the machine respond to the start ( transparent ) of the tape and goes to PLAY or STOP the electronic part of the VCR is fine and your problem is the brake pads of the reel brakes.

If the mechanism does not respond to the start of the tape the problem is electronic.

[winston_1]

Originally Posted by vhs doctor

HI
With your mobile phone camera check if the LED transmits IR.

As long as it is not a iPhone which has infra red filters in the lens.

[jhalphen]

Hi to all,
Hi Winston_1,

i have tested IR remotes with an i-Pad.
The front camera has indeed an IR filter & shows nothing but the rear camera is IR-sensitive (not filtered) and can be used to test a remote control.

No experience with Android phones, sorry!

Best Regards
jhalphen
Paris/France

[hillsrob]

Originally Posted by vhs doctor

Make the following test with a casstte at the start press PLAY and then REVIEW.

If the machine respond to the start ( transparent ) of the tape and goes to PLAY or STOP the electronic part of the VCR is fine and your problem is the brake pads of the reel brakes.

If the mechanism does not respond to the start of the tape the problem is electronic.

Thanks. So when you say PLAY then REVIEW, do you mean backwards with picture visible? If I understand you correctly then the machine should revert to normal PLAY or simply STOP? So what I am looking for is the fault condition where it runs backwards towards the reel end ignoring the transparent part of the tape?

[vhs doctor]

Yes I mean backwards with the picture. You are looking if the VCR "read" or "ignore" the transparent part of the tape.

[hillsrob]

Originally Posted by vhs doctor

Yes I mean backwards with the picture. You are looking if the VCR "read" or "ignore" the transparent part of the tape.

I understand. I did a test today and can confirm that in REVIEW say from a few metres into the tape it runs backwards and overshoots the beginning of the clear part of the tape a little but stops and winds forwards till the magnet tape is blocking the LED and then it goes to STOP.

I looked carefully at the brake pad on the take up reel which perhaps needs a clean or replacement. I could not find this part online. Sanyo part number 613 022 0196 or 613 022 0106.

I turned my attention to the supply reel brake. This mechanism puts spring pressure on the back tension band to effect the braking function. The back tension band is very worn at the point of contact with the reel. See pictures. This part is available online. Sanyo part number 613 021 9701.

It occurred to me that as the majority of the tape mass is on the supply reel, poor braking of the supply reel may have most of an effect on overshoot at take up reel and vice versa. Ideally I should replace both the take up reel brake pad and the supply reel back tension band.

[vhs doctor]

OK

So your problem is the reel brakes. You can replace the pad only (you cab take the material from the useless tension band) but you must cut and reglue again.
Check also the surface of the gears that came in touch with the brake pad.

You can replace the tension band but you must mark the position from the old one and install the new in the same position.

[ben]

I'd star by replacing that brake pad. It looks pretty puny to begin with.

I find pound shop 'anti slip' pads useful for this sort of thing. There's one pack with a variety of thicknesses which is ideal. You might want to add a tiny drop of superglue if you're concerned the adhesive may not be man enough for the job!

The supply reel/backtension is a bit more demanding, a cut up strip of thin felt might be what you need.

[vhs doctor]

Does anyone know the name of the friction material that is used on the tension band and brake pads

[Maarten]

Probably felt.

[hillsrob]

I had similar thoughts about replacing just the take up reel brake pad material. In fact the pad came off while I was cleaning it and I super glued it back. I'm going to order a couple of back tension bands while they are still available. I do have a JVC back tension gauge cassette and this shows that the back tension is about right, fluctuating around 50 gcm. I understand that the correct procedure is to get the back tension pole position right first then the back tension measurement should 'come out in the wash'. There's also a 'flagging' check that can be done while observing the displayed picture with the horizontal hold offset.

[vhs doctor]

Thank you Maarten I will try to replace pads with felt to check the result.

Hillsrob
You can install the new tension band in the same position as the old and "fine tuning" the back tension with the cassette.
Donberg have only one brake pad https://www.donberg.ie/descript/1/14248-g.htm