Bad surprise with N1702

[OldieSt]

Hello,

Yesterday I turned back again trying to digitalise some of my VLCs before 6 months without time to do it, but, what a surprise! My N1702 shows a b/w image on TV with a lot of moving stripes and without any audio:





I played different tapes and even cleaned the capstan and the other rolling parts, without luck...

The service manual says that it should be checked the voltage of the E-U551, and it must be 12V. Mine is 11'60V so it send to replace the TS 501 or TS 502 (maybe both?). I have located them on the board, but I have read too that the electrolytic capacitors must be replaced too.

I'd like asking to the experts:
Where is the problem, on the modulator or on the chroma-filter (where are the TS501 and TS502)?
Which components must I replace?

Thank you very much in advance. Regards.

[gromsound]

Never mind that voltage, close enough so dont introduce more faults...
Cleaned the head disk thoroughly? Looks like dirty heads. Audio will mute if video is too bad.

Over to otto for more info i guess

[Otto]

Typical dirty video heads. Not chroma or other parts.
When the chroma part is broken, you got black and white video, no color.

As gromsound say.. The audio will be muted when the video is bad!

Clean the heads with pure alcohol. No other stuff!!
Most of the time the capasitors are still good after all these years.
Other question..
What type of tape you use? 1500 or 1700

[OldieSt]

The heads should be clean, I used to do it isopropyl alcohol (99'9% pure - CH3CHOHCH3).

It's possible that the tapes were recorded on a VCR device (fast speed), these tapes were sold to me like VLCs!!

I hope it was this silly... I'm going to try with other videocassettes. I'll back later.

[Otto]

It's possible that the tapes were recorded on a VCR device (fast speed), these tapes were sold to me like VLCs!!

When the tape is recorded with an 1500 machine (high speed) yeah.. Than you have a problem.
1500 is not compatible with 1700 tapes.

The difference between 1500 / 1700 is:
- Tape speed.
- Videohead position is not the same.

[OldieSt]

Hello again,

Yes Otto, I knew that the speed was different between VCR and VCR-LP, and that they are incompatible and not interchangeable... Remember that I have an N1501 too, purchased this year because I'm a fan of the old technology, like you...

I have just discovered I have more VCR tapes "fast-speed-recorded" than I thought... The tapes that I checked yesterday came in a pack and the longest were LVC 150, fully playable with an N150x type.

I've checked an 180' tape, to be sure it was recorded with an LP, despite this my N1702 has yet a problem with the image, it's shown correctly but before some seconds it begins to be unstable and the audio disapears too. It could be that the tapes are in poor condition?



Before about 10 seconds, the tracking makes nothing:



Yesterday I did an image-proof to tune it to my TV and it was perfect (the proof with the start and rec buttons).

I'm going to try with Basf VLCs, maybe they will be played correctly (they were the best).

Thanks

[rini]

The Basf tapes are your best bet.
Other tapes can gum up your heads in seconds. (scotch tapes)
Research for "sticky shed syndrome".

I always have a tape laying around that is know good, one with my recording on it.
For that purpose, use a tape that has nothing interresting on it. (a basf tape)

Use that tape to check if the heads are not gummed up.
Most of the time the the tape is the problem.
You can also play that tape to clear the heads.
Sometimes it will work in seconds, sometimes you need to clean the heads with pure alcohol.


Good luck!

[OldieSt]

Goedemorgen!

I played other tapes recorded with an LP device (Philips and Basf) but there wasn't luck. I've read too, that sometimes a bad contact on switch SK201 could cause this problem. The image distorsion begins at the bottom and a few seconds before it fulls all the screen, and the audio goes missing. It does it even before the tape is wound or rewound...

Maybe when I cleaned it inside, I didn't realize and I "shook" the dust and the dirt to the electronic contacs, so I'm going to try cleaning them again, and the capstan and the tape roller guides...

Thanks.

[gromsound]

Check tape travel around drum and capstan. Might be the pinch roller is out of alignment, tape slowly runs up or down. Looks like a mechanical fault, you might be lucky.

[OldieSt]

I see myself doing this:

https://www.youtube.com/watch?v=k0R0bN7JIAI

Cleaning up all my tapes against the "sticky shed syndrome"...

Do you think that this is a good method to improve the video quality of these disastrous videocassettes?

[OldieSt]

After trying today to play a Philips tape, it became crazy...

The belt of the head drum was expelled from its motor-wheel again and again, until it was replaced by a new one that I had. But the device seems to have a problem with the tracking or the servo, I've tried to play some tapes, with the same success: unstable image and sound, without losing the colour...

I show you in this video what happens:




What could I do to fix it? Thanks in advance.

[Otto]

Ah, you need a new pinchroller.
U can use it from another 1500/01 1700/02.

[rini]

Did you hear that crackling? @ 0:32, 0:38 and 0:54
Sounds like this tape has some wrinkles in it.
And it is a phlips tape = suspect for trouble.

[OldieSt]

Did you hear that crackling? @ 0:32, 0:38 and 0:54
Sounds like this tape has some wrinkles in it.
And it is a phlips tape = suspect for trouble.

Ah, you need a new pinchroller.
U can use it from another 1500/01 1700/02.

UAU!! What two so good doctors!!!

Is it easy to get another pinch roller?

And probably yes, this Philips tape has some wrinkles, made when I cleaned it... Sometimes the tape gets tangled up in my "rewind-machine"...

Thank you very much

[Otto]

Maybe you can ask Rini. He's the pinchroller King he made it from old printer stuff.
I got only used rollers.

André (gromsound) is the VCC doctor.
I'm VCR doctor