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Old 13th Nov 2018, 6:33 pm   #1
amtrakuk
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Default A couple of problems - Ferguson Videostar 3V30

During playback I get the occasional "spark" across the screen almost like a sprite - Is this "static"

Replacing a loading belt I "think" I have mis-aligned timing guides, although they thread and un-thread the tape ok, on occasions there is a "triple click" (almost like saying the word Trampoline) from the solenoid.

Finally there is a band of very slight interference about 4/5ths from the top of the screen, Above and below it, the picture is fine. I have cleaned the head with iso and paper. Is it an alignment issue?
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Old 13th Nov 2018, 7:07 pm   #2
HamishBoxer
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Default Re: A couple of problems - Fergerson Videostar 3V30

Loading pole alignment can cause it but do not just go "twiddling",really you need an alignment tape to check.

Should not be off changing the loading belt though.
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Old 13th Nov 2018, 8:56 pm   #3
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Default Re: A couple of problems - Fergerson Videostar 3V30

It is possible to lose the correct timing of the guides when changing the loading belt, one of the guides can spring forward as they are under tension in stop mode. I used to do it by winding the belt driven worm gear until the unload switch just open circuits and only then removing the loading assembly.

If this is the case you will find that one of the guides is not fully located into the V blocks in play mode. Easiest way to recover is with the machine in stop mode remove the loading block then fit an elastic band to each of the guides and the reel table it's next to then refit the loading motor block. Don't adjust anything until you've ruled everything else out.

The occasional flash is probably due to tape drop out or the tape shedding it's coating if it's old. Static on the drum exhibits itself as multiple tadpoles which may be fairly stationary or move slightly left or right. Cleaning and retensioning the discharge brush which contacts the cap on the upper drum spindle should cure it.

John
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Old 14th Nov 2018, 2:08 am   #4
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Default Re: A couple of problems - Fergerson Videostar 3V30

About the last problem you mentioned…
Check the connection between the head drum and the head pre-amp board. On my 3V23 there was poor connection and that cause noise in the picture. Contact cleaner fixed it.

Fivos
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Old 18th Nov 2018, 10:42 am   #5
amtrakuk
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Default Re: A couple of problems - Fergerson Videostar 3V30

Thanks. Sadly I haven't got an alignment tape or scope. Its not that bad but not as good as the 3V29 I have which has a perfect picture.

Next time I get it out (space is at a premium just now) I'll re-plug the head cable - I think that's the white wide plug?
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Old 21st Nov 2018, 10:44 pm   #6
amtrakuk
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Default Re: A couple of problems - Fergerson Videostar 3V30

The video on https://www.youtube.com/watch?v=6qxa7yjSYNY shows the "sparkles" as he calls them I have on my 3v30 but much worse. I have checked the cabling is all ok.

The comments below suggest two reasons a) Lose ground screw? b) Dirty or worn out head.

Where would be the ground screw on a 3V30?
Is the head the same as what is on a 3V29?

I have got a 5 channel demodulator and hopefully be putting a VCr into service. Obviously the multi timer of the 3V30 would be more preferable to the single event timer of the 3V29

Thanks
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Old 22nd Nov 2018, 9:41 am   #7
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Default Re: A couple of problems - Fergerson Videostar 3V30

A distinct 'line' 4/5 down the screen does suggest misalignment. The loading belt can be changed on these without any serious dismantling.

Didn't the 3V29/30 have the familiar static brush on top of the drum, a small sprung carbon contact resting on top of the drum motor shaft? If you very lightly hold a finger onto the spinning drum while playing a tape then you may see static appear on screen. The static brush should stop 95% of that.

I'm not sure now on the spec of the heads as there were two types in common use, one for models with freeze frame and trick functions and the other for more basic machines. The difference was in the head gap spacing and if you fitted the wrong type to a freeze frame model then the resulting freeze frame was poor with a noise band on screen. Apart from that they were interchangeable although I think the record FM drive voltage might officially have been a little different which needed a scope and manual to adjust.

If you haven't a scope and so on then you can (with care) set the guides visually using an E180 (thinner tape the better) and a torch. Turn both exit guides down until you just begin to detect curl of the tape on the lower lip of the drum. You look at visual reflections on the tape to determine this. As soon as a reflection begins to distort even the slightest amount as the tape contacts the drum means you have reached the approximate correct position. From that point you can then set the guide by looking at the playback picture on screen and by backing off the guide from the point at which curl occurs. Keep altering the tracking to maintain best picture quality and adjust both guides together initially to get the tape running 90% true before final adjustment.

If I recall correctly there was also a slider bar somewhere around the front of the drum that could stick due to grease solidifying. Can't remember the exact fault now... could have been failure to unload fully and the drum kept spinning.

Must be over 25yrs since I last did one of these
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Old 27th Nov 2018, 11:13 pm   #8
amtrakuk
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Default Re: A couple of problems - Fergerson Videostar 3V30

Thanks for the reply. I think i'll have to try and find someone to check the alignment. I have done it without a scope on the basis there is no tearing along the top or bottom of the picture.

Yes there is a static leaf on the top centre of the drum however it doesn't seemed to make any difference. with it on or off. The "sprites" aren't that bad but appear noticeably worse than the 3v29 I have.

Thats an interesting alignment technique I'll have a go at it to see if it improves the bar of lower quality reproduction. Is that a custom technique?

Fingers crossed my 5 channel DVB modulator should be upa nd running soon. Im just waiting on a couple of F connector to coax would you believe!
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Old 27th Nov 2018, 11:48 pm   #9
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Default Re: A couple of problems - Fergerson Videostar 3V30

You will be able to tell easily if the drum discharge is doing it's job by lightly letting a finger rest on the top edge of the rotating head drum. If it's not 100% in contact the tadpole interference will increase significantly.

Could you possibly post a picture directly above the guides in stop mode with the carriage removed, just to confirm the ring gear is not misaligned?

John.
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Old 28th Nov 2018, 9:32 am   #10
Mooly
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Default Re: A couple of problems - Fergerson Videostar 3V30

Using visual reflections to check the accuracy of a tape path was a technique I originally developed when working on Betamax machines but it works so well that it was possible to use it on VHS transports. It was accurate enough to be able to perform head replacements in the customers home as a field service call.

Its always worth making a judgement call on head wear as well. Good heads should protrude sufficiently from the drum to be easily 'felt' with a finger. With an old tape playing you can carefully place a finger against the tape and feel the heads. If the heads are barely detectable using this method then they are worn down.

New heads protrude enough to visible protrude into the tape.
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Old 29th Nov 2018, 12:05 pm   #11
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Default Re: A couple of problems - Fergerson Videostar 3V30

Just a quick thought...

Are you using this vcr with a plasma tv? I know from experience that old vcrs don't like plasma tv's due to the noise it creates through the A/V connection.

Just a thought though.
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Old 29th Nov 2018, 4:38 pm   #12
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Default Re: A couple of problems - Fergerson Videostar 3V30

Given the mechanical clicking sound and the noise bar at the top of the screen I would suspect that the left hand guide is not seating properly in the guide block. If the noise bar were at the bottom of the screen then it would be the right hand guide.

Somewhere I have alignment tapes, a new type L replacement video head drum which I think is for the 3V29-30 or HR7200-7300 machines and the JVC HR7200 service manual which uses the same mechanism.

You can usually get away with aligning to a prerecorded tape but they weren't all as accurate as they ought to have been.

A worn lower head drum can also cause a noise band, especially if the machine was used with Scotch tapes. They were guaranteed for life but they didn't say how long the life of the machine would be if you used them ! The lower drum should have very fine lines running around it where the tape runs. If areas look polished or smooth then it is worn.

Last edited by See_Mos; 29th Nov 2018 at 4:45 pm.
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