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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 12th Mar 2018, 9:29 pm   #1
phildil
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Default Sony AV3670 VTR (VideoCorder)

Hello all

I've inherited one of these vintage half-inch reel to reel VTRs and have been working on getting it going.

It had some minor mechanical issues, which I've fixed; it now runs OK and with a known good tape (Scotch brand, not the flaky Sony stuff) it replays audio just fine.

On the video side though I just see snow, no picture at all, and the video meter is pinned at full. I suspect damaged (chipped?) video heads. I have two more Sony EIAJ VideoCorders: these are the portable Video Rover machines model AV-3420. Neither of these will power up and run, so I'm wondering if they use the same heads as the 3670 then I could use one as a donor machine.

I'm sure someone on here is familiar with these old VTRs; does my head-swap idea sound workable?

cheers
Phil
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Old 12th Mar 2018, 9:59 pm   #2
dj_fivos_sak
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Default Re: Sony AV3670 VTR (VideoCorder)

Is this format the same as the CV2000 machines?
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Old 13th Mar 2018, 5:24 am   #3
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Default Re: Sony AV3670 VTR (VideoCorder)

No, the AV3670 machines are EIAJ standard and the hardware is different.
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Old 13th Mar 2018, 5:55 am   #4
TonyDuell
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Default Re: Sony AV3670 VTR (VideoCorder)

Having got both the AV3670 and the AV3420, I am pretty sure the head beams are the same. Take great care if you remove them, the head tips are very fragile and will break off if the touch just about anything.

One of those machines (I think it's the AV3420) has what I feel is a design error. The head beam mounts onto a disk on the end of the shaft. This disk is fixed to the shaft by a central nut, which is the normal right-hand thread. The problem is that the direction it runs tends to loosen the nut at which point the disk and head beam wobble and the head tips are shattered when they hit the fixed drum parts. The nut should be left-hand thread.
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Old 13th Mar 2018, 10:56 am   #5
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Default Re: Sony AV3670 VTR (VideoCorder)

Hi Phil, the part numbers shown for these two machines are almost identical, 8-829-510-12 and 8-829-510-14, both being described as 'HO1-12' heads. The difference is possibly cosmetic or a production change only. Sony recommend scribing the upper drum assy. before removing it to access the heads so the same position can be found on reassembly. Look forward to success.

Peter
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Old 13th Mar 2018, 5:15 pm   #6
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Default Re: Sony AV3670 VTR (VideoCorder)

I totally agree about scribing the upper assembly, I always did this & one could ensure reasonable compatibility.
Although I wouldn't have done it at the time, now, because spare heads are very hard to find, you can in desperation, change just the actual head tips if necessary. Fiddly, but I have done it on both reel-reel & Umatic.

There may be a slight dihedral error, but with care you can tweak this out, either using a known well-recorded tape, or if possible, an alignment tape. Very rare, but I do still have one!

Good luck,

David.
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Old 13th Mar 2018, 5:49 pm   #7
TonyDuell
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Default Re: Sony AV3670 VTR (VideoCorder)

I once fitted betamax head tips onto the beam from one of these machines. Althpugh totally incompatible format-wise with the originals, they were electrically similar enough (right inductance, etc) to be able to record and play back (its own recordings only, of course).

The head beams are very hard to find, but they do turn up. Last year I was at a swapmeet and one seller had a box of VHS, etc head drums. I jokingly said they were too new for me and that I was looking for the head beam for the old Sony EAIJ reel-to-reel machines. Delved in said box and pulled out.... A brand new, in Sony packaging, head beam. Yes I do need it for my pair of machines.
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Old 13th Mar 2018, 6:41 pm   #8
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Default Re: Sony AV3670 VTR (VideoCorder)

At the time these machines were popular, the dealer I worked for sold hundreds of them. I once went on a weeks preventative servicing of all the major MOD sites in the U.K., changing heads & etc on a huge number of Sony 1/2" machines in the one week. I went by train, as the schedule would have meant gruelling hours in the company car. Stayed at all the best hotels & used taxis to site!

I changed all the heads, most of them still good for at least another 500 hours, not to mention pinch rollers & belts.

I wonder which landfill site they went in?? Seems terrible now, I wish I still had them.

David.
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Old 14th Mar 2018, 11:14 am   #9
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Default Re: Sony AV3670 VTR (VideoCorder)

Quote:
Originally Posted by Vintage Engr View Post
I once went on a weeks preventative servicing of all the major MOD sites in the U.K., changing heads & etc on a huge number of Sony 1/2" machines ...I wonder which landfill site they went in?? .
I'm sure I recall seeing a few machines of this type at Anchor supplies Nottingham in the late 1990s. One thing I definitely picked up there was a Sony lo-band U-matic.
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Old 14th Mar 2018, 11:36 am   #10
phildil
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Default Re: Sony AV3670 VTR (VideoCorder)

Thanks all for useful notes.

I can report success with this machine! Upon closer inspection it turned out that that the video heads were sound but needed a thorough clean.

So here is a quick phone pic of the AV3670 playing back some contemporary continuity from a tape I received with it - the interference is from the "slow motion" feature on the deck. The actual playback is surprisingly good.

cheers
Phil
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