OT: Cleaning video head on my Betamax VCR

[Gene Heskett]

On Sunday 10 August 2008, Tim wrote:
>Tim:
>>> We had a bit of fun tripping down memory lane resurrecting a VTR to play
>>> back something from 1974 just a few weeks back.  That's a year before we
>>> officially had colour TV in Australia, though I can see that some of the
>>> recordings did have colour sub-carrier present.  Somewhere I've got
>>> another half-inch open-reel tape with "Apollo mission" written on the
>>> box.  It's old enough that it might be a live off-air recording, rather
>>> than some documentary after the fact.  But it's a different format, so
>>> I'll have to do some scrounging for another machine.
>
>Gene Heskett:
>> The Apollo tape sounds interesting!  1974 would probably have been a
>> 3/4" sony u-matic.  Quite common in the day, but that was early in
>> that era too.
>
>Only in the stations.  It would be the early-mid-1980s before Umatics
>were seen outside of them, over here.  Beta and VHS came out a lot later
>here, than overseas, too (mid-late-1980s).  So, in the 70s, it would
>have been reel-to-reel equipment in schools, and the like.  There'd be
>very few home VTRs.
>
>> No idea what the 1/2" format would have been, there were several false
>> starts before u-matic took over the field for 20 years in the smaller
>> markets.
>
>If I remember correctly, it was one of the Sony machines with the larger
>head drums.  I had two of them [1], but they were knackered long ago.  I
>gave them away to someone who collects junk television equipment, and
>didn't really care if they worked or not.  He's got more space than me,
>and if I find the tape, I can always pay him a visit with the VTR's
>service manual and a CRO.
>
>I've still got two other VTRS that had the smaller head drums, one of
>them plays fairly well [2], the other has bad servo hunting and the
>pinch roller doesn't grip [3].  The pivot point for the arm that swings
>it back and forth is stiff, and several hours of lubing and wiggling
>hasn't helped.  But I don't think the tape played on these machines.  Of
>course it's about twenty years since I tried to play that tape.  And the
>only thing I can remember about the pictures on the tape was the rather
>chunky flashing super over the picture (that it was very chunky, not
>what it said, nor what the pictures were).
>
>Someone else's pictures of the same model VTRs:
>1. http://www.oldtechnology.net/images/sonycv2100.jpg
>2. http://www.rewindmuseum.com/images3/nv3030.gif
>3. http://www.oldtechnology.net/images/sonyav3620.jpg

I think I'm lucky, I missed that generation of machines as I sat that era out 
at a transmitter somewhere.  But I did get to fix an IVC 1" once, by doing 
what the factory manual said was an absolute no-no.  The exit guide is 
supposedly factory fixed and is never to be touched, but I couldn't make it 
track reliably, like the tape was wandering back and forth.  So I got a 
micrometer caliper and measured the flange spacing, finding it was actually 
1.038", explaining why 1.000" wide tape went every which way.  So I pulled it 
off after measuring the bottom flanges height so I could put it back on 
somewhere near correct.  Then pulled the assembly apart and stuck the spacer 
in a drill chuck and took a new 14" mill bastard file and took a little off 
the end, rinse, measure, lather & repeat, till it was about 1.002" wide.  
Ditto for the other guide which was something in the 1.023" wide range.  
Reassembled it & remounted it on the machine and and after tuning them with 
the calibration tape & a scope on the rf from the head a bit, it, according 
to the CE at that station, worked far better than it ever had when new, it 
was actually airable, and quite hi-def by the standards of the day.  If the 
tape wasn't headed toward being made out of un-obtainium by then & priced 
accordingly, we were tempted to go get the other 3 they had in storage & do 
them too.  Sony's C format tape wasn't compatible for some reason, probably 
reel hubs or some such silliness.  This one took std NAB 10.5" or 14" hubs 
but with 1.050" spacers.  Serious reel motors in that puppy, and serious 
servos to drive them.

>I've got the service manuals, still, for 1 and 3.  Never had one for 2.
>I used to have one of the portable recorders, but I gave that to a
>friend about twenty years ago.  Yeah right, it's got a handle, a
>shoulder strap, and uses 12 volt batteries, so it's portable, never mind
>that it weighs ten tonnes...

Shirley, you jest.  But yes, we used to call that stuff you needed a good 2 
wheel cart to move "porter-able". :)

>You young people and your DVDs and MiniDVs don't know how easy your have
>it.  One of my cameras weighs as much as I do.  ;-)

We used to have a couple of those, had a 3" set of 3 Image Orthicons for the 
color and a 4th 4.5" for the luminance channel.  I have a tube from one of 
them in my old office at the tv station as a momento.  The TTP pedestal was 
originally build to handle that monster, and most of those are still in 
steady use today, with a 20 pound camera/teleprompter on them, they will 
never wear out if the ops treat the drags with respect.  Sadly, most don't, 
even after pointed tutoring by moi...

-- 
Cheers, Gene
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