[Coco] From the "Don't actually do this department" : if your tapes are old and won't load, bake them

Gene Heskett gheskett at shentel.net
Tue Apr 28 16:30:36 EDT 2020


On Tuesday 28 April 2020 15:15:27 John Guin wrote:

> https://arstechnica.com/science/2020/04/the-chemistry-of-why-baking-de
>graded-reel-to-reel-tapes-can-reverse-damage/

Here is another preservation method.  One of the tv stations I have been 
an engineer at had a cold closet that all the commercial tapes were 
stored in when not pulled out and mounted in a machine for playback.
This closet was on an outside wall and was well insulated, and a small AC 
was mounted with its thermostat shorted out,replaced by a clock that ran 
in about 45 minutes an hour, then let it thaw and drain the coils dry 
maintaining this closet at around 40-45F, and the humidity was maybe 
10%. Tapes came out, got played and put back in this closet. Clogged 
heads on a tape machine to clean were very very rare. Head life, rated 
at 1000 hours on those machines, often exceeded 10,000 hours.  Cold, dry 
tape is quite simply not abrasive. Warm, wet tape, stored in 75+% 
humidity is many times more abrasive, eating tape heads in 500 hours or 
less.

Many years before I was at an ETV station in Nebraska where I learned 
that that the ETV Commission maintained a delay site with similar 
conditions for 3 2" quadruplex videotape machines. Room held at about 
60F, and low humidity by a precipitron equipt HVAC system.  An hour long 
roll of tape went in that room, no smokeing, food, or drink allowed, and 
was put on the machine and not removed until the rewinding damage had 
shortened it to where it wasn't an hour long anymore. Heads were cleaned 
about once a week. Since it was a clean room. heads were 750 hour rated 
soft not the more expensive ferrite. Several years went by, and one day 
a rotary transformer in one of the heads failed. Noting the hours on it, 
that 750 hour head had 9300 hours on it. Returned to the rebuilder, who 
fixed the transformer but didn't rebuild the head, its was returned and 
put back into service, finally failing at just over 11,000 hours. 
pretty good for a 750 hour rated head.  That head probably wore out 3 or 
4 rolls of tape.

The difference? Environment. But try selling that to the average GM.  
Very hard sell.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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