Nearly fifty years back, Sony launched the DVC-2400, their first consumer grade video camera. This unit weighed in at 10 pounds, and recorded only 20 minutes of footage per reel. It left something to be desired for $1250, or nearly $9000 in today’s dollars.
[NeXT] got his hands on one of these camera kits, and began bringing it back to life. While all the pieces were included, the Video Tape Recorder (VTR), which is used to play back the footage, didn’t power up. A little poking found a dead transistor. After determining a modern replacement part, the voltages checked out. However, the drum still wasn’t spinning.
Further disassembly found that the drum’s DC motor was made on the cheap, using a foam instead of springs to apply pressure on the brushes. This foam had worn out and lost its springy qualities, so no electrical contact was made. New foam was cut out as a replacement. Once reassembled, the drum spun successfully. After some adjustment, the VTR was running at the correct speed once again.
With this working, the VTR should be ready to go. However, camera still isn’t working, so we’re awaiting a part 2.
I remember seeing one of these being demonstrated at EXPO 67
Heck, my high school bought one to teach film production techniques (I know, it’s not film – we used it because we got instant feedback instead of waiting for the super 8 to come back from the lab). I fondly recall making the short videotape epic “Adventures of the Mystic Zulu Frisbie” using it. Wish I still had a copy.
Reminds me of my own slightly more recent adventures with Video Toaster and McGruff the Book Dog – a puppet from the library come to life to offer book reviews. If I’d been able to get more hands on education like that in middle and high school, I’d probably be doing Hollywood effects today.
Obviously longevity may not be a concern, but maybe replacing the worn out foam with something like rubber that won’t degrade as quickly would be a better option?
I don’t think they’ll be able to repair it a second time for the same failure, since the rest of the hardware will break down much sooner and become unrecoverable due to a lack of spares on basic components.
Foam. The bane of old electronics. Right up there with old rubber, popped caps and corroded contacts.
That sounded kind of gross.
Visual Studies Workshop up in Rochester NY had some as I recall. https://en.wikipedia.org/wiki/Portapak
Interesting. I feel like the foam was more likely for vibration dampening, and the metal U the brushes sit on is intended to be the spring.What may have happened is the brushes wore down, or the spring relaxed after being stored in its sprung state for so long. This works, for now but I think you will find that the motor will stop spinning again soon unless you thicken the brushes, fix the spring, or add a secondary spring behind it somehow.
Foam. Ewe goo. Sticky time bombs. Cheap cassettes are the bomb, take out player in dash. Take out to fix. Silencing foam wraps in keyboards shed crumbs into contacts.
Was the foam actually providing pressure or was it some thoughtful damping on the resonant springy brush holder that contaminated the motor? Even a tiny brush anomaly would mess with the picture so zinging brushes would be suspect.
Typical Sony. Very expensive electronic product with one marginal, cheaply made part that fails. Some models of Sony Betamax VCRs had a near 100% failure rate due to a crappy mechanical part. 3rd party VCR parts companies made a good profit on properly designed replacements.
If you are referring to the plastic loading arm in the 2700 series machines, I know those so damn well I hate it. There doesn’t seem to be any replacements left and even the updated metal versions Sony sent out to the shops to replace their stock of plastic units seems to of dried up as well. Gonna have to see if new ones can be 3D printed. *scribbles down on TO-DO list*
Typical and trivial.