Videokarma.org TV - Video - Vintage Television & Radio Forums

Videokarma.org TV - Video - Vintage Television & Radio Forums (http://www.videokarma.org/index.php)
-   Recorded Video (http://www.videokarma.org/forumdisplay.php?f=173)
-   -   So what is the "Panasonic power supply issue"? (http://www.videokarma.org/showthread.php?t=274700)

Ed in Tx 03-07-2022 03:31 PM

What's the tape path look like at the guide just after the AC head? I've seen the vertical forward-back tilt or "zenith" of the AC head. or a worn pinch roller, cause tape skew.

If you go messing with the entry and exit rollers you will probably need an oscilloscope hooked to the head amp RF-out to do an alignment assuming you have a known good tape. Put a small mark with a felt tipped marker on the shiny metal part on top of each roller assy just in case, so you can put them back where they were.

starbond 03-09-2022 06:29 PM

2 Attachment(s)
Ed when i check the other end of the path it actually looks okay. If you say a worn pinch roller can cause the same problem then thats exactly what it is. I can see the tape start to spool out loose for a half a second before the roller pulls it back in but its a back and forth battle. I'll try some rubber restore but its pretty far gone. Problem is I dont know how to get it off the transport

Seems like all the rubber parts are in need of replacement. When FFD or RW sometimes the tape gets stuck despite the motor turning, When I press stop and the transport rollers go back in, the tape does not pull in those 3-4" of slack so If I were to hit eject Id end up with a snagged tape, I have to rewind or ffd first for a few seconds before ejecting the tape. Looking at the idler(?) roller between the two tape spindles its also pretty shiny and smooth.
http://www.videokarma.org/attachment...1&d=1646872125
http://www.videokarma.org/attachment...1&d=1646872125

vortalexfan 03-09-2022 11:39 PM

Quote:

Originally Posted by starbond (Post 3240231)
Ed when i check the other end of the path it actually looks okay. If you say a worn pinch roller can cause the same problem then thats exactly what it is. I can see the tape start to spool out loose for a half a second before the roller pulls it back in but its a back and forth battle. I'll try some rubber restore but its pretty far gone. Problem is I dont know how to get it off the transport

Seems like all the rubber parts are in need of replacement. When FFD or RW sometimes the tape gets stuck despite the motor turning, When I press stop and the transport rollers go back in, the tape does not pull in those 3-4" of slack so If I were to hit eject Id end up with a snagged tape, I have to rewind or ffd first for a few seconds before ejecting the tape. Looking at the idler(?) roller between the two tape spindles its also pretty shiny and smooth.
http://www.videokarma.org/attachment...1&d=1646872125
http://www.videokarma.org/attachment...1&d=1646872125

One thing I've had to do with these Pannys from this time period is that the idler tire has to be replaced (they are dry-rotted by now) and I know I had an old Panasonic 4-head Linear Stereo VCR from 1984 that I had picked up from a flea market several years ago for $10 that it had issues with wanting to "eat" tapes and also not want to rewind and fast forward tapes properly, at first I thought it was one of the 3 or 4 drive belts on the bottm of the unit, but when I checked them, they were fine, but then when I checked the idler tire, it was cracked and dry-rotted, so I got a new idler tire installed on the unit and its been fine since (a friend of mine has it now.)

Ed in Tx 03-10-2022 08:57 AM

That pinch roller is shot. No good. When I worked on those it was routine to replace the pinch roller and other rubber parts, idlers, belts. Often replaced the takeup clutch ass'y too, with OE parts. The aftermarket parts I tried usually came back to haunt me. Another wear part is the back tension band. I can almost guarantee there is excessive back tension on the tape because of a worn tension band. But that will be hard to find new and then you have to adjust the tension with either a special tape with a tension scale or a "Tentelometer" which I used.


All times are GMT -5. The time now is 12:35 PM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2026, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.