Panasonic top-loader VCR Issues - Videokarma.org TV - Video

vortalexfan · #1 11-17-2022, 05:35 PM

Hello everyone, today I picked up off Facebook Marketplace a couple of Panasonic Toploader VCRs from 1980 a PV-1650 and a PV-1750 and the PV-1750 still has its original Wired Remote with it yet and the PV-1650 still has its original Dust Cover with it yet.

The Issues I'm having with them is the same with both units and that is that the take-up reel won't turn when the tape is loaded into the VCR after hitting play and the tape is loaded up against the head drum, it loads the tape into the mechanism, but then after a couple of seconds it backs the tape back out of the mechanism.

I did replace any and all bad belts in both VCRs (the weird thing is that the PV-1650 VCR's belts all failed by breaking in half rather than the classis "turn to goo" or "dry-rot" failure seen in most VCRs of this age, in fact most of the belts in both of these VCRs (including the broken belts in the PV-1650, were still soft and supple yet.)

Also in the PV-1750 the VCR will Rewind and Fast-Forward just fine, it just won't play, and the PV-1650 won't rewind, or Fast-Forward in addition to not playing.

Any ideas as to what might be causing the take-up reel to not spin in these VCRs when pushing play or to not fast-forward and rewind?

waltchan · #2 11-17-2022, 11:15 PM

Quote:

Originally Posted by vortalexfan

Any ideas as to what might be causing the take-up reel to not spin in these VCRs when pushing play or to not fast-forward and rewind?

In the PV-1650, there's a separate play idler tire at the right reel where the thin counter-belt is mounted. Clean the tire.

vortalexfan · #3 11-18-2022, 12:56 AM

Quote:

Originally Posted by waltchan

In the PV-1650, there's a separate play idler tire at the right reel where the thin counter-belt is mounted. Clean the tire.

OK, thanks, I will give that a shot.

What about the PV-1750?

vortalexfan · #4 11-18-2022, 12:16 PM

OK so its definitely the idler tires that are bad (they are cracked and have no grip left to them even after a cleaning)

I need to figure out what size of Idler Tires i need for these VCRs because all of the sites I've looked at (SMC Electronics, Russel Industries, etc.) list the parts by diameter (I. D. and O. D.) and Thickness but not by model number that they could be used on.

And Unfortunately I don't have access to the Service Manuals for these VCRs.

Any ideas as to what I need?

jr_tech · #5 11-18-2022, 12:36 PM

Quote:

Originally Posted by vortalexfan

OK so its definitely the idler tires that are bad (they are cracked and have no grip left to them even after a cleaning)

I need to figure out what size of Idler Tires i need for these VCRs because all of the sites I've looked at (SMC Electronics, Russel Industries, etc.) list the parts by diameter (I. D. and O. D.) and Thickness but not by model number that they could be used on.

And Unfortunately I don't have access to the Service Manuals for these VCRs.

Any ideas as to what I need?

A digital caliper would come in handy.

https://www.amazon.com/Digital-Calip...zcF9hdGY&psc=1

jr

djfivos · #6 11-23-2022, 03:24 PM

Hi. For the PV-1750, check whether the play idler (circled in red) is making contact with the take-up spool during play/record. This idler is driven by a belt so that might be the culprit. The NV-7000 or PV-1470 service manual might help. Shoot me a message if you need them.

waltchan · #7 11-23-2022, 03:44 PM

Quote:

Originally Posted by vortalexfan

OK, thanks, I will give that a shot.

What about the PV-1750?

I'm not a fan of the PV-1750 or PV-1770 (with wireless remote). Belts, idler tires, and sensor lamp failed repeatedly more than the other vintage Panasonic VCR models.

vortalexfan · #8 02-01-2023, 01:34 PM

OK so a little update on these VCRs, the PV-1650, I was able to find some replacement idler tires for it, but for some reason it still won't play (it rewinds and fast forwards just fine) but when you hit play it will load the tape against the heads like its supposed to but it won't actually play the tape (move the reel tables) and then it just loads the tape back into the cassette after a few seconds, so I'm not sure what is going on, I checked all of the belts related to the playback mechanism and replaced them all, so I don't know what else could be causing the VCR to not play, and all the motors are fine because they all spin up as they should when powering on the VCR, the service manual for the VCR just lists belts as being the only issue that could cause the VCR to fail to play, but I've alreay replaced all of the belts, unless the belts I used were not the proper length (too long) and weren't supplying the proper tension for the reel tables?

The PV-1750 I was able to get it to Rewind and Fast Forward as well, and the playback idler needs a new tire for it, but I can't seem to find one that is the proper diameter (its around an inch in diameter for the outer diameter and about 7/8" inner diameter), and I had ordered an idler tire assortment from one of the electronics parts suppliers and they didn't have any idler tires of that size in their assortment for some reason, they had one that was the next size up from that one but not that exact size, and that's all that's keeping the PV-1750 from working properly, even the remote was fully functional still when I tested it.

Phil · #9 02-01-2023, 04:20 PM

This may not be helpful at all, but I have had the same problem in U-matic machines, obviously not the same thing as VHS, but anyway the problem was caused by a failed or mis-adjusted microswitch which tells the logic the tape is threaded and ready to play. If it doesn't get this signal it will unload the tape. You might check to see if there is such a switch in your machine.

vortalexfan · #10 02-08-2023, 08:03 PM

Quote:

Originally Posted by Phil

This may not be helpful at all, but I have had the same problem in U-matic machines, obviously not the same thing as VHS, but anyway the problem was caused by a failed or mis-adjusted microswitch which tells the logic the tape is threaded and ready to play. If it doesn't get this signal it will unload the tape. You might check to see if there is such a switch in your machine.

Well according to the service manual for my VCR there's a Take-up and Supply Phototransistor that I think is performing the same function as the "microswitch" you're referring to. Would something like that failing cause the troubles I'm having?

vortalexfan · #11 02-17-2023, 10:47 AM

Well I got the PV-1750 to play tapes finally, it was a combination of a bad play idler tire and a belt that was too big on the underside.

But now that I got it playing tapes again, I've noticed that it plays tapes too slow, and I'm not sure why.

When its playing the audio sounds like a 45 RPM record being played at 16 RPMs, and the picture has large scanline bars going across the screen that look like a movie having tracking issues but its not a tracking issue because its not correctable with the tracking controls.

I can make a video and post it to youtube so you can see what I'm talking about if that's necessary.

Electronic M · #12 02-17-2023, 11:17 AM

What speed is the tape recorded at and what speed does the machine report it's playing at (if it can report that)?

If it's got an electrical problem such that it's trying to play a SP tape at LP or EP that could account for what you describe. I've seen decks do that before. I typically junk decks when they get that bad if they aren't anything special especially the newer ones that do everything in 2-3 chips.

vortalexfan · #13 02-17-2023, 12:32 PM

Quote:

Originally Posted by Electronic M

What speed is the tape recorded at and what speed does the machine report it's playing at (if it can report that)?

If it's got an electrical problem such that it's trying to play a SP tape at LP or EP that could account for what you describe. I've seen decks do that before. I typically junk decks when they get that bad if they aren't anything special especially the newer ones that do everything in 2-3 chips.

I'm not sure, the VCR in question has a switch on it that can go through SP, LP and SLP but I don't see anything on the VCR that tells me what speed its playing at (that I can see of) I do know that I tried several tapes on it and it did the same thing on all of the tapes I tried out.

The tapes I used to try out the VCR were all tapes that were around 50 minutes or longer up to about 110 minutes or so so I don't know if that says anything about the speed the tapes were recorded at or not, but the boxes that held the tapes didn't say what speed they were recorded at.

The VCRs that are the subject of this thread I think would be worth trying to fix because they are both 4-head VCRs and at that they are very early 4-Head VCRs.
Plus I've always wanted a top-loading VCR with a wired remote to monkey around with because I went to a church daycare when I was a kid that had some of these types of VCRs and always remembering how much of an interesting thing they were because I had up to that point only ever seen front-load VCRs but never a top-loader and that was what kind of got me interested in old electronics.

Also they are very solidly built units and they have several boards inside for controlling everything instead of having things all on one or two chips like the more modern VCRs did, and also they have nice big Linear Power Supplies instead of Switchmode Power Supplies which make them nice units to work on.

Anyways is there anyway to figure out what speed the VCR is playing at or what speed a tape is recorded at when the VCR doesn't show a playback speed or a tape doesn't say what speed it was recorded at?

vortalexfan · #14 02-17-2023, 12:51 PM

UPDATE: I used another VCR I had laying around that was known working and did show the tape speed, and the tapes I tried using to test the VCR with were all SP mode tapes, and the VCR does play SP mode tapes but doesn't seem to be able to detect them properly. I found a tape that was recorded in EP mode and I'll see if it can handle one of those, if it can, perhaps maybe the switch inside the VCR that detects the playback mode of the VCR got "stuck" and so it just needs another tape that can "free-up" the switch.

Electronic M · #15 02-17-2023, 01:15 PM

The playback speed is not sensed with a switch. It's detected from the linear control track of the tape by the electronic circuits that control tracking.

Usually the only user speed control is for recording mode only.

If it's that old it's probably worth trying to fix even if it's a complex electronic issue, but a service manual with schematic is going to be critical to success.