View Full Version : Sony VCR SLV-750HF plays a movie for a second, then stops.


MRX37
03-12-2008, 04:51 PM
I found a Sony SLV-750HF VCR that looks very nice. I tested it, and it will rewind a tape, but when I go to play it, I see the video for a split second, then a blue screen. The tape still continues playing for a few seconds, then it stops all together.

Is this easy to fix, or should I just pitch this VCR? (I have two other VCR's that work fine and are sitting in storage...

kx250rider
03-13-2008, 10:30 AM
If both reels are moving, and the tape isn't being eaten, then I put money on a very common thing on those; Reel sensors! It's a bit tricky to replace them, but I bet that's it. They're phototransistors located on the bottom transport PC board, and they pick up mirror squares on the bottom of each reel. As the reels turn, the mirrors pass the phototransistor and tell the VCR that the tape is moving.

Charles

MRX37
03-13-2008, 10:36 AM
The tape reels do indeed move for several seconds, and there is no sign of it being eaten. (had the top off and was checking the mechanics as it played. Everything looked fine)

So, whats a "Reel sensor" look like, and could I replace it with one from another VCR? (I found 2 others that work fine, buit they're cheap mono VCR's)

andy
03-13-2008, 11:36 AM
The underside of the reel hubs have a pattern of black and silver squares which these sensors point at. They shouldn't be too hard to find once you take it apart.

I assume you've tried the VCR with the cover on? Room light can hit the end of tape sensors in many 90's VCRs.

MRX37
03-13-2008, 04:01 PM
Tried it with the cover on first, then pulled the cover off to see if the tape was moving.

Hoo... I'd have to tear into it eh? Somewhat tempting as it's a nice looking VCR, but like I said I have 4 others...

I dunno about this one...

wbain
03-14-2008, 03:29 AM
The SONY VHS VCR's are excellent. I have two and still have my BETA as well.

Blast
05-02-2008, 10:38 PM
First the small print: it's been years since I worked on VCR's but from 1990-2000 that's pretty much what I did. These guys are probably on top of this with the reel sensors thing. I HAVE replaced a few reel sensors in Sony's and that's a very strong possibility.

BUT one the things that crossed my mind was that "blue screen" thing you mentioned. It was always difficult to tell what was going on when that blue screen came up. Usually when it did there was something wrong with the video signal- wasn't right, or strong enough. On some models (of other brands) I could disable the blue screen and then see that, for instance, maybe a capstan motor wasn't turning the right speed (PG? FG? I forgot...), or that video heads were worn too far. But the blue screen is a "cover-up" and if you can disable it- all the better for diagnosis. If the servo is not receiving a (proper) pulse from the capstan it could be shutting the unit down, too. You'd be able to see that without the blue screen. But scope the pulses from the reel sensors- very likely that's the problem. And it may just be dirt/lint clogging up the light path to/from the sensors. Good luck.

MRX37
05-02-2008, 10:57 PM
Um, the VCR's long gone...

Needed some caps from it, and I have 4 others that work fine.