Sony SLV-N71 VCR Repair?

[Pudding_man]

Greetings,

I've been running Sony SLV-N71 VCR's for years.

One failed this week. When I attempted play-back, I got a mixture of play-back image and audio/video static.

Perhaps most importantly, when I set the remote to 'video' with no tape playing, I get a blue screen, some audio static, and a weird (and loud) 'scratch-scratch' sound that repeats endlessly. When I set the remote to 'TV', I get the normal reception images (tuned from a cable box).

I assume this is a serious problem. If it might be repairable, even requiring cannibalized parts, I'd like to know about it.

I'm not tremendously adept at electronic repair, but I'm willing to try, can solder a little, etc.

Zaphod, are you out there?

Thanks,
Puddin'

[zaphod7501]

Well, the obvious first step is to clean the heads, including the audio/control track. Might not help but you shouldn't overlook the obvious. Sometimes just letting the tape run will clean the heads also. You should load the tape with the top off to see if it follows the guides and pinch roller normally.

That said, the 51/71/81/91 were exchange models that differed from the 50/70/80/90 in a critical way. They never wrote a service manual and had 0 (zero) parts available. They had identical features, cabinetry, and cost but were completely different electronically. With no schematics or parts, electronic failures are almost impossible to fix. Mechanically, there are similar units and some of those problems can be solved.

[Pudding_man]

Well, the obvious first step is to clean the heads, including the audio/control track. Might not help but you shouldn't overlook the obvious. Sometimes just letting the tape run will clean the heads also. You should load the tape with the top off to see if it follows the guides and pinch roller normally.

Will do. It's on the workbench now.

That said, the 51/71/81/91 were exchange models that differed from the 50/70/80/90 in a critical way. They never wrote a service manual and had 0 (zero) parts available. They had identical features, cabinetry, and cost but were completely different electronically.

That makes me wonder if Sony even made the guts of the things. Maybe they farmed that out to another electronics company?

I wish I'd known they were "exchange models" years ago, when I started collecting them (I have 3 in service).

For future reference, if I want a good VCR with similar features, I should look for, say, an SLV-N70? Ebay still has a few, I think.

With no schematics or parts, electronic failures are almost impossible to fix. Mechanically, there are similar units and some of those problems can be solved.

Well, doesn't the fact that the unit won't even pass-thru the signal from my cable box when the VCR is set to "video" suggest a failure of certain parts of the circuitry?

I have to tear into the thing: I can't just pitch it. Don't mind a "Wild Goose Chase", but I'm not very learned about where to start.

Much Thanks,
Puddin'

[Pudding_man]

I cleaned the heads. Twice.

No help.

It will do playback a little (of stuff that was long ago recorded).

It records only garbage.

And it displays only a blue screen and yields the funny "scratch scratch" sound when set to "video".

Any help much appreciated.

Puddin'

[zaphod7501]

You could try tapping on the tuner or chassis with a plastic or wooden stick to see if it is an intermittent solder connection.

Even the 70s were outsourced. You have to back to the "H" chassis to get a Sony built unit: those were almost indestructible. I can literally count on my fingers the failure modes and they were all repairable with improved parts. It's hard to give model numbers since they used similar model numbers and cabinet designs (and even remotes) to hide the fact that they were selling inferior models that just looked like the good ones. If you give me a model number, I can tell you if it was a good'n or a bad'n.

[The Robman]

Wow, that's like if Toyota started letting GM build some of their cars!

[tennessee titan]

"Wow, that's like if Toyota started letting GM build some of their cars!"

NUMMI (New United Motor Mfg Inc) Fremont, CA - Builds Pontiac Vibe and Toyota Matrix

[MaskedMan]

All the Sony vcrs I ever had did the same thing, cut up the edges of the video tape.

My first Sony vcr was the slv-575, upgraded to the slv-676 with flying-erase head. Moved on the SLV-R5 s-vhs model. Then had two each of the 940 & 960. During this time I went through 5 evs-550 8mm vcrs. I finally had enough.

[zaphod7501]

The TV/VCR combos were even worse. Only Panasonic ever built their own, all of the rest were rebranded machines.

I once drove to Chicago for a training class to discover, after 5 hours, that the Sony combo was a Goldstar mechanism, an unidentifiable main board, with a Trinitron picture tube. They had no info on anything in the set other than the power supply.

The first Sony VHS machines were from Hitachi (without LP/4hr playback capabilities). Then the great machines. Later models came from Sanyo, Funai, then some unidentified companies.

When they started selling VHS, they went back and rewrote the specs on the Beta and VHS formats. They reduced the Beta specs to match the worst machine they ever built, a single speed, 2nd generation product. They listed the VHS numbers for pre-recorded, direct transfer movies as the spec, despite the fact that you could not make any self-recordings near that level.

[zaphod7501]

All the Sony vcrs I ever had did the same thing, cut up the edges of the video tape.

This was usually caused by the grease drying out on the RVS arm. A cleaning, lube, and adjustment was normally a permanent fix. The shaft of the capstan motor could also bend over time but the bearing was available as an improved ($10) part.

During this time I went through 5 evs-550 8mm vcrs. I finally had enough.

These had a number of annoying problems. The guides would come loose and alter the alignment. (align and tighten the set screws) The guide locating pin would move and drop the guide off. (I formed some tools from paperclips to reattach the guide without even taking the bottom off of the unit, then install the custom retainer they designed to prevent reoccurrance.) But the real killer was leaking capacitors (fish-caps) that would destroy the circuit boards after 5-7 years (never buy a used one). Since Sanyo and Hitachi never brought 8mm players into the USA, Sony had no incentive to improve the product or reduce the price. (no competition)

[The Robman]

I take it back, GM would have done a better job. I can't believe a respectable company like Sony would sell such crap.

[Pudding_man]

Even the 70s were outsourced.

I've got the front and back off the unit. Inspected the bottom of the mainboard. No burnt components, visably cracked solder joints, etc.

Half expected to see some markings that indicated at least what country the main-board came from. Haven't seen anything yet.

I'll keep looking, 'though I don't know what I'm looking for.

Thx,
P

[The Robman]

If you have a digital camera, maybe some pics would help Steve.

[Pudding_man]

If you have a digital camera, maybe some pics would help Steve.

Thanks, Rob .

Steve, if you think some pics might help, I can get some out there in fairly short order. Let me know.

Thanks,
P

[zaphod7501]

I take it back, GM would have done a better job. I can't believe a respectable company like Sony would sell such crap.

They even shut down all of their tech support phone lines that servicers used to contact the factory, to save money. They canceled 180 authorized servicers for no reason other than being small. They said it cost $5600 per year to support an authorized servicer. (BS) If you multiply 5600x180 you get almost exactly a million dollars so someone thought they could save that amount by eliminating servicers. It doesn't work that way.

Pictures won't help. They didn't write a service manual. No schematics, no board layouts, no parts. They told us that they would distribute a manual after the units were out of warranty but changed their minds. The only part available was the battery cover for the remote. They issued a one page manual with that part number and picture.

Make sure you check all the inputs and outputs including RF and line. A bad tuner could kill the Ch3 output but not the line out, and bad jack connections could leave the Ch3 working but not the line out.