OT: Warning about old VCRs DSR-11 etc

farss wrote on 4/16/2010, 4:40 PM

Had a friend do a UMatic to DVCAM transfer for a client and he hit a snag. The signal going into the DSR-11 was clean. The signal coming out of the DSR-11 and recorded by it was not. If you hadn't looked carefully with a waveform monitor you might have simply thought it was how the old analog tape looked anyway.
What was happening was ripple and noise being added to the signal. Thankfully this guy had seen this problem before with a DSR-20. That VCR was fixed by replacing the power supply, at considerable cost. Sony will not release schematics for the power supplies and insist they are replaced as a unit. Fair enough from a safety perspective but not so reasonable when you have to search the planet to find a spare. Probably even more of an issue given what is possibly going wrong.
My money is on the capacitors. This is surfacing as a huge problem with electronic devices. An entire generation seems to have been manufactured with substandard electrolytic capacitors leading to premature failure of just about everything from PC motherboards to routers, TVs and VCRs. That's a much wider topic than what I'm on about here.
My concern is someone could miss seeing the problem with these failing VCRs. They seem to continue to work just fine for digital signals, only recording from the analog inputs has a subtle problem.

It maybe possible to breathe new life into these old machines by simply replacing the capacitors. You do need to know what you're doing or else find a good tech to do the work. You are dealing with parts containing lethal voltages, no recommended unless you are qualified.

Bob.

Comments

B.Verlik wrote on 4/16/2010, 4:54 PM

Sort of off topic from your announcement.
My Visioneer 7100 Scanner's AC adapter quit working, so I plugged in my handy Radio shack spare, set the voltage, and made sure the tip was set the same as the old adapter. It powered up, but OMG, everything I scan now has what looks like the worst Video noise in the world. I mean, you can hardly see what you've scanned because of the noise and wavy lines. I tried putting those magnet clamps on the end of the cable, but nothing changed.
Now what?

rmack350 wrote on 4/16/2010, 4:54 PM

Thanks Bob. A good reminder for people to watch things carefully and then test playback.
My own DSR11 never has a monitor attached so I wouldn't spot this until after capturing an analog source. Hopefully I'll remember to check a short bit before doing a big capture.

Rob

farss wrote on 4/16/2010, 5:04 PM

Sounds to me like something inside the scanner itself died and took out the AC adaptor in the process. If you unit is a high end model might be worth the cost of a tech delving into the innards. If not seems like time for a new one.
I too hate this. I'm no greenie but....

Bob.

plasmavideo wrote on 4/16/2010, 5:25 PM

Better than 80% of the repairs to electronics I do at the station on monitors, receivers, tape machines and other things involve merely locating and replacing bad caps. Most all other electronic components these days are very stable.

Sometimes you can instantly spot the bad cap, as it's very puffy on the top, or has a small split on the side or around the bottom.

ushere wrote on 4/16/2010, 6:26 PM

all i remember is the smell - especially noticeable when you had a beta sp rig on your shoulder!

Former user wrote on 4/16/2010, 7:09 PM

The DSR-11 uses an external power supply / wall wart module (at least the one sitting on my desk does). As long as you can provide it 12VDC at 1.3A you should be good to go.

Chienworks wrote on 4/16/2010, 7:32 PM

I've replaced a lot of capacitors in old equipment belonging to friends and family. There was one old receiver that had a cap that dried out first, then burst. The inside of the unit looked like someone had blown a handful of flower into it. Took a LOT of careful cleaning before i could see what i was doing to make the repair.

At least modern capacitors are much better sealed than the ones from 50 years ago, so they should last a lot longer.

MarkWWW wrote on 4/17/2010, 6:58 AM

> An entire generation seems to have been manufactured with substandard electrolytic capacitors

Yes, there's a lot of it about - see here.

Mark

ChrisMN wrote on 4/17/2010, 7:00 AM

I used to be an authorized Sony repair technician and I would agree with the comments mentioned above, it's most likely to be the failure of aluminum electrolytic capacitors in the secondary side of the power supply. A good tech would not need the schematics to repair this. Power supply modules have essentially been the same design for nearly 25 years. Although the new solid state components have made them more compact.

I would not necessarily agree that the failure of the caps is due to inferior components but in my experience it's because of long periods of non-use. Electrolytic caps like to have electrons flowing through them otherwise the electrolyte tend to change characteristics and fail. I would recommend firing up old gear for a day at least once every 6 months to help prevent this.

Chris

plasmavideo wrote on 4/17/2010, 7:50 AM

Chris,

You are right concerning the Sony caps being decent quality in general. Most of the cap failures in Sony monitors or Beta machines I saw were the secondary PS caps, or for monitors, those related to the horizontal or vertical output caps.

In DVC Pro desktop machines, we saw a huge number of bad surface mount caps on boards for machines purchased during a certain time frame, so I think there was a bad run of caps, especially in the tiny, but high capacity caps.

And speaking of stink, there's NOTHING like the stink of the non-polarized vertical output caps in old small Panasonic b/w monitors. When one of those let loose, the smoke and stink could be smelled at the other side of the building - not to mention the cleanup of the fluffy white crud!

A. Grandt wrote on 4/17/2010, 10:17 AM

I had a motherboard where I'd estimate that about 90% of the caps on it had started to "grow hair" on the top.