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Is an unused Yamaha CR 820 a fire hazard?

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Posted on November 15, 2020 at 10:27:37
Vegman70
Audiophile

Posts: 134
Location: N.E. Ohio
Joined: February 20, 2016
A neighbor has this old receiver that hasn't been used since 2002 and wanted advice about selling it to a young man who helps around the house.

My take was don't sell it to anyone you know, as it may be hazardous to operate without first getting it checked out by a reputable electronic repair tech. I've seen several messages on this site that stated that as a minimum the capacitors should be replaced on a receiver that's 30-50 yrs old.

What do you think?

 

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RE: Is an unused Yamaha CR 820 a fire hazard?, posted on November 15, 2020 at 11:23:03
airtime
Audiophile

Posts: 10590
Location: Arizona
Joined: February 4, 2003
That's fairly low voltage going into the PS. Typically with those older SS units, a fuse would most likely blow before anything serious could happen.

But a lentiginous minded person would cut the power cord off. Then it's the other persons actions that caused the fire.

 

RE: Is an unused Yamaha CR 820 a fire hazard?, posted on November 15, 2020 at 12:33:57
Story
Audiophile

Posts: 4011
Location: NJ
Joined: December 11, 2000
Contributor
  Since:
February 21, 2019
the cap replacement is an age issue, yes, with caps that have actually been used and not sitting unused since, but I would recommend a slow turn on with a variac from 0 volts to 120 in a few seconds, maybe 3, just to find out if the fuses blow or not.

Check the fuses first, then hook up to cheap speakers or nothing at all and give it a go to see what happens, then take it from there to check fuses and see if any blew. How equipment has been treated over the lifetime, like exposure to wall voltage spikes etc, and what brand of caps in the first place make a difference. I have a JBL subwoofer amp for the back porch that sits in a hot summer and cold winter room with no problems and it's 50 years old. Those old American made Sprague's were made very well.

You may find the Yami needs a bunch of other kinds of work though, noisy pots, controls....

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RE: Is an unused Yamaha CR 820 a fire hazard?, posted on November 15, 2020 at 22:34:50
JURB
Audiophile

Posts: 1790
Location: North Ohio
Joined: May 29, 2016
You need a dim bulb tester.

I you are not familiar what what that is get back and I can tell you how to build one from parts from a DIY or "electicians" store.

It is better than waiting for the fuse to blow as something loses its smoke. The DBT limits current and almost completely prevents any further damage. It is better than a variac and is nowhere near as costly. I think you can throw one together for ten bucks.

Turn it on and the (INCANDESCENT) light will light and dim down as the main caps charge. Then it when you look for smoke.

If something does smoke let it and be sure. Then on the board it may say "R134" or some shit. Then we get the print and see where that is in the actual circuit. In some cases I can tell you pretty surely what to replace. And do as thou wilt on the caps, but get it working first. Always.

Once it works, MAYBE recap some and test, if it doesn't work look at the most previous work, then more caps then more caps until done, maybe by board. Whatever. But don't just do them all at once in the whole thing. If one little thing goes wrong you could be, well the technical term is fucked.

Few capacitors in most equipment can cause the failure of other components. It can happen but not as much as many think it would. Then your transistors and diodes, all those don't get bothered by sitting idle like caps sometimes do.

When that bulb dims down it should work fine into cans. If so, turn it all the way down and connect speakers. Note them the might get brighter as you turn it up. Then turn it down and take a screwdriver and hit it all over the place with the handle. At zero output there should be no increase in the brightness of the bulb. If it does it has a bad connection that WILL destroy components and then it has to be looked over by someone experienced in that.

If all goes well up to this point plug it directly in the wall, (never put bypass switch on a DBT) and crank it up some on speakers.

LISTEN to it. Some units had really good caps, you do NOT want to replace those unless they went bad. If it sounds thin or muddy it might really benefit from some caps. But if it is shaking the floor, dimming the lights and sounds great, the technical term for that procedure is fukit.

 

That's good advice..., posted on November 16, 2020 at 05:02:20
musetap
Audiophile

Posts: 26018
Location: San Francisco
Joined: July 8, 2003
Contributor
  Since:
January 28, 2004
He should sell it to someone he doesn't know.

He should GIVE it to the guy helping around the house.

The guy helping around the house can have a tech check it out.

Chances of it being a fire hazard are minimal to zilch.


"Once this was all Black Plasma and Imagination"-Michael McClure


 

RE: That's good advice..., posted on November 16, 2020 at 10:48:36
JURB
Audiophile

Posts: 1790
Location: North Ohio
Joined: May 29, 2016
"Chances of it being a fire hazard are minimal to zilch."

True, but the idea is to prevent component damage.

 

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