In a Kenwood receiver. It is steel, not aluminum.
What is its purpose ?
In a Kenwood receiver. It is steel, not aluminum.
What is its purpose ?
Not sure, I don't think it's being used a Mu metal, cause I don't see anything alarming there?
It could be there to enclose the rupthure if the caps explosed I guess ? Who knows. :)
Jamie
What was the original question?
Mark Z.
"Capacitor shield?"
At least, that was in the subject header.
Michael
And, whatever it does, why is it asymmetric?
-- Jeff
Is there any trace of someone having been in there before? On the extended part of the "U" , into the large heatsink, is there a purpose made anchor point there also ? A part left over, buggered if he could remember where it came from, but thought it best to leave it inside somewhere, JIC. Haven't we all been there at sometime , with odd bits of metal work? On that front I picked up one of those dash-board cam gizmos last week , with 1 second spaced stills setting, recording to SD, to suspend over the banch for when disassembling the next complicated mechanism, with no exploded views in a manual
Really tells me nothing. I work in audio, but Kenwood also is a major player in the amateur radio biz. SO, I would like to know more details. Type of equipment, model number, problems / issues, whatever.
Maybe I can be of help, maybe not. I cannot know until I have:
MORE DETAILS.
mz
Blast shield so when the caps let go they don't spread goo onto the nearby circuit. :^)
(Maybe electrostatic shielding it looks to be on the caps right after the rectifiers???)
George H.
George H.
My guess too. Post-production development. They have used an existing board fixing hole. Possibly radiation into audio channel as one capacitor can will not be at ground potential - although if the cap was doing its job...
Remove and listen for difference.
I there a fan for forced air cooling? If so, maybe it is for directing cooling air?
Just another guess.
Pretty sure that is a Kenwood KR-4070. The question was originally posed on Audiokarma by a guy who services and restores vintage audio.
He also noted that he worked on one with a later serial number and it had no such shield.
That's pretty much all we got.
That is a GREAT idea! I am now going to buy one. I do mostly mechanical stuff and even though I try to document everything I take apart I sometimes make a misteak. Thanks for posting your idea. Eric
I've always been in the habit of felt-tip marking the joins of plates , ith a straight line across the join, before taking apart. And small boxes for sub-sections that go together. But even then I sometimes end up with unplaced parts. This dash-cam is Nikkai ER-130V. Make sure whatever you get comes with a viewer that allows selecting single frames
I would have though that viewing single frames would be standard. Thanks for the heads up. Lots of the stuff I take apart has to be cleaned and this removes marks. Right now I try to take pictures but it can be a hassle. But just being able to hold an assembly in focus and not have to stop and take a picture would be great. Eric
looks weird, like an afterthough.
Is there anything fastening the metal "shield" to the PCB below? Maybe they had that board rattle apart of break loose with the large caps and bridge rectifier attached to it. I'd almost expect the caps in something of that age to be screwed down with a collar and have wire wrap terminals or something weird like they did then.
There's quite a bit of stress on the parts in those big heavy receivers as they get shipped across the world.
Heard from one guy that sent to the factory where they had audio gear manufactured that the power transformers were all being screwed down wrong, with the spring washer in the wrong place. He told the production people that's not going to work, but they ignored that.
By the time the stuff made it to the US, every transformer busted free. It all had to be reworked in the US. Whoops.
No there wasn't. This receiver is from the late 70's and had a more than adequate heat sink. Worked on quite a few of these back in the day and I don't remember this piece of metal.
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Maybe just to fix the capacitors (instead of using glue)?
Not really convinced
Reinhard
I have used steel plates to help cut magnetic feed to sensitive circuits. Steel changes the magnetic path. Can't say otherwise.
Greg
No real clue except an explosive shield.
There is a polarity on non-polarized caps. It is suggested that the "foil side" go to the low Z point in the circuit. Typically this would be important in a vacuum tube circuit. Not all caps are marked alike, "Foil side" used to be a common marking.
Wait. That sort of "polarity" had nothing to do with DC voltage, but about which side went to ground. And it was because paper capacitors were so large, and could be a source of noise pickup if the outer side wasn't going to ground.
It never really came up because by the time of transistors, the paper capacitors had mostly faded away.
Michael
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