I'm sitting here biting my nails: How long does it take for a stereo to blow up?

chadbang

chadbang

Well-Known Member
First of all, here is my bow to all the electronic repairmen, recappers and devoted hobbyist who manage to keep their cool while repairing and noodling around with their gear. I just replaced 7 caps in my 500B and I turned it on about ten minutes ago. I'm listening to the soundtrack from "Interstellar" ... waiting for my receiver to blow up. How long would that take?

Honestly, it was painstaking and scary. I took me from 3pm until 8:30pm to change out seven capacitors. I assume that was slow? I replaced everyone that was courtesously pointed out and identified by another member through a labeled photo. I believe I was messing around with power supply caps. I don't know exactly.

All I do know is that I kept repeating the supposed mantra of the Gemini astronauts: "Dear God, please don't let me @$# up."

I hope he was listening.

So how long will it take until fire flares up and ravages my beloved receiver if I did something wrong? 10, 20, 30 minutes. Hours? I won't leave its side until I turn it off. Trust me.

I felt like Dr Christian Barnard transplanting his first heart. My fingers felt like lead fishing weights. I fumbled, I drop. Caps rolled on the floor. And all the time in the background, in my head: "Did I discharge that right?" Oh, man.

This game is not for me. The other melody playing in my head: "So if I blow it up, so what? It's just another stereo biting the dust." Not a happy tune.

Lots of nagging other questions during surgery. What, how can this Nichicon caps being a quarter the size of that ROE one and still do the same thing? What is this modern devilry! I read that parts listing over a thousand times! Why is this so small?


20 minutes and still playing. I'm staring at the output tubes as I write. If I see colors that would inspire Francis Scott Key to writing another anthem, I'll drive for the plug.

This is excrutiating. After this, I'm sticking to finger puppets and tile mosaics, like a good boy scout.
 
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I admire your courage Chad - to solder in the caps, and to wait and see if you did things correctly. But you've taken it this far without anything happening. Maybe you should shut it down now and wait until one of the guys who really knows all this stuff, comes on. It's late, and if anything happens you won't have anyone to really talk with.

Maybe you could take a pic of the work you did, and have one of them look at it. It might be reassuring if they feel the work looks solid.
 
Sounds like you did good but get others opinions. I would also unplug it when not in use and your sleeping for a while
 
jgannon said:
I admire your courage Chad - to solder in the caps, and to wait and see if you did things correctly. But you've taken it this far without anything happening. Maybe you should shut it down now and wait until one of the guys who really knows all this stuff, comes on. It's late, and if anything happens you won't have anyone to really talk with.

Maybe you could take a pic of the work you did, and have one of them look at it. It might be reassuring if they feel the work looks solid.
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This might be a good idea.
 
Usually a misinstalled part will make it puke almost instantaneously. If it hasn't done it already, it's not gonna do it anytime soon from what you installed. But there is always the option it has of crapping out from a part being weak and now stressed from trying to work at it's original parameters. Just keep an eye on it for now and only listen to it while you're in the room. If it's got you that flustered, it's probably safer just leaving it unplugged.

Take a picture or two of what you've done to it, so we can see what you've done and calm you down. A few STRONG SHOT's of SINGLE MALT wouldn't hurt right now.

Larry
 
larryderouin said:
Usually a misinstalled part will make it puke almost instantaneously. If it hasn't done it already, it's not gonna do it anytime soon from what you installed. But there is always the option it has of crapping out from a part being weak and now stressed from trying to work at it's original parameters. Just keep an eye on it for now and only listen to it while you're in the room. If it's got you that flustered, it's probably safer just leaving it unplugged.

Take a picture or two of what you've done to it, so we can see what you've done and calm you down. A few STRONG SHOT's of SINGLE MALT wouldn't hurt right now.

Larry
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:thmbsp:

Good advice. I'm a firm believer of in-for-a-penny. I played it for two and half hours and then shut it down. I always hear guys say, "It was working great, but when I turned it on the next day..." So I thought I'd run a test like that. I let it cool for a half hour and fired it up again. Been playing fine for an hour and a half and sounding pretty darn good. But I really like your advice. Brilliant deduction about a weak part going bad after others getting a makeover. I tell you, most of those "dog turd" caps were looking pretty sick. They were definitely not up to the standards of the ROE caps (which I felt sad removing, but in-for-a-penny). I will only let it play with my adult supervision for a few weeks (which is usually what I do with my grandfatherly component, anyway.) Cheers!
 
chadbang said:
Honestly, it was painstaking and scary. I took me from 3pm until 8:30pm to change out seven capacitors. I assume that was slow? I replaced everyone that was courtesously pointed out and identified by another member through a labeled photo. I believe I was messing around with power supply caps. I don't know exactly...

So how long will it take until fire flares up and ravages my beloved receiver if I did something wrong? 10, 20, 30 minutes. Hours? I won't leave its side until I turn it off. Trust me.
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Geez I hope it wasn't my photo... When I get around to recapping mine I'm sure I'll be working at a similar rate so you are in dubious company.

larryderouin said:
Usually a misinstalled part will make it puke almost instantaneously. If it hasn't done it already, it's not gonna do it anytime soon from what you installed. But there is always the option it has of crapping out from a part being weak and now stressed from trying to work at it's original parameters. Just keep an eye on it for now and only listen to it while you're in the room. If it's got you that flustered, it's probably safer just leaving it unplugged.

Take a picture or two of what you've done to it, so we can see what you've done and calm you down. A few STRONG SHOT's of SINGLE MALT wouldn't hurt right now.

Larry
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I would expect almost immediate disaster if it was to be.
 
Having put capacitors in stuff backwards (always TRIPLE CHECK POLARITY!!) my opinion is that IF it was going to blow up it would have done it within the first couple minutes
 
^ yeah backwards elec caps especially in the power supply will blow up real quickly, quite a scene actually. I think most of what the OP replaced were film caps though from his description.

Getting those "brown turd" out of there is important. Losing a coupling cap can allow high levels of DC to spill into the signal path and do some devastating. Hopefully, you have researched checking bias on the Fisher and have installed some 1% 10ohm cathode fusistors. Cheap insurance.
 
Here is what has been done! (I also replaced the selenium rectifier with the recommended radio shack one). Yes, I've done just film caps as people here said that's the first and minimum thing do do. Any suggestions for something major missed that I MUST do? Any poor component choices, soundwise?

That WIMA cap wasn't x rated it was Y2 rated which I read is also okay. It was that damn tiny Vishay .01uf 600v at C41 that had me questioning the size as it was so much smaller than the old ROE cap.

whatsbeendone_zps40b8bba3.jpg
 
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scotterics said:
Having put capacitors in stuff backwards (always TRIPLE CHECK POLARITY!!) my opinion is that IF it was going to blow up it would have done it within the first couple minutes
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I hope so. I already 3 hours playing today. Raising the volume a bit more from last night. Oh yes, Lots of checking went on. That's probably why 5 1/2 sweaty hours reading the net and working.

After these installs I think I'm getting a bit more detailed (yet still smooth and airy) sound. Sounds quite good!
 
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What could possibly go wrong?

nuclear-rectifier.jpg


Trick is to check and double check your work. When you're done, go over it again one more time with an eagle eye for good solder and leftover tails that could short. Put the fire to it, and if it survives an hour or so, you should be golden.

Bonus points if you use a dim bulb tester on the first start.
 
sKiZo said:
What could possibly go wrong?

nuclear-rectifier.jpg


Trick is to check and double check your work. When you're done, go over it again one more time with an eagle eye for good solder and leftover tails that could short. Put the fire to it, and if it survives an hour or so, you should be golden.

Bonus points if you use a dim bulb tester on the first start.
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Hahhaa. Yeah, that was my great fear. I spent a lot of time eyeing each solder and making sure caps and leads were insulated or isolated. But it was still "push and pray" time when I fired it up.
 
Usually the point where you feel comfortable and think you did a great job! GJ dude, you're good!
 
chadbang said:
This needs to be done.
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Yeah, pretty much a first phase item. If you haven't already purchased them, consider the metal films instead of the carbon comps. The metals explode, nicely for our purposes. The carbons sorta rumble and sizzle before they go. If something is causing them to open, you want it to be pronto! Bang, and it shuts down. With the carbons, you get that deer in the headlights, "what the hell is that smoke and noise" look on your face :eek: before you realize what's happening. Having had both experiences, my preference is the former. :yes:
 
notdigital said:
Yeah, pretty much a first phase item. If you haven't already purchased them, consider the metal films instead of the carbon comps. The metals explode, nicely for our purposes. The carbons sorta rumble and sizzle before they go. If something is causing them to open, you want it to be pronto! Bang, and it shuts down. With the carbons, you get that deer in the headlights, "what the hell is that smoke and noise" look on your face :eek: before you realize what's happening. Having had both experiences, my preference is the former. :yes:
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Metal film. Got it. I take it I can use my local Fry's stock of NTE resistors for this operation, audiophile quality not required?
 
NTE is a 4 letter word around AK, unless it's for an otherwise unobtainable or obsolete part that they are the only supplier for, and it's last resort. Radioshack has better one's and they are a bit cheaper in price too. 1/4watt 10 ohm metal film. Like a $1.49 for a 5 pack.

FYI. all but 1 of the caps you put in are non directional or bipolar. The one Nichicon is put in right or it would have blown already. So go ahead and play it.
 
chadbang said:
Metal film. Got it. I take it I can use my local Fry's stock of NTE resistors for this operation, audiophile quality not required?
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Like Larry said, NTE blah. Always lowest bidder rebadged stuff with minimal quality control.

Get some 1% metal film 1/4w so there is little variance between the four.
 
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