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Sometimes I love exploding capacitors

David_M

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Along with the 5170 I picked up on the weekend I also got 3 XT clones and a number of XT and 286 motherboards.
One of the 286 clone boards has a socketed Dallas RTC, so no battery leak damage and easy to modify to use an external battery. I thought great an easy repair.

That thought was short lived because when I powered it up the power supply went into overload shutdown. Now I'm thinking of all the effort it is going to take to find the faulty component.

I pondered that dilemma for a few minutes and then a heard a loud crack and saw a flash of light near the motherboards power connector. It seems I had neglected to turn off the power supply.
Shortly after that loud crack I heard a beep from the speaker, looking up at the monitor I saw the Award BIOS startup screen.

So I switched off the power supply and examined the area of the board that seemed to be the source of that crack and flash, my short investigation revealed the remains of a tantalum capacitor.
I had no idea what value that capacitor used to be but the 15 other tantalum cps on the board are all 10uF 16v. I ordered a bunch of new capacitors and plan to replace them all, but for now the board works happily without the caps near the power connector.

So thank you exploding capacitor you made the repair quick and easy.
 

Chuck(G)

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You'd change your mind if it was a glass-and steel "Vitamin Q" capacitor exploding. Had one do that and it scared the dickens out of me--while embedding steel shrapnel in the ceiling.
 

Malc

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I've been hit in the face by an exploding tant before, Luckily i was wearing my specs at the time as a burning ember hit the lens. I always wear safety specs now when working on old mobo's etc.
 

David_M

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I've been hit in the face by an exploding tant before, Luckily i was wearing my specs at the time as a burning ember hit the lens. I always wear safety specs now when working on old mobo's etc.

My old eyes.. I need glasses to see what I'm working on these days.

Over the years I've been hit by fragments of exploding parts a few times and I'd still choose that over the hassle of finding a shorted capacitor on a board.
Sadly my laziness trumps my fear of projectiles lol
 

Agent Orange

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Happened to me yesterday. I pulled down a 486 ISA/PCI mobo from the garage loft and when I applied power, it went off like a celebration. Don't think I have the time or inclination to troubleshoot the thing.
 

VERAULT

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I had an electrolytic cap from a cold cathode lighting board blow in my face. I was able to close my eye in time but the metal jacket hit my eyelid with so much force it pushed my eyeball back in the socket till it had a slight rupture. They called it a hyphema. Was extremely painful. I ran to a mirror and watched as my eyeball started turning red from internal bleeding. Lost vision for two weeks but fully recovered.
 
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Unknown_K

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I wear glasses anyway but lately I take them off to do close up work. I need to get bifocals someday. Luckily for me I never had a cap blow up when I was working on something, just heard the noise of one whistle as it died.
 

compaqportableplus

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I had a cap blow up in my face on a Paradise EGA card I was testing. Luckily nothing hit my eyes. Scared the hell out of me though!

The card worked perfectly once I replaced the cap and is now installed in one of my IBM 5150s.
 

Chuck(G)

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I wear glasses anyway but lately I take them off to do close up work. I need to get bifocals someday. Luckily for me I never had a cap blow up when I was working on something, just heard the noise of one whistle as it died.

Wait'll you get cataract surgery. You'll find that aside from the single vision that the bits of plastic in your eyeball are designed for, you'll need glasses for everything else. :)
 

KC9UDX

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I have a pair of vented goggles on my bench for these occasions. I do need to get some new ones, they are so old the straps are stretched out. They've saved my bacon on several occasions.
 

Unknown_K

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You can buy safety glasses at the dollar store with the side pieces to protect your eyes and the ear pieces are adjustable in length. I use those or something close when grinding metal or plastics with a dremel.
 

KC9UDX

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The trouble with standard safety glasses with side shields is that (in my experience) things always go flying over, under, or around, and get trapped inside. And yes I do wear them twelve hours a day at work for decades, and frequently wear them when metalworking, woodworking, or working on vehicles at home.

For the electronics bench, where I will only need eye protection occasionally, the extra protection from these is what I prefer:
cJub66


Flying hot goo capacitor innards, shrapnel from components, and shattered cutoff wheels just don't get past them.
 

David_M

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I get that there is a risk with flying debris... but putting that aside for a minute.. you have to admit it's nice when a faulty component self identifies.
It's like the trash taking itself out.
 

Unknown_K

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Depends on how you look at it. A capacitor blows up because it shorts to ground or in case of tantalums got over voltaged. You start to wonder what else in that circuit has had a bunch of extra current going through it before the cap finally popped. Replacing a blow cap is easy, sometimes the system works without it, but if a hard to replace exotic part went poof with it then game over man.
 

David_M

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Depends on how you look at it. A capacitor blows up because it shorts to ground or in case of tantalums got over voltaged. You start to wonder what else in that circuit has had a bunch of extra current going through it before the cap finally popped. Replacing a blow cap is easy, sometimes the system works without it, but if a hard to replace exotic part went poof with it then game over man.

They breakdown due to age, the voltages were fine.
 

paul

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Along with the 5170 I picked up on the weekend...
The beauty of living in a 230VAC country is that the next vintage EMI capacitor drama is just around the next corner. When my 5170 blew an X2 cap a few years back I was surprised to find there was no mains fuse inside the PS, so I added a pair while it was apart.


IMG_0318.jpg
 

David_M

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The beauty of living in a 230VAC country is that the next vintage EMI capacitor drama is just around the next corner. When my 5170 blew an X2 cap a few years back I was surprised to find there was no mains fuse inside the PS, so I added a pair while it was apart.


View attachment 47691

Yes I noticed the lack of a fuse when I swapped out the X2 caps. Being lazy I checked the schematic before fitting one. R2 and R3 will do the job of a slow blow fuse.
It was just pure laziness, I have 200 of those little pcb fuse clips I got on ebay for $1 to replace a couple of corroded ones in an Apple 2 supply. I had the parts on hand... so laziness is my only excuse.
 

Jmdlcar

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Kids are Kids I don't know what wrong with kids today. Back in 1986 I was a press operator and the press I was operation cut off 3 of my finger on my left hand and I was left handed they put them back on but I have no used of them. I wish it didn't happen but it did.

So go ahead and keep exploding capacitors those might kill you or you might go blind.
 

David_M

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I've gone 40 years without being killed by a capacitor.... god must love me. I think I can risk it for a few more years :)

Kids are Kids I don't know what wrong with kids today. Back in 1986 I was a press operator and the press I was operation cut off 3 of my finger on my left hand and I was left handed they put them back on but I have no used of them. I wish it didn't happen but it did.

So go ahead and keep exploding capacitors those might kill you or you might go blind.
 
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