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Oh My God. My 5150...is dead :(

JohnElliott said:
Not sure what to do about the power supply, though. The fuse is fine. The first time I switch on, the fan turns about 1/8 of a revolution before cutting out; on subsequent attempts nothing happens except an ominous click from somewhere near the switch.
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Some modern power supplies DO require a load. So maybe it does? I used a modern form-factor power supply once to supply power to an external floppy drive. At first the powerpack didn't work except for a slight turn of the fan. I thought it was broken, so I tried again with another one. Same result.

After some web searching I found a discussion which talked about newer power supplies requiring to be plugged into a motherboard in order to activate them (presumably by supplying a load). The advice was that if you wanted to use it just for a periferal device you short out two of the pins on the motherboard connector, (I think it was any black to green). The PSU thinks there is a motherboard attached and activates.

Anyway, I tried this with a paper clip and it worked. The PSU sprang into life and functioned without a problem.

Now please don't follow this advice without doing some more web checking or verifying it somewhere. As far as electronics go, I'm just a very short step up from illiterate. It worked for me with a MODERN power supply, but you might have an entirely different problem.

Tez
 
Yes, most switch mode power supplies (modern or old) require some form of load in order to start up.

Regarding the 5160, the thread http://www.vintage-computer.com/vcforum/showthread.php?t=8636 is where I calculated the individual power consumption of devices in my 5160, and determined that for the genuine IBM 130W PSU, a device that draws at least somewhere between 6W and 15W (exactly what is unknown to me) is required to enable the PSU to start.
 
tezza said:
After some web searching I found a discussion which talked about newer power supplies requiring to be plugged into a motherboard in order to activate them (presumably by supplying a load). The advice was that if you wanted to use it just for a periferal device you short out two of the pins on the motherboard connector, (I think it was any black to green). The PSU thinks there is a motherboard attached and activates.
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PSUs for the 5150/5160/5170 are switched on/off only by the power switch on the PSU.

In modern PCs, the PSU is switched on/off by a signal from the motherboard, and that signal was probably what you were simulating with the paper clip. If one looks at the pinout for ATX type PSU's (eg. http://pinouts.ru/Power/atxpower_pinout.shtml), by shorting green and black, you were doing just that. Even so, the PSU would still have probably required an adequate level of load to actually start up.
 
Well, that saved a certain amount of time and trouble. The PSU works with a load (I used a 486 motherboard) so I don't need to gut it. Thanks to everyone on this thread for their help.
 
crazypigeon said:
I plugged it in to the mobo, nothing happened for a couple of seconds, then POP, the capacitator at C6 EXPLODED, hitting me, and leaving a burning ember of what once was a capacitor burning on the mobo. I quickly unplugged the psu, and realized what I had just done.
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I just had a similar episode upon pulling my own PC out of storage today. Capacitor C9 on the original IBM CGA board failed upon power-up, letting out a fair amount of smoke and leaving a nice big black burn mark on the inside of the case cover, as well as on the CGA board itself. Thankfully the rest of the system, including the motherboard and other expansion boards, weren't damaged.

So, does anyone know the correct value of C9? The original one is three-pin. I'd rather just get an aftermarket "snow-free" CGA card, but if nothing else on the IBM CGA board got damaged, then it'll be an easy fix.
 
that's harsh.. ugh. it's not your fault though. any AT power supply even one you go buy brand new today would be just fine to power an XT motherboard. nothing changed PSU voltage and pinout wise between the very first XT board made and the very last AT board made.

i can't really blame it on it being old either. it all depends how it was taken care of. my mustang has 140k miles and has been taken care of meticulously... my dad's has 115k and it barely works lol. burns more oil than gas. you can literally watch it blow out of the back in the rear view.

if that 5150 was somewhere that sees some moisture, that's the problem. what you should probably consider is getting a nice cheap XT clone motherboard and sticking it in there, unless you really do care whether or not it's a true original IBM. i'd sell you a spare "TURBO-XT" board i have, but something tells me i should hang on to it... you never know what could happen to the other board i have.
 
I've just had the same things happen on a couple of 5150 motherboards. One literally spat fire and another popped with an almighty bang. They have since been replaced and the boards are working. Just dodgy memory to sort out...
 
Mike Chambers said:
nothing changed PSU voltage and pinout wise between the very first XT board made and the very last AT board made.
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There was a subtle difference. In the move the AT, an unused pin in one of the power connector plugs/sockets became used for an extra +5V line. Obviously only a possible problem if one tries to run an AT board from a 'true' XT PSU.
 
Oops! I spoke too soon about the rest of my PC. After removing all the expansion boards, I flipped it on and one of the 13 capacitors on the motherboard marked as "C7" shot itself apart like a firecracker, complete with bright yellow flying embers!

These C7's on the 64KB-256KB PC motherboard appear the serve the same purpose as the six C6 capacitors on the 16KB-64KB mobo, as described by modem7 earlier in the thread. In my case, the one nearest U5 (74LS30 chip) blew itself half-apart.

I'm using an aftermarket 200W power supply, as this PC has been ever since I installed a hard drive in it some 15 years ago. I tested the output, and with just the full-height IBM floppy drive and a Seagate ST-225 hard drive connected, I get:

Red: +4.92V
Yellow: +11.15V
Orange: +4.92V
Blue: -11.31V
White: -5.10V

The +/-12V line is a little below spec, but that's certainly better than being above-spec, and the PS continues to perform flawlessly despite the two capacitor blow-ups so far!

I also have an early 16KB-64KB PC with the original black-case 63.5W power supply, but with this experience on my newer PC, I'm now hesitant to just plug it in and fire it up. On that one, I think I'll get a variable power supply and slowly bring each supply voltage up to spec. That gradual ramping-up of voltage is known to help capacitors in old radios "re-form" after years of nonuse. (But yet I recently powered up an even older Commodore VIC-20 after years of storage and it works flawlessly... go figure, IBM quality!?)
 
Those are scary stories *shudder*

Hmmm...that 5150 that Eric (Frozenfire71i) gave me hasn't been run for a month. I just might fire it up and run it for a few hours tonight while we have dinner.

You guys have got me worried now! :)
 
Regular (but not necessarily constant) use is the key. A car that's driven once a week or even once a month is going to start a lot easier than a car that has been sitting for the past five years... same thing with electronics. But just like a car, once you get it running, it's best to keep it running for a while, until it gets fully warmed up. (Of course, turn down the monitor brightness or use a screen saver to prevent burn-in.) On a PC, keep it cookin' at least until the air coming out of the PS fan is warm to the touch.
 
Yup, I run my computer every day. My 5150(B) or whichever is setup(usually it or the AT&T) get to check my mail, word process, do finances, etc. So clearly it is vital that I have one running. OK, I can technically got ALL that on a new computer. At the same time. So what.

Anyhow, I click all computers that are on the desk when I wake up. When I go to bed, they are all turned off. So they have about 16 hours on time per day and 9 hours of being off. Plenty of time to get to a stable temperature in both ways, heat and cooling.

Due to the vitality of their existance in my life, I also need to make sure they are in top shape at all times. Regular cleaning, maintenance(drive cleaning), etc are all part of it's life. Usually once a month it gets a tune-up. Of course, I follow alot of the general guidelines out there to prolong computer life. I hear it is best to run the PC constantly unless it will be off for 2 or more days, and even though it makes sense in the form of the electricity jolts when turned on/off as well as the uneven heating(until stable temp in a few hours) and uneven cooling(the very same). Although making sense, it makes no sense in that it wastes electricity and is hard on the bearings in the fan and if applicable, HDD.

Which is why I prefer external HDDs. You can turn them off and leave the system on. Wait. That wasn't the point at all.

--Ryan
 
I must not live right.

I turn on stuff that hasn't been fired up in twenty years and nothing explodes. Superior electrolytics, I suppose. And I KNOW that this stuff hasn't been powered on because it's been sitting in my basement all that time.

No exploding chips, no flames, no snowstorms. Possibly the occasional blown fuse, but, it's replaced and away it goes.

Maybe if I throw a handful of change into some of them before I turn them on.....
 
Druid6900 said:
I must not live right.

I turn on stuff that hasn't been fired up in twenty years and nothing explodes. Superior electrolytics, I suppose. And I KNOW that this stuff hasn't been powered on because it's been sitting in my basement all that time.
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Who knows, maybe IBM cheapened out and only specified their capacitors to last 20 years, instead of forever. ;) It's nothing new. The IT guys where I work just had to replace a whole bunch of Dell motherboards due to bad capacitors. It was all covered under warranty, but still a big hassle.

And in this case, it's actually the tantalum capacitors that are failing, not electrolyics. There are no electrolytic capacitors anywhere on a PC motherboard.
 
Druid6900 said:
I turn on stuff that hasn't been fired up in twenty years and nothing explodes. Superior electrolytics, I suppose. And I KNOW that this stuff hasn't been powered on because it's been sitting in my basement all that time.

No exploding chips, no flames, no snowstorms. Possibly the occasional blown fuse, but, it's replaced and away it goes.
Click to expand...

LOL, no snowstorms, eh?

I've never had any of that happen, either. Hmm... No blown fuses either. Well I have good luck too, I suppose. That, and I only buy 1 or 2 owner systems, unless the price is too good. System is all rusty and looks like it has been in an unfit enviroment for a few years? No thanks, I'll pass.

Sounds like bad luck you've been having there, VWestlife. That system sounds like alot of trouble. Have you tried calling an exorcist for that system? It sounds like a ream demon. I guess with some work, it could be a diamond!

Oh me and my lame jokes....

--Ryan
 
flavio75 said:
I can't believe what I'm reading... this EXACTLY the same thing that happened to my 5160 motherboard some time ago. Is the C6 a three-legs capacitor or a two-legs one ? If it is a three-legs capacitor, I bought a few replacement caps here: www.mouser.com. It was some time ago, though... so I do not know if they still have them.
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Yes they do - I recently bought and received some.
If others are seeking these 10uF/16V tripple-lead tantalums, the Mouser details for the part are:

Mouser part number: 80-T398E106M16AT
Manufacturer part number: T398E106M016AT
10/16V TRIPPLE LEAD
Kemet Dipped Radial Tantalum Capacitor
 
I've also had the orange tantalum cap fail on an IBM CGA card. Top corner near the bracket screw, sits across the 5V bus. Mine simply shorted while in storage and so the PS would not power-up, leading me to be quite concerned until I unplugged the card. Just clipped it out for now.

But having two 64-256 5150's that have been sitting around the house for more than two years without being powered-up does concern me a bit, and I think it would be wise to replace the few present. I don't think the short itself is a big deal but even minor physical damage to the machine would bug me.

It would not hurt us to compile a list of preventative maintenance replacement parts (and locations) for these machines, including electrolytics in the PS.
 
Ah, happy memories... I've just been rereading this thread to check that the spare caps in my toolbox were the right spec to replace a blown C7 cap on my 5150. Over ten years since I first posted on this thread and now I'm swapping out capacitors like... well, still like a clumsy amateur, but it's the thought that counts :D Had to do the mains filter caps in the power supply, too.
 
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