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latvija13
June 7th, 2012, 06:26 PM
Hello all,

My brothers were cleaning out my parents garage the other day and ran across an IBM 5155 Portable PC. It appears to be in decent condition; however, when I try to turn it on, the floppy drives flash once and then nothing happens. I took off the cover and looked around a little bit inside. I was surprised to see how good of a condition the inside was considering the PC has been sitting in a garage for 15+ years. I'm wondering where to start with troubleshooting turning it on? Obviously power is getting to the computer since it at least flashes once. I was wondering if the fuse on the power supply could be bad?

Any thoughts would be great!

Thanks

Ole Juul
June 7th, 2012, 07:00 PM
What did you get on the screen? Does it have a HDD? Do you have a boot disk?

If you are booting without a disk and there is no HDD then when it checks the drive (light flashes) then it won't be able to proceed without an OS.

This is a great machine. I've got one, and it is nice to have an XT without taking up a lot of space.

latvija13
June 7th, 2012, 07:48 PM
What did you get on the screen? Does it have a HDD? Do you have a boot disk?

I'm getting nothing on the screen, and I don't believe that it has a HDD. From looking at the Repair Information PDF that I downloaded for the 5155 it looks almost exactly like the Interior View except four of the expansion slots are occupied instead of just two.

I do not have a boot disk so I'll have to see if I can it at my parents house among their junk. I wasn't sure if the screen should turn on at all if there was no book disk/HDD. I was expecting to find some corrosion or something to that nature inside the box but from what I can tell, it looks fine. Would the computer try to turn on and then just turn off without even attempting the POST with no boot disk or is that the single flash the I'm getting from the floppy drives? Is it simply looking for a book disk and since it's not finding anything, not powering on at all?

ibmapc
June 7th, 2012, 08:36 PM
Assuming you have the original motherboard in there, you should see the memory start to count up. Then the floppy drives should make some noise as they are tested. then it should beep once. Then drive a: should look for a boot disk. With no boot disk or hard drive, it should go into rom basic. So you've definately got at least one thing keeping it from coming on.
I would start by removing all of the expansion cards but leaving the speaker plugged in. Then power it up. The power supply fan should start up and after about a minute, you should get some beeps from the speaker (error codes telling you that there is no display adapter or floppy adapter). If the fan doesn't start, then you have a problem with either the power supply or the mother board. If the fan starts, but no beeps then the problem is probably with the motherboard, but still could be the psu. If you get beeps, then turn it off and plug in just the video card, and try it again. Keep adding cards (with power off) one at a time 'till it fails to start. The last board added is your problem. Note, don't turn on the psu without the motherboard attached. It won't hurt the psu, but it'll make you think that the psu is bad since the fan will not come on without a sufficient load attached to it. (Been there, done that)

Ole Juul
June 7th, 2012, 08:41 PM
I'm getting nothing on the screen, . . .

There are two pots on the front. One is for contrast and the other for brightness. Turn them too far and there's nothing on the screen. Check that, just in case.

pearce_jj
June 7th, 2012, 09:46 PM
Use a multimeter to check the PSU outputs for example on a floppy disk power connector - should be 12V between yellow and black, and 5V between red and black. If nothing remove all four expansion cards then re-test, and work back from there.

Just a word of caution - be VERY careful if you remove the shroud over the CRT (screen) itself, as with any CRT there are voltages in there which will certainly kill you if direct contact is made.

HTH!

cchaven
June 8th, 2012, 06:18 AM
If I remember the interior of my 5155, there isn't room anywhere inside for a hard disk unless you remove one of the floppy drives. So it sounds like, among other things, that it isn't finding any boot disk at all. As has already been mentioned, if you have the brightness and contrast turned down too much on the amber monitor you won't see anything either.

They are nice machines...I got rid of a dual floppy version years ago but still have one with a hard disk installed. I've run all kinds of OS's on it..MS-DOS/PC-DOS, CP/M-86, Concurrent CP/M-86, and the UCSD Pascal P-system.

Jeff

MikeS
June 8th, 2012, 08:14 AM
Just a word of caution - be VERY careful if you remove the shroud over the CRT (screen) itself, as with any CRT there are voltages in there which will certainly kill you if direct contact is made.

HTH!Well, caution is always good, but "will certainly kill you" is a bit extreme; the only harm is usually from whatever you hit when you reflexively jerk your hand away.

The voltages (currents, actually) in the power supply are far more likely to hurt or (if you're extremely unlucky) kill you.

latvija13
June 8th, 2012, 12:24 PM
I would start by removing all of the expansion cards but leaving the speaker plugged in. Then power it up. The power supply fan should start up and after about a minute, you should get some beeps from the speaker (error codes telling you that there is no display adapter or floppy adapter). If the fan doesn't start, then you have a problem with either the power supply or the mother board. If the fan starts, but no beeps then the problem is probably with the motherboard, but still could be the psu. If you get beeps, then turn it off and plug in just the video card, and try it again. Keep adding cards (with power off) one at a time 'till it fails to start. The last board added is your problem.

I tried removing all of the expansion cards and then turning the power on after removing each card. I still got the same result, the 2 floppy drives flash once and then nothing. I'm guessing that the problem is with the PSU because the fan doesn't turn on either.


Use a multimeter to check the PSU outputs for example on a floppy disk power connector - should be 12V between yellow and black, and 5V between red and black. If nothing remove all four expansion cards then re-test, and work back from there.

Testing the PSU output on a floppy connector, the multimeter jumps to 12V when I flip the power switch, but then it drops down to 0 in less than a second. I'm wondering if that would confirm that the PSU is bad? I did notice that the PSU makes some sort of sound, when I turn the power on, almost like a tube TV turning off. I think I'll go ahead and poke around the PSU next.

mikey99
June 8th, 2012, 01:40 PM
Its possible you could have a shorted tantalum capacitor on the motherboard.
Try disconnecting the power supply connectors from the motherboard, and see
if the power supply voltage will stay up, check both +5 and +12 lines.

There could also be a short in the floppy drives, try disconnecting those also.

marcoguy
June 8th, 2012, 01:48 PM
Just a word of caution - be VERY careful if you remove the shroud over the CRT (screen) itself, as with any CRT there are voltages in there which will certainly kill you if direct contact is made.

HTH!

I refer you to this (http://lowendmac.com/tech/crt_danger.html). I have actually been shocked really bad in the solar plexus by one of those. I was essentially giving a 21" CRT a bear hug to lift it up. It hurt like hell, but I'm still here typing away on this forum, aren't I?

modem7
June 8th, 2012, 02:50 PM
I tried removing all of the expansion cards and then turning the power on after removing each card. I still got the same result, the 2 floppy drives flash once and then nothing. I'm guessing that the problem is with the PSU because the fan doesn't turn on either.

Testing the PSU output on a floppy connector, the multimeter jumps to 12V when I flip the power switch, but then it drops down to 0 in less than a second. I'm wondering if that would confirm that the PSU is bad? I did notice that the PSU makes some sort of sound, when I turn the power on, almost like a tube TV turning off. I think I'll go ahead and poke around the PSU next.


Its possible you could have a shorted tantalum capacitor on the motherboard.
Try disconnecting the power supply connectors from the motherboard, and see
if the power supply voltage will stay up, check both +5 and +12 lines.
There could also be a short in the floppy drives, try disconnecting those also.

Note that the 5155 PSU will not operate unless it has a sufficient load.
Refer to http://www.minuszerodegrees.net/5155/psu/5155_psu.htm

Based on the info on that web page, see if the PSU will operate when the only thing connected to the power supply is the motherboard.
Of the two motherboard connectors, P8 and P9, try it first with only P9 connected.

latvija13
June 8th, 2012, 03:50 PM
Note that the 5155 PSU will not operate unless it has a sufficient load.
Refer to http://www.minuszerodegrees.net/5155/psu/5155_psu.htm

Based on the info on that web page, see if the PSU will operate when the only thing connected to the power supply is the motherboard.
Of the two motherboard connectors, P8 and P9, try it first with only P9 connected.

Wow, that did work. With only P9 plugged in it does turn on. However, when I plug P8 in it goes back to the same problem. So based on that, what does it tell me? Is the PSU probably being overloaded?

modem7
June 8th, 2012, 04:21 PM
Wow, that did work. With only P9 plugged in it does turn on. However, when I plug P8 in it goes back to the same problem. So based on that, what does it tell me? Is the PSU probably being overloaded?
P8 supplies plus and minus 12 volts. As Mikey99 suggested, you probably have a shorted tantalum capacitor on your motherboard (overloading the PSU), and from your experiment, it will be on either the +12V line or the -12V line.

Refer to http://www.minuszerodegrees.net/failure.htm
The first step is to visually inspect the tantalum capacitors on your motherboard. If a tantalum has gone short, it may be showing visible indication of failure.

modem7
June 8th, 2012, 04:41 PM
The IBM 5155 was supplied with an early 5160 motherboard, the 64/256K one. The circuit diagram for that motherboard shows:

+12V line: Capacitors C56 (10 uF tantalum) and C55.
-12V line: Capacitors C58 (10 uF tantalum) and C57.

So if the cause is a shorted tantalum capacitor, it will in your case, be either C56 or C58.
Shorted tantalum capacitors are a very common problem on these motherboards.

Use of a multimeter on its resistance setting will reveal which line is short, and therefore point you to a particular tantalum capacitor, C56 or C58.

Alternatively, you could cut both C56 and C58 off the board, with the view to replacing them later. They help filter out noise on the +12V and -12V lines.

latvija13
June 8th, 2012, 04:52 PM
The IBM 5155 was supplied with an early 5160 motherboard, the 64/256K one. The circuit diagram for that motherboard shows:

+12V line: Capacitors C56 (10 uF tantalum) and C55.
-12V line: Capacitors C58 (10 uF tantalum) and C57.

So if the cause is a shorted tantalum capacitor, it will in your case, be either C56 or C58.
Shorted tantalum capacitors are a very common problem on these motherboards.

Use of a multimeter on its resistance setting will reveal which line is short, and therefore point you to a particular tantalum capacitor, C56 or C58.

Alternatively, you could cut both C56 and C58 off the board, with the view to replacing them later. They help filter out noise on the +12V and -12V lines.

Ok, I can see that C56 is the problem, C56 looks like it's burnt out while C58 appears fine visually. I'll see if I can find a replacement. Looks like I'll need to get a soldering iron :D

modem7
June 8th, 2012, 04:59 PM
Ok, I can see that C56 is the problem, C56 looks like it's burnt out while C58 appears fine visually. I'll see if I can find a replacement. Looks like I'll need to get a soldering iron :D
For now, you could simply cut C56 off the motherboard using a pair of side cutters.

modem7
June 8th, 2012, 05:35 PM
In anticipation of C56 being proven as the problem cause, I have updated my 'Motherboard Failure' document:
http://www.minuszerodegrees.net/vcf_motherboard_failure_history.htm

On 5155/5160 motherboards, failure of C56 (filtering +12V) is much more common than C58 (filtering -12V).
Possibly not a statistically significant sample (I only have a novice's knowledge of statistics).

latvija13
June 8th, 2012, 05:48 PM
For now, you could simply cut C56 off the motherboard using a pair of side cutters.

Should I be able to plug P8 after cutting off C56? The computer is booting up to "The IBM Personal Computer Basic Screen." Without any disks I doubt there's much more I can do for now. Thanks for the help everyone!

modem7
June 8th, 2012, 06:02 PM
Should I be able to plug P8 after cutting off C56? The computer is booting up to "The IBM Personal Computer Basic Screen." Without any disks I doubt there's much more I can do for now. Thanks for the help everyone!
Besides plus and minus 12V, P8 also supplies the POWER GOOD signal from the PSU. Without the POWER GOOD signal, the motherboard won't start. Obviously, because your 5155 is now booting to BASIC, you must have reconnected P8.
Yes, it it quite okay to have P8 plugged in without C56 being present. Ideally, you should fit a new C56 later.

latvija13
June 8th, 2012, 06:15 PM
Besides plus and minus 12V, P8 also supplies the POWER GOOD signal from the PSU. Without the POWER GOOD signal, the motherboard won't start. Obviously, because your 5155 is now booting to BASIC, you must have reconnected P8.
Yes, it it quite okay to have P8 plugged in without C56 being present. Ideally, you should fit a new C56 later.

Hmmm... I only have P9 plugged in and it's booting to BASIC. I'm still getting the same problem with the power when I plug the P8 connector in. I also reconnected the floppy power connectors back in and the floppy drives flashed at me and appeared to be searching for a disk. I was curious about not having the P8 connector plugged in and am scratching my head now about it booting to BASIC without it being plugged in.

modem7
June 8th, 2012, 06:47 PM
I'm still getting the same problem with the power when I plug the P8 connector in.
So did you remove C56 ?
If not, that symptom is what we expect until you either remove C56 or fit a new C56.
If you did remove C56, then there must be another short, on either the +12V line or the -12V line.


Hmmm... I only have P9 plugged in and it's booting to BASIC.
That is not the norm for a 5155/5160 motherboard. The POWER GOOD signal from the PSU (activated when all voltages are present and stable) is what releases the motherboard from a reset state. Either someone has modified your IBM motherboard, or it has a second fault, one associated with the POWER GOOD signal.
Is it of concern? It might be if the motherboard is starting before the +5V has stabilised. If you later see intermittent starting problems, this POWER GOOD issue may be the cause.

latvija13
June 8th, 2012, 07:04 PM
So did you remove C56 ?
If not, that symptom is what we expect until you either remove C56 or fit a new C56.
If you did remove C56, then there must be another short, on either the +12V line or the -12V line.
Yes, I did remove C56. I did not remove the motherboard, though. I just clipped the top wires off of C56 so the solder is still probably on the bottom of the motherboard if that matters at all.



That is not the norm for a 5155/5160 motherboard. The POWER GOOD signal from the PSU (activated when all voltages are present and stable) is what releases the motherboard from a reset state. Either someone has modified your IBM motherboard, or it has a second fault, one associated with the POWER GOOD signal.
Is it of concern? It might be if the motherboard is starting before the +5V has stabilised. If you later see intermittent starting problems, this POWER GOOD issue may be the cause.

I don't think it's really of concern since it appears to be booting fine without the P8 connector being plugged in. I'll have to power the computer off and on a few times to see if there's intermittent starting problems. The last 3-4 times it started just fine, but I did have one occasion where the screen was just flickering and did not boot to BASIC. That was before I removed C56. All of the dates that I've seen on components are from 1984 (the PSU has a test date on it) so it would be hard to say with my knowledge of older PC's whether the motherboard is a standard 5155/5160 board. Really, I'm happy to get it to turn on at all.

modem7
June 8th, 2012, 07:22 PM
Yes, I did remove C56. I did not remove the motherboard, though. I just clipped the top wires off of C56 so the solder is still probably on the bottom of the motherboard if that matters at all.
The solder in the holes won't be a problem. There is a possibility that C58 also went short. Do you have a multimeter? If so, you can use that to determine which line has the short. I'm sure that you don't want to cut off C58 unnecessarily.


I don't think it's really of concern since it appears to be booting fine without the P8 connector being plugged in.
The plus and minus 12V from P8 are fed by the 5155/5160 motherboard through to the expansion connectors, for possible use by an expansion card.


All of the dates that I've seen on components are from 1984 (the PSU has a test date on it) so it would be hard to say with my knowledge of older PC's whether the motherboard is a standard 5155/5160 board.
I'm using the term "5150/5160 motherboard". A 5155 motherboard is actually an early 5160 motherboard. One is pictured at http://www.nadbor.pwr.wroc.pl/yesterpc/Hardware/ISA%20motherboard/IBM%20XT/item.htm

modem7
June 8th, 2012, 07:28 PM
It has occured to me that you have plugged at least one expansion card back into the motherboard. The second short could be on an expansion card. Remove all expansion cards and then see in plugging in P8 stops the PSU from running.

ibmapc
June 8th, 2012, 08:03 PM
It has occured to me that you have plugged at least one expansion card back into the motherboard. The second short could be on an expansion card. Remove all expansion cards and then see in plugging in P8 stops the PSU from running.
Absolutely right. I've seen TWO seperate CGA cards(like the one in the 5155) with shorted Tantalums at C8. That's a three legged capacitor on the +12v line. If you check for a short between the middle leg of C8 and ground, it'll tell you if it's ok. If it shows short, it could also be C9 which is right below C8.

mikey99
June 8th, 2012, 08:18 PM
I've had several shorted tantalum capacitors recently on motherboards and expansion cards.
Most recently on a Tecmar Captain card. Replaced the capacitor and it works fine.

One on a 386 motherboard ..... lit up like a bulb when I applied power. I have a couple of scrap
motherboards that I steal replacements from.

latvija13
June 9th, 2012, 06:26 AM
It has occured to me that you have plugged at least one expansion card back into the motherboard. The second short could be on an expansion card. Remove all expansion cards and then see in plugging in P8 stops the PSU from running.

I removed all of the expansion cards this morning. I turned the computer on after each card was taken out and still had the same power problem if P8 was plugged in. I do have a multimeter; however, (you can tell I've never used one before) it belongs to my father-in-law and it's an older analog one so I'm not sure if I tested the voltage correctly.

According to the technical reference for the PSU about the P8 connector, it looks like the pins I need to test are 3(+12vdc) and 4(-12vdc). I put the black probe in pin6 for the ground pin and then used the red probe to test the other pins. Pin 3 looks like it's outputting around 10v and then I don't get anything when I test pin 4. So either the -12v is the problem or I'm doing something wrong with the multimeter. I wasn't sure how to check the resistance on this multimeter.

modem7
June 9th, 2012, 01:52 PM
I removed all of the expansion cards this morning. I turned the computer on after each card was taken out and still had the same power problem if P8 was plugged in.
So the short is definitely on the motherboard.


I do have a multimeter; however, (you can tell I've never used one before) it belongs to my father-in-law and it's an older analog one so I'm not sure if I tested the voltage correctly.
According to the technical reference for the PSU about the P8 connector, it looks like the pins I need to test are 3(+12vdc) and 4(-12vdc). I put the black probe in pin6 for the ground pin and then used the red probe to test the other pins. Pin 3 looks like it's outputting around 10v and then I don't get anything when I test pin 4. So either the -12v is the problem or I'm doing something wrong with the multimeter. I wasn't sure how to check the resistance on this multimeter.
As I posted before, four capacitors are involved:

+12V line: Capacitors C56 (10 uF tantalum) and C55.
-12V line: Capacitors C58 (10 uF tantalum) and C57.

C55/C57 are of a very reliable type. C56/C58 are of type tantalum which fails relatively regularly in vintage computers. You have removed physically damaged C56. The voltage check you done just now suggests a short on the -12V line (a resistance check will prove it). Since you've already cut off C56, I suggest that you take a chance and do the same now for C58. Or do you want to do a resistance check first?

latvija13
June 9th, 2012, 03:50 PM
As I posted before, four capacitors are involved:

+12V line: Capacitors C56 (10 uF tantalum) and C55.
-12V line: Capacitors C58 (10 uF tantalum) and C57.

C55/C57 are of a very reliable type. C56/C58 are of type tantalum which fails relatively regularly in vintage computers. You have removed physically damaged C56. The voltage check you done just now suggests a short on the -12V line (a resistance check will prove it). Since you've already cut off C56, I suggest that you take a chance and do the same now for C58. Or do you want to do a resistance check first?

What should I be looking for with the resistance check? I was using this page (http://www.techrepublic.com/article/put-your-power-supply-to-the-test-with-a-multimeter/5034541) as a reference for checking capacitors and according to that it looks like I should be getting a high resistance; however, when I test both the +12 and -12 pins I get 0 resistance.

modem7
June 9th, 2012, 04:32 PM
What should I be looking for with the resistance check? I was using this page (http://www.techrepublic.com/article/put-your-power-supply-to-the-test-with-a-multimeter/5034541) as a reference for checking capacitors and according to that it looks like I should be getting a high resistance; however, when I test both the +12 and -12 pins I get 0 resistance.

What should I be looking for with the resistance check? I was using this page (http://www.techrepublic.com/article/put-your-power-supply-to-the-test-with-a-multimeter/5034541) as a reference for checking capacitors and according to that it looks like I should be getting a high resistance; however, when I test both the +12 and -12 pins I get 0 resistance.

I was positive that since you removed C56, that the +12V line was not going to measure zero ohms (or near that).

Take a look at http://www.minuszerodegrees.net/5150_5160/MDC/no_beeps_2_2.htm
In that way you can verify which pins are used for the +12V and -12V resistance measurements.
Are those the pins you are using?

And per the web site you pointed to, did you have your old meter set to a low ohms range, e.g. 0-100 ohms ?

So that you are confident about measuring resistance, with power off, measure the resistance of R1. It is next to slot 8. You should measure about 500 ohms.

latvija13
June 9th, 2012, 05:36 PM
I was positive that since you removed C56, that the +12V line was not going to measure zero ohms (or near that).

Take a look at http://www.minuszerodegrees.net/5150_5160/MDC/no_beeps_2_2.htm
In that way you can verify which pins are used for the +12V and -12V resistance measurements.
Are those the pins you are using?

And per the web site you pointed to, did you have your old meter set to a low ohms range, e.g. 0-100 ohms ?

So that you are confident about measuring resistance, with power off, measure the resistance of R1. It is next to slot 8. You should measure about 500 ohms.

Ok, I was doing the resistance test wrong. I was putting the probes inside the power connector P8 instead of testing the motherboard. My multimeter only has one OHM setting which is X1k, I'm guessing that means I just multiply whatever I get by 1k. When I test R1 I get 1 on the multimeter so it's putting out 1000 ohms. When I test the +12 line I get 3.5, so 3500 ohms. When I test the -12 line I get .2 on the multimeter which would be 200 ohms; however that's what confused me because my father-in-law said that was a 0 resistance because when I touch the two probes together I get 200 ohms too. So maybe this multimeter is off?

modem7
June 9th, 2012, 05:40 PM
however that's what confused me because my father-in-law said that was a 0 resistance because when I touch the two probes together I get 200 ohms too. So maybe this multimeter is off?
There is normally a 'zero adjust' adjustment on the front panel of the analogue meter. When you change resistance ranges, one normally shorts the two probes, then adjusts the 'zero adjust' adjustment so that a reading of zero shows.
The other possibility is that the battery in the meter is low (although I can't remember what symptom that produces).

latvija13
June 9th, 2012, 05:48 PM
Yup, I found it. So you're right R1 is 500 ohms. +12 is 3000 ohms and -12 is 0 ohms.

modem7
June 9th, 2012, 05:50 PM
Yup, I found it. So you're right R1 is 500 ohms. +12 is 3000 ohms and -12 is 0 ohms.
So you've been unlucky - two shorts.
Time to clip off C58.

latvija13
June 9th, 2012, 05:59 PM
So you've been unlucky - two shorts.
Time to clip off C58.
How does clipping C56 and C58 effect the PC? I just got it to boot up now, after clipping C58, with P8 plugged in so that's a positive!

modem7
June 9th, 2012, 06:10 PM
How does clipping C56 and C58 effect the PC? I just got it to boot up now, after clipping C58, with P8 plugged in so that's a positive!
C56 (together with C55) help remove noise on the +12V line.
C58 (together with C57) help remove noise on the -12V line.

The 5155/5160 motherboards do not use the +12V or -12V from the PSU. The +12V and -12V from the PSU is routed via the motherboard to the expansion slots, for possible use by an expansion card.

I myself would not be fussed by leaving C56 and C58 off the board, since I expect that any expansion card that uses either/both +12V or -12V will have its own filter capacitors, rated such that the card does not depend on the motherboard's C56/C58. Other people will have a differing opinion.

But ideally, C56/C58 should be replaced.

latvija13
June 9th, 2012, 06:20 PM
C56 (together with C55) help remove noise on the +12V line.
C58 (together with C57) help remove noise on the -12V line.

The 5155/5160 motherboards do not use the +12V or -12V from the PSU. The +12V and -12V from the PSU is routed via the motherboard to the expansion slots, for possible use by an expansion card.

I myself would not be fussed by leaving C56 and C58 off the board, since I expect that any expansion card that uses either/both +12V or -12V will have its own filter capacitors, rated such that the card does not depend on the motherboard's C56/C58. Other people will have a differing opinion.

But ideally, C56/C58 should be replaced.

Ok. I won't worry about it for now. I doubt that I'll put any of the expansion slots to use anyway. If I did want to replace C56/58 I'm looking for the Three-legged 10uF/16V replacement referenced http://www.minuszerodegrees.net/failure.htm here?

modem7
June 9th, 2012, 06:33 PM
Ok. I won't worry about it for now. I doubt that I'll put any of the expansion slots to use anyway. If I did want to replace C56/58 I'm looking for the Three-legged 10uF/16V replacement referenced http://www.minuszerodegrees.net/failure.htm here?
I have been meaning to revise that web page (post research) because I had noticed that IBM did something odd.
For example, on a 640K 5160 motherboard I have, the connection points for C58 are wired -|+|-, but the connection points for C56 are wired +|-|+
That means that although both C56 and C58 are 10uF/16V, their pinouts are different.

Also, you can use a 2-legged tatalum instead of a 3-legged one. 2-legged ones are easier to source, but they must be inserted in the correct orientation, negative leg into negative hole and positive leg into positive hole.

When you're ready to get replacements, revisit these forums.

latvija13
June 9th, 2012, 06:58 PM
When you're ready to get replacements, revisit these forums.

I'll do that. I appreciate all the help. It's been a great learning experience for me working on this PC. Thanks!