Need help with a IBM 5155

[VintageC]

Someone gave me a IBM 5155 today and the good guy told me it was broken.
He thought something with the power suply (also my guess when I tried turning it on).

After some research and great help from Modem7's and hes amazing site of IBM fixing (Thanks Modem7`s ) I managed to get to the bios beeps.

Then.. after Ive put everything together I got nothing on the screen so I disasambled everything again and when no ISA cards are in the system I get a yellow screen with nothing on it (sounds like it suppose to) but when I put in the video card I get no screen at all.
Allready tried an other video card from a IBM 5160 but still nothing.

I guess its not the video card but something else which keep holding me from playing with my new system.

If someone can give me a push in the right direction it would be very appreciated ??

BTW when I turn it on with only the video card I get 1 long beep and 2 short ones.

 

[Agent Orange]

Someone gave me a IBM 5155 today and the good guy told me it was broken.
He thought something with the power suply (also my guess when I tried turning it on).

After some research and great help from Modem7's and hes amazing site of IBM fixing (Thanks Modem7`s ) I managed to get to the bios beeps.

Then.. after Ive put everything together I got nothing on the screen so I disasambled everything again and when no ISA cards are in the system I get a yellow screen with nothing on it (sounds like it suppose to) but when I put in the video card I get no screen at all.
Allready tried an other video card from a IBM 5160 but still nothing.

I guess its not the video card but something else which keep holding me from playing with my new system.

If someone can give me a push in the right direction it would be very appreciated ??

BTW when I turn it on with only the video card I get 1 long beep and 2 short ones.

Here's what the book says: http://ibm-pc.org/manuals/ibm/5150/PCXTSmry.pdf.

Look at page 5. Not much help but gives you a place to start.

 

[modem7]

If someone can give me a push in the right direction it would be very appreciated ??
BTW when I turn it on with only the video card I get 1 long beep and 2 short ones.

You should not be hearing that beep pattern (which indicates a video related problem).
When you finished the diagnostic procedure, did you restore the two motherboard video switches back to either of the two CGA settings?

 

[VintageC]

Thanks for the manual Ill look into it.
Maybe try a external monitor. I dont think its the power suply or the system board. The seller told me he had it working until he tried the last time and only heard a click which I fixsed so there shouldn`t be a big problem but you`ll never know....
If anyone else have some suggestions im glad to hear them.

 

[VintageC]

You should not be hearing that beep pattern (which indicates a video related problem).
When you finished the diagnostic procedure, did you restore the two motherboard video switches back to either of the two CGA settings?

I didnt switch anything back. Could that be the problem? I know the old settings of the switch, should I turn them back to old state?

 

[modem7]

I didnt switch anything back. Could that be the problem? I know the old settings of the switch, should I turn them back to old state?

Yes, that is sure to be it. Via the switch block on the 5155 motherboard, the motherboard needs to be 'informed' of the video card type.

 

[VintageC]

Yes, that is sure to be it. Via the switch block on the 5155 motherboard, the motherboard needs to be 'informed' of the video card type.

I fixed the IBM :D!! Thanks a lot modem7, I could not do it without you .

The capacitors C56 and C58 are off the main board. Im wondering what they are for if they are not needed?
Also do I need to do some effort to getting new ones on the board or does it keep working without forever?

Again thanks a lot modem7 !!

 

[modem7]

I could not do it without you

Your problem would have been solved by other knowledgeable people here.

The capacitors C56 and C58 are off the main board. Im wondering what they are for if they are not needed?

I would not say that they are unneeded. It is like this: If I remove the interior light within my car, my car still works. I should not deduce from that that the interior light is unneeded.

The capacitors are part of a distributed electrical noise filtering network - rather than one big capacitor on a voltage line, there are many capacitors distributed over the length of the line (to cater for resistance in the line).

Nothing on the 5155 motherboard uses plus or minus 12V. C56 and C58 add to the filtering of the plus and minus 12V lines going to the motherboard's expansion slots. Removal of C56 and C58 results in the expansion slot +/- 12V lines being less filtered than normal. For the 5155, it is not a big deal. Expansion cards that use plus or minus 12V (and there are not many of those) will in the vast majority of cases add their own filter capacitors to the 12V line, and do so in a generous way.
For that reason, if I had to remove C56 and C58 in my 5155, I would not bother replacing them. Other capacitors are a different story.

 

[VintageC]

Your problem would have been solved by other knowledgeable people here.


I would not say that they are unneeded. It is like this: If I remove the interior light within my car, my car still works. I should not deduce from that that the interior light is unneeded.

The capacitors are part of a distributed electrical noise filtering network - rather than one big capacitor on a voltage line, there are many capacitors distributed over the length of the line (to cater for resistance in the line).

Nothing on the 5155 motherboard uses plus or minus 12V. C56 and C58 add to the filtering of the plus and minus 12V lines going to the motherboard's expansion slots. Removal of C56 and C58 results in the expansion slot +/- 12V lines being less filtered than normal. For the 5155, it is not a big deal. Expansion cards that use plus or minus 12V (and there are not many of those) will in the vast majority of cases add their own filter capacitors to the 12V line, and do so in a generous way.
For that reason, if I had to remove C56 and C58 in my 5155, I would not bother replacing them. Other capacitors are a different story.

So if I get it right its just an extra capacitor. But what happends if the capacitors of a 12v expansion card fails?

 

[modem7]

So if I get it right its just an extra capacitor. But what happends if the capacitors of a 12v expansion card fails?

There are capacitors in the PSU for the +/- 12V lines, but due to no capacitors near/on the card, the 12V lines at the card would be more noisy than normal.

If we were back in the eighties or nineties, and your PC used for business or goverment purposes, then I would recommend that the caps be replaced. Why? Because for all I know, the PC could be later used in an important/critical application (eg. controlling a furnace). It was important then that PCs be maintained to the manufacturer supplied level. But today's hobby environment is a different story.

It sounds to me like you are slightly concerned. If so, then I suggest that you replace the capacitors for peace of mind.

 

[VintageC]

It sounds to me like you are slightly concerned. If so, then I suggest that you replace the capacitors for peace of mind.

Its not like im concerned but I like to know as much as possible so that I also know where im doing it for. Offcoarse its nice to keep everything original but to replace them costs to much I guess. Plus im not that good of a solderer so its not getting any better when I replace them

 

[modem7]

Offcoarse its nice to keep everything original but to replace them costs to much I guess.

A compromise is the use of locally sourced (cheap) 2-legged replacements.
Shown as the second option on the web page [here].

Plus im not that good of a solderer so its not getting any better when I replace them

Basic soldering skills are good to have for this hobby.
Maybe you could practice on something thrown out (an old VCR?).
There is some soldering information in the links [here].

 

[VintageC]

A compromise is the use of locally sourced (cheap) 2-legged replacements.
Shown as the second option on the web page [here].


Basic soldering skills are good to have for this hobby.
Maybe you could practice on something thrown out (an old VCR?).
There is some soldering information in the links [here].

Thank you for your info I will try to solder some old stuff which I dont use anymore and when its working out for me I will replace the capacitors. Anyway thanks for the time and info!

 

[VintageC]

Its working nicely now but I am still not able to run Dos on it.

I have tried Dos 3.30 boot disk and normal Dos disk but it only search for it on disk A but after searching I end up with the normal screen output (the one with 9 f commands) which I dont understand and could not find anythin about on the internet.

Its possible to run Dos 3.30 on a IBM 5155 right?
If so, could it be that the disk drive is broken even it it searches for the disk?

 

[Stone]

Sounds like it's booting to BASIC because it can't find a bootable disk. Either the disk is not bootable (have you tried it on another machine?) or the drive is faulty. Try cleaning the drive's heads.

 

[VintageC]

Sounds like it's booting to BASIC because it can't find a bootable disk. Either the disk is not bootable (have you tried it on another machine?) or the drive is faulty. Try cleaning the drive's heads.

Then I think its the disk drive because it was working fine on a IBM 5170. I copyd the original disk on the 5170 with diskcopy command which was only on the Dos disk so not on the machine itself. I'll try to clean the drive and see if that works

 

[modem7]

Its possible to run Dos 3.30 on a IBM 5155 right?

Yes

Then I think its the disk drive because it was working fine on a IBM 5170. I copyd the original disk on the 5170 with diskcopy command which was only on the Dos disk so not on the machine itself.

The standard floppy drives in a 5155 are 360k, and the standard drive on a 5170 is a 1.2M
Are you aware of the interchangeability problem created by writing to a 360k floppy in a 1.2M drive? (see here).
Or, is your 5170 like mine; one with a second floppy drive; a 360k ?

 

[VintageC]

Yes


The standard floppy drives in a 5155 are 360k, and the standard drive on a 5170 is a 1.2M
Are you aware of the interchangeability problem created by writing to a 360k floppy in a 1.2M drive? (see here).
Or, is your 5170 like mine; one with a second floppy drive; a 360k ?

Im not sure which kind of floppy drive it is. I didnt know it could give some problems eather but Ill try to figure out what the problem is. Thanks for the info

 

[modem7]

Im not sure which kind of floppy drive it is.

The standard drive supplied by IBM (or reseller) in a 5170 was a 1.2M
Any optional second drive supplied was often a 360k (because of the interchangeability problem) and IBM differentiated the two drive types by an asterisk on the front panel of the 360k.
You can see an example of both types of drives [here] (asterisk is in bottom-right corner of drive).

Of course, your drive might not be the IBM supplied one. An Internet search using the drive's part number should reveal whether it is a 360k or a 1.2M