Questions About a Recently Acquired 5160

[BetaCarotene]

As the title suggests, I recently gained a complete 5160 system, with Model F and 5151 monitor to round it out. I've even managed to get it to the point of booting off of the 10MB full height drive. That being said, it sounds rather unhappy when it is going, so I'm avoiding using it until I have my XTIDE. It also has an EconoRAM RAM card to bring the system up to 640k. As for the questions, they are somewhat simple.

• My system has a Senstron PSU, is this an aftermarket one or original? And by extension, would it be possible to replace the fan inside it to prevent the squealing I can currently hear?
• The motherboard is a 256K model with the older ROM/BIOS, and apparently has a somewhat corrupted second half of the ROM as well, because it gives me a F6000 ROM Error every time it boots. Is this something to be worried about, or is it something that will not even be a problem if I find a way to Upgrade to the final BIOS revision?
• The MDA card that came with the system seems to be faulty. It has exclamation marks all over the screen from about 2/3rds of the way down. Is there something I can do to fix the card? If not, it isn't a big deal as I have a Paradise Autoswitch EGA 350 in the system already.
• It seems to have the default Floppy controller card from IBM. If I were to upgrade the BIOS, would that prevent me from using higher density drives?
• The system also came with an AST IO Plus II. I was planning on copying any files from the HDD I could find related to it, but is there anything I would need to do to get the card running on a fresh install of DOS 3.3? I'm far more used to later DOS systems where option roms and plug and play are happening.

I've also thrown in my Sound Blaster 2 in there for the sake of it, since I might eventually find something that both uses it and can run on an 8088. I'm happy to have it, even with the minor issues.

 

[jafir]

IBM used a few different brands of power supplies. Does it have an IBM style part number on it? Perhaps sharing a photo would help.

The error code you're getting during post is described here along with some possible troubleshooting steps. Do you have a way to write an EEPROM if you need to replace one?

The stock floppy controller does not support HD floppies, but there are options available to replace the controller with one that does, some upgrades bring their own BIOS to support HD floppies and drives.

It looks like the manual for your AST card is available here.

 

[BetaCarotene]

IBM used a few different brands of power supplies. Does it have an IBM style part number on it? Perhaps sharing a photo would help.

The error code you're getting during post is described here along with some possible troubleshooting steps. Do you have a way to write an EEPROM if you need to replace one?

The stock floppy controller does not support HD floppies, but there are options available to replace the controller with one that does, some upgrades bring their own BIOS to support HD floppies and drives.

It looks like the manual for your AST card is available here.

Thanks for the help. I don't have a way to write an EEPROM as far as I am aware, unless I could use something like an ISA networking card to do it. I have also tried reseating the ROMs to no avail. As for the PSU, it is below.

 

[modem7]

My system has a Senstron PSU, is this an aftermarket one or original?

The photo indicates aftermarket.

And by extension, would it be possible to replace the fan inside it to prevent the squealing I can currently hear?

Yes.

Do you know for fact that the PSU is the noise source? Right beside the PSU is the ST-412 hard drive, and that can make a horrible sound due to a bearing lubrication problem.

The motherboard is a 256K model with the older ROM/BIOS, and apparently has a somewhat corrupted second half of the ROM as well, because it gives me a F6000 ROM Error every time it boots. Is this something to be worried about, or is it something that will not even be a problem if I find a way to Upgrade to the final BIOS revision?

I have also tried reseating the ROMs to no avail.

So, probably a faulty U19 ROM. Per [here], because you have a 1982 dated motherboard BIOS, all that is compromised is Cassette BASIC.

If a faulty U19 (the most likely cause by far), if you decide to upgrade the BIOS, that upgrade replaces both U18 and U19.

The MDA card that came with the system seems to be faulty. It has exclamation marks all over the screen from about 2/3rds of the way down. Is there something I can do to fix the card?

Is that the IBM MDA card, the 'IBM Monochrome Display and Printer Adapter' shown at [here] ?
If so, the circuit diagram for it is available.
That means that someone here should be able to use the symptoms that you provided and the circuit diagram, coming up with something like, "Chip xx is most likely the cause."

 

[modem7]

It seems to have the default Floppy controller card from IBM. If I were to upgrade the BIOS, would that prevent me from using higher density drives?

The stock floppy controller does not support HD floppies, but there are options available to replace the controller with one that does, some upgrades bring their own BIOS to support HD floppies and drives.

Per the following at [here].

A warning. A 1986 dated IBM 5160 motherboard BIOS may prevent booting from a 1.44M diskette in a 1.44M drive. See [here].

 

[modem7]

The system also came with an AST IO Plus II. I was planning on copying any files from the HDD I could find related to it, but is there anything I would need to do to get the card running on a fresh install of DOS 3.3? I'm far more used to later DOS systems where option roms and plug and play are happening.

It looks like the manual for your AST card is available here.

Per the manual.

Page 1: Optional. Super-Drive software.
Page 1: Optional. Super-Spool software.
Page 18: Desirable. Support software for the real-time clock (RTC).

In the manual, you will read that those are part of the 'Superpak software utilities', which are available at [here].

 

[BetaCarotene]

The photo indicates aftermarket.


Yes.

Do you know for fact that the PSU is the noise source? Right beside the PSU is the ST-412 hard drive, and that can make a horrible sound due to a bearing lubrication problem.



So, probably a faulty U19 ROM. Per [here], because you have a 1982 dated motherboard BIOS, all that is compromised is Cassette BASIC.

If a faulty U19 (the most likely cause by far), if you decide to upgrade the BIOS, that upgrade replaces both U18 and U19.


Is that the IBM MDA card, the 'IBM Monochrome Display and Printer Adapter' shown at [here] ?
If so, the circuit diagram for it is available.
That means that someone here should be able to use the symptoms that you provided and the circuit diagram, coming up with something like, "Chip xx is most likely the cause."

I thought I would ask about the PSU fan just in case it was a known quantity. Since it probably isn't I'll just open it up and see what I'm working with in due time. I do know it's the PSU, though as the squeaking was present without the HDD hooked up.

As for the Display Card it is indeed the IBM original with the printer port. It even has a brown PCB. Here's a picture that I was able to take. I'm sure it's something horribly specific since it starts in a specific spot in the screen.

Per the following at [here].
View attachment 1277185
A warning. A 1986 dated IBM 5160 motherboard BIOS may prevent booting from a 1.44M diskette in a 1.44M drive. See [here].

Thanks again. the floppy stuff isn't too big a deal for me currently, it would just make it easier to transfer things off of the HDD while waiting for things like the XTIDE to be delivered.

Per the manual.

Page 1: Optional. Super-Drive software.
Page 1: Optional. Super-Spool software.
Page 18: Desirable. Support software for the real-time clock (RTC).

In the manual, you will read that those are part of the 'Superpak software utilities', which are available at [here].

Thanks again. I'll get that downloaded when I can.

 

[modem7]

Is that the IBM MDA card, the 'IBM Monochrome Display and Printer Adapter' shown at [here] ?
If so, the circuit diagram for it is available.
That means that someone here should be able to use the symptoms that you provided and the circuit diagram, coming up with something like, "Chip xx is most likely the cause."

As for the Display Card it is indeed the IBM original with the printer port. It even has a brown PCB. Here's a picture that I was able to take. I'm sure it's something horribly specific since it starts in a specific spot in the screen.

I did the analysis, and deduced the RAM chip at position U14. I then did a test using my IBM Monochrome Display and Printer Adapter. At a blank screen (except for the cursor), I temporarily connected pin 14 of U14 to +5V (some risk in that), and during that time, the blank screen filled with thick exclamation marks. It all points to a bit 0 failure in your U14, a failure that does not affect all of U14's addresses.

The circuit diagram shows that the RAM chips on the card are a model "2114L-2". IBM omitted the prefix, the portion that informs us of the maker. But there are equivalents from other makers. For example, my card is pictured at [here], and as can be seen, in use for U14 is a MN2114N-2L. On another card that I have, the RAM chips are AM9114EPC.

 

[BetaCarotene]

I did the analysis, and deduced the RAM chip at position U14. I then did a test using my IBM Monochrome Display and Printer Adapter. At a blank screen (except for the cursor), I temporarily connected pin 14 of U14 to +5V (some risk in that), and during that time, the blank screen filled with thick exclamation marks. It all points to a bit 0 failure in your U14, a failure that does not affect all of U14's addresses.

The circuit diagram shows that the RAM chips on the card are a model "2114L-2". IBM omitted the prefix, the portion that informs us of the maker. But there are equivalents from other makers. For example, my card is pictured at [here], and as can be seen, in use for U14 is a MN2114N-2L. On another card that I have, the RAM chips are AM9114EPC.

Thanks for that, I wasn't expecting to get so good an answer. I will hold off on trying to figure out how I can get to fixing that specific issue for the time being, but eventually I can see if a reflow or even just a swap can fix the issue. I'm currently at the point of getting my system running using the XTIDE.

 

[modem7]

I did the analysis, and deduced the RAM chip at position U14. I then did a test using my IBM Monochrome Display and Printer Adapter. At a blank screen (except for the cursor), I temporarily connected pin 14 of U14 to +5V (some risk in that), and during that time, the blank screen filled with thick exclamation marks. It all points to a bit 0 failure in your U14, a failure that does not affect all of U14's addresses.

After more analysis, it could be U14 or U15. On my to-do list is to work out which.

 

[BetaCarotene]

After more analysis, it could be U14 or U15. On my to-do list is to work out which.

Thanks for the update. It's certainly an interesting failure mode. Is there anything I can potentially do to help figure it out? The card is currently just sitting in my parts bin as I managed to snag an ATi VGA BASIC-16, which works out of the box with a 5160. the card uses the ATi 28800-5 chip, which might mean that other cards with it can also work.

That in turn has let me use my regular CRT and a serial adapter to run Windows 1 in full color, which is always fun despite how useless that all is. I have also learned that if you plug an XTIDE's SD card (maybe a CF as well) in to a modern Macintosh, you will need to run FDISK /mbr from DOS 5.XX to allow it to boot once more. MacOS 14 somehow does something to upset the partition just enough.

 

[modem7]

After more analysis, it could be U14 or U15. On my to-do list is to work out which.

Thanks for the update. It's certainly an interesting failure mode. Is there anything I can potentially do to help figure it out?

I looked more at the circuit diagram.

U12 and U13: Character - bits 7 to 4
U14 and U15: Character - bits 3 to 0
U8 and U9: Attribute - bits 7 to 4 (attribute is blinking, etc.)
U10 and U11: Attribute - bits 3 to 0

Each chip covers about half of the screen. The first 'half', the top, is 1024 characters. The second 'half', the bottom, is 976 characters. 80 x 25 characters = 2000 = 1024 + 976

Because of the way the circuit is wired, my experiment back at post #8 affected two chips, not one.

I am very confident, based on more examination of the circuit, and a different experiment that I did, that U13 and U15 are for the top 'half' of the screen, and U12 and U14 are for the bottom 'half'.

And so, if I had your IBM MDA card, U14 is what I would be replacing.

I have also learned that if you plug an XTIDE's SD card (maybe a CF as well) in to a modern Macintosh, you will need to run FDISK /mbr from DOS 5.XX to allow it to boot once more. MacOS 14 somehow does something to upset the partition just enough.

That will be noteworthy for those in your situation. I should add it to [here].

 

[BetaCarotene]

That will be noteworthy for those in your situation. I should add it to [here].

At some point in the next few days I can do some testing if you'd like. I do know that this situation doesn't happen with DOS 6.22 drives using FAT16, as that is what I use for my pentium machine. I am thinking it's something specific to DOS 3, and do have spare SD cards to work with to see if it affects earlier and later versions.

 

[modem7]

At some point in the next few days I can do some testing if you'd like ...

That is up to you. For now, I will just create an entry along the lines of, "As reported at xxxxx, it appears that in certain circumstances, MacOS 14 overwrites part of the MBR, necessitating the use of FDISK /MBR (from DOS 5 or later) to restore booting from the IDE device ..."

 

[BetaCarotene]

That is up to you. For now, I will just create an entry along the lines of, "As reported at xxxxx, it appears that in certain circumstances, MacOS 14 overwrites part of the MBR, necessitating the use of FDISK /MBR (from DOS 5 or later) to restore booting from the IDE device ..."

Cool, that works.