• Please review our updated Terms and Rules here

Breathing new life into 1981 IBM 5150

VERAULT said:
Ok I need a Sanity check. I got the 1MB Lo-tech RAM board in for my 64KB 5150 and I am having some issues.

SW1 is set to: 1-8 On,on,off,off,on,on,on,on

SW2 is set to this image:
View attachment 1245415

This is what the lo-tech card is set to:
View attachment 1245416View attachment 1245417


I only have a video card in the machine at the moment with the Lo-tech Ram card. It wont post with video and the RAM card installed. What obvious thing am I missing?
Click to expand...
Can't say for sure but I'm thinking you're having an addressing issue; i.e. a conflict with something in the BIOS area.

Tom
 
It looks like from your picture you have *all* the switches from A000 on up set to "on"? That's totally not going to work.

If you have a CGA or monochrome card and no other option cards like an XTIDE or whatever installed you can turn them all on except for B000. (MDA/Hercules resides at B000, CGA at B800). If you have VGA installed you need to turn off A000 through C000; VGA uses the whole 128K from A000-BFFF for various configurations of video memory and it needs (usually 32k, occasionally more from) C000 for the BIOS ROM.
 
Turn off Sw2.3-2.8, otherwise the Lotech board might be in conflict with ROMs and memory regions on your video card.

Make sure you also check your motherboard DIP switches are all set correctly to 640 kB and reflect your graphic card choice.
 
BarryM said:
Turn off Sw2.3-2.8, otherwise the Lotech board might be in conflict with ROMs and memory regions on your video card.

Make sure you also check your motherboard DIP switches are all set correctly to 640 kB and reflect your graphic card choice.
Click to expand...
I posted the board settings in #80

Eudimorphodon said:
It looks like from your picture you have *all* the switches from A000 on up set to "on"? That's totally not going to work.

If you have a CGA or monochrome card and no other option cards like an XTIDE or whatever installed you can turn them all on except for B000. (MDA/Hercules resides at B000, CGA at B800). If you have VGA installed you need to turn off A000 through C000; VGA uses the whole 128K from A000-BFFF for various configurations of video memory and it needs (usually 32k, occasionally more from) C000 for the BIOS ROM.
Click to expand...

I figured the VGA card might be a conflict. I will try again when I have time. We just got back from Michigan last night and I have a few things outside I need to work on today. Will post back.
 
VERAULT said:
I figured the VGA card might be a conflict.
Click to expand...

Any standard video card is going to need at least some upper memory space. (IE, the B-page.) But EGA/VGA is, yes, very expensive if upper memory is what you're after; a whopping 160K from A0000-C7FFF, non-negotiable. Your best strategy with the Lo-tech card and VGA is give it the D and E pages, assuming you can keep your other BIOS ROMs (hard disk, etc) to what's left over in C8000-CFFFF.

In theory at least the most RAM you could possibly have in 5150 with standard (not-breaking compatibility) parts would be to install a CGA card (only needs 32K from B8000-BFFFF) and hack the lo-tech card/build your own to give you 96K from A0000-B7FFF, fill the C-E pages with 192K more, and I *believe* it may also be possible to place a (maximum 16K) option ROM at F0000 in the 5150/60 so you can even have XTIDE in this build. (I *think* the onboard ROM sockets only decode the top 48K, not the entire F page, and that the option ROM scanner is willing to look for signatures up to F4000, but I'm not entirely 100% solid on that claim. I run XTIDE at F0000 in my haxorred Tandy 1000HX so I know its scanner counts that high.)

If you do have memory in the A0000 (contiguous with the lower 640K) page it's actually possible with a little trickery to use that directly as conventional RAM in old versions of DOS that don't understand the whole upper memory thing. But, again, this is off the table with VGA.
 
Eudimorphodon said:
Any standard video card is going to need at least some upper memory space. (IE, the B-page.) But EGA/VGA is, yes, very expensive if upper memory is what you're after; a whopping 160K from A0000-C7FFF, non-negotiable. Your best strategy with the Lo-tech card and VGA is give it the D and E pages, assuming you can keep your other BIOS ROMs (hard disk, etc) to what's left over in C8000-CFFFF.

In theory at least the most RAM you could possibly have in 5150 with standard (not-breaking compatibility) parts would be to install a CGA card (only needs 32K from B8000-BFFFF) and hack the lo-tech card/build your own to give you 96K from A0000-B7FFF, fill the C-E pages with 192K more, and I *believe* it may also be possible to place a (maximum 16K) option ROM at F0000 in the 5150/60 so you can even have XTIDE in this build. (I *think* the onboard ROM sockets only decode the top 48K, not the entire F page, and that the option ROM scanner is willing to look for signatures up to F4000, but I'm not entirely 100% solid on that claim. I run XTIDE at F0000 in my haxorred Tandy 1000HX so I know its scanner counts that high.)

If you do have memory in the A0000 (contiguous with the lower 640K) page it's actually possible with a little trickery to use that directly as conventional RAM in old versions of DOS that don't understand the whole upper memory thing. But, again, this is off the table with VGA.
Click to expand...
VGA is just so I can use the monitor on my bench. ITs not a deal breaker but ID like to use it at least when working on the machine yaknow.. That way I dont have to go to the basement and drag up a real CGA monitor.
 
Ok I have turned off Dips #3,4,5 on SW2 on the Lo-tech card (A000 to C000) and the VGA card is working [again this is just temporary as I will be putting a Hercules card in this machine as a permanent video card most likely.

I am getting getting an Error Beep with 9098 201 on screen.

I am trying to use an XT IDE next as I want to run some programs. I have mine configured pretty stock with a base address of 300 HEX. The XTIDE menu comes up but when it tries to boot it just freezes of course.
XT-IDE Rev 4 - jumper configuration - IDE functionality.jpg

What address should I configure the XT IDE to?
 
Make sure you didn't flip off sw 2.2 on the lo tech by accident. That's where the failure in your error code is. Also probably why your xtide isn't working
 
Well that's not good - do you have another xt machine you could test the memory card on to see if it is defective?
 
IIRC the XTIDE uses the very top of conventional memory to store variables, so it makes sense it's crashing based on that memory error you've got. I'd focus on the memory card for now
 
maxtherabbit said:
IIRC the XTIDE uses the very top of conventional memory to store variables, so it makes sense it's crashing based on that memory error you've got. I'd focus on the memory card for now
Click to expand...

It doesn’t if you don’t have it configured for “full operating mode”, but that mode is incompatible with ROM BASIC and a few other obscure things.
 
maxtherabbit said:
IIRC the XTIDE uses the very top of conventional memory to store variables, so it makes sense it's crashing based on that memory error you've got. I'd focus on the memory card for now
Click to expand...
Well I only put the XTIDE card in because it seemed to be working. The vga was functioning and I was getting 600+ in BASIC memory (forgot the exact amount displayed)
 
VERAULT said:
Well I only put the XTIDE card in because it seemed to be working. The vga was functioning and I was getting 600+ in BASIC memory (forgot the exact amount displayed)
Click to expand...

BASIC never will display more than 60K-ish of memory free, so expansion memory matters naught to it.

The "9098" in front of the 201 implies an error at around the 578K mark. Did you boot from a floppy before installing the XTIDE card or *just* go to BASIC? I wonder if you wouldn't see the code without going through a normal disk boot.

If the 9098 is consistent you could do some poke-peek testing with BASIC to see if there are obvious gross errors. As a temporary "try it and see if it works" you could set your motherboard switches for 512K or 576K and see if excluding the 9-page fixes the error.
 
No floppy drives were connected. Just went into BASIC. Ill set the MOBO switches to 512 or 576 and see if that gets rid of the error,.
 
I have owned a couple 5150’s that would not allow more than 576k of memory, changed the mobo dip switches to 576 even though I had 640 and all was well.

Both came to me as configured, I believe I tried updating the bios on one and still had it crap out on 640k operation.

The strange part was both had the same problem and using the newer bios did nothing, I still wonder if the memory card or some other card was causing problems.
 
You must log in or register to reply here.
Back
Top