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Breathing new life into 1981 IBM 5150

VERAULT

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Ok this is strange. This morning I tried writing the 82 5150 bios: http://minuszerodegrees.net/bios/BIOS_IBM5150_27OCT82_1501476_U33.BIN

Writing to an ST M2764A EPROM in the go4retro 23xxx adapter and I verified the write. I put the eprom in the adapter and in slot u33 and NOTHING...... I checked the connections.. nothing.




Edit: You know what maybe I am not understanding this product. I thought this device automatically works with 27X eproms but maybe you need to make solder jumpers to pads: http://www.go4retro.com/products/23xx-adapter/

Which is a bit misleading as they are hidden under the socket. I bought it preassembled instead of a kit since it only cost a few dollars (cummon im not a massochist). Anyone familiar with this adapteR?
IMG_3518-300x187.jpg
IMG_3077__39369.1328660861.JPG
 
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VERAULT

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This thing has me a bit lost. According to this image
23XX-Configuration.png


And this info from the manual:

ICNotesABC18202101234567
2316!CS1,!CS2,CS32-32-32-3X
2716!EP,!G,Vpp2-32-32-3X
2332!CE1,CE2X1-22-32-3X
2364!CE1XX1-22-31-2X
2364!CE1 (Alternative, no ‘138 needed)1-21-21-2
2364CE1XX1-22-31-2X

I am using the last entry for 2364. I have shorted pads A and C. And 18 pads 1 and 2 shorted. 20, pads 2 and 3 shorted. And 21 Pads 1 and 2 shorted. Pad 2 also shorted.

That should be correct no? Still nothing. Should I try the other two entried for 2364?
 

Plasma

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I think you need the first 2364 config in that table since the M2764A has !CE on pin 20.

I have used a similar adapter in my 5150 with no issues. So yours should work.

You may be interested in the Super PC BIOS. For a 5150, enable the IBM_PC define and disable TURBO_ENABLED.
 

modem7

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That should be correct no? Still nothing. Should I try the other two entried for 2364?
Yes, your adapter is different to the one that the minuszerodegrees web page points to. ('2364 Adapter' versus '23XX Adapter')

See post #3 of the thread at [here], where I determined that the "2364 - !CE1 (Alternative, no ‘138 needed)" option is what is expected to work. Let us know how you go.
 

VERAULT

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thanks guys but you both say different ones. Soldering this tiny board is a pain. Ill check the thread modem 7.
 

modem7

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thanks guys but you both say different ones. Soldering this tiny board is a pain. Ill check the thread modem 7.
In that thread, the OP came back with, "The fourth configuration works properly, ...", which looking at the table you posted above, is the "first 2364 config" that Plasma suggested.
But I'm sure the "2364 - !CE1 (Alternative, no ‘138 needed)" configuration option is going to work too.
 

framer

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I might have missed it but do you have all 4 ram banks filled? I remember working on mine many years ago and there seem to me a glitch in the bios that require all the RAM banks to be filled.
 

modem7

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I might have missed it but do you have all 4 ram banks filled? I remember working on mine many years ago and there seem to me a glitch in the bios that require all the RAM banks to be filled.
That requirement ([here]), if not met, does not prevent the motherboard from starting and displaying something on-screen.
 

VERAULT

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I might have missed it but do you have all 4 ram banks filled? I remember working on mine many years ago and there seem to me a glitch in the bios that require all the RAM banks to be filled.
yeah.. board populated to a full 64kb of ram.

In truth i have never come across a 5150 or 5160 that was not fully populated.
 
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VERAULT

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Thanks for the help everyone. I guess I just didnt understand how this adapter worked at first. In truth I dont remember why I bought it in 2017 and why I never ended up using it to begin with?!

I did as plasma suggested Max. Since it was the easiest tweak and soldering tiny pads under the socket cross members is a pain on this tiny board. I know now why its sold as a kit.. It should be only sold as a kit.

Its working now with the 1982 5150 bios. I will play with other bios' in time as well. I have it working with no other cards other than my WDC 8 bit vga card as seen on this lcd shot.
IMG_20220807_124231.jpg

Again this is not how I intend to keep the computer. I just want to actually try doing things on it.

Funny thing to note. With 64KB of ram on board BASIC only has less than 12KB free? Is this correct or an incompatibility between the 1981 BASIC roms and the 1982 BIOS?

Mick
 

modem7

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Funny thing to note. With 64KB of ram on board BASIC only has less than 12KB free? Is this correct or an incompatibility between the 1981 BASIC roms and the 1982 BIOS?
I am not seeing that with the same configuration.

Per [here], confirm for us that the motherboard switch settings are set as follows:
- On switch block SW1 (closest to center of motherboard), switches 3 and 4 both OFF.
- On switch block SW2 (closest to edge of motherboard), switches 1 through 5 all ON.
 

VERAULT

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@modem7
Ok some good news.

I was using this guide for setting the dip switches: http://minuszerodegrees.net/5150/ram/5150_ram_16_64_SW2.jpg

Since 5 to 8 were NA they were set to OFF. I switched 5 to ON.

Banks 1,2, and 3 are socketed and Bank 0 is all soldered on. I was able to check all the ram chips socketed in an Apple II I am also repairing. I found one bad RAM chip and replaced it.

I am not getting this screen. I take it this number is correct?

IMG_20220810_101810.jpg
 

modem7

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I was using this guide for setting the dip switches: http://minuszerodegrees.net/5150/ram/5150_ram_16_64_SW2.jpg
Since 5 to 8 were NA they were set to OFF. I switched 5 to ON.
Yes, an example of a BIOS upgrade requiring a change of switch settings.
It's caught a few people out.
One of the examples that I have at [here].

I am not getting this screen. I take it this number is correct?
Yes, Cassette BASIC version C1.00 on my 5150 motherboard (configured for 64 KB) displays "61404 Bytes free".
 

VERAULT

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I realize I made a typo. What I meant to say is
"I am NOW getting this screen..." so one step closer to functionality.
 

BarryM

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The lotech board you can get from TexElec is good. Helped me get some expansion slots back on my 5150 versus 2 * 256k cards and some additional UMB too.
 

VERAULT

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The lotech board you can get from TexElec is good. Helped me get some expansion slots back on my 5150 versus 2 * 256k cards and some additional UMB too.
funny you should say that. I bought the 1mb lo tech board from texelec this morning!
 

VERAULT

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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:
5150_ram_16_64_SW2.jpg

This is what the lo-tech card is set to:
IMG_20220829_114706.jpgIMG_20220829_114719.jpg


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?
 
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