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I’ve run CP/M and Northstar DOS on my Sol-20 computer with Northstar disk controller. I’d like to know if it possible to run PTDOS on the Sol-20 with a NorthStar disk controller.

I picked up a Northstar micro disk drive assy (SA-400 drive with power supply in blue cabinet) a couple of years ago. I found that the +5V output was not right and now, would like to fix this problem. The power supply board assy is like the one in the attached picture. I have been able to find...

I was looking through the available programs for the SOL-20 and noticed that there was no Visicalc-type applications for the SOL-20. I find this kind of hard to believe. Does anyone know if a spreadsheet application for the SOL-20 was ever produced?

Hi Ken, Did you ever find software for you Versawriter? I was going through some Apple II disks and found a Versawriter disk. I've included some pics of the main menu and disk catalog. I can make a copy of the disk and send it to you, if you like. -Gil -Gil

My SCSI hard drive quit working on my Mac SE/30 and I am looking for a solid state replacement. I have a Floppy Emu and Ruminator II installed. I have tried to use the FloppyEmu as an HD20, but my System 6.08 and System 7.1 disk images are not working right. They both boot up fine and provide a...

Thanks for the replies. I read the manual a few more times and found that I needed to create the GRAPHI file (see attached pics). After reading the second page a few times and looking at the example code I have come to the conclusion that this example code is just meant to show examples of the...

I have a IBM PC RevA with 128K RAM and I would like to learn how to write a Pascal program using graphics. I am using the IBM PC Pascal Compiler from 1981 and reviewed this example program in the Pascal Compiler manual Program file: (*$INCLUDE:'GRAPHI*) PROGRAM PLOTBOX (INPUT, OUTPUT); USES...

I've been trying to clear Supersoft ROM errors for a few months on my 5150 RevA 16-64K motherboard. I was successful with clearing the U36 8255 error by replacing the 8255 chip. Unfortunately, I still had 16K Critical Memory Region errors. I referenced the Supersoft manual and it recommended...

I received my null modem cable setup and tried to establish a working connection between my 486 laptop with 9-pin serial interface and my Sol-20 serial interface, but have failed. My 486 Laptop is an HP Internet advisor workstation. Back a few years ago buying one of these was a cheap way of...

I purchased a NorthStar Horizon computer a couple of weeks ago. I bought it for the double density floppy disk controller and 5.25 floppy drive to use with my Sol-20 computer. The more I look at the NorthStar Horizon computer, the more I think about trying to get it working and seeing what it...

I was checking the memory in my Sol-20 and I have a generic 32K RAM card that works fine. I can write and read all bits just fine. I have an 8K RAM Processor Technology board that appears to have a stuck bit in MSB (Bit 7) position. I have the 8K RAM setup to start at 8000h. When I enter data...

Hugo, there seems to be different types of null modem adapters or I may be misunderstanding your detailed Null Modem description. I was shopping for a 25pin null modem adapter and found this It appears to have an additional wires crossed than just 2 and 3 and 4 and 5 Would this type of null...

The PROMs on my MDC-A2 controller appear to be the 6301-1 256x4 type for all 3 PROMs. I dumped more of the PROM and compared it to the listings at DeRamp.com. Looks like my card has Ver 2 PROM. I was able to get the disk drive to make 'loud click sound', LED light, and the center spindle to spin...

Ok. It has been a while, but I have replaced the +12V caps (all 5 of them) and I am still getting no beeps at power on. I installed the Supersoft ROM and got the following results. Same as before. Not sure what the next step should be. I'm thinking that I should unsolder the Bank 0 RAM and...

I've finally found some time to work on my old IBM 5150. I had posted some questions about 6-8 months ago and members had posted some useful information that I would like to now reference. How does one find/view older posts?

I had some S100 cards in my garage and found that I had 2 different floppy disk controllers. First one is a California Computer System (CCS) 2422. The second one is a Tarbell 2022. From information on an S100 board website it seems that the CCS may be able to be used with North* Shugart drive...

Here are some pictures of the North* drive. I found that it has some broken wires that look like they are supposed to connect to head assembly (see red circle). I also found that one of components (another red circle) is loose and moves around. Not sure what this component is and how it should...

I picked up a NorthStar disk drive from eBay for my Sol-20. I'nm not sure what model it is or if it is a single density or double density drive. How does one tell? Is there a model number on the drive mechanism? There is no model information on the outside case of the drive. Only a NorthStar...

Does anyone make a floppy disk drive emulator for the Sol-20 computer? I've been looking for actual floppy disk drive and controller card for a while, but have yet to see these for sale anywhere, except for the Helios drive which in most cases is very expensive and have a finicky reputation.

I was working on my 5150 Rev B 256K MB 2 full height Tandon 5.25 drives and CGA card. I am able to read floppy diskettes fine (have tried several diskettes - no problem reading). When running DOS 2.1 I try to format a double-density diskette in Drive A and it completes the format (some times I...