Windows 95 on a Tandy 2500 SX/25...sort of.
Hello all!
I have an interesting project and an interesting problem with the project. I recently obtained a Tandy 2500 SX/25, that is, an AMD 386SX, at 25 or 8MHz, 85MB HDD, and 2MB of on board RAM, of which was upgraded to 6MB total (My Macintosh Plus finally came in handy :P). When I got it, it ran DOS 5.0 and Win3.1. And I've used both of those for the longest time, nothing new except the programs on the machine. So I figured, why not give 95 a shot. I meet the requirements, and while the video doesn't support any more than 640x480 at 16 colours, still would be a cool little project.
But there's the problem. Ever since I got the Tandy, it hasn't ever run at 25MHz, always at the 8MHz mode. The BIOS says fast, but everything else, even the DOS tool for switching CPU speed on the fly (speedsx.com), all say slow or 8MHz. I can never find anything on the 'net regarding anything similar to the problem, so all I can think of is something on the board is dying. On initial inspection I didn't see anything that stuck out as obviously broken, so I honestly have no idea for sure what's going on. All I can think of really is the clock multiplier or something relating to the switching from 25 to 8MHz. Because while I don't mind running Windows 95 at 8MHz, it's definitely an experience, I'd like to get this fully working/restored.
Fingers crossed,
FoxPro (Faintshadows)
I have an interesting project and an interesting problem with the project. I recently obtained a Tandy 2500 SX/25, that is, an AMD 386SX, at 25 or 8MHz, 85MB HDD, and 2MB of on board RAM, of which was upgraded to 6MB total (My Macintosh Plus finally came in handy :P). When I got it, it ran DOS 5.0 and Win3.1. And I've used both of those for the longest time, nothing new except the programs on the machine. So I figured, why not give 95 a shot. I meet the requirements, and while the video doesn't support any more than 640x480 at 16 colours, still would be a cool little project.
But there's the problem. Ever since I got the Tandy, it hasn't ever run at 25MHz, always at the 8MHz mode. The BIOS says fast, but everything else, even the DOS tool for switching CPU speed on the fly (speedsx.com), all say slow or 8MHz. I can never find anything on the 'net regarding anything similar to the problem, so all I can think of is something on the board is dying. On initial inspection I didn't see anything that stuck out as obviously broken, so I honestly have no idea for sure what's going on. All I can think of really is the clock multiplier or something relating to the switching from 25 to 8MHz. Because while I don't mind running Windows 95 at 8MHz, it's definitely an experience, I'd like to get this fully working/restored.
Fingers crossed,
FoxPro (Faintshadows)
Comments
Please keep us updated how you make out
http://support.radioshack.com/productinfo/DocumentResults.asp?sku_id=25-1611&Name=Tandy%20Desktops&Reuse=N
Surprisingly, the CMOS battery has kept a charge all these years and keeps the time and date and all settings perfectly. And I've extensively read into Radio Shack's support documents, I forgot to mention that in the original post. According to the pages, there are two ways to switch CPU speeds, the BIOS and a command line utility entitled SPEEDSX.com, of which both I can set to fast but if I run SPEEDSX it says "CPU SET TO SLOW." Running "SPEEDSX FAST" says "CPU SET TO FAST," then no change, and running the tool again says slow.
I've tried looking for schematics for the board so I could maybe identify which part is the clock multiplier, or whatever makes it able to switch from 8 to 25MHz, but to no avail, there seems to be no schematics that I could find on the board.
I plan to make updates on this little endeavor so in case anyone else has this same issue down the road.