Recent content by mrthreeplates

new board ordered

Messed around a bit more today with my 5150 I have further convinced myself that a 8.33 MHz system clock (25 MHz oscillator) is stable. My 5150 passes dozens of passes of the Giller/Black ROM-based ram tests. Even up to 25.9 MHz, I am not getting any RAM errors. Booting GlaBios and my...

Success! My 5150 boots & runs at 8.33 MHz, which I'm pretty happy about and seems stable. 10 MHz fails badly. Details below. I discovered that the Picomem f/w (Jan 1st) isn't very happy running at close to 8 MHz. I either get boot hangs or some kind of boot init failure. Once in a while...

Continuing my project, I worked on my Lo-tech ram errors next. TLDR: I have been able to find a workaround for the memory failures, details below. I noticed that when I disabled only the first 64K block of the Lo-tech board, with the remaining 9 visible/testable 64K blocks enabled, I didn't...

For what it is worth, I am very pleased that "Tucs Workbench" on eBay is offering my remapper boards for sale. Hopefully, this initial programming/testing gotcha is now a thing of the past. It is definitely something to watch out for, should you want to make your own. This is the benefit...

So glad it worked and thank you for sharing your tips!!! Best regards,

Sorry, I just have 26-2110, 26-2119, and 26-1080. And I was looking forward to have an excuse to get one of those fancy new book scanners that I see on YouTube.

OK, which manual (name and catalog #) has not yet been scanned and archived? Just asking in case I may have it.

Is the manual in question here the " model 4/4p technical reference manual" 26-2119 ?

Great, I will try to help as much as I can. Unless the Pic is damaged, installed incorrectly, or the wrong/fake part, it probably will work after reprogramming. However, I offer no guarantees! And yes, that is the intent of the self-tests. They are designed as a one-time, post-manufacturing...

Hi view836, Sorry you are having trouble. I don't think you have done anything wrong. It sounds like both boards are running into a self test failure. See: https://github.com/mrthreeplates/TRS-80_floppy_remapper/blob/master/Design.md When the pic is first programmed, and it boots for the...

Hi everyone, This is a continuation of my IBM 5150 restoration / exploration here, having a great time playing with one of my retro projects. Posting this here in case others find this as interesting as I do. My next step is to overclock the 5150. This is nostalgic for me as my first IBM PC...

I continue to have a lot of fun with my picomem, thanks for all the great work! With regards to a real floppy controller coexisting with one or more virtual picomem floppy images: I am able to get one real floppy and one picomem floppy, but not two of each. I tried setting my 5150's...

I'd like to add some more detailed measurements for future reference. I first measured PCLK as generated by the PC-Sprint when in turbo mode (with a 22.x MHz turbo crystal). I expect this to be a solid 2.38Mhz, 50% duty cycle, 420ns cycle time. And it was (see first attachment)...

Thanks! Yes, I found a complete 5150, so I'm good.