General Stuff(tm)

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stephen_usher
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Re: General Stuff(tm)

Post by stephen_usher »

Oh, VSCode is an IDE. I won't be using one of those, just a text editor and command line. I may not even bother starting X-Windows. :-)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
stephen_usher
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Joined: Mon Nov 13, 2017 7:19 pm
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Re: General Stuff(tm)

Post by stephen_usher »

I hate bit-rot. :-)

I had decided to have one of my spare BBC Model Bs as a prize for the high score competition at Lavecon this year. So, as part of my preparations I brought the machine down to test...

Turn it on.. Boop-Beep!

Oh good.

Now let's test the floppy interface. Oh dear, reads all zeros from any drive and any media.

I've seen this before with a poor floppy cable connection but... I can trace the data right from the interface, through the LS logic and into pin 27 of the Intel floppy controller chip. (I made sure to measure on the actual pin of the chip in case it was a poor socket connection.)

Bad controller chip? Nope, swapped with one from one of my other Beebs and it has the same problem! *sigh*

Oh well, more diagnostics.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
stephen_usher
Posts: 3367
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
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Re: General Stuff(tm)

Post by stephen_usher »

After going around in circles and even trying to fit the FDC chip into a socket tower (which didn't work 'cos the turned pins wouldn't sit into the original socket) I got nowhere.

Then a reply on Stardot forums noted that the FDC used the NMI to signal that data was ready. The INT pin on the FDC goes through a NAND gate, with the other input held at 5V, the INT line is also connected to a jumper, S9, which is factory fitted. and holds the line at 0V, meaning that the FDC can never raise an interrupt! A quick Google confirmed that this link must be cut when the floppy disk interface is fitted!

A quick cut of the link and the machine can read disks!

Whoever fitted the floppy interface (a) didn't cut the link, and (b) never tested the machine with a floppy drive.

Given that this machine was used at work as a terminal with a ROM based terminal emulator I'm not surprised that this was never spotted.

Anyway, it all works now! :-)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
stephen_usher
Posts: 3367
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
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Re: General Stuff(tm)

Post by stephen_usher »

Well, it worked for a while... but now it looks as if the SEEK signal isn't being sent to the drive so trying to load any files ends with the Error 18 (though *CAT works). I'll have to make sure that the Gotek hasn't gone wrong before opening the machine up again.

*sigh*
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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rubber_jonnie
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Re: General Stuff(tm)

Post by rubber_jonnie »

stephen_usher wrote: Sun Jun 19, 2022 10:49 pm After going around in circles and even trying to fit the FDC chip into a socket tower (which didn't work 'cos the turned pins wouldn't sit into the original socket) I got nowhere.

Then a reply on Stardot forums noted that the FDC used the NMI to signal that data was ready. The INT pin on the FDC goes through a NAND gate, with the other input held at 5V, the INT line is also connected to a jumper, S9, which is factory fitted. and holds the line at 0V, meaning that the FDC can never raise an interrupt! A quick Google confirmed that this link must be cut when the floppy disk interface is fitted!

A quick cut of the link and the machine can read disks!

Whoever fitted the floppy interface (a) didn't cut the link, and (b) never tested the machine with a floppy drive.

Given that this machine was used at work as a terminal with a ROM based terminal emulator I'm not surprised that this was never spotted.

Anyway, it all works now! :-)
IIRC one of my BEEBs arrived with an intel 8271 in it, though I never hooked up an FDD as I didn't have one. The link was snipped in that one I'm sure, I can go check if you want.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
stephen_usher
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Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
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Re: General Stuff(tm)

Post by stephen_usher »

Yeah, S9 needs to be snipped on Issue 4 & 7 boards
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
stephen_usher
Posts: 3367
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: General Stuff(tm)

Post by stephen_usher »

OK, I seem to have got the machine stable, though the DFS 0.9 ROM does cause issues with Elite, with 12 second waits before it accesses the disk.

I tried using an EEPROM with DNFS 1.2, as I have in my other Beebs, but the machine doesn't like it. Oh well.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
stephen_usher
Posts: 3367
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: General Stuff(tm)

Post by stephen_usher »

Hmm... Looks like I may be picking up a Faclon030 in a little over 3 weeks time.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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alexh
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Joined: Tue Oct 17, 2017 4:51 pm

Re: General Stuff(tm)

Post by alexh »

stephen_usher wrote: Tue Jun 21, 2022 11:55 am Hmm... Looks like I may be picking up a Faclon030 in a little over 3 weeks time.
Nice. Just in time for the re-release of the CT63?
Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
STfm,STe,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
stephen_usher
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Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
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Re: General Stuff(tm)

Post by stephen_usher »

I'll keep it as stock as possible I think.

It'll need the clock chip looking at. I'll probably just grind the top off the case and solder a CR2032 holder to it. It'll probably also need the clock patch.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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