OSI 600D Superboard Build

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rubber_jonnie
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Re: OSI 600D Superboard Build

Post by rubber_jonnie »

stephen_usher wrote: Tue Apr 09, 2024 2:09 pm Actually, thinking about it, 1.5A at 5V is only 7.5 watts. It just seems a lot.
I suppose the last time I looked at an ST it was just shy of 3A with a real FDD running, so not terrible, but like you say, it seems a lot :)
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...
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rubber_jonnie
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Re: OSI 600D Superboard Build

Post by rubber_jonnie »

@stephen_usher I just checked and the build manual for the 600D states:

Screenshot 2024-04-09 at 14.20.01.png
Screenshot 2024-04-09 at 14.20.01.png (55.96 KiB) Viewed 6976 times

So 1.5A is pretty OK. With the original build it did have all the 5v regulation circuitry, so that may have added additional load?
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...
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stephen_usher
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Re: OSI 600D Superboard Build

Post by stephen_usher »

How are you getting on with the tape interface?
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: OSI 600D Superboard Build

Post by rubber_jonnie »

stephen_usher wrote: Wed Apr 10, 2024 10:01 am How are you getting on with the tape interface?
Well, not got any further, I replaced the IC but no different.

I lifted a leg of the cap and no difference, and the cap was the right value.

I also lifted the leg on the resistor before the cap and the value is correct and with the leg lifted the signal passes through the resistor.

However that signal is just the 1.2khz signal from the LS76, and is unaffected by the data coming into the LS76.

Much headscratching has ensued since the data does leave the 6850,it does pass through an inverter and arrive at the 74LS76, which is the last stop before the output to cassette.

There are jumpers that need to be set for the cassette to work and I've set them and checked but I'll check again.
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...
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stephen_usher
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Re: OSI 600D Superboard Build

Post by stephen_usher »

Sounds like something isn't clocking in the data on the 74LS76, or the clear is being kept low. That would be my next point of investigation.
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: OSI 600D Superboard Build

Post by rubber_jonnie »

stephen_usher wrote: Wed Apr 10, 2024 2:48 pm Sounds like something isn't clocking in the data on the 74LS76, or the clear is being kept low. That would be my next point of investigation.
I did check all the inputs and I'm sure clear was OK, but certainly worth another look.
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...
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rubber_jonnie
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Re: OSI 600D Superboard Build

Post by rubber_jonnie »

A quick aside, one of the guys over on Osiweb.org has created a new monitor ROM that allows for 48 columns as well as 24, selectable at boot time.

As well as the new ROM, there is a small bodge, represented by a jumper wire here:

IMG20240411085229.jpg
IMG20240411085229.jpg (325.3 KiB) Viewed 6926 times

And the results are great:

IMG20240411085334.jpg
IMG20240411085334.jpg (273.28 KiB) Viewed 6926 times
IMG20240411085225.jpg
IMG20240411085225.jpg (305.7 KiB) Viewed 6926 times

And I think I'll be keeping it, so need to do a more permanent change underneath in place of the jumper wire.
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...
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stephen_usher
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Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
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Re: OSI 600D Superboard Build

Post by stephen_usher »

Oh, that's so much more usable.
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.
User avatar
rubber_jonnie
Site Admin
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Posts: 10944
Joined: Thu Aug 17, 2017 7:40 pm
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Re: OSI 600D Superboard Build

Post by rubber_jonnie »

stephen_usher wrote: Thu Apr 11, 2024 9:29 am Oh, that's so much more usable.
It is isn't it :)
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...
User avatar
rubber_jonnie
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Re: OSI 600D Superboard Build

Post by rubber_jonnie »

And the 24/48 mod is now permanent :)

IMG20240411111203.jpg
IMG20240411111203.jpg (377.46 KiB) Viewed 6915 times

And working great :)
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...
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