Megafile re using the case

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Tomswork
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Megafile re using the case

Post by Tomswork »

I have an old megafile 20 case and having been thinking about removing the guts as the drive is dead. Removing the db19f connectors and putting a buffer board in the case that has a 20idc for a ultrasatan allowing it to live onThe schematic shows 1 ls245 buffering the acsi data lines between in and out is this all there is to get the pass thru to work

Tom
Tomswork
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Re: Megafile re using the case

Post by Tomswork »

Here is a snap shot of the area you can see the ls245 and ls08 handling the bi dersctional control between the 2 db19 is there anything else other than a 20 pin idc header
Screenshot_20200302-210153_Adobe Acrobat.jpg
Screenshot_20200302-210153_Adobe Acrobat.jpg (255.89 KiB) Viewed 3796 times
Tom
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frank.lukas
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Re: Megafile re using the case

Post by frank.lukas »

There is also a LS244 and a 7438 ...
Tomswork
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Re: Megafile re using the case

Post by Tomswork »

Cant sleep. The asci bus seems simple the logic out side of the path is for the cpu and adapter chips. The bus only needs the buffer to pass the signal down the line on the data. With a diode off the r/w line to I'm not sure yet to the oe and dir pins on the ls245. Plus some current control. Have a 20pin header for a ultrasatan before the ls245. And the case will work noise free with a basic 5v ps. Oh and what software library has those old db19 pcb files

Tom
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rubber_jonnie
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Re: Megafile re using the case

Post by rubber_jonnie »

Maybe I'm under thinking this, but the Ultrasatan would normally plug into the extrenal ACSI DB19 plug.

What you're suggesting is putting it at the end of a cable in a box with it's own PSU unless I've read it wrong, so why the need for a buffer?

Not trying to be awkward here, I'm genuinely interested as to why you'd need it, unless of course you're reusing some of the other internals from the Megafile 20.
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...
Tomswork
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Re: Megafile re using the case

Post by Tomswork »

Hi rubber_jonnie yes fair quesstion. I would like to keep the looks up and having both the in and out asci ports working. Also I was told I'm 55 and I need a hobbie that does not involve model trains


Tom
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rubber_jonnie
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Re: Megafile re using the case

Post by rubber_jonnie »

Tomswork wrote: Tue Mar 03, 2020 12:12 pm Hi rubber_jonnie yes fair quesstion. I would like to keep the looks up and having both the in and out asci ports working. Also I was told I'm 55 and I need a hobbie that does not involve model trains


Tom
I see, makes sense. Same age as me, and I've managed to steer clear of model trains!

I do often get told (Ususally by my wife) I have too many hobbies for somebody who's not yet retired.
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...
Tomswork
Posts: 775
Joined: Fri Nov 22, 2019 10:05 pm

Re: Megafile re using the case

Post by Tomswork »

I am just looking for some pcb software that has a library for this db19 . I may have to check autocad

Retirement I would go crazy

Tom
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