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Megafile re using the case
Posted: 03 Mar 2020 03:51
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
Re: Megafile re using the case
Posted: 03 Mar 2020 05:05
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
Tom
Re: Megafile re using the case
Posted: 03 Mar 2020 08:23
by frank.lukas
There is also a LS244 and a 7438 ...
Re: Megafile re using the case
Posted: 03 Mar 2020 08:47
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
Re: Megafile re using the case
Posted: 03 Mar 2020 10:41
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.
Re: Megafile re using the case
Posted: 03 Mar 2020 12:12
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
Re: Megafile re using the case
Posted: 03 Mar 2020 13:07
by rubber_jonnie
Tomswork wrote: 03 Mar 2020 12:12
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.
Re: Megafile re using the case
Posted: 03 Mar 2020 17:52
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