Stuff and Things.

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cmorley
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Re: Stuff and Things.

Post by cmorley » Thu Jul 30, 2020 11:30 am

rubber_jonnie wrote:
Thu Jul 30, 2020 10:19 am
That damn mobo socket is so easy to get wrong :(
I don't know what happens if you plug one of my EPROM emus 1 pin off in a 42 pin socket... it might survive or kill one of the buffers, I'm not sure. Best not to try :?

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rubber_jonnie
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Re: Stuff and Things.

Post by rubber_jonnie » Thu Jul 30, 2020 1:05 pm

cmorley wrote:
Thu Jul 30, 2020 11:30 am
rubber_jonnie wrote:
Thu Jul 30, 2020 10:19 am
That damn mobo socket is so easy to get wrong :(
I don't know what happens if you plug one of my EPROM emus 1 pin off in a 42 pin socket... it might survive or kill one of the buffers, I'm not sure. Best not to try :?
Yep, I will be double checking and making damn sure it get's plugged in the right way round and into the correct pins!!

I will let you know, the mobo is currently in our airing cupboard drying out, so can't do anything until later.

EDIT: Orientation confirmed 100% :)
Collector of old Atari things:
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Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
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Tomswork
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Re: Stuff and Things.

Post by Tomswork » Thu Jul 30, 2020 3:38 pm

Do you have a tl866 ii ? The adapter kit should have the 40 to 42 pin adapter.

Tom

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rubber_jonnie
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Re: Stuff and Things.

Post by rubber_jonnie » Thu Jul 30, 2020 4:41 pm

Tomswork wrote:
Thu Jul 30, 2020 3:38 pm
Do you have a tl866 ii ? The adapter kit should have the 40 to 42 pin adapter.

Tom
I do have a TL866 II Pro, but don't think I have a 42-40 pin adapter, but I'm sure I can either make or buy one If I need to. I will try @cmorley's emulator if my ROM still doesn't work, but I presume I could use the 40 pin 27C400's to replace the ROM if it is bad.

Any suggestions welcome!
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

Tomswork
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Re: Stuff and Things.

Post by Tomswork » Thu Jul 30, 2020 5:36 pm

@rubber_jonnie

Ebay item 183888405810 from poland

Tom

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rubber_jonnie
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Re: Stuff and Things.

Post by rubber_jonnie » Thu Jul 30, 2020 9:10 pm

@Tomswork thanks
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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rubber_jonnie
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Re: Stuff and Things.

Post by rubber_jonnie » Fri Jul 31, 2020 10:05 pm

Ok, so on the off chance I have kille the ROM in my Mac Classic, I have an adaptor for my TL866 Pro on the way so I can burn a new one, plus before that I will likely try going down the route of trying the ROM emulator from Mr Morley.

I also ran into an interesting feature, in that I thought I'd found a short in a little 8 pin voltage regulator, but it turned out to be a blind alley.

First you have to ask the question "When is GND positive?"

Answer is simple when you get down to a bit of research - When the voltage is negative. Turns out the data sheet for the regulator even shows it in an example configuration. The polarised capacitor has + connected to GND and - connected to -5v and the schematic for the Mac shows exactly the same configuration.

It took a little research, but nice to know that it isn't a short. Better keep digging I suppose!
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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exxos
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Re: Stuff and Things.

Post by exxos » Fri Jul 31, 2020 10:11 pm

rubber_jonnie wrote:
Fri Jul 31, 2020 10:05 pm
First you have to ask the question "When is GND positive?"
It's all relative ;) :lol:

split-rail-power-supply-circuit.gif
split-rail-power-supply-circuit.gif (13.7 KiB) Viewed 73 times
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rubber_jonnie
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Re: Stuff and Things.

Post by rubber_jonnie » Fri Jul 31, 2020 10:13 pm

@exxos Indeed it is:

negativeispositive.jpg
negativeispositive.jpg (10.13 KiB) Viewed 69 times
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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JezC
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Re: Stuff and Things.

Post by JezC » Fri Jul 31, 2020 10:34 pm

When I used to have to design circuits with ECL logic (especially when interfacing with TTL/CMOS logic) it was a nightmare working out what signals were active (and what polarity that was)...no chance of the logic analyser sorting it out, so we had to rely on a 'scope!

At least the majority of modern electronics (and I'm generously including the ST and Amigas in that category!) don't have that pesky-5.2v supply to confuse things further!
Even just using PECL made a world of difference...

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