External floppy settings

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olivier.jan
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External floppy settings

Post by olivier.jan »

Hi,
I purchased an external floppy for Atari ST a few months ago, it’s a no name containing a simple power circuit and a TEAC FD-235.
I tried it yesterdays it’s not working, Floppy LED turns on briefly at startup but after that the drive is not recognized.

I troubleshooted a bit this morning, the 7805 chip was dead giving 4.4V when powered with 5V and 5.5V when powered with 6V. I replaces it with a new one and now I get a steady 5V but still not working.

I wanted to replace the TEAC drive with one of my spare to try but no luck ☹️ I tried with two different EPSON 380 and an Amiga 600 drive but still nothing.

I tested the cable and I have continuity on all wires and it seems to be properly wired.

I was wondering, as all my spare drives are originally internal ones, do I need to change DS0 to DS1?
Retro stuff
520 STF/ 1040 STE / Mega ST / 2 Mega STE / 2 H5
2 x 600XL with U1MB /SOFIA 2/ AVG CART / and a few 1050
Apple //c, Commodore 128, Mac Classic, SE/30, LC, IIvi and PB G3 (Clamshell)
Amiga 600 and a few 486 and 386.
Many Nintendo G&W and other electronic games from the late 70s/early 80s.
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exxos
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Re: External floppy settings

Post by exxos »

6V input sounds a bit low still. IIRC they need 2volts high minimum, but you would have to check the datasheet. 9V would probably be better.
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rubber_jonnie
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Re: External floppy settings

Post by rubber_jonnie »

I use 9-12v with my external FDD, it has what sounds to be a similar 7805 circuit to mine.

And yes, it needs to be DS0.
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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olivier.jan
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Re: External floppy settings

Post by olivier.jan »

Thanks guys, you were spot on, I was too shy with my 6V.
After using proper 9V the FDD works fine.
A new 7805 and proper voltage and I now have my first external floppy.
Retro stuff
520 STF/ 1040 STE / Mega ST / 2 Mega STE / 2 H5
2 x 600XL with U1MB /SOFIA 2/ AVG CART / and a few 1050
Apple //c, Commodore 128, Mac Classic, SE/30, LC, IIvi and PB G3 (Clamshell)
Amiga 600 and a few 486 and 386.
Many Nintendo G&W and other electronic games from the late 70s/early 80s.
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rubber_jonnie
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Re: External floppy settings

Post by rubber_jonnie »

olivier.jan wrote: Sun Oct 17, 2021 7:53 pm Thanks guys, you were spot on, I was too shy with my 6V.
After using proper 9V the FDD works fine.
A new 7805 and proper voltage and I now have my first external floppy.
Good stuff :)
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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