Help! Need Casio MX-10 or MX-101 cassette pinout

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By edanuff

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13-10-2005, 20:03

I've recently acquired a Casio MX-101, which I believe is a first generation MSX1 computer. It has a 5-pin DIN cassette connector rather than the standard 8-pin adapter. I'm pretty sure it's not the same pinout as the Gradiente uses in it's 5-pin DIN cassette connector, nor does it seem to be the same pinout used by some Commodore computers which have 5-pin DIN cassette connectors. I don't want to risk damaging it through too much trial and error, so I'm hoping someone has a Casio that came with the cassette cable that can check the pinning.

Thanks

Ed

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By djh1697

Paragon (1614)

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14-10-2005, 00:47

Try checking the faq

www.faq.msxnet.org/connector.html#cassette

5-pin is also standard

By edanuff

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14-10-2005, 00:53

Thanks, but I looked at that already - the 5-pin pinout on that page is used by the Gradiente MSX and from some Google searches appears to also be used by some Commodore computers. The Casio is using different pinout.

By edanuff

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14-10-2005, 19:05

I tried the "trial-and-error" approach and the magic smoke came out.

R.I.P. little Casio
Crying Crying Crying

By flyguille

Prophet (3028)

flyguille's picture

15-10-2005, 05:09

ohhh no!... how can be? if there is only an input and an output.... and is a high impedance circuit, and also is the relé... just a switch

mmm...

By flyguille

Prophet (3028)

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15-10-2005, 05:10

how high yo settled the volume of the recorder ???? it was a data-recorder, no?

By edanuff

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15-10-2005, 06:43

Here's what I think happened - there were three possible pin connections - tape in, tape out, and remote switch. Two are outputs (tape out, remote) and one is an input. I most likely had the output of the tape recorder to either the Casio's tape output or remote switch outputs. I looked at the motherboard and the tape connections hook directly to the controller IC (some sort of Hitachi MSX engine IC) without any resistors in between to limit the current. So the current flowed out the tape corder and directly into the IC resulting in a short.

By flyguille

Prophet (3028)

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15-10-2005, 15:58

uh man!, but you have to put the volume very high as for resulting in an output voltage signal like more than 5v peak to peak

By edanuff

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15-10-2005, 21:23

The volume was probably too loud, but it didn't have to be over 5v peak to peak to do the damage as long as the current was high enough. Even a 1V peak to peak signal could have been responsible. If a pin on an IC is outputting a 0 logic level, and you apply external current to it, the current flows through the pin. into the IC and to ground. This is basically a short circuit within the IC and the result is the IC overheats and breaks down. The slightly surprising thing is that there were no resistors between the cassete jack connector and the IC to prevent this kind of damage from occuring. I should have been more careful, but I was excited to get a tape loaded and didn't take more time to study the situation.

FWIW, the IC in question is an odd Hitachi HD62003 which is probably irreplaceable, since I can't find any online documentation for it. It looks like it performs the same function as the "MSX engine" IC's like the Yamaha S3537 and S1985, combining the tape i/o, sound, and PPI into a single chip. This is kind of surprising to find in a first generation MSX1 computer, since these types of chips were introduced with the MSX2 units to lower manufacturing costs. Unfortunately, from what I can tell, it's a different pinout from the S3537 and S1985, so I can't substitute. I'll probably have to write this one off unless I can find another broken Casio or find a compatible substitute iC from a different manufacturer.

By flyguille

Prophet (3028)

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15-10-2005, 23:23

that will hard to find....

yes, the current does the damage..

but I can thinks in the situation 2

the output was in HIGH state... and you just make a short connecting the cassete-recorder's output on it...

By flyguille

Prophet (3028)

flyguille's picture

15-10-2005, 23:23

is a shame that CASIO did that crap of design...

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