VOGONS


First post, by precaud

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Yesterday I found one of these 8-bit ISA cards (Rev B) in my pile of old pcbs. It's missing two things:
: The bios chip (that is easily fixed; the image is on Minuszerodegrees website). The EPROM was probably removed by me many years ago before I knew what the card was.
: Crystal X2 in the upper left corner. What frequency is it?

I found a couple pics of this board on the web, but they're not high-res enough to be able to read the printing on this crystal. X1 just below it is 4.8MHz.

Does anyone know what frequency this xtal is?

Thx for any help.

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Reply 3 of 11, by Tronix

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precaud wrote:

Is there a reason for 8 ?

As written in the datasheet (see attachment): "CLK. Clock (input). Single phase 8MHz square wave clock". Also, Z0765A08PSC Zilog marking mean 8 MHz chip, by analoge with Z80 CPU marking.

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Reply 5 of 11, by precaud

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I replaced the missing crystal and EPROM, made sure the 5V rails weren't shorted to ground, installed the card and powered it up. A loud SNAP emitted from one of the PAL chips, and just a hint of smoke. The card is toast.

Win some, lose some. Thanks for your help.

Reply 7 of 11, by georgel

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maxtherabbit wrote:

old PALs are a scourge

The rabbit is wrong again and is posting logical, wise and useful replies! Look at the picture. The PAL is plugged incorrectly and is rotated 180 degrees in its socket Thus the power supply to it is inverted. The controller was doomed in such skillful hands.

Reply 8 of 11, by maxtherabbit

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georgel wrote:
maxtherabbit wrote:

old PALs are a scourge

The rabbit is wrong again and is posting logical, wise and useful replies! Look at the picture. The PAL is plugged incorrectly and is rotated 180 degrees in its socket Thus the power supply to it is inverted. The controller was doomed in such skillful hands.

why are you such a prick?

Reply 9 of 11, by Doornkaat

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georgel wrote:

Look at the picture. The PAL is plugged incorrectly and is rotated 180 degrees in its socket Thus the power supply to it is inverted. The controller was doomed in such skillful hands.

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Reply 10 of 11, by precaud

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georgel wrote:

Look at the picture. The PAL is plugged incorrectly and is rotated 180 degrees in its socket Thus the power supply to it is inverted. The controller was doomed in such skillful hands.

You are correct; I didn't notice that. However, the heavy judgmental attitude is unnecessary and uncalled for. Mistakes happen.

Reply 11 of 11, by dmuntz

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precaud wrote on 2019-09-19, 14:49:
Yesterday I found one of these 8-bit ISA cards (Rev B) in my pile of old pcbs. It's missing two things: : The bios chip (that is […]
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Yesterday I found one of these 8-bit ISA cards (Rev B) in my pile of old pcbs. It's missing two things:
: The bios chip (that is easily fixed; the image is on Minuszerodegrees website). The EPROM was probably removed by me many years ago before I knew what the card was.
: Crystal X2 in the upper left corner. What frequency is it?

I found a couple pics of this board on the web, but they're not high-res enough to be able to read the printing on this crystal. X1 just below it is 4.8MHz.

Does anyone know what frequency this xtal is?

Thx for any help.
lcs-fdc.jpg

I have a card that looks _very much_ like this one. On mine, that crystal is 8.3333 MHz. BTW, I stumbled on this thread because I need to know jumper settings for my similar card. They're not all identical, but mostly the same (my card is JE-1043). Specifically, mine has your card's JP1, JP2, JP3, and JP5. and JP4 but with 4 positions. My card also has another jumper below the 4.800 MHz crystal, between the 7348N and the 7406P (fwiw, that jumper has 3 pins, and has 2-3 jumped). Also, I have a ROM in the ROM slot (version E6610 C2).