Blizzard IV 1230 MK won't work

[sirkope]

sirkope wrote:
At once I've read an article about an RBG -> SVideo converter, and because I could buy the converter chip, I built an external converter with it, and - I've supplied with the amiga RGB port +12V pin. The circuit use about ~46mA, and when I test, and later use it the turbo card was installed. So I used an amiga 1200HD with an 1.6GB HDD, a Blizzard 1230 Mk IV turbo card, a 68882 FPU, 16MB Ram, and an external converter unit supplied from the machine.

Ouch I wrote false info: not from +12V, I supplied from 23.pin (5V/100ma)

[sirkope]

I do not use +12V, only 5V.

I went to a kind fella this afternoon to try the card in a different a1200, but still didn't work.
I left it at him to try a few thing with it.