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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: OldB0y on November 21, 2007, 02:31:19 AM

Title: A1200 clock port
Post by: OldB0y on November 21, 2007, 02:31:19 AM

Hello there!

This is the first time I've posted here since 2001, although I've forgotten the user name I had then. So to all intents and purposes, hello for the first time:-)

I have two A1200's, one of which is in its original desktop case, and doesn't appear to have a clock port.  It does however have the solderpoints where the header would go on the mobo.  

Would I be correct in assuming that if I simply solder the pins for the clockport header in place it will work, or did some A1200 revisions simply have the clockport functionality taken out altogether?

I can probably find out the mobo revison number when I'm next in front of the computer on Friday if that helps.

Title: Re: A1200 clock port
Post by: rkauer on November 21, 2007, 03:57:58 AM

 Are you sure?

 I never see or take notice of an A1200 without the clockport header.
 Are you sure?

Title: Re: A1200 clock port
Post by: rkauer on November 21, 2007, 04:21:40 AM

 BTW: you see the header over the memory banks? There is supposed to have nothing. The Clock Port header is the frontmost (under) the memory banks.

Title: Re: A1200 clock port
Post by: Matt_H on November 21, 2007, 04:49:55 AM

A few 1200 motherboards seem to have no clockport pins whatsoever. I don't know if it's constrained to a specific revision or maybe just a single production batch.

At any rate, this (http://amigahardware.mariomisic.de/download_photos/a1200mb_rev1d4.jpg) image from the BBoAH shows the typical (correct) layout. Soldering the pin headers will probably work if they're not present.

Title: Re: A1200 clock port
Post by: Argus on November 21, 2007, 12:10:09 PM

This is probably a question for Jens, but I always wondered if any utility would be found by soldering in the pins for P9A for example adding another clockport or such to the motherboard.  P9A is the uppermost header where the original A1200 design would have allowed the addition of an additional meg of chipram on machines shipped with only 1MB on the m/b.

Title: Re: A1200 clock port
Post by: Homer on November 21, 2007, 12:22:28 PM

Hi OldBOy, my A1200 mobo was the same. I did solder on the header in an attempt to use an early catweasel to allow the use of HD drives with it, but unfortunately I never got it to work.
I ended up using an LS120 drive on the IDE bus to use HD floppies  :lol:
So, does anyone know if it should have worked ?

Title: Re: A1200 clock port
Post by: OldB0y on November 23, 2007, 12:53:18 AM

Cheers guys,

I *may* have a go at adding my own header pins at some point and see what happens.....

I don't want to blow the 1200 up though, I've had it since 1992. Its survived being put in and then taken out of 2 tower conversions, and is currently back in its original case. I just fancied adding USB to it, but will probably go down the PCMCIA compact flash adaptor route instead.