A1200 motherboard modifications guide

[Stedy]

Hi,

In order to make life a bit easier (and stop the same questions keep being asked) I have prepared a guide on the A1200 motherboard modifications. this include the timing fixes and wire link modifications present on some REV 2B boards.

I'll stop typing, you take a look at:

http://www.ianstedman.co.uk/Amiga/amiga_hacks/A1200_Mobo_fix/a1200_mobo_fix.html

I have also added some information on soldering skills for those willing to have a go.  :-D

Any comments etc appreciated. :-)

[amigamad]

A very good site should be quite usefull.How about adding something about replaceing a leaked battery as this is getting to be a very common subject. :-)

[Doobrey]

Nice one Stedy..
 I spent ages the other day trying to find  E123&E125 on the top side of the mobo!
 Brain must have been firing on 3 cylinders, as I didn`t think to look underneath !   :crazy:

[Wain]

Very nice!

The mod-geek in me thanks you...

[Dragster]

Hello Stedy,

great site!  Thanks for the information and the effort. !!

Now, regarding A1200 motherboard revisions, I got a mobo yesterday that it deems to be 1D something, but I don't really know.. it just says 1D (not 1D.1 as the other one I have). I was expecting it to be 1.D4 but I don't know...

[Stedy]

Hi

To all who replied, thanks for your comments, much appreciated. I hope you can all fix your problems now.

To Amigamad:

I am thinking about a NiCad battery replacement document, see how my time goes. I have replaced a NiCad with a NiMh with no problem so far, better for the environment too!

I have 5 more articles in preparation:
1) Scandoulbers, how they work and how to fix the DCE one.
2) IDE buffers, how they work, truth behind the marketing.
3) How to repair an Amiga mouse, with a dissection of a Wizard mouse.
4) converting an Apollo 040 to an 060
5) A1200 networking/samba/linux.

I hope to publish the first 4 around christmas.

[Doobrey]

Well, I did all the fixes on my 2B board tonight..
 A little tip for adding the 470R pull up by the ROMs..
 I found it #@~ing impossible to solder the other end of the resistor to the via on the board.
 I simply used a thin piece of insulated wire, and soldered it to the bottom side of the +5V on the floppy power connector, and then soldered that to the resistor.
 There`s probably a much easier and neater way, but I went for the quick fix !

Edit.. Sorry, I`m speaking outta my arse..I didn`t read Ian`s site properly  :roll:
  Don`t bother doing what I just described, it doesn`t do anything.. as the connection at the cap near the ROM is the +5v...silly me, I thought it was the trace I needed from Alice .