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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Miloo on December 09, 2008, 11:42:03 AM

Title: A1200 motherboard fix
Post by: Miloo on December 09, 2008, 11:42:03 AM
Looking at :
 http://www.ianstedman.co.uk/Amiga/amiga_hacks/A1200_Mobo_fix/A1200-timingfix.jpg

It says to remove 123C and 125C but on the picture 123R and 125C are circled - which is right?
Title: Re: A1200 motherboard fix
Post by: RedskullDC on December 09, 2008, 11:49:17 AM
Remove the caps only. 123C, 125C

Red
Title: Re: A1200 motherboard fix
Post by: Tension on December 09, 2008, 01:34:52 PM
BEWARE!!! I TRIES FIXING MY A1200 MOBO WITH THIS BLOODY TIMING FIX, AND THE BOARD NEVER WORKED AGAIN!!!
Title: Re: A1200 motherboard fix
Post by: Miloo on December 09, 2008, 01:35:12 PM
Damn I desoldered what was circled :-o
Title: Re: A1200 motherboard fix
Post by: klx300r on December 09, 2008, 02:36:12 PM
never understood what exactly this mod supposedly fixes :-?
Title: Re: A1200 motherboard fix
Post by: jj on December 09, 2008, 04:57:14 PM
It fixes timing isusses which cause locks and software failures on some accelerator boards.

This is usally with the faster Apollo cards as they are not buffered.

Where as never had trouble with blizzard cards cause they are buffered but subsequently run slower
Title: Re: A1200 motherboard fix
Post by: BuzzBrain on December 09, 2008, 06:51:55 PM
Hi


My A1200 (rev. 1d4) had lookups and other problems when I used a Apollo 1260 card.

Then I did the mobo fix.

Now my a1200 works like a dream :)

I'm happy with this mod.
Title: Re: A1200 motherboard fix
Post by: orange on December 09, 2008, 07:18:47 PM
I also used some of those hacks, and they fixed problems with Mtec 030 accel.
(the A1200 used to freeze with no reason before with 030)
Title: Re: A1200 motherboard fix
Post by: Miloo on December 09, 2008, 07:30:19 PM
Whats the cap that I've got to resolder, I cant find the one I desoldered :boohoo:
Title: Re: A1200 motherboard fix
Post by: klx300r on December 09, 2008, 07:54:05 PM
ahh ok thanks :-)  never had a lock up with my Blizzard 030 with my Rev1D4 board but good to know ;-)
Title: Re: A1200 motherboard fix
Post by: AmigaMance on December 09, 2008, 08:39:24 PM
Quote

JJ wrote:
It fixes timing isusses which cause locks and software failures on some accelerator boards.

This is usally with the faster Apollo cards as they are not buffered.

Where as never had trouble with blizzard cards cause they are buffered but subsequently run slower


 What i have read in various threads, is that the Appolo cards are indeed more prone to this problem, but every card with a 68040/68060 CPU can be affected by this.
 "Unfixed" motherboards can also cause problems with fast IDE interfaces.
Title: Re: A1200 motherboard fix
Post by: StevenJGore on December 09, 2008, 09:22:30 PM
It's easier to use cardpatch and cardreset which can be found on Aminet. Much easier than hacking motherboards.

Steve.
Title: Re: A1200 motherboard fix
Post by: AmigaMance on December 09, 2008, 10:01:35 PM
@StevenJGore
 I think you are off topic.
Title: Re: A1200 motherboard fix
Post by: clint on December 09, 2008, 10:19:41 PM
@AmigaMance

StevenJGore is right, they do the same fix.

clint
Title: Re: A1200 motherboard fix
Post by: Damion on December 09, 2008, 10:25:07 PM
PCMCIA fix involves soldering a cap near Gayle (which is a different fix).


Title: Re: A1200 motherboard fix
Post by: AmigaMance on December 09, 2008, 11:27:43 PM
Whatever is happening to us, it's scary..
Title: Re: A1200 motherboard fix
Post by: rkauer on December 11, 2008, 02:19:11 AM
Quote

clint wrote:
@AmigaMance

StevenJGore is right, they do the same fix.

clint


 No, they don't!

 Cardreset and cardpatch are fixings to the PCMCIA locks. Taking out E123C and 125C (just the capacitors, not the resistors!) will fix spontaneous Guru & locks when a fast accelerator (040, 060 and PPC ones) is plugged in the 1200's trapdoor.

 BTW: the missing resistor E125R have the pretty same value as the E123R unit ;-)
Title: Re: A1200 motherboard fix
Post by: StevenJGore on December 11, 2008, 08:37:34 AM
Quote
Cardreset and cardpatch are fixings to the PCMCIA locks. Taking out E123C and 125C (just the capacitors, not the resistors!) will fix spontaneous Guru & locks when a fast accelerator (040, 060 and PPC ones) is plugged in the 1200's trapdoor.


Ah, I didn't realise that. Thanks for the correction.  :-)

Steve.