Timing fix for A1200 1.D4 motherboard?

[Painkiller]

I'm looking for timing fix to this board. Does anyone know how to do it or if it is even necessary for this board? I'm having weird crashes every now and then with my Blizzard A1260.

[DoogUK]

the timing fixes are relatively simple and can be found

HERE

[AmigaMance]

 I see that there are no instructions for 1.D1 motherboards. Is it because they don't require a fix or they are just not available at that page?
 

[DoogUK]

IIRC, it was just the id4 and 2b revisions that required the timing fix.

[monami]

i think thats a slightly different fix than i saw on the 2b board. are there different versions of the fix also out there?

also "NOTE: My Rev 2B motherboard does not have the following 3 modifications and it works OK. AFAIK it came from a Commodore A1200."

does this mean what i think? that he doesn't have the link work etc but did remove e123c and e125c and changed r118 to 220 ohm resistor? that would be easier. i wonder how long it has been running ok like that?

[Painkiller]

Uh silly me the board was 1.D1 so anyone got timing fix for 1.D1 or any other hints in getting the system stable. I'm using a ATX psu with it and I have connected the powercord to the motherboards floppy power connector to ensure stable power supply.

[rkauer]

 Is your system unstable?

 If so, check:

 1- the contact between the motherboard and the accelerator;

 2- The voltage levels (on power conector, floppy power connector and accelerator);

 3- Substitute all electrolithyc capacitors (14 of them around);

 4- If all failures, check your Workbench installation, specially libraries and executables.

[DoogUK]

Quote:

Firstly during manufacter and in order to cut costs during the availability of components, Commodore produced various revisions of Amiga 1200 motherboards. Only revision 1D1 boards are suitable for this type of heavy expansion. Later 1D4 and 2B boards are known to have timing problems with regard to the onboard Gayle and Budgie chips. Revision 2B boards are somewhat more prone to these aforementioned incompatabilities. These faults can be fixed on these motherboard revisions with some careful work with a soldering iron, but it is easier to just use a 1D1 revision motherboard in the first place.

it seems your problems may be originating somewhere else.

Could it be heat issues? i know the 1260 runs cool but do you have other addons in the case if so you could require extra measures for cooling.

In what way is the system unstable?

[monami]

"Only revision 1D1 boards are suitable for this type of heavy expansion."

the fix works for 1d4 boards. and then you can expand them. and they work 100% well i know i did it on mine. :-)

[alexh]

DoogUK wrote:
Quote:

Firstly during manufacturer and in order to cut costs during the availability of components, Commodore produced various revisions of Amiga 1200 motherboards. Only revision 1D1 boards are suitable for this type of heavy expansion. Later 1D4 and 2B boards are known to have timing problems with regard to the on-board Gayle and Budgie chips. Revision 2B boards are somewhat more prone to these aforementioned incompatibilities. These faults can be fixed on these motherboard revisions with some careful work with a soldering iron, but it is easier to just use a 1D1 revision motherboard in the first place.

Where did you get that quote from? The 1D4 and 2B boards were designed to take fixed versions of the Gayle and Budgie chips. However these chips were never made in the end and someone, somewhere, forgot / took a gamble to release the boards anyhow.

[Painkiller]

DoogUK wrote:
Quote:
Could it be heat issues? i know the 1260 runs cool but do you have other addons in the case if so you could require extra measures for cooling.

In what way is the system unstable?

It is not the heat issues as the crashing happens the most when I cold start the machine. (Which now leads me to thinking that some of the capasitors needs to be replaced).

I have also tried to refit the board couple of times to see if it is a bad contact.

The problem it self just freezes the Amiga with no guru or anything just freezes the screen. Sometimes I can go hours and sometimes it crashes in a few minutes or imidiately after boot up.

[monami]

couldn't you just use the amiga and add bits back? a process of elimination... you will find the troubled component. i luckily swap parts with my other machines when things start acting up.

[Painkiller]

DoogUK wrote:
Quote:
Only revision 1D1 boards are suitable for this type of heavy expansion.

FYI I went and removed the E123C and E125C capasitors from my 1.D1 board and it hasn't crashed since.

But anyways I'm just glad the problems are now solved Hopefully some other people will find this info helpfull.

[DoogUK]

Cool!...Gotta love an Amiga success story.....enjoy.

[jj]

I was under the impression that you shouldnt have a problem with blizzard cards and timing problems, thats because the bus is buffered.  That is why apollo cards are generally faster but prone to timing issues.

I would look elsewhere for the problem