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Author Topic: A1200 motherboard timing fix again  (Read 1136 times)

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Offline lapenoTopic starter

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A1200 motherboard timing fix again
« on: November 30, 2009, 02:02:11 PM »
Hi,
 
I have an Apollo 1240/40MHz board for my A1200 and it was stable for years but since I have installed Indivision AGA the accelerator crashes with Guru. When I remove Indivision AGA then it is stable.
Motherboard is 1.D4 with budgie rev 01 (indeed rev 0 but the part namber has a -1 at the end) so the two capacitors (E123C and E125C) were removed by me long ago. I have replace PSU but still the same (using a 300W ATX PSU now but tried with 400W Corsair too).
Interesting is that I have tried to put back E123C and E125C and the system seemed to be more stable but still crashes.
Now I am planning to try the additional fixes but cannot find XR358 on the motherboard. Does anyone know where is it located?
Regarding the additional pull up resistor to Alice's pin 43 I have seen photos where the resistor is connected to the clock port's 5V pin2 but where is the other end connected to? Does anyone have a high res photo of a modified motherboard with this patch?
I have a feeling that these two patches need to be applied to 1.D4 motherboards even with budgie rev 1.
 
Thanks
Lapeno
 

Offline lapenoTopic starter

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Re: A1200 motherboard timing fix again
« Reply #1 on: December 01, 2009, 10:19:26 PM »
So no one knows where that XR358 pul up resistor is located?
I don't think that resistor exists at all... Everyone just copies the Big Amiga Hardware Book's comment about motherboard revisions and fixes but no one mentioned at all about the inconsistencies.
(e.g. someplaces mention the capacitor removal for 1.D3 motherboards, some others mention it for 1.D4 budgie rev 01)