Unstable Apollo 1260

[Kasio]

I have an unstable Apollo 1260 that I hope can be repaired and - if possible - later upgraded to a 80MHz version.

I think there might be some damage from battery leakage.

Some high-resolution pictures of the card can be found here:
Battery area, Front, Backside.

Lots of random error messages appear within a minute of operating. Sometimes Workbench is loaded, but the longer I keep the Amiga on (with warm reboots) the sooner errors arrive.

Any thoughts?

 

[rkauer]

The SMD 74F74 (the TTL chip near the battery, marked as "F74") got some battery leakage. You must have someone near you to replace it.

Don't use any other type of TTL series chip (LS, L, S and even ALS will not work), just the F series work in this board.

Also the filter capacitor in the centre of the board had leaked and must be replaced. That's a very easy task and the value is 47 micro-Farads with at least 10V.

Start by replacing the capacitor, then try a reflux in the TTL chip to check if things improves. No deal, dessolder the chip and put a replacement.

If all the above does nothing, buy a PLCC extractor, remove both socketed MACH chips and clean them with a soft pencil eraser OR dip the chips into a glass containing lemon juice or spirit vinegar for no more than twenty minutes. Then wash the chips under tap water, let them dry for a day or two or dip them in isopropylic alcohol to expel the water, let dry for some time and reinsert in the correct orientation.

 

[bebek]

74F74 is not used with 060 ... I think, and jumper should be on 060

 

[rkauer]

Yes, it is. The chip is responsible for the jumper selection inputs and not much else.

I really don't know why they used such chip for this purpose, but it is there.

 

[Kasio]

With 060 jumper on a black screen is all there is. No boot.

 

[bebek]

Yes, it is. The chip is responsible for the jumper selection inputs and not much else.

I really don't know why they used such chip for this purpose, but it is there.

I thought this IC is only to double clock for 040 nothing more. Checked this sometime ago but can be mistaken .

 

[mjnurney]

The jumper settings on my apollos @ 50mhz

Are:

040 - 060 (jumper on 040)
Scsi off
O60 on
Resistor on CLK , resistor off (GND)

This is set up on a xc68060rc50

You will get a blank screen on 040-060 that's how it should be when the clk resistor is moved from GND. It's for the ram speed.

Mike

---------- Post added at 21:41 ---------- Previous post was at 21:33 ----------

Have you done the obvious stuff?

Cleaned the damaged area. ? Changed the ram / crystal / CPU ?

I would inspect the area around the battery very closely for other damage..


Mike

 

[Kasio]

Card sent to Stachu100 for diagnostic/repair.

 

[Kitch]

How's the diagnostic repair going?

 

[Kasio]

No luck so far.

MACH chips have been soldered directly, electrolityc capacitor replaced , 74F74 area cleaned. Still dead.

Haven't got as far as replacing the TTL, as rkauer suggests. Is this the correct chip for replacement?

 

[roy_bates]

could be mach 210 failed(memory controller) or one or more of the four 74F257AD's


oh, and yes to your link as long as it really is in a so 14 package.

 

[Kasio]

What is the function of the chip with the "60 / 651"-sticker?

 

[roy_bates]

What is the function of the chip with the "60 / 651"-sticker?

its the bootrom of the card.