Just got my first A2000! :)

[Tenacious]

...  If you have an old portable phone battery 3.6v you might try that.  

If that doesn't work check the continuity of the tracks from the RTC chip to the battery.

I use rechargeable 3.6VDC phone batteries, too.  I remotely mount them so they can't damage the MB if they leak.  Food for thought.

Are you handy with a meter?

[Tenacious]

Mike

Do you need an A2000 schematic?

I have the one for Rev 6.  It's 12 pages!

[Tenacious]

@Tenacious - schematics would be great!  Do you have them somewhere I could download, or can you email them to me at CompTechMike at gmail dot com?  The only ones I've been able to find online so-far are ones for the A4000, which have been less than helpful.  :-/


**shakes my fist at the sky in the direction of C= designers who went with these leaky batteries, LOL**

Mike


We only had time to scan the 8th page for now.  If something else is vital to your project, we can scan that too.  Soon, I hope to scan the whole thing and upload it to some place logical.

[Tenacious]

Your dropping some voltage across R803.  Gertsy may be right about the coin batteries not really having enough volts for this chip (same chip as other Amiga models?).  

You might try the neg probe (carefully!) on pin 9 to ensure your not reading a drop thru the case.

IIRC, the coin batteries are not rechargable like the original.  Is there a diode in this kit to prevent charging while powered ON?  Does it replace R803?

[Tenacious]

Get the schematics out and trace connectivity to each pin on the clock chip from agnus or wherever it's supposed to connect.  It could be the variable cap affected by corrosion as well - you could probably take one from a 500 memory expansion.

Good idea.  As a cross check, chip pins are numbered counter-clockwise (looking down on the component side of the board) around the body from pin 1, which is the next pin after the notch.

You could confirm power to the chip while powered up.  

You are certain there is no moisture remaining under this chip?  Check continuity from pin to pin and cross check to the schematic.

EDIT:

With a scope or possibly a logic probe, you could test for a pulse train out of Y800.

If you replace U801, use a solder sucker AND solder wick (Radio Shack) to remove as much solder as possible.  It would hurt the MB the least to gently snip the old chip out and then remove each remaining pin individually.  When you install the new one, align the notch.  Sparsely apply solder to the pins on BOTH sides of the board to ensure that all the layers in the MB are connected to each pin.

It would be a shame to waste the work you have in this board already.