Cold reboot throws guru on my A600

[jarp]

Hi all,

I got Amiga 600 rev. 2D motherboard only from eBay just in case my Amiga 300 some day dies. Anyways I recapped the board when I got it (and I must say doing it for rev. 2D is SO much easier than for rev. 1, they added a space around caps later on it seems).

However, I am now facing weird problem (though I really do not know if recapping did it or did it exist already when I got the board):

1) First cold boot works fine

2) Subsequent Amiga+Amiga+Control warm reboots works fine, always

3) Subsequenct cold reboots (power-off-on from the switch) shows guru meditation immediatly after screen has turned white 9 times out of 10 with few different codes cycling between each boot:
8000 0008
8000 0004
FF30 0004
FF40 0004
FF40 0003

4) If I do warm reboot when guru is showing again machine boots ok no problem

5) If I turn power off and let machine coold down for 30 seconds cold boot works again

Any ideas why this would happen? I mean I am suspecting cold joint somewhere there but I really cannot understand why soft-reboot works without any problems then? I do not have OS installed yet so I do not know if machine really works or if it just "works" as I've been staring insert disk screen all the time.

I'd appreciate if anybody could throw any ideas! Next I'll go out and buy some cold spray and see if I can find any chip or spot which causes this by cooling them down one by one just before cold re-boot...

Thanks!

[jarp]

Hrm unfortunatelly machine won't work even when it boots, after using workbench a while it crashes straight to guru.

Interesting twist was that this rev.2d mobo did not boot from HDD. I was sure whole mobe is totally borked until I spotted that somebody had put 37.299 kickstart on the board! I upgraded it to 37.300 and got it booting.

Even more interestingly my working A300 won't boot from CF-IDE adapter but boots happily from SDHC-IDE adapter. This non-working A600 happily boots from CF-IDE also. Must be something to do with Gayle-01 vs Gayle-02.

[jarp]

Hrmrh. I was able to locate general area of problem with cold spray, but I am unable to pinpoint exact location. I re-soldered every single component on that area including ICs like Denise, but no luck. Neither does spraying any individual component help, it helps when I spray PCB itself a lot and let cold creep around.

So it must be micro-crack on the PCB traces then I think? This is becoming problematic, I may have to declare the mobo dead. Damn, should've tested it properly before I recapped it, now I am unable to return it as faulty since I have modified it myself.

This is very unfortunate since I would've needed this to replace my A300 rev.1 mobo which does not like my CF-cards like I found out. Not sure if other brand CF cards would work.