How to determine if Buster is failing

[efrenmgp]

Hello!

I have an A4000T that refuses to "see" a Picasso IV board. It does not show in the early startup and the p4flashupdate program cannot find it either, no matter which slot it is in.

Dragster and I spent several hours testing everything we could think of. We also tried a Deneb card and even when that one is seen by the early startup, the boot animation does not show at all. Both cards (Picasso IV and Deneb) are happily working in an A4000D so we know they are OK, and the Deneb animation plays everytime it is turned on. Also the Picasso IV board was reflashed to the latest 7.5 using the A4000D.

After lots of testing & swapping processor boards, adding and removing additional components such as hard drive, floppy, memory, etc we always got the same results.

We are suspecting the Buster chip may be the one to blame... but we don't know what test to do to know it for sure (maybe we already proved it?)

Does anyone has had a similar experience? Is there some diagnostics software that can be used? Any advice and/or shared experience will be most welcome

Thanks!
efrenmgp

[efrenmgp]

I did notice that my Buster socket is warped. It bulges in the middle of 3 sides. I plan on getting a new one soldered in and the caps done (minor leaking just starting) to see if it fixes it but haven't got around to it yet. The 4000T (and 4000) look like the Buster socket is cheaper than the 3000(T) sockets.

The one I have here has the Buster soldered and we were considering getting a socket so we could switch busters and test... but it would be an expensive test

About caps, we didn't consider that because everything looks completely clean but those are not too expensive and I guess it's better to change them sooner than later anyway.

Regards,
efrenmgp

[efrenmgp]

I did notice that they had different chips on them (daughterboards on A4000D have 2 chips), so maybe try identifying the equivalent chips on the A4000T (if they exist) and replace them, if changing caps doesn't work.

Thanks Jose! I'll take a look at those chips and see if I can find their counterparts on the A4000T. But depending on how small they are maybe I won't dare changing them myself :eek:

Regards,
efrenmgp

[efrenmgp]

The grounding points and connections to the motherboard should be cleaned if not already. Maybe this could be a grounding problem? Some of the 4000T main power connectors to the motherboard have arched and have black carbon. It might be worth pulling the power connector and looking. Mine had minor arching carbon. I replaced the AT power supply with one from newegg but it didn't fix the Zorro slot problems. Problems like these probably aren't always the same.

Hello matthey!

We did check the power connectors and they are all nice and clean, however we didn't verify voltages... I'll do that and see if everything is as it should be. (I kind of hope it isn't) :laugh1:

Thanks!
efrenmgp