Random lockups - help needed!!

[Neo]

I have an A3000D with a CyberstormPPC board and found out that if you
by mistake put the motherboard clock source switches wrong you may get
some odd lockups and many times the machine didn't even boot
correctly.

Also I use my Amiga to watch DivX movies, due to my main PC has died
and my other PC's are less than 500MHz machines and so are worthless
for movie playback..

One problem I had with FroggerNG (may apply to other apps too) was
that during playback Frogger apparently just freezed. It showed up
that this problem was drastically reduced if I increased the system
oscillator on my PPC board from 50 to 60MHz. Now I run at 66MHz and my
Amiga rarely look-ups. As a bonus some DivX movies ran 5 times faster
after the modification.

It appears to me that PPC and 68k task doesn't always coexist to well,
which can be helped by increasing available bus cycles and so reducing
the risk of bus collisions.

Unfortunatly overclocking might cause you some new troubles so this
might not be the way to go for you.

[Neo]

Ofcourse, could also be related to heat. I've got heatsink frency on
my PPC board and added a heatsink to the 040, the programmable logic
chips between the two memory rows closest to the oscillator cans and
to the programmable logic chip at the bottom side of the PPC board.

Also, I added a fan to the 040 and replaced the PPC fan with a larger
but less crappy one. There is also a fan placed at the side of the PPC
board to create an airflow above and below the board.

Did also the same to the CyberVisionPPC board.

Simple way to test the need for a heatsink is to run your amiga with
the lid of and after some time of use try touching different
components with your finger. If you can't keep the finger on the
component you should get a heatsink and maybe a fan too.

Regards,
Göran

[Neo]

As what I found out is that the proper setting for the CyberstormPPC
board is the following.

This is for A3000 but should be similar for A4000
J100 QUADCLK set to EXT
J102 BRDCLK set to EXT
J104 CPUCLK set to INT (Motherboard CPU gets fryed otherwise)

One problem I had when QUADCLK or BRDCLK was set wrong, was that the
system required to warm up for about 1 minute then turned off for 30
seconds and the turned on again to boot.

This problem didn't occour immidiatly but it came when the fan on the
PPC was starting to give up. (When the fan isn't working properly it
steals alot of current from the 5V line, thus causing a voltage drop
that weakens the signal levels at the CPU bus, resulting in
instability)

As a consequence of the latter problem I replaced the fan with a 12V
one that is connected to the harddisk power cable instead. I suggest
anyone with a CyberstormPPC board to do the same. On my A3000 I had to
cut a hole in the second drive bay to fit the fans, but allows for a
better airflow. (No point having two floppies anyway)

/Göran