Crazy over heating cables. [Fixed...]

[iamaboringperson]

I find that my A4000T keeps restarting.

And the power (P8 & P9) cables get very hot, the red wires especialy are getting hot, and on the connector the plastic arount the pins that are connected to the red wires is melting and burning and turning black/brown. It's really not a pretty sight.
I'm wondering if you could tell me where the problem is.

I will be replacing the PSU + wires. But That might only be a short term solution.
The problem only seems to be at the connector end. Could it just be cruddy connectors?

[KennyR]

Do you have a CPPC by any chance? This is a common problem of that model of CPU card.

[iamaboringperson]

It's just commodores ####ty old A3640 :-(

[KennyR]

Hmm, if your connectors were crap then you'd get less current and so less heat. Something in your system is drawing too much power. They tend to do that when they get too old.

I suppose you could always polish the connector pins a bit (carefully!) and get new power feed cables. If you cpu card has a fan you might be able to take some of the load off the motherboard by powering the fan straight from the PSU (if it's not already).

I have this problem with my Amiga too, and I never really managed to fix it. Without the two extra powerfeeds (one in the fan, one in the floppy power feed), my Amiga probably wouldn't work at all. :-(

[Oldsmobile_Mike]

CPPC is JUNK!   A3640 mil spec is the best accelerator for your Amiga 2000HD Professional!
;-)

Do you have a CPPC by any chance? This is a common problem of that model of CPU card.

@KennyR -

Do they give a reason for this?  (Although it does sound like a lose connection problem to me)

@iamaboringperson -

Good to hear you're replacing the PS but be careful, and in the meantime, keep a fire extinguisher nearby!  :-o

Good luck,
Mike

[iamaboringperson]

CPPC is JUNK! A3640 mil spec is the best accelerator for your Amiga 2000HD Professional!

:lol:

Good to hear you're replacing the PS but be careful, and in the meantime, keep a fire extinguisher nearby!

Don't worry, I've had plenty of experience with AT PSU's ;-) (And no, I wont be opening it :-/ )

[KennyR]

Oldsmobile_Mike wrote:
Do they give a reason for this? (Although it does sound like a lose connection problem to me)

I guess it's because the Amiga was never meant to power CPUs as powerful as the PPC, and the CPPC has one and a 68k. The problem is worst on 040+233. Some people don't have it at all though, maybe it only happens with earlier produced boards. And sometimes they don't have it at first but it comes on as the board gets older. It's worse on BPPC. Mine started misbehaving some 2 years after I got it - loss of picture, crashes, melted cables, etc.

[Damion]

If the system is drawing current through
connectors that can't handle the load, they can
indeed get too hot and melt the plastic
connector bodies.

-edit-
As a starting point, my advice would be to first
replace any dodgy connectors with nice thick
ones, any wires that may not be up to the task
(too thin) and check all grounds/etc.

[Oldsmobile_Mike]

While not computer related, this link contains a short summary on something with which I have personal experience, related to power connectors and fires.  Since then, all replacement alternators of the model used by Ford at the time contain an integrated (hard-wired, not removable) power connector.

[iamaboringperson]

hmm, Thanks for the link Oldsmobile_Mike.

I think I will replace my PSU now. :-)

[csirac_]

@KennyR

Hmm, if your connectors were crap then you'd get less current and so less heat. Something in your system is drawing too much power. They tend to do that when they get too old.

Actually, you are right that the m/b will get less current but it means that a dodgy connection with high contact resistance will be dropping more voltage, wasting power/creating heat.

Cheers,

- Paul

[JaXanim]

I had exactly the same problem with my P8 & P9 connectors. They were clearly running too hot in places and were turning the plastic connector block a dark brown colour.

The problem is the internal blade connections within P8/P9. They seem to be too maleable for my liking and are easily displaced . The result is too much juice going through too small an area. It gets hot.

You can fix this by carefully releasing the internal connectors one at a time and making sure there's plenty of contact with the mobo pins.

You need a very thin/rigid tool to release the retaining tang on the connectors. They readily pull out of the socket with a little bit of practice. Make sure the retaining tangs are repositioned so they 'bite' when the refurbished blades are pushed back.

I've had no problems since making this little fix.

Cheers,

JaX

[unclewilli-amigalover]

? you may want to check the wall socket where your cable plugs into the wall, many times a loose connection there will cause small unnoticed electric arc that can cause problems like that. electricity needs good firm connections. but the red wires if i remember right are( 5+ volts ) and could be a indication that something is pulling to much power,so i would guess that the power supply has a weak compacitor or failing, and changing the power as you suggested is the best first responce.

[darksun9210]

no no and thrice no! i thought this was only me!

the A4000T comes with an AT type power connector, and by design the actuall contact area between the pins off the mainboard, and the connector "shoe" in the plug is a very small area. (about 2mm by the width of a human hair)

loading this up with power sucking cards like 040's or (in my case) my PPC card and other various zorro cards, (see signiture below) would cause the plug to heat up due to the amount of current required by the mainboard to support all these devices running through a very small contact area.

hence power lead plugs melting burning and discolouration. i originally thought this was a software fault as it kept crashing, then after a couple of months after buying my CS-PPC it wouldn't boot at all. replaced the power supply, all fine and dandy for a while, then after a few months, same problem. took the machine to pieces to see what was up. and looked at the power plugs. burnt out on the 5 volt lines (the red leads if memory serves me correctly), to the point that the connectors in the plugs had burnt away completely.

fortunatly the mainboard was fine, i just wasn't too happy about going back to a 25Mhz EC030 and IDE drives for the sake of power problems. so i ended up cutting off the plugs, stripping the ends of the wires, and jamming them in the back of end respective pin on the mainboard. nice wide connection area. worked a treat forever. (till i sold the machine)

a more permanent solution would be to solder some flying leads off of the mainboard power connector, screwed into a block connector. the other side of the block connector would have the lines from the power supply screwed into it.

but yes. a heavily loaded A4000T mainboard will overload the AT power connecter. sad but true.

[sir_inferno]

REGARDLESS...i'd suggest you get a GFCI and a CO2 fireextinguisher to put near the comp..