Quote:
Originally posted by pHaestus
[b]I have a nice PID controller that I believe MAY be able to do the temperature control with some accessory parts. I don't at the moment have an adjustable voltage PSU that could power the 2 226W peltiers though.
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What kind of output does your PID controller have? If it has a 0-5V output, it would be quite easy to generate a PWM circuit to control the power to the TECS. If it had a 0-20 mA output it would be nearly as easy. 4-20 mA would be slightly more difficult, but no real problem. (You'd connect a fixed 12-15V supply to the PWM circuit, and the output would be a pulse width modulated signal with the duty cycle proportional to the PID controller's output.)
What kind of inputs? A voltage input would be ideal. Preferably some sort of differential voltage input.
What I envision as a sensor setup is four pairs of differentially wired thermocouples. One junction of each differential pair would be thermal epoxied to the CPU substrate at a corner and the other junction of the pair would be thermal epoxied to the motherboard at the corner of the socket. With all eight junctions glued down, the differential pairs would be soldered in series. This setup would give a 0V output when the average of the four dT's was 0.
A simple amplifier would go between the thermocouples and the PID controller input. The gain (scaling) accuracy of the amp would be irrelevant since the goal would be to maintain the PID controllers input at 0. Only the offset of the amp would matter.
Of course, doing this leaves you with a CPU that is glued to a tether attached to the mobo, but why should anything be convenient?
Quote:
Originally posted by pHaestus
[b]do you think they could handle soldering wires in such tight quarters?
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I don't know what the pin spacing on the A64's is like, but assuming it is similar to a P4 Northwood...
I'd say if the two diode pins were 'at the edge of the forest', then yes. If the diode pins are not along an edge of the grid, I don't see a way to do it. The best that might be done is to solder wires to the tips of the pins, but then serious surgery would need to be done to the socket to get the CPU installed. Not something I'd take on with an expensive chip.
Quote:
Originally posted by pHaestus
[b]Also I am wondering if my money and time might not be better spent on finishing die simulator
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Definitely a good question.
In terms of benefit to the watercooling community as a whole, the die simulator is almost definitely the better investment. While the results of this CPU testing may well be very interesting to a few of us, I doubt that much of practical value would come of it.
However, what you enjoy doing is the most important criteria, IMO.