I got ahold of a proto1 smoke unit..was missing a capacitor..stock is 330..went to radio shack..the had 220 and 470..was told to use a 470..my tas has a 470 on it..fan wont pick up speed..tried another fan and it done the samething..what resistor regulate the fan voltage?..wonder if that bad? ..or if you might know why ,please tell me.
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If the cap is not bad, the next suspect would probably be the 5V regulator on that board. Did you measure the voltage going to the fan when the smoke unit is connected to power? Have you tried powering the fan directly from a 5VDC source to see if it runs at normal speed?
Here's a schematic of the PS/1 smoke unit, as you can see the capacitor is merely a filter for the incoming rectified AC, so the exact value is not critical, and 470 is fine there.
You'll have to click on the picture to expand it to actually read the values.
Attachments
which one is that? the Ic1 that looks like a D? or the rectfire that looks like a rectangle?
The 5V regulator is in a TO-92 package.
D