Originally Posted by chimaychanga
Originally Posted by IT Diva
The green and blue wires are the PWM and tach wire for the D5 connector.
That mod goes right on the D5's 4 pin connector that plugs onto the A6.
The easiest way to do it might actually be to make up a short extension cable with the mod on the extension cable's plug.
Google Zener Diode, and you'll see how they work so they can create a 5V source from the 12V that's present on the power pins of the A6 fan connectors.
But why do you have 2 of each wire ?? and did you solder the diode and resistors on to the fan terminals?
I see now.. you have 2 D5 pump cables underneath your sleeving
Yes, that cable was made as a Y cable for a dual D5 setup, but could seem confusing with the extra wires.
The diode and large resistor are each soldered to a terminal.
Here's the easiest way to implement the mod, . . . . as a short, 2 wire extension for the PWM and tach signals
Here's the little modded extension cable installed, note that the pullup resistor is a 3.3K, basically a workable compromise for either single or dual D5's, but really better suited to a single:
Here's the scope with only 1 of the D5's PWM line connected, notice that the pulse voltage is right about 3.4V max, and very near 0V min.
Ideally, the max should be right at 5V, but the D5's electronics load the circuit down some.
Now here's the scope with both D5's PWM line connected, notice it's now loaded down to about 2.5V.
The lower max pulse voltage can be accounted for with slightly higher percentage settings in Aquasuite.
Note also that max voltage for both single and dual setups does go up a little as the pulse width is increased.
What's really important in both cases, is that the pulse's "off time" voltage stays very close to 0V.
If the pullup resistor is lowered to 1k or so, the max voltage comes up very close to 5V, but the "off time" voltage climbs up closer to .8V or so, and then the pump doesn't see it as off time any more , and runs full speed with no regards to the pulse width.
That's why if you have a dual D5, use a 2.2K when you make your cable, and a 3.3K if you have a single D5.
DarleneEdited by IT Diva - 3/16/14 at 10:19am