Radio Shack resistors for the P-Lead Pickoff

[melkel2000]

I'm unable to locate the resistors that came with my D-180 but the instructions say that they are 30k Ohm. Radio Shack carries only 33K ohm 1/2W resistors (http://www.radioshack.com/product/index.jsp?productId=2062332). Would these suffice?

 

[dynonsupport]

Yes, anything in the 30K-60K range and 1/4W or greater will work fine. I assume these are the resistors for the tachometer that you are talking about?

 

[melkel2000]

Yes, for the tach. Thanks!

 

[N8RV]

Anybody have a picture of how the resistor is wired in-line to the P-lead? The instructions say to place it as close to the P-lead as possible, but those things are pretty fragile looking. How have others done it?

(if you have a pic of your installation, feel free to e-mail or post)

N8RV *at* gte.net

Thanks!

 

[N8RV]

Anybody have a picture of how the resistor is wired in-line to the P-lead?  The instructions say to place it as close to the P-lead as possible, but those things are pretty fragile looking.  How have others done it?

(if you have a pic of your installation, feel free to e-mail or post)

N8RV *at* gte.net

I think I figured out the source of my confusion, but would appreciate confirmation from someone with Dynon Support.

The original installation instructions I have did not have a drawing, and the narrative said to put the resistor as close as possible to the P-lead. That tells me that it should be AT THE MAG END of the wire, not back at the switch.

However, the current instructions have a drawing that shows the resistors at the SWITCH end, on the lead between the Dynon unit and the switch, NOT the line from the switch to the mag. Big difference.

Hope that's right ...

Thanks!

 

[dynonsupport]

Yes, the resistors go at the switch, between the switch and the EMS. If you put them between the P-Leads and your switch, the mags would always be hot.

 

[65xx]

If you put the resistors in-line with the P-leads, be sure to heat shrink the resistors adequately agains vibration/movement. The solid resistor leads will not tolerate vibration very long before they fail. An alternative is to mount the resistors in a small, 1"x1" circuit board, then solidly attach/support the circuit board somewhere close. The P-leads then attach to one end of the circuit board resistors and continue out the other end to the switch. Vibration proof as much as possible without reinventing the wheel. Dan

 

[N8RV]

Yes, the resistors go at the switch, between the switch and the EMS. If you put them between the P-Leads and your switch, the mags would always be hot.

Thanks, DynonSupport. However, I don't follow the logic. If I ran the wire from the D120 to the mag with a resistor in the line right at the mag, how would that make the mag "hot all the time"? The wire from the P-lead to the switch would still be there and the switch would ground the mag when I turn it off, wouldn't it? The wire to the D120 would only be "monitoring" the output from the P-lead, right?

 

[65xx]

Dynon is correct about resistors and P-leads. I may have not explained properly and confused some folks (and me) about the P-leads from the mag and the EMS P-lead pickups for the tach. The resistors (circuit board) go between the ignition switch and EMS pickups for the tach. Dan