Calling all electrical freaks!

kwikbb · Post by **kwikbb** » Mon Apr 21, 2003 4:29 pm

ok heres the skinny, i'll start at the beginning. i fried my 27mhz pcb (no love lost there) and first attempt at a dual mod (soul crushing experience), in an attempt at redemption i re-built my other 45mhz chassis, which was to be the donor for my ZZ chassis, out of the 27 spare parts.

everything went very well with the transplant and revival [pats himself on the back], except one perplexing thing.

for some reason my franken-bit is not as fast, by a long shot, to my other straigh out of the box 45mhz.
both are set-up the same way with a 160mah single cell upgrade, 2.6's, only motor i've got multiple copies of, and orange gears. i've already swapped the motors the gears and the even the batteries, same results every time.
now i was feeeling a bit saucey after having givin it some thought and a few coronas, so i broke out the multimeter;

Now here's where you come in, I need you to tell this undereducated monkey if he did this correctly!
the results are as follows;
rebuilt franken-bit in blue
out of the box new in red
here's where i touched the PCB to get voltage being delivered from the battery to the PCB (i think anyway)... negative to the left and positive to the right

rebuilt current = 1.32V
new out of box current = 1.28V
these results were taken from 160mah batteries on a 45 sec. charge

here's where i touched the PCB to get voltage being delivered from the the PCB to the motor (i think anyway)... negative to the left and positive to the right (again this may only be valid in my own mind)

rebuilt current = .97V
new out of box current = .935V
these results were taken from 160mah batteries on a 45 sec. charge

so now i ask, if the voltage on the rebuilt is more than the voltage on the new out of box wouldn't that warrant more power being delivered to the wheels. but instead it's all backwards, it's friggin bizzaro world!
so if someone could tell me i'm way off the mark here or by some miracle i'm actually doing this correctly maybe shed a little light on this cro-magnon skull.

thank you, i'm here all week

Namuna · Post by **Namuna** » Mon Apr 21, 2003 4:47 pm

Weird, you're only reading .9x volts from PCB to Motor? I usually get readings of whatever the battery voltage is.

When I test, I put the leads on the motor mount points (where the endbell touches and where the barrel rests). I usually get a rating of very near equivalent to battery voltage (in the area of 1.4v if fully charged).

Looks like yur DMM can handle current...Have you tried that yet?

hogjowlz · Post by **hogjowlz** » Mon Apr 21, 2003 4:54 pm

it could be the pcb. ive had two pcbs same freq and same brand with different power outputs.

kwikbb · Post by **kwikbb** » Mon Apr 21, 2003 5:01 pm

Namuna wrote:Weird, you're only reading .9x volts from PCB to Motor? I usually get readings of whatever the battery voltage is.

When I test, I put the leads on the motor mount points (where the endbell touches and where the barrel rests). I usually get a rating of very near equivalent to battery voltage (in the area of 1.4v if fully charged).

Looks like yur DMM can handle current...Have you tried that yet?

hmm not yet, i'll have to give it a whirl tonite... it'd be a hell of a lot easier if i had some alligator clips

hogjowlz wrote: it could be the pcb. ive had two pcbs same freq and same brand with different power outputs.

it was a consideration, but then i got the readings from the MM and they said different.
the slower cars getting the more juice

i don't know it's just weird!