I am having problems with my Futaba 3PK. It has been upgraded to the Spektrum SM1001 tx and SR3000 rx. I am using this setup for my RC8. I killed the AE steering servo so I replaced both servos in the car with Futaba S3305's as that was what the shop had. The car ran great with the new servos for a couple of tanks. Half way thru the third tank, the car no longer would respond. Thankfully, the car became hung up on tubing around the tack. Thinking that my rechargeable rx pack was dead, I replaced it with 4 fresh disposable AA's. However, it still didn't come to life. I tried the rebinding process for the rx and the tx but all I got was a fast flashing green light on the rx. I made sure that the servos were plugged in correctly (black wire facing out word) and nothing. I made sure the radio didn't change from the PPM setting which it had not. I then unplugged both Futaba servos and what do you know, the flashing green light on the rx stopped. I plugged the old AE throttle servo into the rx and it worked. Are Futaba's S3305 servo's not compatable with the Spektrum system? Any other thoughts?

I don't think disposable AAs have enough current capability to power a pair of higher power servos. And maintain enough voltage for the receiver to work properly.

I had the same problem with my Jammin back in April. Ended up having a bad throttle servo. I switched servos around, even went from the spectrum module (i had a KO Helios) back to the synthesized module. I tried a different throttle servo (borroed an ACE from a buddy) and that didn't work, then switched back to a different servo and haven't had a problem since.

I was using a Hitec 5997 servo, and now i'm using a 5925 temporarily until I send in the old servo to get fixed.

I have been able to get a good charge on the rx pack and it still didn't fix the problem.

EDIT: After pondering your thoughts for a few minutes, I decided to recheck everything over. As it turns out, the rx pack that I purchased with the servo's is a NiMH and not a NiCd as I had thought. I hope that I didn't kill the pack when I plugged it into the standard NiCd rx/tx wall charger. When I tested the volts in the rx pack, it was at 5.9(ish). I'm recharging it correctly as I type.

UPDATE: As it turns out, a weak battery pack was the culprit. Thanks to those that replied.

As a side note, is .5a to much to charge a 5-Cell 6V 1600mAh NiMH Rx pack at?

Thats fine - 0.5amp is considered a slow charge, for a fast charge, you can use 1amp. Thats the most I would recommend for a rx pac. I slow charge mine when I have the time and when I don't, I charge at 1amp.