All the threads say no diode in the 9C. Sirius' web site says "no diode in the 9C"

So how come I buy a 9C this week, and clearly in the manual, it says the 9C has a diode, and you must remove the batteries from the unit to cycle? Did I buy an "old" 9C?

No diode. The manual has been corrected:
http://www.futaba-rc.com/manuals/9c-addendum-02.pdf

Jim, I see that this manual inserts the word "No" diode. Did you hear if this was a typo error originally, or maybe they were using the manual that went with an older 9C that did have a diode? Just curious.

Well... hmmm.... I never checked the manual until I read your post. Mine has the error as well. I am assuming the original manual is wrong, and has always been wrong.

I can measure the battery voltage via the charge jack - so there is no diode in mine.

Ask on the Futaba support forum, they'll know.

There is no diode in the 9C , never was, There is what "they" call a Polyswitch which give reverse polarity protection (the purpost of the diode in previous models) and still allows charging and discharging, ie cycling through the "charge" jack without haveing to remove the pack.

If there is no diode them why can't my Alpha 4 charge it. The Alpha 4 is designed to sense a current before it begins charging.

Somebody else posted a logical answer to this recently. Try searching "alpha 4 and 9C"

I have a Hanger 9 voltmeter, that applies a 400 mA load @ 9.6 volts. This one:

http://horizon.hobbyshopnow.com/prod...sp?prod=HAN111

It measures 9.4 volts - that is loaded (~400 mA). So there is current flowing. However, the 9c tells me 9.9 volts.

So, I will step out on a limb here and assume the poly-switch has a resistance of (9.9-9.4)/.4 = 1.25 ohms.

Perhaps that is giving the alpha 4 some problems. To charge it at 400 maH you have to supply .5 volts more than would be required in the absence of the fuse.

.... just a guess.

Perhaps someone can dig up the specs on the poly switch. That might help.