JR PCM-9 help
 

Hey guys,
I had hoped to breath some life into my JR "PCM 9 G-Series" single stick Tx; old but hardly, very hardlyused at all.I had removed thebatteries awhile back and grabbed a replacement pack at aswap meet this weekend, along with the old style black connector. I though I had recalled where the old battery plugged in, and did so according to the connector's orientation (yep, threw out or misplaced the old pack). On power up, I heard a snap/pop.... yep, a big ole @(&^**& escaped my mouth. I was able to pull the fuse but it appears okay. Before I contact Tony at RSI for a quote, I was wondering/hoping that someone might know the polarity of the JR connector or have some pics of the battery connect terminal. It is numbered 1 and 2 with the red wire being the #2 and that coincides with my JR Century VII Tx. I'm aware of the JR charger polarity issue compared to others, but.... Checking with a multi meter, the batteries are of the same polarity, that is red ispos and black is neg. I did assume the Tx was 9.6V, could I have been wrong there? Thanks for any feedback, thoughts, or ideas guys. Wish I hadn't sold the Futaba SS now, may have to hurry up that Kraft Spektrum mod.
Mark
AMA 63845
SPA384

RE: JR PCM-9 help
 

Mmm...

sorry to hear the bad news Mark. I was going to indicate the charger issue but in any event it is unrelated. I would assume that JR wouldn't switch polarity at the connector end at random and certainly not on identical vintage plugs. If your C7 radio is wired and connected like your PCM9 battery is, then the TX should use the same connector and polarity as well. But I can't be sure.

I had no issue replacing packs on my C7 although after a couple of decades the connector point needs a little love and care - I would sometimes see the RF/voltage needle just zero out when the switch was powered on. A little cleaning took care of it but I still don't trust it. I think a full checkup is in order.

I love the look and feel of the old analog switch masters! My C7 even converted to 2.4 with hardly any issue (module slight misfit).

David.

RE: JR PCM-9 help
 

Thanks David.
Interestingly, I removed the PCM-G circuit board; on the connector (which is not the same style as the C7) there was a suspicious black mark (like a sharpie) on one side. I plugged the battery in according to that (at least I hope that -black is neg- is an industry standard) and the power light did come on, no monitor light and no output on the meter other than a wiggle. In hindsight,the Tx module was not in place nor was the antenna. However, I don't think that it would/could damage the Rf deck as it would with a 2.4 module. So, in comparison, it does appear to be differentin this case.UNLESS, the JR factory battery (that I bought at a LHS) is wired inreverse polarity right from JR.That battery had the white connector on it, I cut it off and soldered the originalblackone on, the C7 powered up and works great (has the metal rudder cup too). Again though, if I were to plug that into the PCM-G according to the plugs tab orientation, it would be the red wire going into were the black presumably should. I checked the polarity on a meter and the red is positive though, so I'm back to thinking JR did something different on the PCM-G series. I'll probably send it to Tony for an eval, but at this point the money would be better spent putting a MS8K in it or on another C7; whichI can mod to 2.4at least. I have the spektrum 2.4 for my current C7 but cannot get the adapter to fit right, the modules a tad loose but I can shim that. How did you get the 2.4 antenna adapter to fit David?
Thanks for the feedback too.
Mark

RE: JR PCM-9 help
 

I thought the pcm 9 was pcm only .the 2.4 spectrum nmodules require ppm mode.

RE: JR PCM-9 help
 

That is correct Aero. The 2.4 discussed was in reference to the C7's, whichare FM so 2.4 conversions are a snap. The problem is the PCM 9(G). Rather than spend money on the PCM 9 (G series) I would rather get another C7 or convert the PCM to a Micro Star 2000 (I did mean mean MS2K in my earlier post, not MS8K) encoder and Rf deck. I'm kind of stuck, being an arm amputee I need single stick to really get the most out of it, I can fly 2 stick, but did you ever try a four point roll on 2 sticks with one hand!http://www.rcuniverse.com/forum/js/f.../msn/72_72.gif Thus the bummer of losing a good SS radio (for now).
Mark