QPCM rx problem!!!!  
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All Forums >> Radios, Batteries, Clubhouse and more >> RC Radios, Transmitters, Receivers, Servos, gyros >> Radio Manufacturer Direct Support >> Hitec/MultiPlex Radios- Ask Hitec Customer Service >> QPCM rx problem!!!!
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QPCM rx problem!!!! - 9/1/2007 3:20:34 AM   
Frank B.


 

Posts: 82
Joined: 1/17/2003
From: Bayville, NJ, USA
Status: offline 		I am having a problem with a QPCM reciver I just purchased.

The problem is notchy, delayed servo operation, (fail safe off or on) if I move away from the plane (engine not running) the problem seems to be less, but if I extend the antenna it gets worst.

The radio is the Eclipse 7 QPCM version 12 with a spectra module.

With a PPM receiver the transmitter works fine.

I installed an FM module (dedicated channel) out of my Prisom 7 radio into the Eclipse 7 and the QPCM receiver works fine.

Do I have a bad receiver? or a bad module?

Frank B.



       Post #: 1

RE: QPCM rx problem!!!! - 9/1/2007 10:14:08 PM   
A.T.


 

Posts: 592
Joined: 7/20/2002
From: Auckland, NEW ZEALAND
Status: offline
quote:

ORIGINAL: Frank B. I am having a problem with a QPCM reciver I just purchased. The problem is notchy, delayed servo operation, (fail safe off or on) if I move away from the plane (engine not running) the problem seems to be less, but if I extend the antenna it gets worst. The radio is the Eclipse 7 QPCM version 12 with a spectra module. With a PPM receiver the transmitter works fine. I installed an FM module (dedicated channel) out of my Prisom 7 radio into the Eclipse 7 and the QPCM receiver works fine. Do I have a bad receiver? or a bad module? Frank B.


1. "move away and problem less" & "extend TX antenna it gets worse"
Holding TX to close to RX when batteries are freshly charged can induce "swamping" which may disappear after a few minutes when the voltage has stabilised. (especially if a 5 cell RX pack).
2. You do not mention whether the same crystal was used in both the QPCM RX & the PPM RX - try swapping crystals, making sure they are fully seated. If possible, try a change of frequency.
Common receiver problems include turning the receiver on before the transmitter and the use of after market or different brand servos and leads with incorrectly sized connections.
Good references:
Guide to receivers - and solving apparent RX & "Interference" problems - written some years ago, all remains true except the paragraph on swapping crystals - they are no longer interchangeable except as listed on the Crystal Compatability Chart for RC units (courtesy GWS)
Radio Interference Primer
RF Noise - Solving the Servo Jitters
Receiver Antenna - Does Length Really Matter?
Comparison charts of RX with FAQ and photos
Recent RCU thread - Can you HELP diagnose my problem
and much more such as "RC Installations for best reception" under "Radio Systems, Accessories, Alterations and FAQ" on my web page.
In need, Hitec Support details Hitec Repair Request PDF

Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links


(in reply to Frank B.)
       Post #: 2

RE: QPCM rx problem!!!! - 9/3/2007 4:41:43 PM   
Frank B.


 

Posts: 82
Joined: 1/17/2003
From: Bayville, NJ, USA
Status: offline 		Hi Alan, thanks for your input.

What I found is that the QPCM receiver will not work with my spectra module, BUT! it will work fine with the FM (dedicated channel) module, the module is out of my Prisim 7 radio that is ten years old.

The spectra module works fine in PPM mode in all of my planes, I have been using this radio with the spectra module for almost 2 years and never had any problems, and it still works fine in PPM mode to date.

Question; could the spectra module work fine in PPM and not work in PCM (needing to be repaired) or is it a compatibility issue with using the spectra module with the QPCM receiver.

Frank B.

(in reply to A.T.)
       Post #: 3

RE: QPCM rx problem!!!! - 9/3/2007 10:03:56 PM   
A.T.


 

Posts: 592
Joined: 7/20/2002
From: Auckland, NEW ZEALAND
Status: offline
quote:

ORIGINAL: Frank B. Hi Alan, thanks for your input. What I found is that the QPCM receiver will not work with my spectra module, BUT! it will work fine with the FM (dedicated channel) module, the module is out of my Prisim 7 radio that is ten years old. The spectra module works fine in PPM mode in all of my planes, I have been using this radio with the spectra module for almost 2 years and never had any problems, and it still works fine in PPM mode to date. Question; could the spectra module work fine in PPM and not work in PCM (needing to be repaired) or is it a compatibility issue with using the spectra module with the QPCM receiver. Frank B.

No previous experience of that problem, am unable to assist further from this country. An email direct to Hitec Support will surely resolve course of action.
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links

(in reply to Frank B.)
       Post #: 4

RE: QPCM rx problem!!!! - 9/4/2007 4:37:45 PM   
martin salgado


 

Posts: 73
Joined: 4/30/2007
From: Poway, CA, USA
Status: offline 		Hello Frank,

Are you trying to use a QPCM receiver with your older Prism 7 transmitter?

_____________________________

Hitec / Multiplex USA
Customer Service

(in reply to A.T.)
       Post #: 5

RE: QPCM rx problem!!!! - 9/5/2007 2:10:55 AM   
Frank B.


 

Posts: 82
Joined: 1/17/2003
From: Bayville, NJ, USA
Status: offline 		Hi Martin,

I am using the eclipse 7 /software version 12.

Frank B.


(in reply to martin salgado)
       Post #: 6

RE: QPCM rx problem!!!! - 9/5/2007 8:49:07 PM   
MikeMayberry



Posts: 2880
Joined: 1/15/2002
From: Poway, CA, USA
Status: offline 		I would suggest you send in both the transmitter and receiver to have them checked out.

Mike.

_____________________________

Hitec RCD Rep
http://www.hitecrcd.com

(in reply to Frank B.)
       Post #: 7

RE: QPCM rx problem!!!! - 9/18/2007 12:52:16 AM   
Frank B.


 

Posts: 82
Joined: 1/17/2003
From: Bayville, NJ, USA
Status: offline 		All fixed, it turned out to be the receiver after all.

Thanks for everyone's input.

Frank B.

(in reply to MikeMayberry)
       Post #: 8

RE: QPCM rx problem!!!! - 9/18/2007 12:56:36 AM   
CowboyLifesaver


 

Posts: 411
Joined: 7/7/2005
From: Sun Valley, NV, USA
Status: offline 		That's odd................I've ben using that setup for years now. It has always worked great. It does really "flip out" if I have my transmitter too close to my receiver though. Other than that it has been a glitch free wonder of the FM radio frequency world.

_____________________________

"What size engine is that???? You''ve got some serious thrill issues." Desert Lakes Fly''n Group Revver #165

(in reply to Frank B.)
       Post #: 9

RE: QPCM rx problem!!!! - 9/18/2007 1:13:52 AM   
4*60


 

Posts: 1267
Joined: 3/10/2002
From: Blind Bay, BC, CANADA
Status: offline 		As he indicated. Faulty receiver!

< Message edited by 4*60 -- 9/18/2007 1:14:28 AM >

_____________________________

"Of course, that's just my opinion. I could be wrong." the other Dennis Miller

(in reply to CowboyLifesaver)
       Post #: 10

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All Forums >> Radios, Batteries, Clubhouse and more >> RC Radios, Transmitters, Receivers, Servos, gyros >> Radio Manufacturer Direct Support >> Hitec/MultiPlex Radios- Ask Hitec Customer Service >> QPCM rx problem!!!!
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