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Author Topic: need help wiring ACC connection from radio to amp  (Read 7548 times)

Offline radiozed

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need help wiring ACC connection from radio to amp
« on: August 27, 2016, 0305 UTC »
I have a Yaesu FT-817 and I recently purchased a 45 watt QRP amp to use with it.  The amp came with an ACC cable to connect to the back of the 817, but unfortunately they didn't connect the actual ACC plug that goes in to the back of the Yaesu (either that or it fell off during shipping).  The ACC cable coming out of the back of the amp has just two wires, one red and one black.  Here is the wiring diagram for the ACC port on the Yaesu 817:

https://drive.google.com/file/d/0B1Sx8UoqolwlNmVrUFIyeURfaWM/view?usp=sharing

So I guess what I'm looking for is where I connect the red and black wires on the ACC plug.  Any advice would be appreciated! 

Offline radiozed

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Re: need help wiring ACC connection from radio to amp
« Reply #1 on: August 27, 2016, 1646 UTC »
Been reading some more through the dreadful instructions that came with the amp.  Finally found a description of how to connect the ACC wires.  It says the black should be wired to "ground" and the red to "TX-PTT."  Unfortunately neither of these really matches the ACC diagram of the FT-817.  Ground is fairly easy, but I'm not sure whether it should be TX GND or GND.  I'm guessing TX-PTT would coincide with TX INH on the FT-817, but I'm not certain.  The younger me would just figure it out through trial and error but I really don't want to blow up my Yaesu or QRP amp.  Neither were cheap.   :D

Offline radiogaga

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Re: need help wiring ACC connection from radio to amp
« Reply #2 on: August 27, 2016, 1835 UTC »
Hi Zed
Are the red and black wires for keying the amp?
Does the amp have voice operated relay also?
Any voltage between black and red wire?

My guess is that you short the red and black which completes the relay circuit.
If so...black to ground and red to tx gnd.

Verify with volt/ohm meter please

rgg

Offline radiozed

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Re: need help wiring ACC connection from radio to amp
« Reply #3 on: August 27, 2016, 1943 UTC »
Sorry, upon reading my post again I realized it was a little vague.  Yes, it's my understanding that the black/red wire that come out of the back of the amp function the same as the "Relay" connection you'd find on most transceivers/amplifiers.  Bizarre that it's not labeled as such on this amp plus the fact that it's hardwired.  But then again, the Yaesu doesn't have a "Relay" connection either, with the components of such being hidden among the ACC socket pins.  I appreciate the advice.  I'll test out your suggestion and also double check things with my volt meter.  

Offline radiogaga

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Re: need help wiring ACC connection from radio to amp
« Reply #4 on: August 27, 2016, 2018 UTC »
A lil searchin found this:
https://vk2qr.wordpress.com/2014/11/25/mx-p50m-hf-amplifier-review/

 "I have taken the time to check which connections are made to the FT-817 and they are as follows. The Black or in some cases Blue control wire from the amplifier is connected to ground or GND (-VE)  on the radio and the Red control wire from the amplifier is connected to TX GND from the radio. So to operate the amplifier in transmit mode it is a simple matter of shorting the two control wires from the amplifier together when transmitting and open circuit them when receiving."

Is this the amp you have.....?

rgg

Offline radiozed

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Re: need help wiring ACC connection from radio to amp
« Reply #5 on: August 27, 2016, 2021 UTC »
It is indeed!   :)

Offline EliteData

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Re: need help wiring ACC connection from radio to amp
« Reply #6 on: August 27, 2016, 2037 UTC »
if i may ask, what brand/model the amp is ?
you may be better off just tying the red/black wires together and using the amp STBY/OPR switch or the power switch when you want to use it assuming its not being used for two way communications, depending on what type of amp it is and whether its solid state or valves.
edit:
its probably this amp ?
https://www.amazon.com/Amplifier-FT-817-IC-703-Enhancing-Transmission/dp/B00SMH5P8U
if so, you could get away with tying the small red/black wires together and just use the on/off switch to activate it, provided you memorized the band switch dial or physically marked it with a small black marker so you can change bands with the power switch off.
in any case, you will probably be able to do about 20-25w max on AM @ 13.8vdc, anything higher may introduce carrier saturation and envelope distortion on AM.
for cooling, i suggest a 12vdc computer case cooling fan placed on the top of it with the air flow going towards the heat sink fins.
tip: its getting too hot if a crayon starts melting within 5 seconds (easiest method).
good luck !
« Last Edit: August 27, 2016, 2049 UTC by EliteData »

Offline radiozed

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Re: need help wiring ACC connection from radio to amp
« Reply #7 on: August 27, 2016, 2244 UTC »
EliteData - You hit the nail on the head!  I was getting ready to break out the soldering iron when I saw your post.  I just decided to tie the two ends together and BINGO.  I have no need for receive, so this allows me to make the ON/OFF switch my amp control.  This is perfect solution! 

Offline EliteData

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Re: need help wiring ACC connection from radio to amp
« Reply #8 on: August 28, 2016, 0247 UTC »
EliteData - You hit the nail on the head!  I was getting ready to break out the soldering iron when I saw your post.  I just decided to tie the two ends together and BINGO.  I have no need for receive, so this allows me to make the ON/OFF switch my amp control.  This is perfect solution! 
just keep all the gear (including the power supply) running cool with low SWR (no more than 2:1) and everything will work great.