Help wanted

[gareth lacey]

So i have 2 ATR 500 radios all wired up can transmit and get recieve BUT cannot hear them any guru in rdaios can help Cheers Gareth

[440032]

One might think the simplest explanation would be the most likely.

Maybe headphone sockets wired up incorrectly? Did you have it done, or do that yourself? There are three solder tabs, and you generally use just two.

[gareth lacey]

NO,i did it myself and it all bells out for continuity, sidetone is ok, send ok(radio checks from local frequency) but still no receive sound ,the receive icon comes up on radio , i will just have too go through wiring diagrams again , also have a flightcom intercom fitted so will isolate that and see the response 

 Cheers gareth

Edited May 7, 2023 by gareth lacey

[sfGnome]

Are the two radios both wired in at the same time, or are you swapping them in and out and getting the same result for both of them? If it’s the latter, then there a problem with the wiring because both radios won’t have both failed in the same way. If it the former, then perhaps one is loading down (shorting) the other? What happen if only one is plugged into the harness?

[gareth lacey]

I have tested them separately and have a swtch  to change from  radio 1 to radio 2  same result transmit icon ok, sidetone ok and icon for receive shows but no sound have tried both radios on i at a time same result 

methinks it could only be in my mic sockets , will try that 

 

Edited May 7, 2023 by gareth lacey

[RFguy]

mmmm
Is this an external intercom to the radios,  or two radios wired up with a switch, or paralleled outputs or inputs ????
Please provide a mud map !
thanks
glen. 
 

[sfGnome]

Is the switch switching both lines of the speaker, or only one? The speaker outputs will typically be differential, so you can’t have a switch in just one line. 

[gareth lacey]

the switch cuts out receive to headphones only so i can have 4 frequencies, flightcom 403 intercom

[sfGnome]

Ok. As RFguy said, time for a mud map (the less muddy, the better 🙂). 

[gareth lacey]

I will  put radio schematic and my swich in tomorrow cheers gareth

[gareth lacey]

Here are the schematics

[Blueadventures]

On 06/05/2023 at 12:01 PM, gareth lacey said:

So i have 2 ATR 500 radios all wired up can transmit and get recieve BUT cannot hear them any guru in rdaios can help Cheers Gareth

Ground connected?

[gareth lacey]

Yes all grounds are separate and to a bus bar

 

[sfGnome]

Ok, definitely not differential drive, so it’s not that. I’ll apologise in advance for asking, but the squelch isn’t turned up, is it? Failing that, the next steps I’d take (and it all gets a bit painful from here) is to

1. buzz not just that the right things are connected, but also that nothing wrong is connected (ie no shorts to other signals). That takes a while because a) there a lot of possible combinations, and b) because you aren’t expecting to get a buzz, you have to be really careful that you’re actually making connection with your tester to the signals that you’re buzzing. 
    
2. take the switch out of the circuit again - ie take it back to exactly as per the schematic with only one radio and see what happens then. 

If none of that shows up anything, then we’re into poltergeist territory… 😳

[facthunter]

Yes we have been able to fly to the moon but getting aircraft radios to work seems one step too far. Nev

[RFguy]

right....

SO confirm

1) when valid signal present, either radio green 'receive active' LED is lit (indicating receiving a signal), and signal  from a local portable or something , but NO audio?

2) open radio squelch (like pull icom vol knob) , do you hear noise  + green activity LED lit ? (if fn available)

3) transmit voice on either radio is heard by another radio elsewhere  ?

 

It is like there is a remote mute or audio suppression active on a radio pin. or intercom 23,24,25

Can you connect up an earphone between the radio output and ground (IE radio output at the back of the switch) ? Need to verify audio is present at the output of the radios before continuing. an earphone etc will work.  

glen

 

 

Edited May 8, 2023 by RFguy

[440032]

22 hours ago, facthunter said:

Yes we have been able to fly to the moon but getting aircraft radios to work seems one step too far. Nev

There's now a cafe on the moon. Great food, but absolutely no atmosphere.

[gareth lacey]

1. yes receive icon appears

2. no squelch on both radios 

3. not tried that 

 

23,24,25 joined as factory mute

not sure how to get connection for earplug for audio

 

[old man emu]

[RFguy]

factory mute all sounds suspicious. are they just connected together? They should NOT be connected together IIRC. 

[johnm]

On 09/05/2023 at 9:36 AM, 440032 said:

There's now a cafe on the moon. Great food, but absolutely no atmosphere.

I've been there - they have some books on anti-gravity (theoretical analysis) - once reading them ................. they are very hard to put down