Bulk lot of Codans

[VK3ZYZ]

Here is a couple of pictures of some Codens recently arrived.

This is the top of a Codan 7515.....


And the bottom.


The channel crystals are mounted with their trim cap on a small PCB. That makes removing them a lot easier!

As channel 2 was about 3.8Mhz, I have removed the channel 2 crystal and the 1.65Mhz USB one, then fed my Si5351 synth into it and listened this AM to some 80M conversations.
More mods are needed to get it transmitting.


Another is a Codan 6801.....
The, this one is interesting. It has a box mounted on the back.
The top view.


Bottom view.


And in the mystery box.

It is a step solenoid connected to the band switch. Remote control 1970s style.

There is a lot to discover in these radios.

These will be an easy mod for 160, 80 and 40Meters. Cheap 50W HF radio anyone?

 

[VK3ZYZ]

The 6801 manual is pretty extensive, but the 7515 is missing some info.

 

[VK3ZYZ]

Starting the 7515 mods.
Remove the switch and pot.

Switch wires...
Rejoin the white wires and connect the pink and violet wires together. This sets to SSB (I hope).

I've removed the external control socket,

and the associated PCB.

There may be some fixes needed but we will see.

After removing the crystal sub boards, here is the VFO connection.

And a resistor network is tacked on the crystal select pins for Arduino channel selection via an ADC input.

This is pretty rough for now. When I get it all worked out, there will be circuits to show what is up.

The mic socket is removed too as I do not have suitable mics. A bit of a work around will be needed to use a "Standard" 4 pin mic.

There is a PA filter that I have no information on.

I'll have a go at tracing the circuit soon.


So far, I cannot find full Codan 7515 circuits.

 

[VK3ZYZ]

There is a 7003 remote control bot in the stack. It will not be used at all but the case could be useful.

 

[VK3ZYZ]

As I do not have mics for these radios, I thought I'd changed the connectors to a "standard" 4 pin one. So, and order to Aliexpress arrived this morning.
Can you spot the problem?

Hint. The top left is a good one.

 

[VK3YNV]

I have heaps of those connectors, if you want some, ex dsp, I forget what product they were used on.

 

[VK3ZYZ]

Thanks Ray.
I just re-ordered some, than thought, why not just get the correct 6 pin DIN plugs for the Codans so ordered them too.
Lately I have not been doing to well. Ordered 0.96" OLED displays then had to re-order 1.3" ones.
Trying to get an ESP32 VFO running for the Codens and no luck.
So, I think I will delete Arduino IDE and re-install from scratch as a number of my old projects will no longer compile. I do hate updates!

 

[VK3WDE]

"So, I think I will delete Arduino IDE and re-install from scratch" move to VSCode with PlatformIO. You wont regret it.

 

[VK3ZYZ]

I have tried PlatformIO and cannot figure out how to work it.
In fact, I just tried again a couple of hours ago and gave up again, and went to have a coffee and watch a movie.

 

[VK3WDE]

Maybe I can show how to use it at a Thu meetup? Assuming I can get there of course.

 

[VK3ZYZ]

I have been belting my head against the receiver not resolving SSB at all and so finally got an unmodified set to compare levels etc.
Well, it turns out when I removed the AM/SSB switch, one pair of wires that needed to be connected were not so te set was in AM mode.
Linking those wires gave me SSB again
Nor I need to chase up why the analog in for the sensing the band switching keeps changing. I may have a crook Arduino??

 

[VK3ZYZ]

Another red herring.The VFO drive was getting into the band switching.
That has now been changed and is working well.

Now, the voltage to be sensed is from the diodes mounted on the band switch. It is a bit convoluted and the LEDs are there to drop extra volts so the same code will be able to run on the 10 channel version (I hope).

 

[VK3ELV]

How many of these radios are available? Perhaps they would be of more value as 630 metre Mono Banders.

 

[VK3ZYZ]

There are apparently quite a few. still sitting on a pallet at Albury–Wodonga, but I have 6, plus a few other crystal locked Codans that are part converted.
One of the 7515 radios I have operated on 80M on-air and it seems to work well. To get it on other bands, some mods of links and capacitors are needed.

 

[VK3ZYZ]

I've just ordered a batch of the PCBs for the Codan 7515 upgrade.
Just for fun, I chose white.

 

[VK3ZYZ]

The PCBs have arrived in time for tomorrow's meeting

I probably will not get much more done before then.

 

[BillC]

The PCBs have arrived in time for tomorrow's meeting
View attachment 3956View attachment 3957
I probably will not get much more done before then.

Super nice looking boards!