Trio TS711 & 811
 

Hi everyone

I have a Trio TS711 and a TS811

I wanted CTCSS on both radios so my way of thinking was make a couple of copies of the original TU-05 tone board that was fitted in the USA versions and remove the UK 1750hz tone board.

Built two boards as per manual and tested stand alone and both work perfectly

Did the switch mod on the radios to activate the tone menu, this also works

The rest of the mods on the Internet are a bit of a waste of time as all they do is change the frequency step from 12.5/25 khz to 10/5 khz and expand the frequency range neither of which I need or want.

Problem is that the binary output from the control board to the TU-05 board is nothing like what the MX315 CTCSS chip wants to see on it's inputs.

The only ones that are correct is the first one 67.0 Hz all logic 1
fourth one 77 Hz logic 111100
and the last one 250.3 Hz all logic 0

Anyone got any bright ideas?

Thanks Simon - GW6TKK

Re: Trio TS711 & 811
 

Do you have room to squeeze in a PIC microcontroller?

Re: Trio TS711 & 811
 

I might have cracked this I think. Given that the circuit diagram on page 145 of the manual has errors it would seem reasonable to assume that the PCB layout is also wrong. As far as my research goes the CML chip is an industry standard and just about all producers of CTCSS encoders follow their design. It does not seem reasonable to assume that Trio would choose to depart from this as they would have had to have the CML part re-masked to suit.

The forum will not let me post the two truth tables properly formatted so they are readable but I will report back when I have tested my theory which is just transposing outputs.

Re: Trio TS711 & 811
 

Yes but why bother going to the trouble of coding a PIC chip when the original design uses an off the shelf part that is more than capable of doing the job.

That is not to reject your answer, and yes it could be done that way.

I have a feeling this is going to come down to Trio's people not being able to produce a manual that matches the design.

If my theory is correct then I will have to find a way of producing the truth table on the forum because it will not accept one produced in MS Word and all becomes clear when it's laid out as a proper table

Regards

Simon GW6TKK

Re: Trio TS711 & 811
 

Assuming you are using Windows,
Place an image of the Word document onto the clipboard (Alt PrintScreen).
Paste it into Paint or any other graphics app (Ctrl v).
Save as a .jpg image, and post that here.

Re: Trio TS711 & 811
 

Thanks Graham

Will give that a go as it will save an awful lot of re-typing

Simon GW6TKK

Re: Trio TS711 & 811
 

Hoping this works as I think it will, two attached files both in PDF format, ctcss prog is what the MX315 chip wants to see and ctcss actual is what is coming out of the Trio TS711 control board.

I will let someone else check it but it looks like a small re-design of the PCB would solve the problem if I make:-
Expected/Actual
D0 = D3
D1 = D2
D2 = D1
D3 = D0
D4 = D5
D5 = D4

Simon GW6TKK

Re: Trio TS711 & 811
 

As a side note the circuit diagram on page 145 of the service manual is a load of rubbish. I suspect the people producing the manual were working to a data sheet rather than what Trio had actually produced and even then they got it wrong.

Small 1 Mhz crystals are very rare beasts but the circuit works OK with a ceramic resonator as long as you change the 2.2 Mohm resistor for a 1 Mohm

I have the PCB designed in DesignSpark and I am happy to share it with other forum members as well as any other knowledge I have on these radios as I have had to become a bit of an expert to get my 711 working properly, last of this kind of stuff I did was when I was a rig doctor for the local CB'rs

If anyone wants some amateur radio chat I am the Repeater Keeper for GB3UP and we have Echolink on it.

Simon GW6TKK

Re: Trio TS711 & 811
 

Here are the two CTCSS boards.

Simon - GW6TKK

Re: Trio TS711 & 811
 

OK

Thought I would just report back on my experiments to get CTCSS working on a TS711E and a TS811E

Fig 1 attachment below is taken from the Trio Service Manual. The PCB layout is correct but the circuit diagram is not. C2 and C3 should be on the 5v rail not the tone enable line.

I played around with using a 1 MHz ceramic resonator instead of a crystal. While it oscillates fine I could not get the frequency accuracy good enough to give a consistent on frequency tone every time. Finding 1 Mhz crystals was a bit of an adventure but I did manage to obtain a couple and they oscillate bang on frequency.

The output of the chip through R1, R2 and VR1 I can't get to work. I know the values are correct because I have a high resolution picture of an original Trio CTCSS board as fitted in a TS711A. The only way it works for me is to jumper from the non chip side of R2 straight to the tone output pin TI.

For anyone who has found the mod elsewhere on the Internet, cutting the track and linking it on the back of the tone button will activate the CTCSS menu on the display. The rest of the mods involving removing diodes as far as I can see will just mess your radio up and expand the frequency range and alter the step rate on the VFO. I also changed the value of R4 accross the crystal from Trio's 2.2 M ohm to what the chip maker suggests which is 1 M ohm.

I have this fitted in my TS811E as shown in fig2 and it works perfectly and it cost me less than £10 to do.

Re: Trio TS711 & 811
 

Solved the problem of no tone through R1, R2 and VR1. Small solder bridge on one of the tracks, Oooops

Re: Trio TS711 & 811
 

Just to tie up a few loose ends.

To make the mod work refer to fig 4 below. Lift out the control board (very carefully) Add C56 which will not be fitted in an E version radio (470pF disc ceramic). Remove R55 and add wire link W2 and a tall 6 pin header in the unused holes next to the 4 pin header that supported the 1750 Hz tone board.

The original mod is supposed to activate the tone board by placing a logic 1 (5v) on pin TH when the repeater offset is on. I must admit that while I was experimenting I just wire linked pin TH to pin 5C to activate it. However, there is a slightly more user friendly way to do it. As we want the tone active regardless of if the repeater shift is 1.6 MHz or 7.6 MHz as it is here in the UK we can use the output of the mode driver chip (IC23). Refer to Fig 3 below and make up a wire link with a 1N4148 diode in series, insulate with a bit of heat shrink tubing as indicated in red and attach one end to pin 6 of IC23 and the other end to the cathode of D15. This provides a logic 1 (5v) to pin TH in FM mode only. If you have the boards deviation set correctly no one will ever notice on simplex that you are putting out a CTCSS tone.

Re: Trio TS711 & 811
 

And the modification to the back of the tone switch. I suggest that you DO NOT unplug or remove this board to do this, you should be able to do it by removing the mains switch (2 screws) and the side screws and the whole front panel will fold down to allow access. Reset the radio and now when the tone button is pressed the VFO knob will cycle through the CTCSS tones.

Re: Trio TS711 & 811
 

Well Done. I wish my eyesight and nerve was good enough to do the work you have done. Love the CTCSS boards, lot of work but worth it. You should make a few and sell them as there's a few of us enthusiasts still using these very capable transceivers. I also have the TR-751e as well as the base station pair TS-711 and 811. Just bought a second 811, it's working but all the lights are permanently lit on buttons 1,2,3,4,and 5. strange.

Anyway, once again, congrats on your good work.

Re: Trio TS711 & 811
 

These radios still hold their own against modern stuff and are a delight to use.

Superb work. I love that neat little PCB you made. Do you have any left ? I have TS-711E and 811E plus the matching mobile TR-751E.

Really nice job. Well done.

Ken

Re: Trio TS711 & 811
 

Ken

The PCB is just a copy of the original Trio unit and I have it stored in DesignSpark (free to download from RS) format which I am happy to share.

It really was not difficult to do, just laser printed onto glossy photo paper then ironed on to a PCB and etch.

Your 811 with all the button lights on should be pretty simple to fix. Probably something to do with the mode switching IC which is just a bit of 74 logic.

Could certainly check various outputs for you on mine.

Regards

Simon GW6TKK

Re: Trio TS711 & 811
 

If your eyesight is not so good Ken and your not confident to mess around with it then you could always drop the control board out and package it really well and send it down here and I will fix it for you.

Regards

Simon - GW6TKK

Re: Trio TS711 & 811
 

Just done the mod and I had to fit C11 & R12 on the I.F. pcb.
These connect the tone o/p to the Varicap.

Also I don't get any voltage on TH when the offset button is depressed.

Can someone tell me where to pick this up, I Don't want to use the FM hi from the logic and will always be using a -0.6 shift.

Ta!

Stretchy

Re: Trio TS711 & 811
 

Link TH to 5C - that will get the module active.

Re: Trio TS711 & 811
 

Hi Steve, I should have made that clearer.

I only want the CTCSSS enabled when I initialise the shift.

Where can I pick up 5V logic high when the offset is enabled?

Regards.

Stretchy.