Radio acting up

I have a question for all the electronic wizards out there. My radio is only giving a carrier signal but no modulation. I have the following set-up:
Dittel FSG71M
Dittel speaker box F10061 with two DIN connectors for two microphones (only one used)
Dynamic goose neck microphone F10039

I tried both goose neck mic.'s I have in both positions on the box.
The yellow LED on the radio turns on but no voice transmission occurs.
The power supply is provided by two 12V, 9.6Ah Lithium Iron Phosphate batteries in parallel which are rock-solid.

Any suggestion for where to start trouble-shooting?

Thanks,

Uli

I would have initially suggested a bad mic but, since you've tried two,
that's not the likely cause. Since the transmit light illuminates and
you're transmitting carrier, verified, I assume, by a separate receiver,
I'd look at your common wiring between your mic and the radio
connector. Check with an ohm meter. I've seen broken wires inside of
intact insulation.

On 9/19/2016 10:23 AM, AS wrote:
I have a question for all the electronic wizards out there. My radio is only giving a carrier signal but no modulation. I have the following set-up:
Dittel FSG71M
Dittel speaker box F10061 with two DIN connectors for two microphones (only one used)
Dynamic goose neck microphone F10039

I tried both goose neck mic.'s I have in both positions on the box.
The yellow LED on the radio turns on but no voice transmission occurs.
The power supply is provided by two 12V, 9.6Ah Lithium Iron Phosphate batteries in parallel which are rock-solid.

Any suggestion for where to start trouble-shooting?

Thanks,

Uli


--
Dan, 5J

On Monday, September 19, 2016 at 12:23:09 PM UTC-4, AS wrote:
I have a question for all the electronic wizards out there. My radio is only giving a carrier signal but no modulation. I have the following set-up:
Dittel FSG71M
Dittel speaker box F10061 with two DIN connectors for two microphones (only one used)
Dynamic goose neck microphone F10039

I tried both goose neck mic.'s I have in both positions on the box.
The yellow LED on the radio turns on but no voice transmission occurs.
The power supply is provided by two 12V, 9.6Ah Lithium Iron Phosphate batteries in parallel which are rock-solid.

Any suggestion for where to start trouble-shooting?

Thanks,

Uli

Perhaps broken wires inside the speaker box (saw that on a Becker box earlier this year).

Also if booms are connected by plug, check for corrosion, and spring tension on the contacts.

Is this an installation that previously worked or a new one?

On Monday, September 19, 2016 at 3:49:03 PM UTC-4, Dan Daly wrote:
On Monday, September 19, 2016 at 12:23:09 PM UTC-4, AS wrote:
I have a question for all the electronic wizards out there. My radio is only giving a carrier signal but no modulation. I have the following set-up:
Dittel FSG71M
Dittel speaker box F10061 with two DIN connectors for two microphones (only one used)
Dynamic goose neck microphone F10039

I tried both goose neck mic.'s I have in both positions on the box.
The yellow LED on the radio turns on but no voice transmission occurs.
The power supply is provided by two 12V, 9.6Ah Lithium Iron Phosphate batteries in parallel which are rock-solid.

Any suggestion for where to start trouble-shooting?

Thanks,

Uli

Perhaps broken wires inside the speaker box (saw that on a Becker box earlier this year).

Also if booms are connected by plug, check for corrosion, and spring tension on the contacts.

Is this an installation that previously worked or a new one?

Thanks, Dan & Dan! That will get me started.
The installation was done by the previous owner and it did work just fine. Started acting up while in Moriarty this summer and seems to be intermittent. Yesterday, I was talking to the tow-plane on take-off and after the release just fine but couldn't talk to the Lear-Jet driver who called for his final in the opposite direction I was on. Fortunately, his final was much longer and I was off the rwy well before he touched down. That radio picked a bad time to act up!
Uli

So a broken/intermittent wire/connector between the microphone and the radio is a likely culprit. FYI - Dan D. above mentions the speaker box might seem odd on the surface to some who are reading this, but many Becker and Dittel installations have a speaker box as the junction point for the microphone/speaker/PTT.

With two microphones used and still having the problem this seems to eliminate the connection from the microphone to the box. Disassemble the radio's rear panel connector. Disassemble the microphone connector which goes into the box. Check continuity all the way between the two ends. This is two wires and a shield which occupies two (2) pins on the box but three (3) pins on the radio. If no continuity then backtrack towards the radio until you get continuity and then you found the break.

But if continuity is OK, then the radio is suspect. If another pilot has the same model, then try a swap. Otherwise send in the unit for a bench test.

Best of luck,
John

If you end up having to send the radio to the Dittel man in Florida be exceedingly specific about the problem. Some years back my Dittel would transmit but not receive. Sent it to be fixed and it came back with report that there was no problem. There was still. No noise st all over the speaker. Put another identical radio into my glider and it worked (easy system check if one is available). So then spent the money and sent radio to Germany.
Instant report from there -- some small cheap item in circuit to speaker was dead,fixed and it was on way back. The German report was that the circuit that drove a headset was working perfectly, problem isolated to speaker output. Florida had the German believed used headset when it checked.
Lots of added dollar cost for this one.






On Monday, September 19, 2016 at 12:23:09 PM UTC-4, AS wrote:
I have a question for all the electronic wizards out there. My radio is only giving a carrier signal but no modulation. I have the following set-up:
Dittel FSG71M
Dittel speaker box F10061 with two DIN connectors for two microphones (only one used)
Dynamic goose neck microphone F10039

I tried both goose neck mic.'s I have in both positions on the box.
The yellow LED on the radio turns on but no voice transmission occurs.
The power supply is provided by two 12V, 9.6Ah Lithium Iron Phosphate batteries in parallel which are rock-solid.

Any suggestion for where to start trouble-shooting?

Thanks,

Uli

On Tuesday, September 20, 2016 at 9:20:01 AM UTC-4, howard banks wrote:
If you end up having to send the radio to the Dittel man in Florida be exceedingly specific about the problem. Some years back my Dittel would transmit but not receive. Sent it to be fixed and it came back with report that there was no problem. There was still. No noise st all over the speaker.. Put another identical radio into my glider and it worked (easy system check if one is available). So then spent the money and sent radio to Germany.
Instant report from there -- some small cheap item in circuit to speaker was dead,fixed and it was on way back. The German report was that the circuit that drove a headset was working perfectly, problem isolated to speaker output. Florida had the German believed used headset when it checked.
Lots of added dollar cost for this one.






On Monday, September 19, 2016 at 12:23:09 PM UTC-4, AS wrote:
I have a question for all the electronic wizards out there. My radio is only giving a carrier signal but no modulation. I have the following set-up:
Dittel FSG71M
Dittel speaker box F10061 with two DIN connectors for two microphones (only one used)
Dynamic goose neck microphone F10039

I tried both goose neck mic.'s I have in both positions on the box.
The yellow LED on the radio turns on but no voice transmission occurs.
The power supply is provided by two 12V, 9.6Ah Lithium Iron Phosphate batteries in parallel which are rock-solid.

Any suggestion for where to start trouble-shooting?

Thanks,

Uli

Took the 'Dittel speaker box apart yesterday and found some undocumented wiring soldered into the microphone jacks. There is an extra cable coming in from somewhere, which I have to trace to see what it's function is.
The saga continues..

Uli
'AS'

Hi Uli
A likely candidate is the relay. Contacts go bad and sometimes there's no TX modulation, or no RX. With the help of other info on the web I fixed mine, and documented the procedure to share with all:

http://strato.co.nz/pik20/dittel/dittel.html

cheers JR

We had intermittent problems with our K-21 with the same Dittel box and radio. It was traced to a bad BNC connection from the antenna into the radio. Worth a look.