Dittel KRT2 disfunction

[okko kloosterman]

Last week, after a few months of proper functioning, the new KRT2 radio
I have installed this spring suddenly stopped transmitting. Pressing the
PTT button makes it send a carrier wave, but without any modulation. The
receiving section is OK, though.
Anyone run into the same problem? Any hints about the probable cause?
Thanks, Okko (Netherlands)

[Martin Gregorie]

My then-new KRT2 did that when I first installed it in my glider, back in
early 2015. It went back to Germany on warranty and has been fine ever
since.

The problem seemed to be internal, somewhere between the microphone
amplifier and the RF section of the transmitter. I say this because the
unmodulated CW was quite strong and, when the radio was in MIC Setup
mode, I could see the signal level bar responding to speaking at or
tapping the microphone.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[jpg...@gmail.com]

My 2013 model now transmits a squeal when the PTT pressed. It transmits voice OK but sends squeal in all the silences. Swapping radio and aerial between it and an Icom confirms that it isn't caused by the glider aerial, microphone or wiring and seems to be internal.

[okko kloosterman]

Thank you Martin, for your information.
I think I'll have my device sent back tot the manufacturer for repair,
it's less than 8 months old, so still under warranty. Bur first I will
check the microphone setup, as you described.
Okko


Op 24-8-2016 om 22:55 schreef Martin Gregorie:

[Martin Gregorie]

On Thu, 25 Aug 2016 15:49:14 +0200, okko kloosterman wrote:

> Thank you Martin, for your information.
> I think I'll have my device sent back tot the manufacturer for repair,
> it's less than 8 months old, so still under warranty. Bur first I will
> check the microphone setup, as you described.
> Okko
>

Sounds like the right sequence to me. I'd reinstalled the ATR-500 that
the KRT2 replaced because I didn't know how long the repair might take.
So, I was pleasantly surprised to get the radio back much faster than I
expected because it went back to Dittel via the UK agent.

[okko kloosterman]

Today, I tried again and switched the radio on to have a look at the
microphone setup page. To my surprise the transmission was functioning
normally, as if there hadn't been any problem at all...
Most probably it has been a software issue, simply solved by a
restart/reset of the radio. One should think of that when using
computer-driven devices ;-)

Okko (never to old to learn)

[lachm...@gmail.com]

Op woensdag 24 augustus 2016 21:45:40 UTC+2 schreef okko kloosterman:

We have the same. Ans some club members experience this problem too. Before transmitting, we switch the radio off and on again. Then the radio transmits again for a while. De KRT2 2nd edition seems not to have this problem.

[John DeRosa OHM Ω http://aviation.derosaweb.net]

To add to this thread I am helping a friend with exactly the same issue.

Carrier is strong but without audio. I replaced the mic but without effect. No signal shown in the mic setup screen.

Anyone know of a US repair shop?

[Unknown]

Later on I succeeded to solve this problem by changing the microphone
setting to "automatic", which tests the (dynamic) mike before
transmitting. Since then this phenomena didn't occur anymore.
By the way, my KRT2 actually is of the 2nd generation (the type with a
colour display)...

Okko

Op 8-7-2020 om 15:59 schreef lachm...@gmail.com:

[Nick Kennedy]

John
Last year my Dittel had a similar no transmit problem.
I downloaded the user manual available online and fixed it in the troubleshooting chapter.
Do you have the manual?
Nick
T

[John DeRosa OHM Ω http://aviation.derosaweb.net]

Nick,

I searched through my copies of the KRT-2 manual and didn't find any troubleshooting section (searched for "troubleshooting" and "trouble").

Can you provide a link to the manual you found the troubleshooting section in?

Thanks, John

[John DeRosa OHM Ω http://aviation.derosaweb.net]

FYI - Here is the link to the TQ Avionics manuals for the KRT2 series transceivers and KTX-2 transponders.

https://www.tq-group.com/en/support/downloads/tq-general-aviation/manuals/

Still haven't found a troubleshooting section.

[Eric Schwartzy]

Hello,
I have a KRT2 that used to work fine but now it is not anymore!
It is installed in an aircraft with 2 headsets configuration.
For some reasons that I don't understand mic 1 is not working anymore with any headset.
Mic 2 is fine and modulating on the mic menu but not mic 1...
If you have any idea about what it could be or what should I do don't hesitate !
Thanks
Eric

[Andrzej Kobus]

Each mic has its own gain setting. You need to adjust the gain. Mic 1 has also an option for automatic mic detection. It is all in the manual.

[John DeRosa OHM Ω http://aviation.derosaweb.net]

Eric,

I just got done with a struggle getting a Dittel (now TQ Avionics) KRT2 transceiver to work. Help me understand better what you are seeing.

You say that "mic 1 is not working anymore with any headset". ANY headset? Are you swapping known good headsets to test? Is this a headset with plug in jacks (like the power people use) or a boom type microphone (like glider pilots use)?

So assuming that you are swapping known working headsets then this points to either the wiring or the transceiver. It would seem to me that a microphone gain would not spontaneously change (but the setting is easy enough to get to and mistakenly change). Check that the connector at the back of the radio is fully seated. Any wires broken that you can see? The jack that you plug into may have failed or gotten corroded.

Other ideas can be found on my presentation "troubleshooting transceivers" at http://aviation.derosaweb.net/presentations/#transceiver.

Ultimately, you might find that the transceiver needs to be sent in for a bench check. Here in the US the repair station is;

Mid Continent Instruments and Avionics
http://www.mcico.com
9400 East 34th Street North, Wichita KS 67226
Phone: 800-821-1212, 316-630-0101
Email: mc...@mcico.com

[Eric Schwartzy]

I tried with 3 diffrents headets that all work on Mic2 plugs (listening and speaking). I am going to check the wiring with another radio today. Is it possible to have 1 mike "dead" and the other working fine, they have different amplifier or so in the radio ?
Regards
Eric

[John DeRosa OHM Ω http://aviation.derosaweb.net]

On Tuesday, November 10, 2020 at 1:31:05 AM UTC-6, Eric Schwartzy wrote:
> I tried with 3 different headsets that all work on Mic2 plugs (listening and speaking). I am going to check the wiring with another radio today. Is it possible to have 1 mike "dead" and the other working fine, they have different amplifier or so in the radio ?
> Regards
> Eric

Eric,

I assume a traditional headset plugged into jacks and not a boom microphone.

- Different internal amplifiers for the two mics is probably but without a schematic hard to tell. Even so at some point mic 1 and mic 2 audio is combined internally.
- Swapping in a KNOWN GOOD KRT2 transceiver is a very simple way to see if you radio is at fault.
- A loose, corroded, broken, connector on the rear can mimic your issue.
- The microphone 1 gain setting could have be changed but unlikely.
- The headset jack #1 on the panel may be broken. If #1 jack is for the front seat of a tandem aircraft, or the left seat of side-by-side aircraft, then this is the most used jack which could point to this being the culprit.

Report back with what you find.

[Dan Daly]

Possibly your push-to-talk button failed?

[tow...@gmail.com]

I almost bought a KRT2 radio, because I liked that it stored and displayed a name for each frequency. My present radio stores a list of frequencies, but requires me to remember which they are for. Which of course I can't do.

[Dan Marotta]

On 11/10/20 4:56 PM, tow...@gmail.com wrote:
> I almost bought a KRT2 radio, because I liked that it stored and displayed a name for each frequency. My present radio stores a list of frequencies, but requires me to remember which they are for. Which of course I can't do.
>

How about simply remembering the channel numbers? E.g., for Moriarty
using my radio:

Ch1 - AWOS
CH2 - Field freq
Ch3 - ABQ Approach Control
CH4 - Glider freq (123.3)
etc...

--
Dan
5J

[Andrzej Kobus]

On Tuesday, November 10, 2020 at 6:56:56 PM UTC-5, tow...@gmail.com wrote:
> I almost bought a KRT2 radio, because I liked that it stored and displayed a name for each frequency. My present radio stores a list of frequencies, but requires me to remember which they are for. Which of course I can't do.

Indeed that is a nice feature and the reason I bought the radio.

[David Smith]

Lots of reports of loss of modulation so that the KRT2 just transmits carrier. Mine is doing this now after crashing in flight. has anyone solved this problem? Description of fault below:

I have a KRT-2-S transceiver bought new about 4 years ago. It is fitted in a glider.

It suffered a s/w crash recently while flying and it stopped responding to the user controls.

Switching the unit off and on solved this problem but it began displaying a "Not Cleared" message when switched on. This is not covered in the manual.

The unit has now stopped transmitting, only carrier wave is produced.
It shows an error message R_R_mak which is not covered in the manual.

I have tried restoring the unit to defaults which lost all my memory frequencies which took hours to enter.
I have tested the microphone and repeated the microphone set-up process in AUTO mode.

On searching the internet this is a VERY common fault.
This appears to be a s/w fault, is it possible to update the firmware with a bug fix?

[Martin Gregorie]

On Fri, 17 Jun 2022 05:29:24 -0700 (PDT), David Smith wrote:

> Lots of reports of loss of modulation so that the KRT2 just transmits
> carrier. Mine is doing this now after crashing in flight. has anyone
> solved this problem? Description of fault below:
>

My KRT2, one of the earlier units, did this a few years back. The agent
I'd bought it from sent the radio back to Germany for repair. Its been OK
since then. However, this happened before Dittel got bought out by TQ, so
things could be different now.


--

Martin | martin at
Gregorie | gregorie dot org