Keyer malfunction

[ND1Y]

I have been using RRC-1258s with K3 twin for more than 5 years without any problem.
A month ago, all of sudden, the keyer stopped working. It produces dots properly but not dashes. The speed of dots can be changed with the CW knob in the front panel.
Restarting device does not cure the problem. Other than connectivity between my paddles and PAD jack, which I think is OK, what would be the possible cause of this issue? How can I cure this problem?

I have Keyer settings as follows;
Enable yes
Iambic Mode-B
paddle reverse Yes
weight 30
Side tone 500
Side tone -db 50
Lf delay 100
key delay 50
Speed pod min wpm 15
Speed pod mix wpm 40

Your advice would be greatly appreciated.

73!

JL1CNY/ND1Y Sam

[OE7AFT]

HI,
I had once the same issue and the protection diodes had to be replaced.
See this 3D:

https://www.remoterig.com/forum/index.php?topic=2868.msg13000#msg13000

73 de Enrico OE7AFT

[ND1Y]

Thank you for the great information, Enrico. I will look into the diodes.

73!

JL1CNY/ND1YSam

[OE7AFT]

this is the whole communication I had with Microbit:

Dear Mikael,
Unfortunately, the control unit of my RRC-1258MkIIs seems to be faulty.
The internal keyer always generates "dots" regardless of which paddle (left/right) is being pressed (always "dashes", if the "reverse" option is selected).
I have even tried to connect directly the I/O contacts on the RJ-45 connector:
-  grounding #4 works as straight key as expected,
- grounding #1 generates  dots as expected
- grounding #2 does NOT generate dashes.


I have inspected the PCB under the microscope and I couldn't spot any evident defect or short.

Is there any other test / inspection I can do to confirm an Hardware failure? Maybe measuring the resistance of #2 to GND ?
If so, how shall I proceed for repairing?

Best Regards / 73 de Enrico IZ4AFL / OE7AFT

-----
I can't remeber hearing before that a paddle input have stopped
woriking, sometimes the opposit happens when suffer ESD  the protection
diod D11 or D13 ( manual page 233) get broken and make short circiuit to
GND which make the unit to send dits or dah all the time

in this case the DT1 or DT2 may have been hit and broken if not the CPU
it self


73 de mike