Re: Ventilation starts and temperature shows maximum when I plug the LDG IT-100 #all

Steve W3AHL

The problem you describe is caused by the tuner interface placing a voltage greater than 3.3 VDC on TUNER port pin 1, which is TKEY.  TKEY is clamped via two diodes to +3.3 VDC bus and to ground.  When TKEY signal is driven to a voltage greater than 3.3 VDC the 3 volt bus to the CPU is affected also which is connected to the CPU VREF pin, which results in an incorrect A/D converter output.  This causes the temperature gauge to read too high and the fan to turn on when it isn't really needed.

Something has failed on the IT-100's interface port.  LDG never provides schematics for their products, so unless you can find a short or damaged component by visual examination or with a meter, it may have to be returned to an LDG service center.  If you measure the voltage on TUNER port pin 1 to ground (pin 4), that should confirm if this is your problem.

Steve, W3AHL

Something is wrong with my IC-7000 or my LDG IT-100. It used to work very well before, but now I got this.  When I connect the LDG tuner with the cable to the IC-7000 the temperature indicator goes to maximum and ventilation starts. LDG tuner does not tune any more, the radio does not even recognize it. LDG tuner does not answer at all to any button push. ICOM radio works well...sensitivity is not even goes into TX wihout problems..except the temperature indicator.
Any idea about what can it be? IC-7000 seems to work very well without the tuner...and I wonder where is the problem

Aurelian - SA0CAN

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