CH2 hardware problem?

Ton O

Hanno,

After a period of using the Propscope logic analyser part I had to use CH2 again. It failed to operate while all other functions across CH2 seemed to work.

I have the following symptones : depending of voltage range settings for CH2 I get a fixed output undependent of my input signal. ( see attachment for the related values.)
According propscope schematic 32220 I measured the output of OPA2357 and AINB+ from AD8137 in relation with my input and that seems OK.

Can you advice me about the possible cause of this problem and may be some instructions how I can check the LTC2286 chip? As far I can see there is not a relation to a software versions ( I checked vs112 until 2.04)

Attachment: CH2 fault Input signal available.pdf

Regards,

Ton O

Publison

Ton O wrote: »

Hanno,

After a period of using the Propscope logic analyser part I had to use CH2 again. It failed to operate while all other functions across CH2 seemed to work.

Ton O,

Did you mean all functions on Channel 1 seemed to work?

When the DAC card is inserted, I believe it disables Channel 2 on the scope input.

Ton O

Publison,

Thanks for the response.

As you can see in the first screenpicture from the attachment ( on top only 2 tabs) the DAC card was removed. Normally it worked with the DAC card inserted while measuring DC and AC only when DAC was chosen the CH2 input is reused by DAC.

The "seems quote" refers to the function generator, logic analyser and spectrum analyser. They make use of the internal CH2 connection.

Furthermore it is trange that CH2 indicates up to 10 volts while the propscope is powerd from USB ( max 5V ) which is internally transfered to 3 V and 2 V.
Also note that the CH2 indicates constantly "CLIPPED" what indicates that the "measered" signal is bigger than the allowed measured value.

Ton O