Author Topic: problem with fluke 8000A  (Read 350 times)

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Offline patan107

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  • Country: nl
problem with fluke 8000A
« on: April 28, 2019, 02:58:47 pm »
Hi ,

As a retired person , I will start again with the electronic hobby.
And as an old radio amateur , you need to have your equipment up and running and in good condition.
I need some help to repair an unit with emotional value , the Fluke 8000A-01 which has the following problem.
After power up the unit , the display works , however it does not comes down to zero , regardless in which position the switches are. (AC,DC,A,Ohms)
Also when the input port of analogue IC U3 , SC408-2 is grounded , the readout is still high , where it should come down to zero.
So it seems that the compensation in U3 is not working correctly and just gives a readout depending on the temperature of the IC.
I assume that the first part of the IC is broken , also because there is no protection for higher input values to this IC.
Lately I saw in younger units that they used another A/D convertor U3 IC , SC522 and I like to know if this IC is technically the same the same as the SC408 , because I saw no differences on the pc board.
The same components are around.
Both IC's where custom-build for Fluke by Siliconix.
The only difference I see is the ceramic housing for the SC408 and a plastic housing for the SC522.
Looking forward to any reply.
All help is welcome and highly appreciated.

Thanks , Adrian(PA0APB)

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