Help With Fluke PM3082 Scope

[boba]

As in the title I'm having some problems with my Fluke PM3082. Yes I know its an old one but it's all I usually need - 4 channels, easy 100MHz and very good triggering and most of all I know how to use it and can find all the functions in a jif.

It's developed a fault when its warm - the error message is 'No Acknowledge on IIC'. A few functions generate it, in particular the Autocal or 10x Magnification. If I switch it off and on it won't display anything unless it's been left long enough to cool down (I suppose this is because it's failing the self-test). I suppose this means that the uP is having some problems communicating with something but I don't know where to begin.

Anyone familiar with this scope range able to offer advice?
Thanks

[flyback]

Hi Boba,
This scope uses intensively the i2c bus for linking internal modules (No surprise, this is a Fluke ex-Philips, the creator of i2c bus) Your error message is described in the service manual as follow:

The oscilloscope's internal control bus is checked. This is done by addressing N9001 , N9002,
N9003, N8005, N6014, 09009 (unit A1), N1001, N2002 (unit A2) and N1141 (unit A6).
Message: 'NO ACKNOWLEDGE ON 12C BUS'.

To find the non responding module, you can use the REPAIR TOOLS under the UTILITY key. User manual can be found directly @fluke.com, and service manual by searching on google. I remembered that there are solder joints on the PCB to isolate the SDA / SCL lines of the offending IC.
Good luck