17 September 2009

Inside Gould 4072 DSO

In August this year I have received a Gould DSO model 4072, 100 MHz bandwidth, 400 MSPS. It is a totally different concept of oscilloscope to what I am used to (analog), and without documentation it needs some thorough exploration.

The unit appears to be in working conditions, except for the power button that doesn't depress and perhaps broken CRT graticule illumination (don't remember).

According to the OSD menu this DSO has onboard memories for measured waveforms, so it must have a backup battery somewhere. I opened it up removing the upper lid (careful with the printing device connecting cable!) and was surprised to see that it has plug-in boards.
I wouldn't say that these are serviceable, but at least replaceable with similar boards.

With a bit of lucky intuition I found the battery on the "DIGITAL" board. It is 2.4V 110mAh and according to my DVM it still has some charge (~1V). No visible leak. I will replace it as soon as possible.

At the same time I am working on the power button, that seems to close only one contact towards the chassis (!). Or wait, it must be some mechanical thing instead. The button pulls/releases a metallic strip that goes all the way to PSU. I need to follow it all the way in there...

Edit 2014-02-11: I do not own anymore the Gould 4072.