Hi all
Quite a lot of years ago there was a topic posted here that went on for some time but never reached any conclusion as to the cause of the problem...unfortunately the exact problem I think I'm having right now. I wonder if any of you have encountered this and with fresh insight perhaps shine light on the cause? I've done a fair bit of investigation so far but I'm loathe to really get stuck in and start pulling the thing to bits without at least a better likelihood of being sure where the problem probably lies. Some basics - in NON storage everything is perfect and ALL diagnostics pass OK. In this respect there is zero problem. I re-calibrated it all about 18 months ago and have loved this scope for many years. PROBLEM - In STORAGE mode everything seems a bit mixed up. Channel 1 displays a trace but the amplitude is half or less of the real value. Channel 2 is similar but probably a quarter of the real value. Switching to BOTH it looks like there is only one trace but actually they are both overlaid on top of each other and it is not possible to separate them at all. Putting a sine into 1 and a square into 2 then the resulting waveform is an odd hybrid of both but not in the way 'add' would do that. Similar strange things happen with the amplitude also and all the other issues are a combination of this general characteristic. With the 4 wire connector going to channel 2 on the storage board removed and grounded appropriately leaving only channel plug connected watching a sine trace in store mode as I write it is just 20% of the real value but but does keep expanding to around 50% every now and then. The post from years ago seemed to point to U2101 on the storage board that both channels go to first but I'm not sure. Someone actually said it was that chip mixing up the signals but never gave evidence as to why that was so. Those chips just do not exist anymore so if it is then it's game over. I de-soldered mine and put it in a socket so I could take it out easily if I needed to. Is it an issue with the vector board perhaps? That's a pain to get to so I'd like a good idea the issue might be there before I go that route. Finally, time measurements are NOT affected. So, if you've got this far reading I thank you and if anyone has any thoughts please do share, I'd be very grateful. Cheers.
Kevin