24-05-2015, 01:57 PM
Hi Sam,
This is a puzzle! Still, it's easy to forget that we have made progress, and there's no reason to believe that more can't be had. I have dug out my paper copy of the manual, which is obviously easier to read than the PDF, and I've been wondering where best to go next. Of course, a big stumbling point for me is the lack of second oscilloscope. Your DM63 will be much easier, BTW, but let's persevere with this one for a while.
You have given a lot of information in previous posts, but it's too much to take on board and put in to some sort of structure. Let's start at the beginning, taking small steps.
Of course, while you don't have a fully-working second 'scope, the one you do have will be of use. It's not sweeping, but the Y-channels are working sufficiently well to tell us more information than just a DMM. We will take advantage of this.
So, we know the X-amp is working to some extent. But there is no sweep. So we need to answer this question:
Is the sweep generator working, but not getting to the X plates?
And of course, we have a bunch of diode switches that are used to switch between the sweep generator and the vertical channel when the 'scope is in X-Y mode, so it is indeed possible that the sweep is running.
When you are next at the bench, here are two things I need you to investigate:
1. When the 'scope is NOT in X-Y mode, what effect does Channel 2's Y-shift control have on the horizontal position of the dots?
2. With all the controls set as suggested in my earlier post, turn off Channel 2 - that should leave a single dot. Set Channel 1 to 1V/div, and select DC input coupling. Connect Channel 1's input to the sweep terminal on the front panel. What happens to the dot? Does it move to a new position on the screen? Or, does it change into a vertical line?
Let me know what you find, and I'll tell you where to go next
Mark
This is a puzzle! Still, it's easy to forget that we have made progress, and there's no reason to believe that more can't be had. I have dug out my paper copy of the manual, which is obviously easier to read than the PDF, and I've been wondering where best to go next. Of course, a big stumbling point for me is the lack of second oscilloscope. Your DM63 will be much easier, BTW, but let's persevere with this one for a while.
You have given a lot of information in previous posts, but it's too much to take on board and put in to some sort of structure. Let's start at the beginning, taking small steps.
Of course, while you don't have a fully-working second 'scope, the one you do have will be of use. It's not sweeping, but the Y-channels are working sufficiently well to tell us more information than just a DMM. We will take advantage of this.
So, we know the X-amp is working to some extent. But there is no sweep. So we need to answer this question:
Is the sweep generator working, but not getting to the X plates?
And of course, we have a bunch of diode switches that are used to switch between the sweep generator and the vertical channel when the 'scope is in X-Y mode, so it is indeed possible that the sweep is running.
When you are next at the bench, here are two things I need you to investigate:
1. When the 'scope is NOT in X-Y mode, what effect does Channel 2's Y-shift control have on the horizontal position of the dots?
2. With all the controls set as suggested in my earlier post, turn off Channel 2 - that should leave a single dot. Set Channel 1 to 1V/div, and select DC input coupling. Connect Channel 1's input to the sweep terminal on the front panel. What happens to the dot? Does it move to a new position on the screen? Or, does it change into a vertical line?
Let me know what you find, and I'll tell you where to go next
Mark
