Hi,
I purchased a GW-INSTEK GRS-6032A oscilloscope from eBay a few weeks ago. What makes this scope interesting is that it's hybrid - supporting both analog and digital storage up to 30MHz bandwidth and 500MS/s sampling rate with just a press of a button. Anyway it was working well for around a week or two after the purchase when I suddenly noticed something interesting:
1. In analog mode, the display would be shifted down vertically, so the bottom status line showing voltage per division, timebase, trigger settings etc. is not visible. The top status line showing cursor readout remains visible, although it also moves down with the rest of the display.

By using the trace rotation I can see the the status line is still there, just not visible when the display is horizontal:

2. The position of the traces for channel 1 and 2 can still be moved normally using the position buttons, but the readout and status lines cannot be moved. This is however by design.
3. The vertical display offset in analog mode is not constant, but appears to change randomly. When the problem first occurred, leaving the oscilloscope working for a few hours would result in the whole analog display moving up slowly, eventually reaching its intended position. However, currently this no longer happens. In fact - the analog display may sometimes bounce up and down repeatedly, and sometimes remain stable but only at the bottom quarter of the screen.
4. If the oscilloscope is switched from analog to digital mode by pressing the STORAGE button, then all traces and status lines will suddenly move up to their expected position. In fact there are no issues with digital mode, only analog mode:

Suspecting some leaking capacitors whose capacitance will change as they get warmer after a period of usage, I opened up the oscilloscope for a visual inspection but found nothing interesting.
Any advice on what the problem might be? As the oscilloscope seems to have no other problem, my intention is to see if this can be a simple fix. If not, I will just live with the current issues until it gets more serious.
The photos of the analog and digital traces are attached to this thread. Other photos of the inside of this oscilloscope can be found at: https://www.dropbox.com/sh/dcuo1ceqjly32u0/AACrvv3hE1DQN_eyNf4kOMf9a
Thanks in advance for any suggestions.
I purchased a GW-INSTEK GRS-6032A oscilloscope from eBay a few weeks ago. What makes this scope interesting is that it's hybrid - supporting both analog and digital storage up to 30MHz bandwidth and 500MS/s sampling rate with just a press of a button. Anyway it was working well for around a week or two after the purchase when I suddenly noticed something interesting:
1. In analog mode, the display would be shifted down vertically, so the bottom status line showing voltage per division, timebase, trigger settings etc. is not visible. The top status line showing cursor readout remains visible, although it also moves down with the rest of the display.

By using the trace rotation I can see the the status line is still there, just not visible when the display is horizontal:

2. The position of the traces for channel 1 and 2 can still be moved normally using the position buttons, but the readout and status lines cannot be moved. This is however by design.
3. The vertical display offset in analog mode is not constant, but appears to change randomly. When the problem first occurred, leaving the oscilloscope working for a few hours would result in the whole analog display moving up slowly, eventually reaching its intended position. However, currently this no longer happens. In fact - the analog display may sometimes bounce up and down repeatedly, and sometimes remain stable but only at the bottom quarter of the screen.
4. If the oscilloscope is switched from analog to digital mode by pressing the STORAGE button, then all traces and status lines will suddenly move up to their expected position. In fact there are no issues with digital mode, only analog mode:

Suspecting some leaking capacitors whose capacitance will change as they get warmer after a period of usage, I opened up the oscilloscope for a visual inspection but found nothing interesting.
Any advice on what the problem might be? As the oscilloscope seems to have no other problem, my intention is to see if this can be a simple fix. If not, I will just live with the current issues until it gets more serious.
The photos of the analog and digital traces are attached to this thread. Other photos of the inside of this oscilloscope can be found at: https://www.dropbox.com/sh/dcuo1ceqjly32u0/AACrvv3hE1DQN_eyNf4kOMf9a
Thanks in advance for any suggestions.
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