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See_Mos · 2nd Dec 2017, 5:19 pm

I haven't seen inside the HM208 but I had an intermittent fault with my HM204. One of the transistors soldered to the PCB and fixed to the chassis at the back had a poor soldered connection. It took months to find because every time I took the case off the fault disappeared until weeks after the case was put back on.

You can of course still use the scope with a probe to check if its own timebase is running, just use the shift to move the spot across a little and turn the brightness down. Assuming it has an X input you could also connect a low voltage AC source to the X input to see if the X amplifier and output stages are OK.

It could just be the X / Y switch?

2nd Dec 2017, 5:19 pm	#2
See_Mos Hexode Join Date: Nov 2003 Location: Ossett, West Yorkshire, UK. Posts: 483	Re: Hameg HM208 Oscilloscope Timebase fault I haven't seen inside the HM208 but I had an intermittent fault with my HM204. One of the transistors soldered to the PCB and fixed to the chassis at the back had a poor soldered connection. It took months to find because every time I took the case off the fault disappeared until weeks after the case was put back on. You can of course still use the scope with a probe to check if its own timebase is running, just use the shift to move the spot across a little and turn the brightness down. Assuming it has an X input you could also connect a low voltage AC source to the X input to see if the X amplifier and output stages are OK. It could just be the X / Y switch? Last edited by See_Mos; 2nd Dec 2017 at 5:41 pm.