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NikPrice · 5th Feb 2020, 6:01 pm

I changed the TL094 for an equiv TL084, both seemed to give the same results. Checking with the scope there appears to be little or no ripple on T9, although I changed it out just to be on the safe side. The readings on IC5 pins 1+2 show 1.84V 160mV ripple and pin 3 show 2.00V and 240mV ripple.

How accurate this is I can't be sure as my scope is a cheap and cheerful Hantek DSO5102P.

Something else I have noticed is that the voltages, when they settle after power on, appear to not be exactly as they were when last powered on. Rail volts appear to be the same, but REF-L and REF-H differ slightly every time the unit is powered up.

C12 has been changed and I have swapped back in the 470R R21.

5th Feb 2020, 6:01 pm	#15
NikPrice Triode Join Date: Feb 2020 Location: Portsmouth, Hampshire, UK. Posts: 35	Re: Another Quad FM4 problem I changed the TL094 for an equiv TL084, both seemed to give the same results. Checking with the scope there appears to be little or no ripple on T9, although I changed it out just to be on the safe side. The readings on IC5 pins 1+2 show 1.84V 160mV ripple and pin 3 show 2.00V and 240mV ripple. How accurate this is I can't be sure as my scope is a cheap and cheerful Hantek DSO5102P. Something else I have noticed is that the voltages, when they settle after power on, appear to not be exactly as they were when last powered on. Rail volts appear to be the same, but REF-L and REF-H differ slightly every time the unit is powered up. C12 has been changed and I have swapped back in the 470R R21.