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Rochabian · 18 April 2020, 02:59

Well. I've desoldered the U31 and it's the same Vdac still 2.27

I don't understand why Vdac is not 5V, as it's generated by U32 and i've replaced it, and i have 12V on pin 8

It's sure that if Vdac is not 5V, then U15A and U38B can't work normally, because their inputs Vbias and AvRef are based on Vdac

Perhaps the 78L05 that i've replaced is faulty too.....This would be unlucky

In the pic attached i can see Vdac Generating Avref in PAULA/AUDIO DECOUPLING
And Vdac generated by U32 in CD/AUDIO DECOUPLING

I can't see what can be wrong with U31 desoldered......

18 April 2020, 02:59	#11
Rochabian The Big White Cat Join Date: Jan 2005 Location: France Age: 44 Posts: 828	Well. I've desoldered the U31 and it's the same Vdac still 2.27 I don't understand why Vdac is not 5V, as it's generated by U32 and i've replaced it, and i have 12V on pin 8 It's sure that if Vdac is not 5V, then U15A and U38B can't work normally, because their inputs Vbias and AvRef are based on Vdac Perhaps the 78L05 that i've replaced is faulty too.....This would be unlucky In the pic attached i can see Vdac Generating Avref in PAULA/AUDIO DECOUPLING And Vdac generated by U32 in CD/AUDIO DECOUPLING I can't see what can be wrong with U31 desoldered...... Attached Thumbnails Last edited by Rochabian; 18 April 2020 at 03:23.