I was called into to look at a board that has a DAC7846 -16 bit D/A) , which has a history of "failures" according to the previous "tech" (they always replace DAC to fix the "problem" ). They seem to replace these quite often... at $50 buck a chip, this gets expensive.
For some reason (i suspect noise) they piggy-back (manually solder) a 470uF Cap across Analog and Digital ground of the DAC.
Has anyone ever seen this done before... a cap between the two grounds?
The power supply inputs (+15v,-15v,5v) to the DAC only have 47nF caps each (mounted next to the DAC)... seems a little on the small side?
For some reason (i suspect noise) they piggy-back (manually solder) a 470uF Cap across Analog and Digital ground of the DAC.
Has anyone ever seen this done before... a cap between the two grounds?
The power supply inputs (+15v,-15v,5v) to the DAC only have 47nF caps each (mounted next to the DAC)... seems a little on the small side?