Fader problems and V-Pots

[Dreamsequence]

Crash & Joe:

Thanks for the suggestions. I did a fresh OS install (v3.0) twice; no change. I suspect either the +5 regulator or the comparator IC, too, but the voltage divider makes me suspect the caps at either the +5 regulator or C914. Somewhere the reference is off. The puzzling thing is why both channel groups would be off the same amount, unless the Brain Board has the reference messed up. More after I get my hands on a replacement fader board...

[FrankH]

Dreamsequence:

I have been reading this thread and the Modify Levels thing was the first thing I thought of but it got covered in the responses....so I laid out.

Peter wrote:

BTW, "Modify Levels" is found under the "Edit" menu or by selecting Alt-M. It is a function that allows level changes to automation or overall to selected channels. When saved, that's how it stays, either in a startup session or other session, hence my request that you delete all startup sessions and deactivate "Load last session at power up".

and I noticed that you never really responded to this. Did you try this?

[Dreamsequence]

Frank:

I tried "Modify Levels" several times. It sounded like that would be the problem, but no change (although I recall some change from the original condition). Nothing I tried could 'push' the faders to +10dB during calibration, nor 0dB when forcing them to unity. I considered something in the EPROM where the "Modify Levels" info is stored (on the Brain board???), but don't know enough about the protocols. Is there a way to force a 'hard' reset on the Brain PCB or the EPROM, or is that a bad idea? The fact that the 9-fader board calibrates correctly still leads me to believe that somehow the REF voltage is off on both fader groups. I'll try to get readings off the +5 regulator and check the +2.5v reference and the voltages at U904 and U908.

[Dreamsequence]

synthjoe:

You must be psychic: the turntable v-belt was too stretchy. A piece of cotton twine worked much better for spinning the V-Pots. Some brisk spins have cleaned up most of the jitters. The worst ones will need some more cranking...

[synthjoe]