Re: 485 super weak brightness control


The node 1312/1318 is 0.0V in A and -0. 6V in B in the 521 mode
0.9V in A and -0. 6V outside of the 521
That looks suspect
I agree this needs to be investigated further. Easy explanation is N4 signal on <11> is wrong but we looked at it before.

--- copied from our earlier exchange --
In sheet <12> N4 is expected to
be -3V in B sweep and 5/2/1n mode. What voltage do you see at N4 when you
are in B sweep vs A sweep 5/2/1n?
I can see -3.6 when 521 is selected, -3. 7 when B is selected and -5.3
when there is A selected and outside of the 521 range
-- end copy ----------------------------------

Confirming again is a good idea.

How do waveforms look in the following points in 521n setting A vs B at:
"A sweep from Q888" left side of R1307
"B sweep from Q1236" left side of R1322

Again we expect no change.


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