On Mon, 15 Oct 2018 at 15:41 <maxim.vlasov@...> wrote:
Looks like slowly but surely I make some progress. Just found that U2420DI don't know whether that's unreasonable, but -8.8V out of the op-amp is
well within its control range. A TL074 will go to +12/-12V minimum on a
+15/-15V supply so I wouldn't focus there too much. If you look at the
power distribution diagram <11>(?), you'll see U700/U850/U900 get -1.25V
bias, so 11mA is probably reasonable.
Have you observed this on your scopes when repairing?Sadly I haven't measured this - if you're stuck, I can pop the case on my
2467 this weekend and check it. Offhand, I don't think 11mA is unreasonable
One more thing - I've got -04 FW version. It seems like the last versionI updated my firmware from -06 to -09 without incident. Didn't need
re-calibration that I noticed.