¿ªÔÆÌåÓý"What's wrong with your channel 2?" --
Well, it's now channel 1. ;) It started as a bit of instability,
ie: trace jumping around with no change to the controls. And the
position wasn't properly centered, such that to center the trace
the position knob had to be at about 10 o'clock. Swapping all the
transistors from CH1 to CH2 one at a time made no difference. Now
that I've swapped the attenuators, the position centering issue is
still on channel 2, but otherwise channel two works perfectly, so
I'll probably leave it alone for now. Channel 1 had the
instability; until now it has a DC bias that drives it way off the
screen. The invert switches which way it is driven off, and
sometimes tapping on the attenuator module switches it too. Upon
further investigation the trace came back if I disconnected one
side of the differential signal from the attenuator to the main
output board. That's a slide on connector that is right before the
invert switch in the signal path. That's where I am so far with
the troubleshooting.
Respectfully,
On 01/27/2014 06:31 PM, mda231@... wrote:Cliff White, W5CNW w5cnw@... ? |
