Rings on both hands, and a metal watch band......
an accident waiting to happen....
good call!
contrast that with the good technique used by the Carvin tech.
didn't notice in the Carvin picture sequence, any rings or watches.
also, the meter probes were as close to vertical as possible.......that mimizes the possibility of accidentally shorting between solder pads. (aka - Fat Probe Syndrome)
the one thing i didn't quite get:
they write down 2 measurements, one from
each end of R43 to ground.
then they subtract the 2 measurements, and write that down.
why not just measure
across R43, and write it down?
sure would eliminate some clutter.
EDIT:Rune, try this on for size and see how you like it:
Streamlined Bias Calculations:1 - Measure plate voltage
2 - Calculate total plate current for 70% power (a thru d)
____a - max power / valve
____b - multiply by number of valves
____c - divide by plate voltage
____d - multiply by 0.7 (70%)
3 - Measure non-plate current. (divide voltage drop by resistance)
4 - Calculate total system current (add 2 and 3)
5 - Adjust Bias for total system current. (measure at standby switch)
Example:
1 _ Plate voltage = 394volts
2 _ 85.3 mA (from a thru d)
____a - 12watts
____b - *4 = 48watts
____c - /394volts = 121.82 mA
____d - * 0.7 = 85.3 mA
3 _ 7volts / 350 ohms = 20 mA
4 - 85.3mA + 20 mA = 105.3 mA
5 - adjust to
no more than 105.3 mA @ stanby switch.
unk
