Racal 9301A ?
 

Hank:

The Q11 transistor is part of the Pulse Drive Output circuit. The output
from the monostable at the collector of Q7 is fed via R17 to the
differential transistir pair of Q9/Q10 which provide separate outputs to the
sample & hold circuit and clamp the circuit respectively in the processor
PCB. The monostable output is also fed via R25 to the pulse amplifier &
shaper circuit comprised of Q11/Q12/Q13 for the sampling drive in the probe.

Q7/Q11/Q13 are NPN transistors 2N2369
Q9/Q10/Q12 are PNP transistors BFX48
R17 is 560 Ohms 1/4 Watt 5%
R25 is 680 Ohms 1/4 Watt 5%

I am not sure how much the transistors cost, but I have seen $5 each for the
BFX48. Be sure to check all of the other components in this circuit to see
if something else is cooked.

Regards,
Steve Ripper
Email(1):
Email(2):


"Henry Kolesnik" wrote in message
...
I just picked up a Racal Dana 9301A RF MIllivoltmeter and it doesn't work
because Q11 is total carbon. Any info on what Q11 is and what might have
shorted to take it out would be appreciated. Please post here as my email
has problems.

tnx
hank wd5jfr

Hank:

The Q11 transistor is part of the Pulse Drive Output circuit. The output
from the monostable at the collector of Q7 is fed via R17 to the
differential transistir pair of Q9/Q10 which provide separate outputs to the
sample & hold circuit and clamp the circuit respectively in the processor
PCB. The monostable output is also fed via R25 to the pulse amplifier &
shaper circuit comprised of Q11/Q12/Q13 for the sampling drive in the probe.

Q7/Q11/Q13 are NPN transistors 2N2369
Q9/Q10/Q12 are PNP transistors BFX48
R17 is 560 Ohms 1/4 Watt 5%
R25 is 680 Ohms 1/4 Watt 5%

I am not sure how much the transistors cost, but I have seen $5 each for the
BFX48. Be sure to check all of the other components in this circuit to see
if something else is cooked.

Regards,
Steve Ripper
Email(1):
Email(2):


"Henry Kolesnik" wrote in message
...
I just picked up a Racal Dana 9301A RF MIllivoltmeter and it doesn't work
because Q11 is total carbon. Any info on what Q11 is and what might have
shorted to take it out would be appreciated. Please post here as my email
has problems.

tnx
hank wd5jfr