10-08-2006, 09:45 AM
T. Blurr,
There are a couple subtle circuit differences between the virtually idnetical 660 and 665 chassis'.
On the 75 DET tube in the 660, both diode plates are tied together, but in the 655, there is a small value cap tied across the two plates.
Also, in the 660, the Shadow Meter has a 2,000 ohm resistor in parallel with the Shadow Meter coil. The 665 has no such shunt resistor on the Shadow Meter circuit.
There are a couple subtle circuit differences between the virtually idnetical 660 and 665 chassis'.
On the 75 DET tube in the 660, both diode plates are tied together, but in the 655, there is a small value cap tied across the two plates.
Also, in the 660, the Shadow Meter has a 2,000 ohm resistor in parallel with the Shadow Meter coil. The 665 has no such shunt resistor on the Shadow Meter circuit.
Chuck Schwark,
The Philco Repair Bench
[Image: http://www.philcorepairbench.com/images/philog3tiny.gif]
http://www.philcorepairbench.com
