11-12-2021, 06:27 PM
(This post was last modified: 11-12-2021, 06:27 PM by Mike Watterson.)
The Pye is probably identical. Invicta and Pam were simply Pye badges by 1950s.
I can scan my R&TVS P123BQ if you don't get a copy. Any two colour plastic case electrolytics may have dried out if not leaking. Leakage in paper dielectric caps is rarely an issue at the voltages and base currents in Germanium sets.
The Pye 123BQ is very similar to the Pam 710 and the Invicta Transistor may be basically the Pam 710 in the picnic box case.
The transistors are not critical and various Russian military ones will work. The Pye 123 on R&TVS and Trader lists OC71 as alternate V4 (driver) and 2 x OC72 for V5 & V6 (Push pull o/p). Alternates are also listed for V1, V2 & V3 (types I've never seen), but they particularly can be replaced by any cheap PNP Russian type even only 50 MHz ft, though by extra and test gain!
I think more than one Invicta model number was reused.
This is not a difficult set to get going even without circuit.
I can scan my R&TVS P123BQ if you don't get a copy. Any two colour plastic case electrolytics may have dried out if not leaking. Leakage in paper dielectric caps is rarely an issue at the voltages and base currents in Germanium sets.
The Pye 123BQ is very similar to the Pam 710 and the Invicta Transistor may be basically the Pam 710 in the picnic box case.
The transistors are not critical and various Russian military ones will work. The Pye 123 on R&TVS and Trader lists OC71 as alternate V4 (driver) and 2 x OC72 for V5 & V6 (Push pull o/p). Alternates are also listed for V1, V2 & V3 (types I've never seen), but they particularly can be replaced by any cheap PNP Russian type even only 50 MHz ft, though by extra and test gain!
I think more than one Invicta model number was reused.
This is not a difficult set to get going even without circuit.
