10-25-2012, 09:15 PM
According to the Production Change Notices for the 623, Run 4 (Oct. 1, 1935) had the 34 tube changed to the 1A4 and the 1st. IF transformer changed to increase sensitivity.
You your set is a later run version. Production went through 9 Run changes (component changes, additions, removal, etc.) during its production lifetime.
Service Bulletin No. 225 shows the 34 tube used initially.
Chuck
You your set is a later run version. Production went through 9 Run changes (component changes, additions, removal, etc.) during its production lifetime.
Service Bulletin No. 225 shows the 34 tube used initially.
Chuck
Chuck Schwark,
The Philco Repair Bench
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http://www.philcorepairbench.com