Title pretty much sums it up. I've traced the audio signal as far down as entering R97, but not hitting the base of Q25. I've got audio signal at the junction of C92 and R97. Then it just disappears.
I've checked R97, it tests good (82 K +/- 10 %). The Q25 transistor tests good. At -50 dBm input the S-meter is showing S9 like it should. Transmit audio looks good on the scope, PA audio works fine. Electrolytics are new (Thanks, Klondike Mike!).
BTW, the schematic in the service manual (https://bit.ly/3hNP86p, don't even bother with SAMS CB-278) has the order reversed on the parts in the signal path, C92 is definitely in the path before R97, and R97 is connected directly to the base of Q25. At least that's how my version of the radio was built.
I've got about .8 V DC on the base of Q25, .2 V DC on the emitter, and 5.2 V DC on the collector. The audio signal at the junction of C92 and R97 is about 70 mV AC (assuming I'm reading the scope right). Anyone happen to know if those values are anywhere close to correct? I didn't bother checking them before i had the problem.
I'll be more than happy to provide any more detail if requested.
I've checked R97, it tests good (82 K +/- 10 %). The Q25 transistor tests good. At -50 dBm input the S-meter is showing S9 like it should. Transmit audio looks good on the scope, PA audio works fine. Electrolytics are new (Thanks, Klondike Mike!).
BTW, the schematic in the service manual (https://bit.ly/3hNP86p, don't even bother with SAMS CB-278) has the order reversed on the parts in the signal path, C92 is definitely in the path before R97, and R97 is connected directly to the base of Q25. At least that's how my version of the radio was built.
I've got about .8 V DC on the base of Q25, .2 V DC on the emitter, and 5.2 V DC on the collector. The audio signal at the junction of C92 and R97 is about 70 mV AC (assuming I'm reading the scope right). Anyone happen to know if those values are anywhere close to correct? I didn't bother checking them before i had the problem.
I'll be more than happy to provide any more detail if requested.