09-18-2022, 06:58 PM
Hi, RetroRev,
That all sounds about right. Next step is to inject an audio signal. Several places to do so, but the best point is the junction of C47, R26, C42 and R20. Of course, if the radio has a phono / FM Tuner / TV Input, that will work great! Make an adaptor cable where the "ring" and "tip" (The 2 contacts closest to the end of a 3.5 mm "TRS" (Tip, Ring Shield) headphone plug are each connected to a 10K resistor. The other ends of the resistors are joined together and toa 0.91 uF cap. That goes to the above junction. The shield (the long contact on the plug_ Connection is to chassis ground. Use a battery powered device such as a CD or MP3 player to inject a signal (maybe some Big Band music). If you get good audio, controllable by the radio's volume control, then the Amp is good. Let us know, then we can look at the next troubleshooting step.
That all sounds about right. Next step is to inject an audio signal. Several places to do so, but the best point is the junction of C47, R26, C42 and R20. Of course, if the radio has a phono / FM Tuner / TV Input, that will work great! Make an adaptor cable where the "ring" and "tip" (The 2 contacts closest to the end of a 3.5 mm "TRS" (Tip, Ring Shield) headphone plug are each connected to a 10K resistor. The other ends of the resistors are joined together and toa 0.91 uF cap. That goes to the above junction. The shield (the long contact on the plug_ Connection is to chassis ground. Use a battery powered device such as a CD or MP3 player to inject a signal (maybe some Big Band music). If you get good audio, controllable by the radio's volume control, then the Amp is good. Let us know, then we can look at the next troubleshooting step.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
