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It's time to stop groping and do some serious troubleshooting.
First make sure the local oscillator is running, and covers the proper frequency range. Put a signal into the IF and see if it has reasonable gain. After that, you will have enough info to track down the problem.
Generally, you won't find that the 12AT7 functions on AM. You probably have something like a 6BE6 or 12BE6 for the front end on AM.
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