I did one a few years ago and got a lot of help from this forum. Unfortunately I can’t access the archives to find the relevant posts. I’ll dig around and see if I can find any hints.

Couple things you’ll need to consider: - You’ll need to keep the speaker connected because the speaker field coil is part of the amp circuit. - You can’t just put a signal into the input because this amp uses an oscillator in combination with the Cobra needle. To work around this, you can inject a signal after the oscillator stage. I used a frequency generator at this point and then measured the output level. By varying the input frequency you can generate an overall frequency response curve. I found that this amp has a strange dip right in the midrange. I was able to add some circuitry to make the response more flat. I added a micro switch so I could take this circuitry in or out.

Thanks, -steve.

On Feb 9, 2026, at 4:29 PM, Tony Miklos via Jukebox-list jukebox-list@lists.netlojix.com wrote:



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On 2/9/2026 5:07 PM, ascott822 via Jukebox-list wrote: I have recapped the amp and would like to know how to test it out of the box on the bench. Thanks

In the manual on the schematic it shows what pins to jump to others. Look at the power supply and the speaker circuit.

Tony Miklos Tony's Jukebox Repair

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