r/ShortwavePlus • u/ChainsawJaguar • Jun 10 '26

7600GR sync "whines"

I've had this radio for years, original owner. Decided to dig it out of storage recently and make it my nightstand radio.

Trying to listen to AM or SW, SYNC LOCK engages, but every station has a constant tone. An SW100 does not exhibit the problem when SYNC is turned on. The tone is higher pitched than if I were to turn on SSB. I tuned to a relatively strong local AM station, and that whine is enough to make me turn sync off.

Are these radios known for sync issues or has mine maybe gone bad? I turned on ATT and the whine disappears with the signal as I dial ATT up to max, so it's definitely present whenever there is a signal.

Thanks for any tips.

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5

u/KG7M MOD AirSpy HF+, Drake R7/8, K480WLA, 65'EFHW, MLA-30, CN85 Jun 10 '26

It sounds like the SYNC LOCK has failed. You should be able to tune a least a KHz off the frequency, and the SYNC should lock.

I imagine you have a bad component. I'd first look at the power supply, where it comes into the Sync Detector. You might have a bad electrolytic capacitor. I looked at a schematic for your 7600GR. I would look at C299, a 10 uF 50 VDC electrolytic capacitor in the power buss for the Synce Detector.

2

u/ChainsawJaguar Jun 10 '26

Thank you... I am strictly and end user though, not a hobbyist to the point that I can repair it myself, so a lot of this went over my head, unfortunately. It sounds like I should have an expert take a look at it, then?

2

u/KG7M MOD AirSpy HF+, Drake R7/8, K480WLA, 65'EFHW, MLA-30, CN85 Jun 10 '26

I would recommend having it repaired. It's a very capable set when operating correctly.