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There are four electrolytic caps around IC4, the TA7222P audio amp. Any chance one of them has the polarity reversed?

The squeal is usually from a ground loop. The ground side of the counter's power should go to the ground foil where the big filter C134 negative lead is soldered. The ground side of the signal input should have a disc capacitor between the ground wire and the ground foil in the PLL section. A .001 uf disc cap works okay. Passes the 34 MHz RF signal, but not the audio-frequency noises.

Just make sure the counter pc board is totally insulated from the metal chassis.

73

[QUOTE="nomadradio, post: 854777, member: 22"] There are four electrolytic caps around IC4, the TA7222P audio amp. Any chance one of them has the polarity reversed? The squeal is usually from a ground loop. The ground side of the counter's power should go to the ground foil where the big filter C134 negative lead is soldered. The ground side of the signal input should have a disc capacitor between the ground wire and the ground foil in the PLL section. A .001 uf disc cap works okay. Passes the 34 MHz RF signal, but not the audio-frequency noises. Just make sure the counter pc board is totally insulated from the metal chassis. 73 [/QUOTE]

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