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If this radio has the widely-used TA7222P audio-power chip, clip the negative lead of your voltmeter to the negative pin on the inside of the power socket. Touch the top of the red probe the next-to-rearmost pin of the audio chip to read the DC voltage there. This will be pin 9 for those playing along at home. Be careful not to bridge adjacent pins with the tip of the probe. The foil pad that leads away from this pin is larger, and easier to probe than the pin itself, and will get you the same reading as touching the pin directly. Definitely safer.

The reading should be very nearly one-half of your power-supply voltage. If it delivers 13.5 Volts DC to the radio, the reading should be close to 6.5 Volts DC.

The other quick test for this chip is to moisten one fingertip and lay it along all ten pins of this chip. This should create a feedback circuit, and get you a loud screech from the speaker. If the radio will do this, your audio problem is upstream from this chip, and replacing it probably won't fix the problem.

73

<blockquote data-quote="nomadradio" data-source="post: 609860" data-attributes="member: 22">If this radio has the widely-used TA7222P audio-power chip, clip the negative lead of your voltmeter to the negative pin on the inside of the power socket. Touch the top of the red probe the next-to-rearmost pin of the audio chip to read the DC voltage there. This will be pin 9 for those playing along at home. Be careful not to bridge adjacent pins with the tip of the probe. The foil pad that leads away from this pin is larger, and easier to probe than the pin itself, and will get you the same reading as touching the pin directly. Definitely safer.The reading should be very nearly one-half of your power-supply voltage. If it delivers 13.5 Volts DC to the radio, the reading should be close to 6.5 Volts DC.The other quick test for this chip is to moisten one fingertip and lay it along all ten pins of this chip. This should create a feedback circuit, and get you a loud screech from the speaker. If the radio will do this, your audio problem is upstream from this chip, and replacing it probably won&#039;t fix the problem.73</blockquote>

[QUOTE="nomadradio, post: 609860, member: 22"] If this radio has the widely-used TA7222P audio-power chip, clip the negative lead of your voltmeter to the negative pin on the inside of the power socket. Touch the top of the red probe the next-to-rearmost pin of the audio chip to read the DC voltage there. This will be pin 9 for those playing along at home. Be careful not to bridge adjacent pins with the tip of the probe. The foil pad that leads away from this pin is larger, and easier to probe than the pin itself, and will get you the same reading as touching the pin directly. Definitely safer. The reading should be very nearly one-half of your power-supply voltage. If it delivers 13.5 Volts DC to the radio, the reading should be close to 6.5 Volts DC. The other quick test for this chip is to moisten one fingertip and lay it along all ten pins of this chip. This should create a feedback circuit, and get you a loud screech from the speaker. If the radio will do this, your audio problem is upstream from this chip, and replacing it probably won't fix the problem. 73 [/QUOTE]

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