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(sound of raucous klaxon horn)

Pin 9 needs to be half the reading at pin 1. Acceptable range would have been between 6 and 7 Volts DC. They read nearly the same. This indicates likely damage to the TA7222P audio chip. Any time this part is changed, we also change the output-blocking capacitor C213. Any time it goes bad, it can damage that chip.

And the speaker.

Cheap insurance.

The only other faults I know that can cause the voltage reading you saw on pin 9 would be a short in either C217 or C219. Easy enough to find out. Unsoldering one lead of either cap so that it won't touch the edge of the foil pad will take it out of the circuit.

If doing this changes the DC voltage reading at pin 9, this cap has a problem. And if taking one lead out of the circuit (for either cap) does NOT change this reading, that capacitor is NOT the root of the problem, and the TA7222P chip has the problem.

Don't know how many counterfeits of that part are out there, but UTSource on Ebay is fairly reliable. Haven't gotten a fake chip from them yet.

73

<blockquote data-quote="nomadradio" data-source="post: 777176" data-attributes="member: 22">(sound of raucous klaxon horn)Pin 9 needs to be half the reading at pin 1. Acceptable range would have been between 6 and 7 Volts DC. They read nearly the same. This indicates likely damage to the TA7222P audio chip. Any time this part is changed, we also change the output-blocking capacitor C213. Any time it goes bad, it can damage that chip. And the speaker.Cheap insurance. The only other faults I know that can cause the voltage reading you saw on pin 9 would be a short in either C217 or C219. Easy enough to find out. Unsoldering one lead of either cap so that it won&#039;t touch the edge of the foil pad will take it out of the circuit. If doing this changes the DC voltage reading at pin 9, this cap has a problem. And if taking one lead out of the circuit (for either cap) does NOT change this reading, that capacitor is NOT the root of the problem, and the TA7222P chip has the problem. Don&#039;t know how many counterfeits of that part are out there, but UTSource on Ebay is fairly reliable. Haven&#039;t gotten a fake chip from them yet. 73</blockquote>

[QUOTE="nomadradio, post: 777176, member: 22"] (sound of raucous klaxon horn) Pin 9 needs to be half the reading at pin 1. Acceptable range would have been between 6 and 7 Volts DC. They read nearly the same. This indicates likely damage to the TA7222P audio chip. Any time this part is changed, we also change the output-blocking capacitor C213. Any time it goes bad, it can damage that chip. And the speaker. Cheap insurance. The only other faults I know that can cause the voltage reading you saw on pin 9 would be a short in either C217 or C219. Easy enough to find out. Unsoldering one lead of either cap so that it won't touch the edge of the foil pad will take it out of the circuit. If doing this changes the DC voltage reading at pin 9, this cap has a problem. And if taking one lead out of the circuit (for either cap) does NOT change this reading, that capacitor is NOT the root of the problem, and the TA7222P chip has the problem. Don't know how many counterfeits of that part are out there, but UTSource on Ebay is fairly reliable. Haven't gotten a fake chip from them yet. 73 [/QUOTE]

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