The last readings I posted the amp was not powering up.
Checked it today and amp is powering up. Voltage on pin 4 is at +0.190 and pulsing up and down by about 0.010 volts. Noticed as I continued to monitor it voltage slowly starts dropping and still pulsing as I described. After about 2 minutes it gets down to +0.130 still pulsing as described.
Checked it today and amp is powering up. Voltage on pin 4 is at +0.190 and pulsing up and down by about 0.010 volts. Noticed as I continued to monitor it voltage slowly starts dropping and still pulsing as I described. After about 2 minutes it gets down to +0.130 still pulsing as described.
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It is was one of the parts I replaced with one from my other board. The one that was on it appeared to have a spot on it where it had gotten hot. It also had a number of the components on the power side blown. I switched it back to the original one and it does the same thing. So in answering your question it applies to both transformers that I tried.
Yes, it is heating unevenly.
About 7 - 10 minutes.
Not hard at all. Gain on lowest setting. Volume on radio set low at 5 (volume goes to 30)
Yes, it is heating unevenly.
About 7 - 10 minutes.
Not hard at all. Gain on lowest setting. Volume on radio set low at 5 (volume goes to 30)
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Hey Perry, I have an update for you. I was wrong about the transformer heating up unevenly. Apparently my Raytek IR thermometer isn't reading exactly where the laser is pointing, it is reading slighty under it. In paying attention to that, as I go around the transformer, I get a even reading.
The transformer is the only part I can find on the board that is heating up...
Also the amp is intermittently is powering up and down. May power up for 10 seconds and shut down, may power up for 15+ minutes before shutting down. When it does shut down, if I leave the power supply on, the amp eventually comes back on. That also varies, may only take a couple seconds to around a minute or so.
The transformer is the only part I can find on the board that is heating up...
Also the amp is intermittently is powering up and down. May power up for 10 seconds and shut down, may power up for 15+ minutes before shutting down. When it does shut down, if I leave the power supply on, the amp eventually comes back on. That also varies, may only take a couple seconds to around a minute or so.
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I installed the 10k resistor between pins 4 and 7 of the 494. It produced a change it what the amp has been doing. After about 10 minutes of playing, the sound started cutting out. The difference is at this point, the amp never powered down or did the voltage rise on pin 4 as it had been doing.
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