Realistic Chronomatic-223 - dead left channel

[lti]

As the title says, the left channel does not work in this clock radio. When adjusting the volume, popping noises can be heard from the left channel. At all other times, the left channel is completely silent. Also, the right channel plays constantly and only becomes slightly quieter when the balance is turned all the way to the left. Inside, there are two TBA820M amplifier ICs. The left speaker works when connected to another amplifier.

What are some possible failure points? This problem might have existed since the clock radio was new. I was told that it never worked properly.

[lti]

Re: Realistic Chronomatic-223 - dead left channel

I was able to get the left channel working for a few seconds. The volume control is either broken or very dirty. The balance control is dirty.

There are a lot of bad solder joints.

[lti]

Re: Realistic Chronomatic-223 - dead left channel

I got it to work by cleaning the volume and balance controls. I still need to resolder some points. I might work on that tomorrow.

[lti]

Re: Realistic Chronomatic-223 - dead left channel

I resoldered the three points pictured above and cleaned the tone control and the headphone jack. The radio section now works properly.

The Sleep button doesn't seem to work, but I can't get the button board out of the case. The company that made this clock radio for Radio Shack decided to coat the screw heads in some kind of adhesive. Some screws can't be removed.

Also, both the alarm and the radio play at the same time in Alarm mode. If Auto mode is selected, only the radio plays as the alarm.