JVC RCX720 boom box, left speaker out

[tstex]

Hello to all,

Look forward to getting to know everyone. First post, but have been on other forums for yrs.

Have a boom-box I use while in the country, and the left speaker is out...I used to be able to push on the volume knob previously to get it to work and come back on. Now the left speaker is entirely dead.

Is there a fix for this or could you pls indicate what I can do to try to troubleshoot it? Again, it is a JVC RCX720 CD/Radio boom box that has worked for yrs and I just do not want to toss it yet if I do not have to.

Thank you very much for your time and pls let me know if you have any questions.

Best Regards,
tstex

[tstex]

Ok, it is not a "boom-box", but a nice portable stereo. Cannot believe my first post has stumped the crowd!

[I_Daniel]

If you press on the volume control and the left speaker starts playing again then the volume control is faulty. Because it is stereo it is obviously a dual-track volume control (Potentiometer) and it would appear that the carbon track or wiper i.r.o the left channel is damaged.

You can check the volume control with an Ohm meter, but I think you will find that it must be replaced.

If you don't have a multi-meter, a crude way to check it is to use a 1K Ohm resistor across the input to the volume control and the centre pin (wiper)

[newtonph]

Probably one or more of the component become defective, you really need multitester to see which part is not letting pass the correct or totally block out the voltage.

[tstex]

Thanks Guys.

Newtonph, is there any way you can provide me a way to test-diagnose to discern the possible cause(s)? I would appreciate it.

Thank you,
Tstex

[I_Daniel]

You did say when you press on the volume control it sometimes works ! Hence my assumption that the volume control is faulty. In 99% of cases when this occurs then either the volume control is faulty or a dry joint may exist on one of the connection on the volume control.

You will need an audio probe. Start at the speaker, then move forward to the PA, No sound move to the volume control, No sound on the wiper move to the input on the volume control, No sound move to the preamplifier.
If the sound starts at any stage then the fault lies in that stage.
Alternatively start with the Pre-amp. Input to preamp if okay. check the Output from pre-amp - no sound - pre-amp faulty. Sound okay - Check before and after volume control. No sound before - a wired has become disconnected, No sound after - the volume control is faulty. So keep checking stage by stage. O nearly forgot check the balance control and if there are base and treble controls check their input and outputs as well. That was a quick lesson in fault tracing.

Most modern systems use IC's so if the input is okay but no output then the IC will have to be replaced.

[tstex]

IN order, both speakers worked fine and are controlled with one knob...then later, I would turn it on both would work fine then the left would cut out...I used to put something on the volume switch to either push or pull it, and the left speaker would stay on and work...if the object fell, the speaker would cut out...that worked for quite 8-10 months...now, the left speaker will not come on no matter what I do...push/pull/anthing on the vol control knob, and only the right speaker will work. Does this help you to better diagnose the problem?

Thank you very much for your help,
tstex

[I_Daniel]

With the further information provided my diagnosis remains the same - Replace the volume control.

[tstex]

Guys,

Is there a list of reputable vendors that work with the forum that you would recommend to buy the volume control switch...I like to support the forum by purchasing from forum sponsors.

Thanks again and I will post back when/if the VC-Switch fixes the problem.

Regards,
tstex