PS60 Sound Output Problem - Any ideas?

[Melted Goldfish]

Hi all,

I recently bought a second-hand PS60, and am having some trouble with the outputs. Originally I was losing signal to one side of the headphones and, under certain conditions, from the main output jacks. I took it to a local engineer who resolved most of the problems with a spot of solder and a couple of new connectors, however, there's one problem that still persists that has left us stumped and I'm hoping someone can help with.

It works fine in mono (single cable connected to the Left output), but when using both main outputs in stereo, as soon as the Right output jack is connected, signal to the Left channel is lost. The headphones output still works correctly on both sides when in this fault condition. The fault is intermittent, but once it’s occurred it remains latched until I turn the keyboard off and on again. It sometimes recurs immediately on startup, sometimes not for quite a while, and sometimes seems triggered by a change of programme. Unplugging/re-plugging the cables makes no difference (I've also tried multiple new cables so its not a cable fault), it only resets by cycling the keyboard power.

As it's an intermittent fault Murphy's Law has it that every time I've taken it back to the engineer it's worked perfectly fine and he hasn't been able to find anything wrong! Then it plays up again a few hours after getting it home.

He's going to take another look, but has anyone seen this before or can anyone offer any suggestions on what my be causing it, to point him in the right direction?

Thanks!

[T3owner]

I recently bought a second-hand PS60, and am having some trouble with the outputs. [...]

It works fine in mono (single cable connected to the Left output), but when using both main outputs in stereo, as soon as the Right output jack is connected, signal to the Left channel is lost. The headphones output still works correctly on both sides when in this fault condition. [...]

You may have noticed that the left channel line output is "L/MONO", while the right is "R". That's because the R jack has switching contacts built into it, and when nothing is plugged into that jack the right channel signal is connected to the L/MONO jack, providing a mono mix at the L/MONO jack.

If there should be no left signal, with nothing plugged into the R jack what appears at the L/MONO jack will be only the right signal. Under that circumstance, plugging into the R jack will remove the right signal from the L/MONO jack, resulting in what you described.

Since you've said that the headphone output is OK under the fault condition, there's a problem in the left channel circuit somewhere between where the signal is taken off for the headphones and the L/MONO jack. Exactly where that is can't be determined from a description of the problem, but there aren't a lot of parts or connections involved.

Intermittent problems can be "fun" to troubleshoot, but service people deal with them fairly often, and eventually the fault should get resolved.

[Melted Goldfish]

You may have noticed that the left channel line output is "L/MONO", while the right is "R". That's because the R jack has switching contacts built into it, and when nothing is plugged into that jack the right channel signal is connected to the L/MONO jack, providing a mono mix at the L/MONO jack.

If there should be no left signal, with nothing plugged into the R jack what appears at the L/MONO jack will be only the right signal. Under that circumstance, plugging into the R jack will remove the right signal from the L/MONO jack, resulting in what you described.

Since you've said that the headphone output is OK under the fault condition, there's a problem in the left channel circuit somewhere between where the signal is taken off for the headphones and the L/MONO jack. Exactly where that is can't be determined from a description of the problem, but there aren't a lot of parts or connections involved.

Thanks for the reply.

I was aware of how the "L/MONO" worked, but I hadn't really thought about it in terms only hearing the right signal through the MONO mix. In my head it was some sort of problem with the R jack switching contacts that was somehow cutting out the left signal, but as you describe it then it makes far more sense that it's just a left channel fault that's being masked when used in MONO.

Even when it's not in the fault condition, the left channel does seem very marginally quieter than the right (when taking a headphone feed off the mixer); barely noticeable, but the level lights on the mixer show it slightly louder on the right. I also occasionally get some hissing/crackling in the left ear (from the mixer feed) during the startup sequence. I though that was just my imagination, but all together I guess this is pointing clearly towards a left channel fault downstream of the headphone take-off.

Thanks again for the advice. I'll get it back to the engineer and guess I'll just have to leave it with him until the fault rears its head again!

Cheers.