Technics KN7000 :: PX204 with no sound

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Mholbein United States Total Posts: 1 Joined: February 20, 2017	Hello, I have a Technics PX204 which appears to be functioning normally except that there is no sound when you play the keys. All the LEDs and the display light up and appear to function normally. I know it is not an issue with the speakers because I can plug my phone into the Line In and play a song through the piano's speakers just fine. However here is no sound from the piano's built-in speakers when you press the keys. There is also no sound from external speakers through the Line Out nor through headphones. I tried Initializing (or reseting to factory settings) by holding "Mode Set" and pressing the highest F# key. This made the LEDs flash for a moment and then return to normal, however did not bring back the sound. A visual inspection of the interior reveals nothing obviously amiss; all the plugs appear to be attached firmly and the fuse is not blown. Any help finding a place to start looking for the problem would be much appreciated! Thanks! Tags: PX204 Posted on February 21, 2017 at 2:14 AM
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davetutt United Kingdom Total Posts: 166 Joined: January 12, 2015	Re: PX204 with no sound Hi there From your description it sounds like you have a power line missing on the main voice board. I have to say that it isn't really a user repairable job as the design of the board and the method of manufacture demands the skills of an engineer with suitable skills in the replacement of components on the main voice board. I think you have a missing 5volt line. Technics / Panasonic used the same design for most of the manufacturing of all their keyboards so the circuit is well known if you deal with these sort of things on a regular basis. The simple switch power supply design is very reliable but somewhat warm and is likely to have suffered from raised temperature over the years you have had it. It will need the main capacitors on both the input and the output of the power circuit (47uf 35volt, and 1000uf 6 volt) and possibly the main pass transistor. In this keyboard it is also likely that the two 5volt supplies derived from the 15 volt supplies should be measured and repaired if found wanting. You may have found my other notes on the design in other answers to questions on the site as these faults, with the age of these keyboards, are becoming more common. If you do not want to tackle these issues then can I suggest you approach a local electronics engineer who may be able to help you. I am only too happy to offer whatever advice I can but obviously being very remote from your location it isn't possible to be 100% accurate with my diagnosis. By all means ask any other questions if you want more help. Dave Tutt Posted on February 27, 2017 at 11:05 PM

Viewing 1 to 2 (2 Total)

PX204 with no sound

Mholbein

United States

Total Posts: 1

Joined: February 20, 2017

Hello,
I have a Technics PX204 which appears to be functioning normally except that there is no sound when you play the keys. All the LEDs and the display light up and appear to function normally. I know it is not an issue with the speakers because I can plug my phone into the Line In and play a song through the piano's speakers just fine. However here is no sound from the piano's built-in speakers when you press the keys. There is also no sound from external speakers through the Line Out nor through headphones.

I tried Initializing (or reseting to factory settings) by holding "Mode Set" and pressing the highest F# key. This made the LEDs flash for a moment and then return to normal, however did not bring back the sound.

A visual inspection of the interior reveals nothing obviously amiss; all the plugs appear to be attached firmly and the fuse is not blown.

Any help finding a place to start looking for the problem would be much appreciated!

Thanks!

Tags: PX204

Posted on February 21, 2017 at 2:14 AM

1 Reply

davetutt

United Kingdom

Total Posts: 166

Joined: January 12, 2015

Re: PX204 with no sound

Hi there

From your description it sounds like you have a power line missing on the main voice board. I have to say that it isn't really a user repairable job as the design of the board and the method of manufacture demands the skills of an engineer with suitable skills in the replacement of components on the main voice board. I think you have a missing 5volt line. Technics / Panasonic used the same design for most of the manufacturing of all their keyboards so the circuit is well known if you deal with these sort of things on a regular basis. The simple switch power supply design is very reliable but somewhat warm and is likely to have suffered from raised temperature over the years you have had it. It will need the main capacitors on both the input and the output of the power circuit (47uf 35volt, and 1000uf 6 volt) and possibly the main pass transistor. In this keyboard it is also likely that the two 5volt supplies derived from the 15 volt supplies should be measured and repaired if found wanting. You may have found my other notes on the design in other answers to questions on the site as these faults, with the age of these keyboards, are becoming more common.

If you do not want to tackle these issues then can I suggest you approach a local electronics engineer who may be able to help you. I am only too happy to offer whatever advice I can but obviously being very remote from your location it isn't possible to be 100% accurate with my diagnosis. By all means ask any other questions if you want more help.

Dave Tutt

Posted on February 27, 2017 at 11:05 PM

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PX204 with no sound

Mholbein

davetutt

Re: PX204 with no sound

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