Roland HP-1 Electric Organ/Keyboard audio output noise

[notallbad]

Happy to get pictures up of the boards and shall do in due course.

Everything works as it should as far as I can tell.

But on the built-in speakers and the headphone jack output is a regular occurring whoosh noise which is proportionate to the volume control, so the louder you turn up the volume the louder the whoosh noise gets, though it is not particularly loud just obviously present and annoying and occurs immediately after switching on.

Hopefully someone can assist with this and I would be extremely grateful.

[ben7]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Sounds like something oscillates as the power source is turned on. Maybe a bad/dry capacitor, or a bad voltage regulator?

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

OK, thanks.

If I get some photos up would you be able to direct me where and what to check?

Just to be clear I should state that it occurs constantly from powering up and at regular intervals every 3-4 secs. Also it does not effect the acoustics, it plays music fine. If this helps to narrow it down.

Thank-you

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Photos as promised.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Another

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

And lastly.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

CORRECTION:

The sound is definately coming through the speakers and 'plays' over and over again without a break, the sound is just like an old LP playing on a gramophone when it gets to the end of a record, you'll know if your old enough to remember like me, when the needle is at the middle of the LP and keeps turning with no more to play. And at the end of this annoying noise is like a click noise.

Also just to note, there are no external devices connected, i.e. pedals, speakers, amps etc...

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Zipped Audio file

[rhomanski]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

78, 45, or 33 1/3?

Sounds like a transistor going out. It may start motorboating soon. When it goes budda, budda, budda, budda. It'll be close to the output transistors, maybe one of the drivers? You should be able find it with a scope.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Maybe I'm not that old, I remember my grandad playing those really thick plastic LP's on his wind up gramophone, happy memories.

Thanks for your response.

Budha, budha, budha might sound a little better, has a good beat to it!

Sorry, I'm not musically gifted or knowledgeable so probably wrong terminology to use.

How would I connect a scope to check?
Thanks again.

[budm]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

"Just to be clear I should state that it occurs constantly from powering up" But if you have the volume pot all the way down, do you still hear the noise. If not, then it is from something before the volume control. Does this thing has the TREMOLO/VIBRATO effect, or any effects settings are turn on?

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Hi Budm, thanks

With volume control all the way down I can not hear it!

Not sure about those settings, vibrato etc... shall have to look into it.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

It has a Reverb setting, gives the impression that you are performing in a concert hall or similar space, which does work, it can be toggled on and off.
It also has the facility to set the reverb volume level, which also works and changing the reverb volume level has the effect of making the annoying noise louder with the setting high and quieter with the setting low.

The other facilities/options that I have played with all appear to be working but do not make any effect to the annoying noise.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

"Just to be clear I should state that it occurs constantly from powering up" But if you have the volume pot all the way down, do you still hear the noise. If not, then it is from something before the volume control. Does this thing has the TREMOLO/VIBRATO effect, or any effects settings are turn on?

Not sure if this also backs your theory but looking at the service manual there is a test procedure to follow and one of them is 'Panpot Check', in this test there is a 'Sound Off' option, not sure exactly what it does perhaps simply a mute but the annoying noise is still there and pressing the keyboard keys gives no sounds, so this could back what you say.

[budm]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

upload the service manual so I can look at it.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Thanks Budm

The manual covers 2 models HP-1 and HP-2e

Had to zip it due to its size I'm afraid.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Is there any way of connecting an external speaker in-circuit to eliminate at which stage this noise is being generated? Just a thought.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

I have disconnected the keyboard (connectors CN5 and CN6) from the main board and the fault still persists. I thought perhaps it was a key issue but obviously not so thats eliminated the keyboard.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Just to see I'm going to disconnect the headphone jacks, there are 2 of them, at the amp/power board side. I doubt this is causing the fault but worth a try to eliminate.
I did read somewhere in my travels someone had a curious sound issue and had something to do with the headphone jack.

[notallbad]

Re: Roland HP-1 Electric Organ/Keyboard audio output noise

Well that proved pointless as I'm sure 'you' already knew but have now satisfied my own curiosity.