Roland HP-860 electronic piano has HUM - sci.electronics.repair

Message from discussion Roland HP-860 electronic piano has HUM

Gareth Magennis

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More options Sep 6 2008, 5:17 pm

Newsgroups: sci.electronics.repair

From: "Gareth Magennis" <gareth.magen...@ntlworld.com>

Date: Sat, 06 Sep 2008 23:17:39 GMT

Local: Sat, Sep 6 2008 5:17 pm

Subject: Re: Roland HP-860 electronic piano has HUM

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"PeterD" <pet...@hipson.net> wrote in message

news:8436c4143oji42mcdl8ojesrdvordfl9lj@4ax.com...

> On Sat, 6 Sep 2008 14:36:12 -0700 (PDT), "Josh9.0"
> <squalene...@hotmail.com> wrote:

>>No I haven't!
>>Thanks for the tip, and thanks for the quick reply!
>>I'll go and try it now.
>>It has a bunch of different voltages out, and they're labelled on the
>>PCB!
>>I guess I should look for ripple on what should be DC, right??

> Sounds good.

>>Then trace it back to the offending cap(s).
>>Then go buy some new ones of those only.

>>BTW: It has a main voltage going to all the keys of 46V which measures
>>43V.

> Ba-ding... Now I wonder why that voltage is low? Could it be, oh,
> maybe... A bad filter cap?

Er, what exactly is this 46 volts supposed to be doing? I doubt there is
anything like 46 volts anywhere near the keyboard.

Please try again.

Gareth.

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