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, 4:56 pm

Newsgroups: sci.electronics.repair

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

Date: Sat, 06 Sep 2008 22:56:30 GMT

Local: Sat, Sep 6 2008 4:56 pm

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

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"Josh9.0" <squalene...@hotmail.com> wrote in message

news:b5bb74fd-fccb-4579-a414-fa7ac9e673cd@c58g2000hsc.googlegroups.com...

> 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??
> 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.

You seem to be jumping to lots of conclusions for no apparent reason.
This is not going to help you.

What's with this "offending caps" businsess? You seem to have decided there
is a cap problem and replacing them will be the solution.
Stop guessing, it will get you nowhere.

You need to investigate and gather information. You start with the power
supplies, If they are OK then you look elsewhere.

Gareth.

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