"David Farber" wrote in message
...
WLD_Bill wrote:
Pressed power button, unit powers off after 3 seconds.

Bypassed protection mode by holding "Effect" & "Night" buttons while
pressing power button.
Unit displayed the code "PRD PRT 210"

Manual states as follows....

When there is a history of protection function due to abnormal DC
output

PRD PRT:xxx (xxx AD value when the protection function is working)

Cause: DC output of the power amplifier is abnormal.

Supplementary information:
The protection function worked due to a DC voltage appearing at the
speaker terminal.
A cause could be a defect in the amplifier.
If the power is turned on with the abnormality unsolved, the
protection function works in about 3 seconds to turn
off the power.

Ideas where to start? LOL.... DC voltage appearing at the speaker
terminal? None showed
up with a DVM


Maybe something got lost in the translation. DC output of the power
amplifier will only show up at the speaker terminals if the speaker relay
is energized. It's not clear to me what protection functons are being
bypassed by pressing the "Effect" & "Night" buttons. In other words, check
the DC at the power amp output before it goes to the protection relay.
Other than that, perhaps our resident Yamaha expert, Mark Z. will chime in
with some advice. (-:

--
David Farber
Los Osos, CA



The translation is a bit off. It's trying to say that there WAS a DC offset
at one or more speaker terminals, therefore the protect was activated.
The DC is actually detected BEFORE the speaker relays via sensing resistors
going over to the appropriate DC PRT input on the microprocessor.
The value 210 translates as follows:

divide 3.3 by 255. This equals 0.01294117

Multiply this value times the error code 210. The result (2.717647) is the
voltage seen at that input on the microprocessor. Actually it's quite
accurate - no need for a multimeter here.

The acceptable range (maybe 70 to 125 etc) multiplied the same constant
would give the "normal" DC range that should be seen by the microprocessor.

Bottom line - probably one channel has a DC offset caused by a bad output
IC.

That DC voltage can be measured at any of the white emitter resistors
sitting in front of the output IC's. One white dual resistor for each
channel.

In this case, since it is not an over-current shutdown, the protection
cancel method shown in the manual can force the receiver to stay ON so that
voltage readings can be made.

Enough?

Mark Z.