DIYbanter - View Single Post - Onkyo TX-DS 575 / Integra DTR 5 in circuit protection mode

Mark D. Zacharias

wrote:
I've got an Integra DTR-5 (nearly identical to the Onkyo TX-DS 575)
thats in circuit protection mode (immediately goes into standby as
soon as the the power switch is pressed on, and opens the main power
relay). There is nothing connected to the receiver. Jammy Harbin's
reply on a identical subject back on 8/20/04 stated "DC bias on the
output, Shorted finals...". With it disconnected from power, I ohm'ed
the speaker terminals - all the black neg terminals are about .2-.4
ohms, and the red pos terminals are infinite. What exactly do I
check, and how do I check it? Can DC bias be checked while in circuit
protection mode? I don't see any popped capacitors, burnt chips, or
cracked traces, but I should probably get a brighter light. Can the
output amps be checked in circuit?

I've got the service manual and schematics (I can scan and post
specific schematics if necessary), and am comfortable with following
electronics kits, but am new at troubleshooting. If I remove the fuse
which connects the main transformer and then power on, it stays out of
circuit protection (the main power relay stays closed). Thanks for
any help!

Andris

The most likely scenario is one or more bad muting transistors. It's a
fairly vommon problem on these - usually caused by a mild lightning strike
or perhaps a static shock somewhere along the line.

I'll research the parts - there's about 10 transistors involved, and
troubleshooting down to the individual bad one(s) is pretty difficult - and
repost.

The good news is the parts are cheap.

Mark Z.