I have an old Yamaha CR-820 receiver/amplifier that no longer has any sound
output. The meters still show signal strenght when a tune across the AM/FM
bands but I get no audio from the speakers or the phone jack. No hiss. hum,
carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can obtain a
schematic or service manual?

"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has any
sound output. The meters still show signal strenght when a tune across the
AM/FM bands but I get no audio from the speakers or the phone jack. No
hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can obtain a
schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown ) fuse,
then it's most likely that the speaker protection circuit is operating
because of a blown output stage. I've a vague recollection that this one
uses an output hybrid ( big black "IC" bolted to the heatsink with type
STK-xxx ) and if so, it is likely that this is your problem. Some of these
can be very expensive, and many of the older ones are now obsolete and hard
to obtain. If it is one of the models that uses discrete output stages, then
you might struggle to get to the bottom of its problems, particularly
without a set of schematics, which again, might be difficult to find for an
item this old.

Arfa

Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for newbies -
there's fusible resistors inside asbestos tubing which go bad, usually
without any visible clue, and the layout is hardly service-friendly.

Mark Z.

"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for newbies -
there's fusible resistors inside asbestos tubing which go bad, usually
without any visible clue, and the layout is hardly service-friendly.

Mark Z.


Thanks for the information all.

Yes there are 4 heat sinked bipolar transsitors. They cost about $10 each.
They get warm to the touch.

I bought a service manual for $15 bucks.

I will see what I can find out. This was a friend's unit.

I wil check out those fusible resistors.

Dave wrote:
"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for
newbies - there's fusible resistors inside asbestos tubing which go
bad, usually without any visible clue, and the layout is hardly
service-friendly. Mark Z.


Thanks for the information all.

Yes there are 4 heat sinked bipolar transsitors. They cost about $10
each. They get warm to the touch.

I bought a service manual for $15 bucks.

I will see what I can find out. This was a friend's unit.

I wil check out those fusible resistors.

If there's no sound I think I'd look at the regulated power supply areas
first...

Mark Z.

Mark D. Zacharias wrote:
Dave wrote:
"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?



If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa
The CR-820 uses discrete transistors, but the repair isn't for
newbies - there's fusible resistors inside asbestos tubing which go
bad, usually without any visible clue, and the layout is hardly
service-friendly. Mark Z.

Thanks for the information all.

Yes there are 4 heat sinked bipolar transsitors. They cost about $10
each. They get warm to the touch.

I bought a service manual for $15 bucks.

I will see what I can find out. This was a friend's unit.

I wil check out those fusible resistors.

If there's no sound I think I'd look at the regulated power supply areas
first...

Mark Z.



It appears one of the output devices is shorted. For $5 I may try a
repair. I did not see the fusible resistors. There is also a relay. I
suppose it could be bad.This doesn't seem to hard to get to many of the
components.



It looks like one of the power stages was repaired before as it use RCA
SK---- devices.

"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for newbies -
there's fusible resistors inside asbestos tubing which go bad, usually
without any visible clue, and the layout is hardly service-friendly.

Mark Z.

OK, much like the modern Yammy AV amps then ...

Arfa

Arfa Daily wrote:
"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for
newbies - there's fusible resistors inside asbestos tubing which go
bad, usually without any visible clue, and the layout is hardly
service-friendly. Mark Z.

OK, much like the modern Yammy AV amps then ...

Arfa

Well, they aren't flat packs - they're TO-3's - 2SB557 and 2SD427 IIRC.

Four-gang (once again, IIRC) tuner, all analog, silver face, wood cabinet,
rectangular metal knobs, and lots of 14 volts lead-lamps which burn out...

mark Z.

"Mark D. Zacharias" wrote in message
et...
Arfa Daily wrote:
"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for
newbies - there's fusible resistors inside asbestos tubing which go
bad, usually without any visible clue, and the layout is hardly
service-friendly. Mark Z.

OK, much like the modern Yammy AV amps then ...

Arfa

Well, they aren't flat packs - they're TO-3's - 2SB557 and 2SD427 IIRC.

Four-gang (once again, IIRC) tuner, all analog, silver face, wood cabinet,
rectangular metal knobs, and lots of 14 volts lead-lamps which burn out...

mark Z.

I was being facetious Mark, and referring to the fact that it's layout is
not very service friendly ...I went to a Yammy training seminar recently,
and the national service manager told us that the average turnaround time on
an AV amp for a Yammy dealer, was 22 days, which was really too long, and
could anyone venture a suggestion as to why this was. I told him that the
first 16 days were spent looking at it sitting on the shelf, hoping that it
would go away. The next 3 were spent trying to work out what the internal
diagnostics were trying to tell you. The next 1 was spent trying to strip it
apart and work out which screw was still holding it. The next day was spent
fixing it and putting it back together, and the final day was spent either
rejoicing that you could write a bill out for it, or crying whilst watching
all the magic smoke being released again ...!! Sound about right ? d;~}

Arfa

"Mark D. Zacharias" wrote in message
et...
Arfa Daily wrote:
"Mark D. Zacharias" wrote in message
. net...
Arfa Daily wrote:
"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has
any sound output. The meters still show signal strenght when a tune
across the AM/FM bands but I get no audio from the speakers or the
phone jack. No hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can
obtain a schematic or service manual?




If it's nothing straightforward like a failed ( rather than blown )
fuse, then it's most likely that the speaker protection circuit is
operating because of a blown output stage. I've a vague recollection
that this one uses an output hybrid ( big black "IC" bolted to the
heatsink with type STK-xxx ) and if so, it is likely that this is
your problem. Some of these can be very expensive, and many of the
older ones are now obsolete and hard to obtain. If it is one of the
models that uses discrete output stages, then you might struggle to
get to the bottom of its problems, particularly without a set of
schematics, which again, might be difficult to find for an item this
old.
Arfa

The CR-820 uses discrete transistors, but the repair isn't for
newbies - there's fusible resistors inside asbestos tubing which go
bad, usually without any visible clue, and the layout is hardly
service-friendly. Mark Z.

OK, much like the modern Yammy AV amps then ...

Arfa

Well, they aren't flat packs - they're TO-3's - 2SB557 and 2SD427 IIRC.

Four-gang (once again, IIRC) tuner, all analog, silver face, wood cabinet,
rectangular metal knobs, and lots of 14 volts lead-lamps which burn out...

mark Z.


.. If I run the amp with both left channel transistors out of the circuit the
right channel works fine.
I replaced a bad outout transistor after checking it. Now when I turn the
receiver on the main power fuse blows.

My guess is that the original failure took out the power transistor before
the fuse blew.

"Dave" wrote in message
. net...
I have an old Yamaha CR-820 receiver/amplifier that no longer has any
sound output. The meters still show signal strenght when a tune across the
AM/FM bands but I get no audio from the speakers or the phone jack. No
hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can obtain a
schematic or service manual?




Have you plugged in a CD player to it yet?

On Apr 18, 2:43 pm, "Paul Feaker" wrote:
"Dave" wrote in message

. net...

I have an old Yamaha CR-820 receiver/amplifier that no longer has any
sound output. The meters still show signal strenght when a tune across the
AM/FM bands but I get no audio from the speakers or the phone jack. No
hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can obtain a
schematic or service manual?

Have you plugged in a CD player to it yet?

Why would anybody plug in a CD player to a broken stereo stupid?

"Sitre Magana" wrote in message
ups.com...
On Apr 18, 2:43 pm, "Paul Feaker" wrote:
"Dave" wrote in message

. net...

I have an old Yamaha CR-820 receiver/amplifier that no longer has any
sound output. The meters still show signal strenght when a tune across
the
AM/FM bands but I get no audio from the speakers or the phone jack. No
hiss. hum, carckle or pops. JUst solid dead silence.

It isn't worth sending out for a shop base repair.

Has anyone has a similar problem? Does anyone know where I can obtain a
schematic or service manual?

Have you plugged in a CD player to it yet?

Why would anybody plug in a CD player to a broken stereo stupid?


That is what I thiought too. I think the post may have been just a "funny".

On Apr 25, 10:38 pm, "Dave" wrote:
"SitreMagana" wrote in message

Why would anybody plug in a CD player to a broken stereo stupid?


Methinks so you can rule out the tuner, If you plug in a CD player and
you hear music, then you can be sure that the tuner is ****ed.
But if you don't then you work from there.

That is what I thiought too. I think the post may have been just a "funny".- Hide quoted text -

You want to know what else is funny: You and Sitre Magana is a gay
porno video, asshole.

"Brittany Martin" wrote in message
oups.com...
On Apr 25, 10:38 pm, "Dave" wrote:
"SitreMagana" wrote in message

Why would anybody plug in a CD player to a broken stereo stupid?


Methinks so you can rule out the tuner, If you plug in a CD player and
you hear music, then you can be sure that the tuner is ****ed.
But if you don't then you work from there.

That is what I thiought too. I think the post may have been just a
"funny".- Hide quoted text -

You want to know what else is funny: You and Sitre Magana is a gay
porno video, asshole.


I know the tuner works.

Your a real asset to the newsgroup.