A friend asked me to take a look at his Pioneer receiver that no longer
has speaker output. I tried to purchase a circuit diagram on line but all
they sent were the diagrams for the video control sections. I made sure
the tape monitor is off and the preamp jumpers are in place. The final
output power transistors check out OK. When power switch is closed there
is a click in a relay and the panel lights come on and FM signal levels
are displayed. There is no second click or clicks in the DH2SU protection
relay or relays. Does anyone know if this is a common problem with a
simple fix?

Any suggestions would be appriciated.
R. Frist

Seems to me I had one like this. There was a couple small fuses bad hidden
up near the front-left side of the unit. They just blew again after
replacement. After a LONG troubleshooting routine, discovered a shorted cap
which went, I believe, from the PNP to NPN collectors' of the surround
channels(?). Drove me crazy because it wasn't in the schematic I was using.
About 47 or 100 uf.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Ramsey Frist" wrote in message
...
A friend asked me to take a look at his Pioneer receiver that no longer
has speaker output. I tried to purchase a circuit diagram on line but all
they sent were the diagrams for the video control sections. I made sure
the tape monitor is off and the preamp jumpers are in place. The final
output power transistors check out OK. When power switch is closed there
is a click in a relay and the panel lights come on and FM signal levels
are displayed. There is no second click or clicks in the DH2SU protection
relay or relays. Does anyone know if this is a common problem with a
simple fix?

Any suggestions would be appriciated.
R. Frist

In article , "Mark D.
Zacharias" wrote:

Seems to me I had one like this. There was a couple small fuses bad hidden
up near the front-left side of the unit. They just blew again after
replacement. After a LONG troubleshooting routine, discovered a shorted cap
which went, I believe, from the PNP to NPN collectors' of the surround
channels(?). Drove me crazy because it wasn't in the schematic I was using.
About 47 or 100 uf.

Mark Z.

Thanks Mark. You were right about the well hidden fuses under a small
board on the power transformer. Unfortunately they are both intact.
There are actually three protection relays. For left right and center?
The center speaker output and relay are on a separate board. None of the
three click on. I suppose I could check every capacitor in the thing.

R. Frist

Well, I don't have any more than generic advice at this point - try to check
that all the various power supplies are OK, for example.

Near each speaker relay the will be a diode which parallels the relay coil.
At the cathode (band) side of the diode should be the source voltage, maybe
24 or 48 volts. In your case, there would probably be voltage on BOTH sides
of the diode, since the relay isn't being driven. BUT... if there's no
voltage to speak of, then just that one voltage source is missing.


Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Ramsey Frist" wrote in message
...
In article , "Mark D.
Zacharias" wrote:

Seems to me I had one like this. There was a couple small fuses bad
hidden
up near the front-left side of the unit. They just blew again after
replacement. After a LONG troubleshooting routine, discovered a shorted
cap
which went, I believe, from the PNP to NPN collectors' of the surround
channels(?). Drove me crazy because it wasn't in the schematic I was
using.
About 47 or 100 uf.

Mark Z.

Thanks Mark. You were right about the well hidden fuses under a small
board on the power transformer. Unfortunately they are both intact.
There are actually three protection relays. For left right and center?
The center speaker output and relay are on a separate board. None of the
three click on. I suppose I could check every capacitor in the thing.

R. Frist

P.S.

If you haven't already done so, check each amp channel for a DC offset.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Ramsey Frist" wrote in message
...
In article , "Mark D.
Zacharias" wrote:

Seems to me I had one like this. There was a couple small fuses bad
hidden
up near the front-left side of the unit. They just blew again after
replacement. After a LONG troubleshooting routine, discovered a shorted
cap
which went, I believe, from the PNP to NPN collectors' of the surround
channels(?). Drove me crazy because it wasn't in the schematic I was
using.
About 47 or 100 uf.

Mark Z.

Thanks Mark. You were right about the well hidden fuses under a small
board on the power transformer. Unfortunately they are both intact.
There are actually three protection relays. For left right and center?
The center speaker output and relay are on a separate board. None of the
three click on. I suppose I could check every capacitor in the thing.

R. Frist