Hi all new to this forum hoping for some help with me trusty amp. just lately it stopped clicking when tuned on and no sound came out indicating the relay not activating it was intermittent. ive had a go at trouble shooting but now hit the extent of my knowledge.
What a have done so far.
removed the relay and tested continuity. OK
tested the relay operates with a separate psu clicks as it should
removed the power transistors. tested with a mm all seems ok. (but im no expert used a guide on youtube to test)
then i tested the voltage on the board across the pins where the relay actuator lives and I get 48v which i found strange as the relay clearly states 24v. i dont know where to go from here any input would be great full. thanks. I have a full service manual here.
https://www.dropbox.com/preview/Shared/hfe_pioneer_sa-540_service_arp-304-0_en.pdf?
role=personal
Any input would be greatly received.

 

I would have to register to view the service manual.

 

I would have to register to view the service manual.

Hi thanks I have a link here.
https://www.dropbox.com/preview/Shared/hfe_pioneer_sa-540_service_arp-304-0_en.pdf?role=personal

 

The protection circuit deactivates the relay to disconnect the speakers if the current through the amplifier output transistors is too high or if there is a DC level on the amplifier output (which would damage the speakers).

Start with no input signal, volume set to zero, and measure the DC level on the amplifier outputs - amplifier side of the relay contacts - it should be less than half a volt.

 

Hi would I get voltage even when the relay don't connect.

 

It's the presence of the voltage that disables the relay, so yes.
The relay only disconnects the speakers from the amplifier.

 

Easier to measure the voltages at the output of the transistors at the speaker inductor junction L1,L2, or at the Relay changeover terminals , this will give you a idea which channel is at fault, it will probably be around 500mV to 1V.

 

Hi it was less than half a volt with the relay pressed or open.

 

Hi it was less than half a volt with the relay pressed or open.

On both channels?

 

The protection circuit deactivates the relay to disconnect the speakers if the current through the amplifier output transistors is too high or if there is a DC level on the amplifier output (which would damage the speakers).

Start with no input signal, volume set to zero, and measure the DC level on the amplifier outputs - amplifier side of the relay contacts - it should be less than half a volt.

Hi the measurement was less than 1v.

 

If that voltage is low on both channels then the other reason that opens the relay is too much current through the output transistors on one the channels.
The next measurement to make is the across both sections of both R337 and R338 (four voltage measurements).

 

If that voltage is low on both channels then the other reason that opens the relay is too much current through the output transistors on one the channels.
The next measurement to make is the across both sections of both R337 and R338 (four voltage measurements).

If that voltage is low on both channels then the other reason that opens the relay is too much current through the output transistors on one the channels.
The next measurement to make is the across both sections of both R337 and R338 (four voltage measurements).

Hi thanks for the reply the voltage a cross R337-1.3mv 1.3mv
R338-1.2mv 1.2 mv.
Hope this helps.

 

That's good, the amplifier seems to be OK, so the problem is in the protection circuit not activating the relay when it should.
Now measure the collector voltage of Q404 (or Q403) and Q405.

 

That's good, the amplifier seems to be OK, so the problem is in the protection circuit not activating the relay when it should.
Now measure the collector voltage of Q404 (or Q403) and Q405.

Hi thanks for sticking with me . Q404-17.6v Q405-34v. cheers.

 

So I think the problem is either D407 or, most likely, Q405.
Check them with the diode check function of the multimeter.

 

So I think the problem is either D407 or, most likely, Q405.
Check them with the diode check function of the multimeter.

Hi sorry for the late reply just wanted to say a big thank you today I replaced the q405 transistor and my amp sprung to life thanks again.

 

There was a thread on here about an amplifier with a similar circuit that I was helping to fault find which had loads of dud transistors. I'm very glad this one was so much simpler

 

Pioneer SA - 1040 Amplifier Relay Not Clicking

Hi all new to this forum hoping for some help with me trusty amp.
I bought this amplifier from Dubai where they have 220 Volts with 50Hz cycles, but i'm not moved back to Canada where it's 110V with 60Hz cycles electricity.The unit does have the voltage selector to select the voltage like 220V-240V and 110V-120V and i'm using 110V-120V.
For some reason when i turn on the unit, it turns ON with all the lights etc but it's the Speaker protection Relay is not Clicking (not completing the circuit to pass the current).

Is the because of the more Voltage Hz cycles as it was made to get 50Hz but here in Canada it's 60Hz or is the Relay unit itself which is now faulty for no reason all of the sudden ? I could be wrong but the unit was working perfectly fine in Dubai before i moved back.
I have attached the pictures of the circuit and the Relay as well as the the service manual with diagram.

Your time and help would be appreciated.

 

It won't be the power frequency.
It is unlikely to be the relay itself.
The relay operates when various voltage checks inside the amplifier are correct but not otherwise. This is a protection issue principally for the speakers.
So, probably, the amplifier has some problem. To get further we are going to need a schematic and some voltage measurements. Do you have a schematic and a multimeter?

 

https://www.hifiengine.com/manual_library/pioneer/sa-1040.shtml