240V stereomour

[Paul Birkeland]

Yes, sorry, the -reg wires need to connect to each other.

The red high voltage wires can be left floating in the air.

[srhombeus]

Ok,and the ground cable leaving the power supply board,do i have the take it out also? Because I am planing to take completly out the c4s board before connecting to new one ..

Yes, sorry, the -reg wires need to connect to each other.

The red high voltage wires can be left floating in the air.

[Paul Birkeland]

The GND cable leaving the power supply board is one of the two black wires that you need to connect together.

If you disconnect it at the power supply end, then you will open the circuit that would allow current to flow through the power supply, and you will be unable to test the board.

-PB

[srhombeus]

Sorry but I totally dont understand it.. Because there are three black cables leaving the power supply board.Two of them are K cables going through terminals and the third one is GND cable..

The GND cable leaving the power supply board is one of the two black wires that you need to connect together.

If you disconnect it at the power supply end, then you will open the circuit that would allow current to flow through the power supply, and you will be unable to test the board.

-PB

[Paul Birkeland]

The K wires are not ground wires, they allow the cathode bypass capacitors to attach to the hum pot on the 2A3's.  Those wires need to be left in place.

The black cable leaving the power supply PC board GND pad needs to connect to the black wire that connects from -reg to the terminal strip at the front of the chassis.

[srhombeus]

Ok,thank you.I got it know.The ground cable coming from terminal 8. 

The K wires are not ground wires, they allow the cathode bypass capacitors to attach to the hum pot on the 2A3's.  Those wires need to be left in place.

The black cable leaving the power supply PC board GND pad needs to connect to the black wire that connects from -reg to the terminal strip at the front of the chassis.

[srhombeus]

I've made the measurements.All the values for the power supply board and 4 pin sockets are in range.There is no problem with them.But while checking the 220 ohm resistors,I saw that the value for the terminal 7U to B2 is around 240 ohm and 9U to B7 is around 170 ohm. The amp was turned off and unplugged. Is this a problem,this resistor could be damaged also?

The K wires are not ground wires, they allow the cathode bypass capacitors to attach to the hum pot on the 2A3's.  Those wires need to be left in place.

The black cable leaving the power supply PC board GND pad needs to connect to the black wire that connects from -reg to the terminal strip at the front of the chassis.

[Paul Birkeland]

The 220 Ohm resistors are an arbitrary value.  The could be 0-5,000 Ohms without noticeable operating changes.

[srhombeus]

Hi,Can i use 240 ohm 1/4 watt resistor instead of 237 ohm in the c4s board?

[Paul Birkeland]

Yes.

[srhombeus]

Hi,I've newly assembled c4s board.4 leds are ok,all tubes are ok.Voltage checks are ok except terminal 2 and 14.they are a little lower than range.The right channel sound ok.There is also sound in left channel but there are some cracks,pops in left channel.I dont use potentiometer now,i am waiting for alps potentiometer to arrive.Where should I check for this left channel problem?  Thanks again.

[Grainger49]

I would first clean the left channel tube socket and tube pins.  Just remove the 2A3 and insert it 10 times.  Do the same thing with the 12AT7, it serves both channels.

Although Bottlehead buys new tubes and sockets either one could have been sitting on a shelf for a decade and have some oxidation on the metal.

[srhombeus]

I've tried this but my problem still continues.I think side C is left channel and side A is right channel.Where do you suggest to look at it for this weird sounds?

[Paul Birkeland]

Please post the actual voltages that you have.

-PB

[srhombeus]

Here are the voltage checks :

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.hizliresim.com%2FlBkolX.jpg&hash=cc03b37d59b6463a0619a71f91e9b787dbb79f47)