Pioneer 707 not recording right channel

[Wilcocat]

I have a Pioneer 707 that has stopped recording to the right channel. I was in the process of recording an album when I heard a relay click several times. The right replay now does not click when I push the right record switch. No sound on right channel.
The source does register on the right meter but nothing records.

Any thoughts on where to start?

 

[GPS16]

Hi Wilcocat,

Try these checks. With the Left Channel switch out and just the Right Channel depressed, start the machine recording. Does the Rec LED light between the 2 VU meters. If it does then the Right Rec switch is OK.

You will then be checking the relay coils resistance and the RC timing circuit around the relay.

My first thoughts would be the relay coil or the capacitor C314.

As long as the diode D302 is OK. The resistances should be measurable. Make sure that the +ve lead puts a +ve voltage on the +ve terminal of the cap. It will then charge up (if it is not faulty) and give the isolation to measure the resistances. The loop will effectively be open once the cap is charges. Until that point is reached there is a series/parallel combination.

See what you find.

GPS16

 

[audiojones]

In addition the the great advice above you might also try tapping or gently wiggling components in that area while listening for the relay click when the right channel is in record mode, it might be a loose / cold solder joint on the board or a cracked trace.

 

[Hajidub]

Deoxit is your friend. The top set of button's will most likely rectify the situation, but the recording level knob at the bottom will also need an application.

 

[Wilcocat]

Thanks for the replies. I'll check on the above and report back.

 

[Wilcocat]

I have discovered if pressure is applied to the relay on the circuit board the click is there when engaging the on/off button. Is this simply a bad solder or could the relay be bad?

 

[audiojones]

Most likely a bad solder joint. Could just be the solder joint where the relay pins connect to the board, try reflowing the solder joints in that area.

 

[nbndtrain]

could also be a broken trace. check visually and with multimeter