PAS3 blend switch issue - no stereo on left channel

Hi, I'm calling on your help re. an issue on my PAS3. On this unit, tone controls have been bypassed, loudness too, selenium rectifier out, new cap can. It is connected to a ST-70.

The problem only happens when I'm using the phono section. Going counter clockwise on the blend switch this is what it gives, using the balance pot to check between left and right channel:

- 'B' position : loudest volume, both channels working fine.
- 'A' position : no sound at all.
- 'A+B' position : slightly weaker sound than 'B' on both channels.
- 'firt stereo position': very weak sound, weaker on left channel
- 'second stereo position' : even weaker on both channels, especially left
- 'third stereo position' : no sound at all on left channel, full sound on right channel.

I've cleaned the blend switch several times with deoxit, cleaned sockets too, checked the solder joints, resoldered a loose resistor on the blend switch, tried tube swapping and different tubes, yet same thing.

Any help/suggestion as to where to look would be most welcome.

Thank you very much in advance.

Best,
Alyosha.

It seems that there is a problem with the phono board itself, or possibly the input selector.
Have you switched the two tubes on the phono board ? Each tube amplifies each channel. A tube
failure would silence one channel.
Also, try switch theh phono connectors, if the problem switches side the problem is at the vinyl
player ( cartridge cabling for instance)

Hello and thank you for your reply. Tubes are fine, however I tried phono connectors switching and yes, the issue switches sides. Yet, my cart is correctly cabled.
Thanks again.

OK, I've tried with another exactly similar Shure cart, wiring it exactly as the previous one and it now seems to work fine. Could it be a malfunctioning cart (sounds really strange to me). Anyway, thank you for your prompt help again Peter.
Alyosha

alyosha wrote:OK, I've tried with another exactly similar Shure cart, wiring it exactly as the previous one and it now seems to work fine. Could it be a malfunctioning cart (sounds really strange to me). Anyway, thank you for your prompt help again Peter.
Alyosha

Cartridges do fail, they are not human but close.

Alyosha, I had that same problem with a Thorens and 2M red. Could change stuff out and may work awhile; then wingle, may work awhile. Removed the 4 wire clips between the cart and the tonearm.
only bout 1 1/2" long; one strap measured 24 ohms; I just recrimped the lead where it was factory
crimped. All is well. Dale