VTA ST-70 problem

I just installed a VTA circuit board into my ST-70. Everything was going great for a few hours. I have the high gain board and a Foreplay III tube preamp. It was LOUD obviously, but great. I switched the preamp out for an old PAS-3 to tame the volume before I do some work on the Foreplay. Again everything was fine. Then I noticed some static. I am not sure if it was from the amp or preamp so I shut the PAS off to see which one was making noise. 15 seconds later, I remembered I had the ST-70 plugged in the switched power of the PAS. Without thinking, I turned the PAS-3 back on to reevaluate my troubleshooting method. The fuse on the ST-70 blew with some popping and protest. Not a problem I thought. Tonight I replaced the fuse and started the amp to have a quick listen before I take it apart to dial in the bias. A minute later the left front EL34 goes Chernobyl with glow and heat, the speaker is popping with no input signal as I had not even turned on the CD player. After disassembly the voltage across the 1-8 pin just climbs. The right side bias is completely stable .4 volts plus or minus a hundredth or so. The left rear will also bias, yet the voltage on the left front is out of control.

I looked at the solder joints to the socket and they look solid. The wiring looks exactly the same as the working right side. I switched the tubes and it is the same problem at that socket. I am not sure where to start or finish rather troubleshooting. I really hope I did not kill this amp.

Thanks for any troubleshooting starting point, guidance, or wisdom on this.

Hi Bob, I think we are on the right track.
1. The 1000 ohm resistor between 5-6 is at 1000 ohms.
2. I do not have a cap tester, but all of the caps tested the same for resistance.
3. R29, R30, and R32 are testing at 270K. R31 is testing at 16K. I checked the color coding, it is the correct one.
4. For the bias no tubes, the left front is giving 0.00 VDC. The other ones are -42, -43, -46 VDC.

Update: YES!!!! While typing this message and double checking, I found the problem. The wire I ran from pin 6 to the board poked through the board and was touching the chassis. That is never good. Rookie mistake.

It is quite satisfying to keep these amps running. Thanks Bob!

With only one channel of output tubes the bias is set to 0.40 volts. With both sets in, the voltage drops to 0.30 volts. Is this right? Or should the reading be .40 with all tubes in place?

bias reading should be 0.400 vdc on each tube, everytime you adjust one tube it will slightly affect all the others,
it usually takes about 3 rounds to get them all the same, and bias will increase by turning the pot CCW, opposite of what you would think.