What are the Kreg voltages on the back board?
High voltages in final test on CS4 board
- Thread starter dehringer
- Start date
That tells you that each half of the front board is (very likely at least) attempting to deliver the appropriate amount of current.
I would be very suspicious that the 47K 2W resistor on that side of the front C4S board isn't well soldered in.
I would be very suspicious that the 47K 2W resistor on that side of the front C4S board isn't well soldered in.
Could I see some pictures of your D socket wiring?
Your 6922 plate and cathode are about at the same voltage, which is really the root of the issue. This could happen if those pins are somehow shorted together on the 9 pin socket, then the rest of the circuit would respond by trying to correct that issue.
Your 6922 plate and cathode are about at the same voltage, which is really the root of the issue. This could happen if those pins are somehow shorted together on the 9 pin socket, then the rest of the circuit would respond by trying to correct that issue.
Let's also see the C socket as well.
If you pull out the 6922, then measure the DC resistance between pins 1 and 3 on that socket, what do you get? How about between pins 6 and 8?
How about C1 to C2, C2 and C3, C6 to C7, C7 to C8?
Can you run the amp with just the 12AU7 (no 6922, and no EF86s), then let me know what the OA and OB voltages are on the front C4S board? OKA and OKB voltages would also be of interest.
I would attempt to procure a different 6922 or 6DJ8 and try that in the C socket. When your amp is running, it's acting like there's a short between plate and cathode on that side of the 6922, which could be from debris in the socket, but that would appear as a DC resistance difference between sides on the socket and would be persistent with the tube out of the socket.
Perhaps PJ has some ideas about why this might be happening.
Paul Joppa
Moderator
I'll take a closer look, but it may take a few days - PB revised the layout and the PC board to make the Eros II much easier to assemble. It's a great improvement, but I'm not yet intimately familiar with the new board.
