How to add an AU8 Socket, for AD1, AZ1 etc.

Last Update:

I have no intention to test Russian military stuff with it, the military socket #2 is completely useless for me. The good thing is, the mounting hole and screw holes for this socket fit exactly the NOS Au8 sockets I have. What a nice coincidence!

Schematic Detail

If you want to make this modification, read this first.
  1. Take care: With the AU8 socket, the pins are counted in the opposite direction as with the other sockets.
  2. When removing the original socket, you will find two wires on some pins. (see picture above) Keep these carefully together when you remove the socket! Like that you can make no mistakes.
  3. To connect the socket pins to the right lines, you do NOT use the connector board to find out the line numbers (F1....F9). There are some funny and strange confusions possible that way. Better is to use the socket E4 for that. This one is directly connected, so Pin1 is on line F2. Pin2 is in line F2, etc. So you can plug in one pin of the ohms meter in Pin1 and then find out which of the de soldered wires is that. The old socket as only 7 wires. So one of them you have to take directly from Socket E4. The check with the ohms meter is just double check.

Au8 Socket at
position E2
Connect to
Octal Socket
at
position E4
Cross Check with
ohms meter:
Contact 1

Line F1 (or A)
Contact 1
68/1
Contact 2
Line F5 (or E)
Contact 5
72/1
Contact 3
Line F7 (or G)
Contact 7
58/1
Contact 4
Line F8 (or H)
Contact 8
68/2

Contact 5
Line F6 (or F)
Contact 6
67/2
Contact 6
Line F3 (or C)
Contact 3
72/1
Contact 7
Line F4 (or D)
Contact 4
71/1
Contact 8
Line F2 (or B)
Contact 2
69/1

 

Note: When using test cards for Au8 tubes, such as EM4, AD1, AZ1, AL4, EL3n, and many many more, it may be a good idea to build the Au8 socket inside your tester. If you do not want so, you can build an adapter socket, using the above table. With that adapter you can use the Au8 cards that we sell.

Note: Make a good habit, to remove Au8 tubes by the base, not by pulling the glass bulb. For any loose tube base, we sell special glue, which needs no removal of the tube base.

Note: Cross check with the plug desk is just an additional test. You can plug the probe of an Ohms meter in there, and check against Socket #2. As this also connects the cross bars, you can NOT use this to find the lines (F1...F8), because it will give a "connection" with more than one plug holes. Still, when checking, there should be no "open" contact, or you did something wrong. For finding where the "Lines" are, use socket E4, as this socket is wired directly with contact 1 to line F1, contact 2 to line F2, etc. Before doing so, remove all plugs