PMT Proto are protyping poards for making up PMT divider chains. 

Similar in idea to strip board but arranged radialy. For those times when it is neccesary to make up one or two dividers for odd ball tubes and you have'nt got a suitable ready made divider. Maybe you don't even have the correct socket either.

The PCB's are single sided (Could be double but single is enough) and
need to be made up and used in pairs.

Components go verticaly between two boards. With the copper side up or
away from the tube to make it easier to build in stages.

The middle circle of pads is for the resistors which have their leads go
through to put the sockets on.

The inner circle of pads is to solder capacitors across the resistors.

The outer circle of pads is for the interdynode conecting wires and/or
additional components. These are on the outside to make it easier to be
done last and corrected if neccesary when done.

The Pad in the center is purely a marker to make it easy to cut out the
boards using a hole saw (For the centre arbour) and drill press. It
might make aligning the top board onto the bottom board easier after the
componets are soldered into the bottom one. It could also be used to place a 
temperature probe or the signal and power leads.

Sugested order of attack.

1. Solder capacitors into bottom board.
2. Trim bottom capacitor leads
3. Solder resistors into bottom board.
4. Solder link wire into bottom board where there is no resistor requrired.
5. Solder Socket inserts (to suit your PMT) to resistor leads poking through bottom board (Add heat shrink or a socket body as neccesary).
6. Put on the top board poking the leads through the holes (Copper upwards to make life easy).
7. Solder capacitor and resistor leads on top board and trim off excecess.
8. Use insulated wires on outer pads to interconnect the Dynodes top and/or bottom as per the manufacturers pinout.
9. Add signal/power leads, use centre hole if neccesary
10. Test
11. Plug onto Tube and play.

It should be spossible to run up a small number of these types of boards
that would cover most eventualities. The critical part being diameter
of the PMT's pin circle and the number of pins.

Keyed tube pins are usualy just one pin snipped off or left out. The spacing is still
regular so protoboards made up for regular spacing can be used with a number of different tubes.
