17-10-2016, 04:34 PM
(This post was last modified: 17-10-2016, 04:36 PM by Mike Watterson.)
I spent more on sockets for mine than the actual computer board kit! Unlike most designs it only uses a 20V DC supply and four switch-mode converters for supplies rather than expensive tapped transformer (that can cost more than £65). PWM from the 20V for heater, then switchers for -Vg, +Vg2 and +Va.
Remember you need to add an external 470K to 1M resistor to test a Magic Eye (deflector pin or driver triode load).
Kit contents
Main Kit PCB assembled: Just add Windows PC (via Serial), 20V DC PSU and valve sockets!
No physical meters. the microprocessor’s ADC measures actual currents and voltages via Op-Amp based buffers.
The wiring of sockets used later AVO practice of complete loops with loads of ferrite beads. However I use a patch area of 2mm sockets instead of expensive and space consuming switches.
The whole insides (later I added a second PSU for direct filament 0.5V to 5V as the built in PSU is only really OK fro 5V and up, though mains 4V types will be just OK. I use external bench PSU for heaters of 20V)
The top:
The circular part goes to valve bases and the sockets in the middle go to Top cap sockets scattered among the bases.
The first row is the switched supplies, valve is pulsed.
The bottom row is unswitched (magic eyes are low HT drain, so can use that and thus can be on so you can see it!)
PC Windows graph (can be saved as data for text/Excel or image) of EF 80 as pentode, photographed on 16 year old windows 2000 laptop!
And as Triode
You can vary Screen, control grid, Anode or even heater supply in various combinations.
I also have a set of hooked patch leads to connect direct to a valves pins. Some AVOs have an "expansion" socket for this purpose.
I'm still looking for a Nuvistor socket. I have some NOS nuvistors.
If the tester oscillates, then add lots of ferrite beads.
One YouTube video I made of a Magic Eye:
There are more here on my website
Have fun Sparky!
Remember you need to add an external 470K to 1M resistor to test a Magic Eye (deflector pin or driver triode load).
Kit contents
Main Kit PCB assembled: Just add Windows PC (via Serial), 20V DC PSU and valve sockets!
No physical meters. the microprocessor’s ADC measures actual currents and voltages via Op-Amp based buffers.
The wiring of sockets used later AVO practice of complete loops with loads of ferrite beads. However I use a patch area of 2mm sockets instead of expensive and space consuming switches.
The whole insides (later I added a second PSU for direct filament 0.5V to 5V as the built in PSU is only really OK fro 5V and up, though mains 4V types will be just OK. I use external bench PSU for heaters of 20V)
The top:
The circular part goes to valve bases and the sockets in the middle go to Top cap sockets scattered among the bases.
The first row is the switched supplies, valve is pulsed.
The bottom row is unswitched (magic eyes are low HT drain, so can use that and thus can be on so you can see it!)
PC Windows graph (can be saved as data for text/Excel or image) of EF 80 as pentode, photographed on 16 year old windows 2000 laptop!
And as Triode
You can vary Screen, control grid, Anode or even heater supply in various combinations.
I also have a set of hooked patch leads to connect direct to a valves pins. Some AVOs have an "expansion" socket for this purpose.
I'm still looking for a Nuvistor socket. I have some NOS nuvistors.
If the tester oscillates, then add lots of ferrite beads.
One YouTube video I made of a Magic Eye:
There are more here on my website
Have fun Sparky!
