12V Inverter for portable Cossor CDU150 Oscilloscope Design?

[Chris56000]

Hi!

Having donated the mains transformer from a Cossor CDU150 35MHz portable oscilloscope to a Vintage Radio Forum Member, I'm thinking of using it as a test bed for a 12V battery conversion.

The power supplies required are:–

a) +20V at 1A;
b) +150V at 300mA;
c) +67V at 300mA;
d) –67V at 300mA;

The voltage rails quoted above assume the retention of the original power supply stabilization circuits fed off the original 50Hz transformer, now removed.

The power consumption given in the handbook (I have an original ring bound one coming!) is 110VA.

The e.h.t. and p.d.a. comes from it's own inverter circuit which will be retained, and the highly insulated CRT heater supply would be obtained from an isolated dc–dc converter operated from the incoming 12V battery supply.

What size transformer kit would best power this, using a TL494 or SG3524 based flyback design, and where can I obtain easy–to–understand transformer winding data?

It's not necessary for output rectifiers and capacitors to be provided on the new inverter pcb., four isolated a.c. outputs plus the CRT heater from a DC–DC module is all that's needed!

Are there any companies that would manufacture/wind a suitable transformer for me at an economic price I can approach?

Chris Williams