Replacement rectifier.

To summarise all these posts, just fit a 1A or more silicon bridge, all will be fine. I do 'like' the spelling of LITE on the diagram.

[ms660]

Originally Posted by exlecy1

the output on the trani is 244v same at the rectifier ac legs ,,attch
schematic of pwer supply + amp

If you have 224VAC at the input to the bridge rectifier and your reported DC voltage out from the rectifier was 217 volts DC when a silicon bridge was tried (post#25) then there is a problem, the silicon bridge should only drop approx. 1.4 volts and the HT voltage should be higher than the input voltage to the bridge.

Lawrence.

[TrevorG3VLF]

You would expect about the same DC output as AC input with biphase rectification. Looking at the circiut, it appears to be a valve socket with half wave rectification. A bridge plugged in here will not need the filament supply. All very strange.

If you include a resistor to limit the voltage and peak currents, then make it a high wattage one. The power and voltage drop will be several times that calculated from a continuous current. So, 100mA and 100ohms would drop 10V continuous and dissipate 1W. In practice, you could drop up to 50V and dissipate 5W. Remember that the transformer primary and secondary will have resistance.

[ms660]

Half wave? Full wave bridge surely?

Lawrence.

[exlecy1]

i have to say that before i removed the amp from the JB it worked fine, i only removed it to change the old paper caps and the old electrolitic ones, i changed all caps with the values as near as possible to the old values which were no longer available i increased their voltage rating also ,it was reccomened i change the old recifier which brings us to the start, i do not think there is a problem with the amp because it was working fine before removal, i have to re-instal the amp now it's recapped i am mainly concerned about the recifier change before i put the amp back in the JB

[McMurdo]

the datasheet for that rectifier which is an old Siemens and Halske number rates it for 250Vac 250mA selenium.

GD rectifiers made us some cracking selenium rectifiers some years ago

[TrevorG3VLF]

Originally Posted by ms660

Half wave? Full wave bridge surely?

The diagram in #40 shows just a single winding connected to what appears to be a valve base supplied with a heater winding. This cannot be used to supply a full wave output. If a valve is to be used, I would connect the winding between the anodes and a couple of silicon diodes anodes to ground to complete the bridge. The selenium rectifier would likely be a bridge, three connections would be biphase, four connections would be a bridge.

A heater supply would not be needed for the selenium rectifier of course.

The WO8 is a nice little bridge rectifier which would do.

[ms660]

You might be getting confused, the 1st schematic in post#40 shows 235VAC from the mains transformer going to pins 2&3 of a 4 pin chassis socket, the 2nd schematic shows pins 2&3 of that sockets corresponding plug connecting to a bridge rectifier that supplies the amplifiers HT, no valve, no half wave just a full wave bridge rectifier (selenium)

The heater winding in the 1st schematic that connects to pins 1&4 of the chassis socket supplies the heaters for the amplifier valves in the 2nd schematic.

Lawrence.

[TrevorG3VLF]

Thanks Lawrence, I stand corrected.

Trevor