Fisher 800c selenium rectifier pictures

[skiman762]

I did a search and got why to change and how to change so
can someone post pictures of the 800c selenium rectifier so I can tell if mine is original I have a square bridge about 1 inch maybe a tad bigger square and maybe 3/8th inch thick mounted on the side.

Thanks

[chrish]

Maybe post a picture of what you have got, then someone can tell you if it is the selenium rectifier.

[Frank Berry]

If the Fisher is like the old HH Scott amplifiers, the selenium is a bridge rectifier. The size is about correct.
There should be four connections. Two directly from the power transformer, one (the - output) to the electrolytic (possibly through a resistor) and the another (the + output) should be tied to chassis ground.
Hope this helps.

[DigitalJunkie]

Does it look like a stack of square metal plates,with a space between each plate,kinda "finned" looking? If so,it's selenium.

Selenium rects on google images

[Frank Berry]

The selenium bridge in the old HH Scott amplifiers is a flat pack ...
no fins. It has two solder terminals on one side and two terminals on the opposite side. It's mounted to the chassis with a small mounting bracket. Fisher may have used a similar bridge.

[skiman762]

Ok here's some pics

[skiman762]

Mine looks like the bottom one in this picture
Heres the caption from the picture

Two old selenium rectifiers and on the foreground a modern silicium bridge rectifier

[Eli Duttman]

FWIW, I suggest that no prisoners be taken and 4X 100 PIV Schottky diodes be installed. Remember, the negative rail does double duty providing O/P tube bias and heater power. "Zero" switching noise in the bias supply can't hurt and may help. An adjustment to the rail voltage is probably necessary, given the very small forward drop in Schottkys.