[kbm37-630]

Question from the new guy,

I would like to know what value is appropriate for the fuse ? Amps and voltage, I think I read somewhere that it should be a fast-acting/blow fuse. It's for my Philco 37-630. Just about finished the recap and resistors.....

Kurt

[rghines1]

Fast acting fuse is not necessary. They are intended mainly for semiconductor protection. Use a normal blow with the standard 250V rating. Current rating from 1 to 2 amps is good for most situations.

Usually the power consumption is given on schematic and the current can be calculated with ohms law. 140 watt radio plugged into 120V mains is 140/120 gives 1.16 amps. A 1-1/2 amp to 2 amp fuse is Ok.

Richard

[Arran]

I don't even know why a power line fuse is necessary unless you have a lot of lightening strikes or power surges in your area, even in sets with failed power transformers it's usually the high voltage secondary that has failed not the primary, I would be more inclined to fuse the center tap of the high voltage winding. There is a guy on you tube that even installs fuses in AC/DC radios, and with big ugly 20 amp fuse holders, with pig tails, designed for cars, a complete waste of time since the cathode of the rectifier tube already serves that purpose.
Regards
Arran