Quote:
Originally Posted by zeno
That will work. A caution on fusables. At an RCA seminar a few
complained that the fusable always opened & not the fuse. TRUE !
They said its because the fusable protected the fuse. TRUE !
Bottom line is when you turn on a set there is a very heavy
current draw to charge up the filter cans. The fusable limits
that & lets the caps charge slowly. If it wasnt there the fuse
would soon fail. It also acts as a fuse, I have only seen them open
with a shorted rectifier or for NO reason, just age. Sets with
them rarely blew fuses !
Last thing is its important on solid state sets with kick-start
circuits. They depend on the slow & proppor rise of the B+ often.
73 Zeno  |
Zeno,
Remember the Surgistors? The resistor that heated up and closed a bimetallic strip that carried the current? Workman and GC had replacements - I still have a couple, and may add one to my Setchell Carlson.
As to fusibles - Workman had several types - the heavy duty white one, the pink ones in 4.7, 5.6 and 7.5 ohms, and a square cement version called "FUZIT" that they sold in packs of 5. Philcos, RCAs and Sears sets I remember were the fusible killers - always opening up. RCA had one that was soldered to a little phenolic strip, and they dipped the whole thing in varnish. You could tell one had failed - there were flakes of varnish around the resistor.
Nowadays, it's smart to add a CL60/80 NTC in series with the line. Folks think it's something new, but surge/fusible resistors have been used for years, i tell 'em.