Sharp TU-95PA Black & White 12"

[stushug]

I took the set to my friend's house for him to look it over. After checking the diode, and other items, he noticed a wire on the back of the on/off switch was broken. As soon as we fixed that the set worked again!
The original fusistor is broken, one of the leads broke off right where it goes into the body. Right now I have just a one amp fast blow fuse taking its place. You had mentioned placing a 4.7 ohm resistor in series with the fuse. How do I determine the correct wattage? I tried a 1 watt resistor and it blew right away. Can I just use the set with only the fuse?

Thanks again for all of your help. I posted a picture of the broken wire my friend found.

[zeno]

4.7 ohm 5 watt was in 95% of B&W tube sets. Must be a fuseable.

73 Zeno
LFOD !

[stushug]

Thank you, Zeno!

[stushug]

It turns out I need to replace the on/off volume switch. What I found online should work, except that on the power connections, the original switch has four terminals and the new ones I've seen only have two. The ones I saw are SPST switches. Does that mean I need a DPST switch? I think the extra two terminals on the original switch allow the tv to have its instant on feature.
The terminals are labeled as follows, starting with the green lead, counterclockwise:
Green Lead=D
Red Lead=F
Black Lead=C
Jumpered Lead from Green terminal=A

[Electronic M]

Originally Posted by stushug

It turns out I need to replace the on/off volume switch. What I found online should work, except that on the power connections, the original switch has four terminals and the new ones I've seen only have two. The ones I saw are SPST switches. Does that mean I need a DPST switch? I think the extra two terminals on the original switch allow the tv to have its instant on feature.
The terminals are labeled as follows, starting with the green lead, counterclockwise:
Green Lead=D
Red Lead=F
Black Lead=C
Jumpered Lead from Green terminal=A

It is the 115 ohm in parallel with the switch that enables the instant on. I personally don't like instant on as it can wear out the tubes... what I would do is snip out that 115 ohm resistor and bridge the fusistor terminal over to the heater terminal of the switch.... another option that would prevent changing the control and also prevent switch wear is to have the good section of the switch drive a the coil of a 120VAC coil DPST (or a correctly wired DPDT) relay.

[stushug]

The problem is the volume pot is broken, one of the two fingers broke off. The other problem is that the shaft does not activate the on/off cam either. I attached a pic of the on/off cam, I added a small bit of epoxy to the off side so the post would make sufficient contact, but then I noticed that one of the fingers for the volume had broken off. I'm guessing that installing a new dpst switch may be the simplest fix since both sections are broken. Do you agree?