A schematic with voltages and currents is worth 1000 words, and helps analysts to analyze.
Perhaps a very experienced Fisher KX-200 expert can answer your question without a schematic.
A resistor that gets very hot, usually means one of two things:
1. The current through the resistor is too large, caused by a fault that is downstream.
2. The original design tried to save the cost and space of a larger resistor.
Just my opinions
Perhaps a very experienced Fisher KX-200 expert can answer your question without a schematic.
A resistor that gets very hot, usually means one of two things:
1. The current through the resistor is too large, caused by a fault that is downstream.
2. The original design tried to save the cost and space of a larger resistor.
Just my opinions
http://www.fisherconsoles.com/non console manuals/fisher kx-200 sm.PDF
I have not seen one of these in 50 years.
In its day, these ran HOT but did not smoke. Whatever you did, something is wrong.
Is it possible that the CAPACITOR is 'smoking' (boiling), not the resistor?
Where did you find a 3-pin dual 1000u cap can?
I have not seen one of these in 50 years.
In its day, these ran HOT but did not smoke. Whatever you did, something is wrong.
Is it possible that the CAPACITOR is 'smoking' (boiling), not the resistor?
Where did you find a 3-pin dual 1000u cap can?
My Apologies.
Hopefully the schematic works.
I re-stuffed the original can with 1000ufd 65Vdc electrolytics that my local electronics store happened to have.
I felt the resistor and it is too hot to touch so I assume that's where smoke is originating...
Hopefully the schematic works.
I re-stuffed the original can with 1000ufd 65Vdc electrolytics that my local electronics store happened to have.
I felt the resistor and it is too hot to touch so I assume that's where smoke is originating...
Did you get all of the polarities of the new capacitors correct?
I'd use a higher power resistor in that hot environment, regardless.
Maybe a 10W or a 20W part.
I'd use a higher power resistor in that hot environment, regardless.
Maybe a 10W or a 20W part.
It’s funny as I accidentally got polarity right first time,
Then realized the white stripe was negative, reversed it and blew up a cap.
But it is correct now yes.
Then realized the white stripe was negative, reversed it and blew up a cap.
But it is correct now yes.
Yes.The strange thing is other than increasing the bias voltage the circuit is exactly the
same.(other than functioning capacitors that are almost double the Working voltage)
The voltage levels are good, amp sounds normal(at first)
I am afraid to just increase wattage of that resistor because it doesn't seem right that it should suddenly be drawing more current.
I thought increasing voltage should reduce current?
same.(other than functioning capacitors that are almost double the Working voltage)
The voltage levels are good, amp sounds normal(at first)
I am afraid to just increase wattage of that resistor because it doesn't seem right that it should suddenly be drawing more current.
I thought increasing voltage should reduce current?
Making the grid DC voltage more negative will reduce the tube's plate current.
How much voltage ripple is present on the first capacitor in the bias circuit?
Excessive ripple voltage could cause the 15R to heat up more than it should,
since the 15R has to dissipate most of that power.
How much voltage ripple is present on the first capacitor in the bias circuit?
Excessive ripple voltage could cause the 15R to heat up more than it should,
since the 15R has to dissipate most of that power.
That’s a good point.
I don’t know how to measure ripple but when the cap blew it took out
The first 1000ufd and shorted one of the new 8ufd that I put in.
So I put the originals back in just to test.
So maybe those originals have excessive ripple?
I was planning on replacing the 8ufd (again) but need to order more.
I don’t know how to measure ripple but when the cap blew it took out
The first 1000ufd and shorted one of the new 8ufd that I put in.
So I put the originals back in just to test.
So maybe those originals have excessive ripple?
I was planning on replacing the 8ufd (again) but need to order more.
The first two caps (on either side of the 15R) must each be 1000uF or more.
There's around 1A of current. I'd use 2200uF or 3300uF.
You can't use 8uF in place of the second 1000uF.
There's around 1A of current. I'd use 2200uF or 3300uF.
You can't use 8uF in place of the second 1000uF.
I’ m not customizing anything from original schematic.
All just what was Original.
If you look at the schematic there are 2 8ufd caps
All just what was Original.
If you look at the schematic there are 2 8ufd caps