A Zenith radio Model K731. Oh lord!!

[--exray--]

It's a Zenith K731 AM/FM radio with Chassis #7K07.
What do you say guys? Should I replace the ceramic caps just becasue
they have fissures or is there something to coat them with?

Sven, my experience with those ugly Zenith disc caps is that they are
generally ok. I've found a few bad ones where I guess
moisture/corrosion set in but they're the exceptions.
To be on the safe side, replace whatever is connected to the grid of the
audio output tube so you will be able to hear if there are any other
problems.
Definitely swat the bumblebees. One is going to be the AC bypass cap
and it will pop smartly.
-Bill

[Sven Franklyn Weil]

Post by --exray--
Sven, my experience with those ugly Zenith disc caps is that they are

What are those values in? I see numbers like

22.3
0022
01
001
22.14

[--exray--]

Post by Sven Franklyn Weil

Post by --exray--
Sven, my experience with those ugly Zenith disc caps is that they are

What are those values in? I see numbers like
22.3
0022
01
001
22.14

Oh man, I'd have to go look them up. I made a list of what I found once.
It'd be easier just to match em up on the schematic if you have one.
The 0022, 01, 001 are as they say but ones like 22.3 are a p/n and the
printed number doesn't relate to an actual value.

-Bill

[--exray--]

Post by Sven Franklyn Weil

Post by --exray--
Sven, my experience with those ugly Zenith disc caps is that they are

What are those values in? I see numbers like
22.3
0022
01
001
22.14

Here's a few I found noted on a schematic...
22.3 = .01
22.5 = 110pf
22.6 = 470pf

-Bill

[jakdedert]

Also (you probably know this already....) sometimes 'fissures' in ceramic
caps are a sort of fine tuning. They saw a notch in the cap to tweak the
value.

jak

Post by --exray--

It's a Zenith K731 AM/FM radio with Chassis #7K07.
What do you say guys? Should I replace the ceramic caps just becasue
they have fissures or is there something to coat them with?

Sven, my experience with those ugly Zenith disc caps is that they are
generally ok. I've found a few bad ones where I guess
moisture/corrosion set in but they're the exceptions.
To be on the safe side, replace whatever is connected to the grid of the
audio output tube so you will be able to hear if there are any other
problems.
Definitely swat the bumblebees. One is going to be the AC bypass cap
and it will pop smartly.
-Bill

[Sven Franklyn Weil]

Post by jakdedert
Also (you probably know this already....) sometimes 'fissures' in ceramic

Jake,

Naw...these aren't "sawed" fissures. Thse are cracks...sort of like
when you patch a hole in the wall with plaster and the patch shrinks
and cracks...

[Sven Franklyn Weil]

Post by jakdedert
Also (you probably know this already....) sometimes 'fissures' in ceramic

Jake,

I meant Jak. Sorry.... :(

Bedtime...

[Sven Franklyn Weil]

The filter (three section plus can common) is gonna be another joy.
Tight spot to put new electrolytics underneath...

I'm thinking of somehow cutting the filter can open about a centimeter
before the base, leaving the base in place and soldering the new (most
likely axial) caps on the top side of the phenolic disk.

That's gonna look hamfisted...but at least it will not disturb the
connections underneath the chassis and at least leave that original so
that someone in the future doesn't have to decipher where I had to
move this or that to.

Is it OK to replace the 60 and the 80 with 100 mfds? I can't find any
60 or 80 radials. Only axials in the Mouser book (the Sprague Atoms).
At least the radials will not make this already ugly idea look even
more horrendous.

With axials, I'll have the + points of the three ateach tab plus a
common wire running down the side where they are all tied together.
But at least the values will be exact. Less figuring out for the next
guy to do.

Unless someone has a fresh, new three-section can with these values
that they can sell me....but I doubt that...so....on we go.

P.S.:

I've got this love-hate with old radios with PC boards...they seem
easier to replace some components on...you can get away with some
thingson those boards that you can't get away with on metal chassis.

Two or three separate capacitors replacing a multisection filter
capacitor can will look OK on a PC board.....but not on a "real"
chassis. :)

[--exray--]

Post by Sven Franklyn Weil
Is it OK to replace the 60 and the 80 with 100 mfds?

Yes.

I can't find any

Post by Sven Franklyn Weil
60 or 80 radials. Only axials in the Mouser book (the Sprague Atoms).
At least the radials will not make this already ugly idea look even
more horrendous.

Watch out on the physical size on the Sprague caps.

Post by Sven Franklyn Weil
Unless someone has a fresh, new three-section can with these values
that they can sell me....but I doubt that...so....on we go.

See if one of the three is only the cathode bypass cap for the output
tube. If so, it will be a small little guy and can be placed directly
at the tube socket and the + wiring over to the can can be eliminated.

Bill