Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

FADA 790
#1

I am restoring an early 50s FADA AM/FM radio for a friend.  There are a mix of paper and ceramic capacitors inside.  (And a few electrolytics.)

One type that I think must be ceramic are hard, white cylinders, smaller than paper, labeled "Hi Q 1500 mmF 20%."  There are similar caps with other values ranging from 2 pf to about 250 pf.  None are marked with a voltage spec, nor does the parts list say anything about voltage.

My question is, are these high temperature stability caps?  Most of them don't look like they are associated with the oscillators or anywhere else requiring high stability.  The exceptions are some 2 mmf, 10 mmf and 30 mmf caps that the parts list call "FM Oscillator coupling," "osc. feedback," and "osc grid cap," so those could need to be stable with temperature.

Some are bad.  My question is, do I need to look for temperature stable caps, or can I replace them with poly or mica caps 500 volts or higher to be safe?  If I do need high stability caps what type should I use and where would I find them?

Thanks!

John Honeycutt
#2

   
Copy of the sch so other can see what you are fixing.




Users browsing this thread:
[-]
Recent Posts
Philco 91 Speaker Replacement
The spider is glued on the cone and so is the voice coil. I think you can use a cotton swab dipped in acetone and carefu...RodB — 02:42 PM
Restoring Philco 37-604C
Yes I saw that. If I knew, I'd probably try to arrange for getting it myself. But I have just got one. Which does not m...morzh — 01:44 PM
Philco 38-2 Automatic Tuning
When you push the lever, you are supposed to rotate the disk to the desired station. Then the magnetic tuning will acqu...morzh — 01:42 PM
Philco 38-2 Automatic Tuning
I figure out the muting from another picture that helped. Now I need to know how the automatic tuning works. When I push...dconant — 12:11 PM
Philco 91 Speaker Replacement
How would I go about removing the spider from the cone?dconant — 12:04 PM
Philco 38-2 Automatic Tuning
Hello, I am having trouble getting my automatic tuning to stay unmuted. If I play with the tuning handle I can get it to...dconant — 10:51 AM
Does anyone make photofinish replacements?
Here’s the link to the DIY photofinish section of our site: klondike98 — 09:46 AM
Delco car radio Peko vibrator converstion issues
Hi Richard, Thx for posting the schematic.  As I remember as a kid, these were great performers for the time, likely...MrFixr55 — 08:56 AM
Delco car radio Peko vibrator converstion issues
hello mr Fixr, The Electro  Powersupply that I am powering the radio with has a huge choke plus a 10,000ufd electrolyti...radiorich — 10:58 PM
Delco car radio Peko vibrator converstion issues
How about putting a choke in the power supply? The big cap was likely an attempt to stabilize the DC. Kids who cre...MrFixr55 — 09:19 PM

[-]
Who's Online
There are currently no members online.

>