Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x


37-630 code 125 missing all 110 pF caps
#40

Hi sdradioman,
A few posts back you mention the .008uf/100V cap. (on the Factory parts sheet it is part 56). There is a reason for those caps to be rated at 1kv or more. 
If there is a static crash, like from a bandswitch being changed, an close lightening (audio  or sharp spike or similar audio, the tube could go into cutoff and the could cause internal flashover in the trans from the field collapsing.  When the collapsing field in any trans can cause a kickback or flashover spike of high voltage for an instant, the cap rating is needed to mitigate that energy and protect the trans.

 This is the same action that was used for automotive ignitions back ion the day. The opening of points, the collapsing field would cause the ignition spark.

  I personally will seek out the same voltage spec, even higher, on those caps in the output rated for 1KV or more. While the 'normal'
 voltage on those pints may be only a couple hundred volts, the spike Voltage for that instant can reach over a KV or more.

 The late Leigh Bassett and another person made the same comment about using the higher voltage spec caps on the outputs.  

Just passing this along, many of you probably know the reason as well already. Icon_smile
   
   


Messages In This Thread
RE: 37-630 code 125 missing all 110 pF caps - by gary rabbitt - 04-19-2026, 12:02 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
That looks a lot like an aircraft connector of some kind, even if it's a U.S.N power supply. I have a book somewhere abo...Arran — 02:56 AM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
hello david, I have a similar generator in my collection that features a cast iron, single-cylinder Briggs & Stratt...radiorich — 01:00 AM
under chassis parts locator diagram for 1938 Zenith 9s262
Has anyone gone to the trouble of creating an under chassis parts locator image?  Yes, I can identify components by foll...bobloney — 08:57 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Try looking at this site the book mark is for a old generator that I was given. David    https://radionerds.com/index.ph...David — 08:36 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Hello Everyone, I am looking for voltage identification for all the pin positions on the socket of a CRV-20130 power su...Tonym4704 — 08:16 PM
Philco P45-6365 Universal Transformer Instruction Manual
Can anyone guide me to where this may be found?GRG — 03:00 PM
54C Complete Teardown/Rebuild
I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM

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

>