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

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

Philco 20 restoration state: need the voltage chart
#12

Well, today brought some good news - the "Lowboy" just came to life.

I received the Mouser package with resistors, and changed all 5 of them, plus restoring the 1.4Kohm open section of the multi-tap voltage divider bu just soldering 3W 1.4K resistors in parallel.

Now, I started touching anodes (plates) and once I touched the plate of the 24 detector tube, I heard a loud 60Hz buzz from the speaker, so I knew my Audio amp works, and my speaker works.

Then I took off the screen (the one protecting the tubes in HF section) and was able to tune to some buzzes and whistles. Then I heard a faint signal.
Then I swapped couple of tubes places and the reception became very loud, and when i connected the GND wire to the actual Earth GND, it became even louder. I was able to achieve a nice low distortion sound by reducing the volume. At high volume it would go into excitation.

I think one of the three 24 tubes is subpar, but I lack the tester, and a Hickok in a working state is over 300 bucks, so I will start from buying one extra 24 and trying to see if it makes things better.

So far only one station is received clearly and is loud.

The last thing is (have to find out why - thoughts welcome) - when replacing the protection screen over the 24 tubes, I lose the reception almost completely - I can barely hear that station that comes in very well without the screen.

And another question (about the voltage chart you guys gave me the link for):

I am not sure, on the voltage chart, what those figures on top of the tubes mean. The plate voltages etc are in the table, which lists the tubes and their finctions vs. Plate/grid etc voltages. But in the sch on to of the tubes there are volt/curr. figures like "225V 3ma" / "130V 3ma"/"30V"/"115V 3mA".
Not sure. Are these the voltages measured at 3mA through each tube?

And in what mode then the table voltages are measured (the plate voltages are fairly close to what I have now; Grids - different).

PS> The reception is achieved without rebuilding the potted/canned caps. Do you think I should start looking at those?

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.


Messages In This Thread
Re: Philco 20 restoration state: need the voltage chart - by morzh - 11-02-2011, 06:49 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
VTVM meter moves when my hand is next to it & not on
Haha! I hope so. It seemed rather lost and forgotten languishing in the frozen Northeast of England.EdHolland — 02:36 PM
VTVM meter moves when my hand is next to it & not on
Ed - it's in the Cayman's enjoying the good life.RodB — 02:14 PM
VTVM meter moves when my hand is next to it & not on
Static electricity - but the other chaps beat me to it again. I've seen this before with analogue meters. I've also ...EdHolland — 01:56 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Hi Paulo, Welcome to the Philco Phorum. I can see why you want to find good reproduction parts. That is a bea...MrFixr55 — 11:10 PM
HiFi (Chifi) tube amp build - but my own design.
Tim, I have some bakelite sockets in my work shop that I can dig up. I believe quite a few are NOS. I will take photo...RodB — 10:03 PM
Philco 610B oscillator wiring
> The cathode as noted is wired directly to the ground side of the heater filament for that tube, not to the #17 and ...Radioroslyn — 08:12 PM
HiFi (Chifi) tube amp build - but my own design.
Tim; I noticed your post a little late, but I would take one of the junk sockets and try to break a chunk out of it wi...Arran — 08:07 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM

[-]
Who's Online
There are currently 1525 online users. [Complete List]
» 2 Member(s) | 1523 Guest(s)
AvatarAvatar

>