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

1948 Magnavox "Berkeley" Just Acquired!
#16

If you are planning on playing this radio to any extent, I would at least recommend changing the coupling caps connected to the control grids of the 6L6G output tubes. They are marked 35 (.03 uF) and 43 (0.1 uF) on the schematic. Any leakage through these caps will throw off the DC bias of the 6L6's causing them to draw excessive current. This could cause a runaway condition which could take out the tubes, output transformer and eventually the power supply.

You can restuff these two with modern film caps if you want to retain the original appearance.

http://www.nostalgiaair.org/PagesByModel...010334.pdf
#17

If you have not done so already, REPLACE THE POWER SUPPLY FILTER CONDENSERS !!! before you do anything else, before you turn it on again. They are the most likely to go, and if they do they can take the power transformer with them. Actually, I strongly suggest also replacing all the paper condensers, and checking all the resistors for out of spec ones and replace those too. Once done you will have a radio-phono which will be far more reliable, and probably only need a tube replaced now and then for the next half century.
#18

Thinking out loud maybe the reason the set looks so clean is somebody in the past restuffed the caps!
#19

I checked many of the caps and resistors, and it seems that the only caps that were bad were the across the line caps (there were 3 of them and they were all .02 µF 600V Micamold "Domino" style paper caps which were all leaking "wax" out of them, the rest of the paper caps measured fine yet using my Cornell-Dublier Capacitor Analyzer.

I agree with David that quite possibly this radio's cap's were restuffed sometime in the recent past as they tested little to no leakage, there was 2 paper caps that looked like they might of been later replacements, either that or they were sourced from a different source than the rest of the caps in this unit for some reason.




Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
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
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM
Zenith H725
Ed; One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to ...Arran — 11:42 PM
Zenith H725
I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. Th...EdHolland — 08:39 PM
Zenith H725
The PSU filter cap arrived today (thank you USPS!) so I will work on that later. Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM

[-]
Who's Online
There are currently 1561 online users. [Complete List]
» 1 Member(s) | 1560 Guest(s)
Avatar

>