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

Model 20 output trans "surgery", and questions.
#1

Hi all,

I recently found a very nice Philco 20 De Luxe with the bird's eye maple arch, and just starting the process of doing the chassis.

On a preliminary inspection, and familiarization of the circuit, I found the output trans to have one side of the center tap open, The other side had 322 Ohms.

http://www.nostalgiaair.org/PagesByModel...029582.pdf

I decided to disassemble the trans hoping it was a broken wire at the inside terminal. No luck.

I then prodded around the top layer of windings and still did not find any continuity. I then cut a little of the top layer off, went to the second layer, carefullt scraped about 2 turns of wire, I got a reading of 316 Ohms.

Soldered a thin wire to the winding, then added back the heavier lead to the terminal, added the insulation, and a little JB welld for stability, and reassembled the trans.

My question is, will the difference on 6 ohms make any difference in the operation fo the push pull output? I say no, but want to make sure. I suspect there is enough vairence in other parts to make this 6 ohms not matter at all, except maybe on a scope under test conditions Icon_smile.

The second question on this model is what is the voltage rating on the filter caps? I suspect that the 630v caps we use will work fine. It does seem odd to have such a large filter can to hold such small vaule caps.

There are two 1uf caps, a 1.5uf, and a 1.3uf. I have not taken the can off yet to see if there is room in the can for the replacements. I don't want to empty the can, but want the underside to look original. The chassis has never been worked on before.

Thanks in advance, and take care,
Gary [Image: http://www.grabbittradios.com/radio/emoticon.gif]

[Image: http://www.grabbittradios.com/radio/transrep1.jpg]

[Image: http://www.grabbittradios.com/radio/transrep2.jpg]

[Image: http://www.grabbittradios.com/radio/transrep3.jpg]

[Image: http://www.grabbittradios.com/radio/transrep4.jpg]


Messages In This Thread
Model 20 output trans "surgery", and questions. - by gary rabbitt - 01-18-2008, 04:18 PM
[No subject] - by Chuck Schwark - 01-18-2008, 04:55 PM
[No subject] - by gary rabbitt - 01-18-2008, 05:07 PM
[No subject] - by 49Stude63 - 01-18-2008, 09:25 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
Radio city products 664 schematic request
Need a schematic or manual for the 664. The 663 may be similar.daveone23 — 12:38 PM
New Philco Repair Bench
Thanks Gary.dconant — 12:16 PM
New Philco Repair Bench
I tried accessing the site through our library and got the same response. It's reported to our tech gurus. GaryGarySP — 11:50 AM
New Philco Repair Bench
I am sure this is the archive, and not the Chuck's site.morzh — 09:50 PM
Made mistake & did not label connection
It's not like we are good friends with that wire and can tell it from other ptetty identical looking wires. Why'n't you...morzh — 09:49 PM
Made mistake & did not label connection
I'm not sure why that wire wasn't covered in the video. I'm pretty sure the 6A8 won't work until that pin is grounded. Y...RodB — 09:47 PM
Made mistake & did not label connection
You'll have to forgive me, I am not sure what you mean.  Can you explain what you are really saying.  If anyone does not...georgetownjohn — 08:05 PM
Made mistake & did not label connection
Those are details better left to the ones who know. Maybe you disconnected the wrong end of the wire.RodB — 06:22 PM
Made mistake & did not label connection
Maybe this is starting to make some sense in my hard head.  Is this why the wire in question was not in the great Ron Ra...georgetownjohn — 04:34 PM
Made mistake & did not label connection
I was correct with the 6A8 pin connection's, 7 and 8 are connected to ground as well as the tube shield (the broken line...RodB — 02:41 PM

[-]
Who's Online
There are currently 3921 online users. [Complete List]
» 1 Member(s) | 3920 Guest(s)
Avatar

>