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

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

Philco 15DX restoration

The new output transformer should be here by the end of the week. Mind you I'm just going to finish it electrically. I really don't have the room or tools to repair the cabinet properly. Some day I hope to though.

Sounds great!! keep up the spectacular work!!
Terry

The new Hammond transformer arrived today Icon_smile I went with the 125D because it's a perfect fit for the original mounting holes and I believe 10W should be enough. The only downside so far is that it doesn't have any spare mounting lugs for the field coils. I may end up adding a terminal strip to the wooden board.

I hope to fire it up tomorrow.
[Image: https://farm4.staticflickr.com/3892/1445...590b_c.jpg]

On the schematic it looks like one side of both filed coils, #60 and #62 are tied together and connected to the blue and white wire. The other end of one filed coil #60 is connected to the center tap of the output transformer primary #58, both are connected to the green and white wire, which is connected to B+, which is also connected to the output side of the filter choke #67 and the screen grids of the power output tubes. The other end of the other field coil, #62, is connected to the blue wire, which looks like it is connected to chassis ground. The green wire and the white wire are connected from the outside legs of the output transformer primary to each plate of the power output tubes.
If you can't find a decent tie point for the blue and white and the blue leads I would add a terminal strip on one of the speaker baskets with some nuts and screws, just to make it secure, or use one of the output transformer bolts. Although it does look like the larger speaker has a terminal riveted to the basket, that would work for the blue wire. I speak about the colour code that Philco used originally, but I noticed that the Hammond transformer also has a blue wire lead along with a brown and a red one, you don't want to get those mixed up with the originals of course!!
Regards
Arran

Luckily there is some color left on the old wires so it wasn't too difficult to get them wired up.
[Image: https://farm3.staticflickr.com/2904/1447...6b60_c.jpg]

After a few hiccups like forgetting to install one of the tubes and replacing a dead #44, I was treated to booming sounds Icon_biggrin At about 50% it starts to get painful! I'm calling the Hammond replacement a big success. Now to make it all nice and neat and install back in the cabinet...
[Image: https://farm4.staticflickr.com/3887/1428...62d4_c.jpg]

I finally broke out all my Philco globes. Sounds wonderful Icon_e_smile

[Image: https://farm4.staticflickr.com/3879/1447...c324_c.jpg]

[Image: https://farm4.staticflickr.com/3903/1446...3a18_c.jpg]

[Image: https://farm4.staticflickr.com/3878/1428...99cc_c.jpg]

Wow! NIB tubes.

I'm just about to start on my 15X.

"I just might turn into smoke, but I feel fine"
http://www.russoldradios.com/

Nah, none of them are NOS - they're all used. I just had a few old boxes lying around. I wouldn't mind find some NOS Philco tubes though Icon_smile

I figured I might as well see if I can make one good output transformers from the originals. The first few pieces took some patient tapping then the rest fell out easily.

[Image: https://farm4.staticflickr.com/3886/1449...523b_c.jpg]

Bob

in case you need a new one, what I did was buying a Hammond replacement and, having glued a couple of pieces of wood to keep the clamshell from collapsing, glueing the transformer to the shell and assembling it all together.

But what I realized also while bying it, was that the transformer sold by AES for 1/2 the price will work just fine. I am just stubborn enough to try to get a part that is the best, but I doubt I will hear the difference. And 20 bucks is the price of my being stubborn.

Here's the other one taken apart. Initially, I had some hope I could find the break in the primary but no such luck. It's many, many turns of very fine wire (40 gauge?).

This core turned out to be a little rusty too so I've got the pieces soaking in Evaporust.

[Image: https://farm6.staticflickr.com/5559/1429...bbc3_c.jpg]

Bob, I will be watching this. A lot of pieces to put back together! Mike, I liked the way you handled the problem as well.
Jerry

A friend in need is a pest!  Bill Slee ca 1970.

If I had a winding set, I'd probably tackle it, but manually thousands of turns is too painful.
This transformer works well unde 10mA and I am not sure why Philco used this mammoth of a transformer (which did not help it) for the interstage while any 10mA half the size would do.

Do not clean the rust off of the core. It helps provide insulation between the plates. So unless it is crumbling rust. leave it alone. If you have already cleaned the core you could paint it before reassembly. Believe it or not, a core works better if the plates are isolated. That is why it is not one large iron lump.

"I just might turn into smoke, but I feel fine"
http://www.russoldradios.com/

Keeps eddy currents at bay, reducing losses. But better done by using warnish (seen on new transformers).




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Yes, 57 is an electrolytic cap that should be 12 mfd 400 volts according to the parts list from the Phorum library schem...RodB — 06:01 PM
Philco 42-345 Restoration/Repair
Looks like if I am reading it correctly it looks like the silver capacitor#57 that appears to be a replacement is of a l...osanders0311 — 05:09 PM
Philco model 38 code 121 not receiving signal.
Thanks Arran. Yeah this plastic is pretty thin. It's a little thinner than the original stuff. It kinda reminds me of p...Stormlord5500 — 04:37 PM
Testing a speaker and output transformer Trutone A2-G
The equivalent of one short turn is basically the same as that of a shorted load. If it is the primary's turn, then the ...morzh — 03:53 PM
Testing a speaker and output transformer Trutone A2-G
I've never had an output transformer become shorted, the failure mode is usually an open primary, or in a center tapped ...Arran — 03:52 PM
Philco model 38 code 121 not receiving signal.
As long as the plastic sheeting isn't too thick, I think that the thickness of photographic film would be just about rig...Arran — 03:19 PM
Philco model 38 code 121 not receiving signal.
Well why not! :lol:Stormlord5500 — 03:14 PM
Philco model 38 code 121 not receiving signal.
Good luck next thing you know you will be winding coils just for the fun of it. DavidDavid — 11:29 AM
Testing a speaker and output transformer Trutone A2-G
morzh Short-circuited turns can be considered as a half-dead transformer. But on this case transformer will hot and s...Vlad95 — 11:01 AM
Testing a speaker and output transformer Trutone A2-G
I am not sure how a transformer could be weak. It could be inadequate, but only when you replace the original with somet...morzh — 09:56 AM

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

>