Posts: 1,402
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
About two years ago, I started the restoration of a Philco 19 chassis. I did a total recap, replaced a few out of tolerance resistors. The feedback winding of the oscillator coil was open. I removed the coil, unwound the tickler and baked the form at 200 degrees for about an hour. I rewound the coil and installed it in the chassis. When I started to do the alignment, I discovered, the oscillator would die out on the low end of the dial (I believe it was the low end, it's been a while). I had already changed the oscillator cathode resistor to 10K. I tried another tube, no good. I then tacked another resistor in parallel to the 10K to bring the resistance down to about 7500, still no good.
I have restored four or five 19/89 chassis and this was the first time I was unable to get the oscillator to work. I waved the white flag and put the radio back on the shelf. About two months ago, I decided to take another crack at it. I removed the coil and added a couple more turns to the feedback winding. After reinstalling, the oscillator would not work at all. I'm sure I messed something up when I installed the coil but. At that point, I was pretty discussed. I made the decision to do Ron's "Super" mod. Take a look here http://philcoradio.com/phorum/showthread.php?tid=14919
I didn't have a very good seven pin tube socket so, I ordered a few made in China ceramic sockets. I had an extra coil form so, while waiting for the sockets to arrive, following Ron's instructions, I wound the new oscillator coil.
[Image: https://c1.staticflickr.com/3/2942/33618...115d_k.jpg] 109_0238 by Steve Davis, on Flickr
The sockets arrived. They look to be well made.
[Image: https://c1.staticflickr.com/3/2937/33618...5659_b.jpg] 109_0240 by Steve Davis, on Flickr More to come in a few days. Steve
M R Radios C M Tubes
(This post was last modified: 03-31-2017, 09:05 PM by Steve Davis.)
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
This should be a great thread! I came very close to doing that with a model 19B last weekend...but finally, after a very long alignment session, it straightened out and began tracking properly across the band.
--
Ron Ramirez
Ferdinand IN
Posts: 667
Threads: 11
Joined: Sep 2014
City: Bellmawr, NJ
That socket seems to be the tightest tube socket ,,,I have ever seen,,,bought 2 of them ,,,Myself for radio,,,,
Posts: 619
Threads: 42
Joined: Mar 2017
City: Gap Mills Wv 24941
wow,,, can t figure out what more to say,, thats some very bad a** looking coil work for sure!
BTW,, i think play things of the past has 7pin sockets.
yeah,, i just checked he has a lot,, mostly 50cents to 3$ ea
Posts: 1,114
Threads: 14
Joined: Feb 2013
City: Irvington, NY
Make sure you get the small 7 pin sockets for the 6A7. The 7 pin comes in two sizes, small for the 6A7, large for the 59 and transmitting tubes like the 1625.
They are not interchangeable, but you may be able to force fit the tube in the wrong size socket which would not be recommended.
Posts: 4,682
Threads: 51
Joined: Sep 2008
City: Sandwick, BC, CA
Another factor to watch with some Chinese replacement tube sockets is that they are designed to fit under the chassis verses on top of the chassis. That metal mounting flange looks like it's for the later, but it could probably be taken off, flipped over, and remounted to the socket.
Regards
Arran
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
The original Philco sockets in the 19 fit under the chassis.
--
Ron Ramirez
Ferdinand IN
Posts: 1,402
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
The socket is the small seven pin. It looks like the hole in the chassis will have to be enlarged slightly.
[Image: https://c1.staticflickr.com/4/3937/32904...7c96_b.jpg] 109_0243 by Steve Davis, on Flickr
I have to work this weekend, so it will be sometime next week before I will be able to get back to project.
Steve
M R Radios C M Tubes
Posts: 1,402
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
I had some time to work on the radio today. I forgot to take pictures until almost finished. The tube socket looks like it was meant to be mounted on the top side of the chassis. I figured out that I could do a bottom mount by using spacers about a 1/4 inch long between the mounting "ears" and the chassis. I had to enlarge the hole in the chassis about 1/8 inch so that the porcelain portion of the socket would protrude.
[Image: https://c1.staticflickr.com/4/3666/32904...dc74_b.jpg] 109_0245 by Steve Davis, on Flickr
I removed the original oscillator coil and installed the modified coil. Following Ron's instructions I began reconnecting everything. Ron's instructions were clear and easy to understand. It reminded of assembling "Heathkits" years ago.
[Image: https://c1.staticflickr.com/4/3951/33436...1ffa_b.jpg] 109_0253 by Steve Davis, on Flickr
After looking at pictures of Ron's restoration, I'm almost ashamed to show pictures of mine! I do plan to replace 51K resistor that has the spliced lead that you see in the picture, along with a few others where I had used film resistors with new dog-bone resistors.
Steve
M R Radios C M Tubes
Posts: 1,402
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
Time for the "smoke" test. I plugged it in and turned it on. Disaster strikes!!!!! After about 5 seconds, "POW" then the smoke started coming from under the chassis. I quickly pulled the plug. The input filter had exploded! Now to figure out what went wrong.
Steve
M R Radios C M Tubes
Posts: 1,475
Threads: 69
Joined: Nov 2012
City: Kansas city, MO.
Sorry to hear that. Maybe just a backward installed Ecap.
Posts: 15,691
Threads: 551
Joined: Oct 2011
City: Jackson, NJ
As long as the transformer is alive, you're ok.
There are just two major causes of electronic malfunctioning: 1) a connection where it is not expected and 2) no connection where it is expected
And the filter paper is cheap!
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.
Posts: 1,402
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
I found the problem. I have found when something goes wrong, take a look at the last thing you have done, even if it seems to be totally unrelated. While working on the chassis, the rectifier tube fell out of its socket. I plugged it back in and had nearly forgotten about it. Looking at the rectifier, I noticed it was turned 90 degrees from where it should be. Apparently sometime in the past, someone had forced the tube into the socket with the wrong orientation. wallowing one of the small holes. Now the tube can be plugged in two ways with little effort. of corse, I plugged it in the wrong way. This caused one end of the filament to be connected to HV winding of the transformer. The other end of the filament was connected to the B+ line, putting high voltage AC on the filter capacitors. After correctly installing the rectifier, I replaced both filter capacitors.
Ok, "Smoke Test", Take-Two
I powered it up again. No smoke. I have a Sony headphone radio I keep in the shop just for checking oscillators. The radio has a digital display, so I can tell the exact frequency. I put the headphone radio on and started rocking the dial on the 19. Success! No stations, but I have an oscillator. The oscillator was running about 200KC low. I did an alignment on the oscillator and the front end and the "Super"19 began to sing!
Enough for today. More to come.
Steve
M R Radios C M Tubes
Posts: 15,691
Threads: 551
Joined: Oct 2011
City: Jackson, NJ
I saw a guy force a speaker plug into a wall outlet of 220V. The plug pitch was the same but the prongs were twice the diameter, but the guy was strong arms weak mind type and by breaking the backelite forced them in.
8 ohm speaker into 220VAC.
The speaker spewed the cone across the room and never spoke again.
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.
Posts: 807
Threads: 49
Joined: Feb 2013
City: Shenandoah,
State, Province, Country: Pennsylvania
Steve I had the same problem with the rectifier socket on my 37-116. For some reason there was a second slot in the socket which allowed the keyway on the tube to go in the wrong spot. I was lucky enough to not burn any components as I had installed a fuse in the primary of the power transformer which blew immediately! Something out of the ordinary.
Ron
Bendix 0626. RCA 8BX5. RCA T64
Philco 41-250. Philco49-500
GE 201. Philco 39-25
Motorola 61X13. Philco 46-42 Crosley 52TQ
Philco 37-116. Philco 70
AK 35 Philco 46-350
Philco 620B. Zenith Transoceanic B-600
Philco 60B. Majestic 50
Philco 52-944. AK 84
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
Jackson 715 not working
|
Now that you posted the schematic, I don't know why that Sprague electrolytic cap is across the meter, as it is not indi...MrFixr55 — 05:51 PM |
HiFi (Chifi) tube amp build - but my own design.
|
What may be lacking in the PP Tube amps may be the 2nd harmonics, which some, especially RCA back in the day called &quo...MrFixr55 — 05:32 PM |
Jackson 715 not working
|
Usually in an emission tester, the tube under test is measured as if it were a diode. So, some testers connect all the g...RodB — 04:17 PM |
Restoring Philco 37-604C
|
Yep. F5 is green, D5 is Red.
Red is Bad.
Green is Clean.morzh — 01:30 PM |
Jackson 715 not working
|
I did start to do that but I stalled out because I could not figure out how the grid and plate get voltage. In this diag...daveone23 — 11:52 AM |
Restoring Philco 37-604C
|
(Insert Homer Simpson "DOPF" Here.)
When all fails, look at the can. Took the Ron Ramirez advice, red Caig D...MrFixr55 — 09:23 AM |
Philco 91 Speaker Replacement
|
From your text I am not sure if you intend to use the existing speaker with a resistor instead of the field coil.
It wo...morzh — 08:44 AM |
Philco 91 Speaker Replacement
|
My field coil is bad. I am still hoping to find an original, but if I can't I will go with a fitting Philco speaker, 125...dconant — 08:34 AM |
Philco 91 Speaker Replacement
|
As Rod said, it is OK to use a fitting speaker, and then look for an original one.
If you buy a Hammond 125 output tr...morzh — 08:15 AM |
Philco 91 Speaker Replacement
|
Yes, I often have to substitute, then keep an eye out for an original. In the meantime, the radio is working and being e...RodB — 08:02 AM |
Who's Online
|
There are currently 4265 online users. [Complete List] » 1 Member(s) | 4264 Guest(s)
|
|
|
|