Restoring my 37-116. It plays now! - Printable Version
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+--- Thread: Restoring my 37-116. It plays now! (/showthread.php?tid=6718)
Restoring my 37-116. It plays now! - morzh - 05-22-2013
Well
I am still taking a breather after 38-15, but tonight I was bored out of my mind and the choice came down to:
1. Rummage through the fridge
2. Have a 250 calories worth of an Irish ale, or
3. Start on the tube checking.
I chose the latter.
Now the very first tube, the 5U4, of course, what else, it sticking as a you know what naturally I picked it first, it tests DEAD. And dead means - reeeely dead. No movimento absolutamente. None.
At tbe same time it gets hot and the filament really drags down the Line indicator. Which I figure is probably OK. But no emission, whatsoever? On BOTH diodes? Weird I say.
Anyone seen'em like this, heating and full dead? (I did check for shorts, it is good).
There is another tube 6J5 that is bad, but it is "mostly dead" being 150 at some 1500 or such.
And even 6A5 output tubes are probably ok at 1500 with 3000 nominal. Both are the same.
I have another few tubes to go through; the thing is dirty as heck and one tube had pins oxydized though tested fine. And the extraction is a bit difficult.
Well as we say, "a woman had no worries so she bought herself a piglet".
Gonna be fun!
RE: Starting on my 37-116 - BrendaAnnD - 05-22-2013
I have an RF sled for one of these, if you should need any parts therefor.
RE: Starting on my 37-116 - TA Forbes - 05-22-2013
Hmmm.... That's pretty strange. Did you center-adjust the line test after placing the 5U4 in the socket? The 5U4 draws 3A of current.
Output tubes should be 6B4G, am unfamiliar with the 6A5.
RE: Starting on my 37-116 - TA Forbes - 05-22-2013
Oh yes, and with respect to the 6J5, do NOT replace with a 6J5GT or 6J5 metal tubes, as they will not insert into the ones that have a tube shield base. A 6C5G or 6L5G will work in place of a 6J5, but both have much less transconductance.
IF output tubes are 6B4G, 1500 is too low to be use-able. NOS is 3000umhos, and without breaking out my tester, I believe the min is vic 2100 umhos.
6B4Gs are fairly expensive tubes. Bob Dobush and Alton Smith usually have them about as reasonably as you will find them.
Bob is at findatube.com
Alton is at tubes@antiqueradiotubes.com
RE: Starting on my 37-116 - Mondial - 05-22-2013
The 6A5G is a 6B4G with indirectly heated cathodes, It looks just like a 6A3 or 6B4G, but if you look carefully there are tiny cathode sleeves placed over each filament. The 6A5G was designed to eliminate the hum caused by heating the filament with AC. There is a separate pin for the cathode connection which is also connected internally to the filament center tap.
http://www.bunkerofdoom.com/tubes/syl43/DATA/1949/6A5G.GIF
RE: Starting on my 37-116 - TA Forbes - 05-22-2013
Thanks for that info!! It was not in any of my Receiving Tube Manuals, the newest being an RC-30.
Assume the NOS umhos rating is 3000 ??
RE: Starting on my 37-116 - TA Forbes - 05-22-2013
Just checked out the website. Pretty good!!!
RE: Starting on my 37-116 - Ron Ramirez - 05-22-2013
How about that, so there is one out there! I was aware Philco made a version of the 37-116 with 6A5G outputs, but I've never actually seen one. Every 37-116 I've encountered so far has had 6B4G triodes in them.
RE: Starting on my 37-116 - morzh - 05-22-2013
I am pretty sure the 6A5 tubes are original. Also they are Philcos, as are most of the tubes in the set.
I think they will be enough to produce some sound, and then we'll see.
TA,
Yes, I adjusted the Line. It draws pretty hefty, once the tube is inserted, the line drops significantly and the fuse lamp starts to glow. And as I adjust it it glows even more which made me kinda nervous although I realized it was probably normal.
For rectifiers the bias is brought to zero, and the English adjusted to the value of, I think, 35 and 30 for this tube. But....no arrow movement when pressing P3. None whatsoever, and this is what makes me wonder. I even suspected the socket but then other tubes test OK in it - all the tubes I have are octals.
RE: Starting on my 37-116 - Ron Ramirez - 05-22-2013
I have no doubt they are original. What I meant was I've never had a 37-116 cross my bench that used 6A5G tubes, even though Philco made a version with them. Low production, maybe? I don't know.
RE: Starting on my 37-116 - morzh - 05-22-2013
I am looking at that beast of a radio and I feel that healthy rage building inside me. Like, c'mon, give your best punch. Preferably not an electrical one.
And I am sure there will be plenty of surprises.
Q: I had a good experience washing my 20 tuning cap in my dishwasher.
Has anyone washed the one from 38-116? I just want to make sure the material the cap is made of will lend itself safely to the procedure.
Q: What's a good way of removing the daughter chassis (I am sure I will figure it out but it's always good to be forewarned about possible traps and pitfalls.
BTW it feels springy and does not rattle like my other radios with grommet-padded tuning shelf so whatever dampens it may still be good.
RE: Starting on my 37-116 - vinzer - 05-22-2013
I washed my 38-116 tuning cap. in the dishwasher came out ok.
RE: Starting on my 37-116 - morzh - 05-22-2013
Thanks Vinzer, good to know.
RE: Starting on my 37-116 - Arran - 05-22-2013
I don't know what tube tester you happen to be using but on most of mine there is a separate test button for rectifier tubes, mind you you would know if you hit the wrong button pretty fast as the needle in the meter goes crazy and the fuse flashes. It is entirely possible that the 5U4 could be shot if the set had shorted filter caps, that's usually the first thing that dies. I thought these 116 sets used a 5X4 not a 5U4, but that never stopped Philco from swapping tubes during the production run.
Regards
Arran
RE: Starting on my 37-116 - morzh - 05-22-2013
Question:
To my understanding there is no appreciable difference (at least for testing) between 6J5G, 6J5GT and 6J5GT/G.
This radio has 3 of 6J5Gs, two of them being 6J5GT/G and one 6J5G.
Now the "G" tests at 1,850 @2,600 nominal.
But both "GT/G"s test at 150 or so, that is the arrow barely moves. I find it suspicious that both test exact same way, near-dead.