Philco 37-650 Plate voltage

[Peter Heembrock]

The resistors and any capacitors connected to this 6J5 should be checked to ensure they are within spec etc. Or maybe it is a bad 6J5?…

• This reply was modified 2 years, 2 months ago by Peter Heembrock.

[Rick D]

Hello Fellows
I put both my voltage meters on the plate of both 6F6 tubes last night and powered up the radio
and I did it about five times this morning,the set just came on with no crackling and no
stopping ,the voltage was 284 volts on one and the other was 289,I tried to make it act up
but it would not,this set is a mystery.The voltage on the 6J5 tube was -3.9 volts on the plate
when I touched the plate contacted with the probe I got a click and the same when I took it off.
Peter I know the voltage has come down,this seemed to happen when I put in new resistors,they
were #52 @ 35K and #46 @ 330K and # 53 @ 490K and also the candohm @ 19 and 109 ohm.
I am going to try and explain something I know is wrong but this is the way it was when I
got the set,what I did is replace all caps and resistors the same way they were when I got the set,I took
photos and drew sketch,s so I would not mix anything up.But what I see of the #30 cap block it,s not right
although it worked fine for about two months,it,s still not the way it is on the schematic.This cap has
two 110 PF caps, #1 strip is ground #2 is the 1st 110PF cap and #3 strip is the second 110PF cap.
The way it is hooked up is on the 1st strip ground is the start of the 240K #32 resistor it goes two
the second strip then off to #43 cap and on to the volume switch,also on the second strip
is the other 240K #31 resistor it goes on to the black wire on the IF transformer,now
this is the part I don,t understand,running along with that 240K resistor and going to
the same contacts is a .05UF cap,I don,t think it belongs there,I think it should
be taken out and a wire from where the 240K #31 resistor hooks to the IF transformer
be put in and should go to the #3 strip on the block cap wich is the 2nd 110PF cap.
I made a sketch and
I marked the cap in question with an X on the wires I think should be taken out and a red line
for the wire that I think should be put in.I would have told you guys about this befor
but I did not think it mattered because the set worked fine with this hook up.I know
if you look at this with a schematic you would see it,so thinking it would help
I attached a sketch.On one of my last post I put down the readings on the cap and
resistors around the 6J5 tube,they are not right on but close,should I change
these or just leave them alone?,fellows I know I am going on but I am trying
to give any info I can that would help you help,I am so thankful for all
the help all the very best Rick

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[Rick D]

Hi Guys
Could any of you fellows tell me do the IF transformers on my set look original,the
reason I ask is the solder joints from the wires that come from the IF transformers
in my set look a bit sloppy,not a factory job at all.On the one close to the front
of the set it has three wires coming out of the bottom,a black and an orange and green,
two of these wires have black tape around where it was soldered to the wire it is
joined to,also on the wire coming out of the top and going to the tube cap it is
joined and has black tape at the joint,the second IF has 4 wires coming out of the
bottom ,two green one black and one red.The reason I ask is I was going to change the
way the #30 cap block is hooked up,but one of the wires from this cap goes to the IF
transformer and I am afraid if I make the change the set won,t work,please take a look
at the photos I sent of my set showing the IF transformers and let me know,if they look
original,and if they do I will go ahead and make the change,thanks all the best Rick

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[Peter Heembrock]

Those are not the original I.F. transformers…see my photos of the one I just completed.
PH

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[Peter Heembrock]

I found some photos of the underside of the chassis if this helps…I re stuffed the capacitor blocks and changed all other caps and some resistors in the power supply…

PH

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[Rick D]

Here is the photo_ Rick

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[Jean Marcotte]

Rick,

just the way they were mounted proves that thay are not the original ones. I checked my Philco chassis from that period. My 37-116 has two big square cans but these are special being ajustable for bandwith through the tone control. The third can is the round one. My 38-10 also has the round cans.

Jean

[Rick D]

Hello I tried to post this yesterday but could not
Thanks Peter
Thanks for the photos,they tell me why mine looks like it had some changes,now I don,t know if
I should change the way it is in the set to the way it is on the schematic, the same as the sketch I drew,I have
no idea why that .05UF cap is there,maybe they used it in place of the110PF cap third strip in the #30 cap
block?.Looking again the IF transformer that it is going to it has four wires not three as I thought,the
set works now although I have not run it for more than a few minutes at a time,I don,t know what to expect.
Do you think even though it seems to work fine I should change it or just leave it alone,I did change those
two resistors #34 and #35 now there are two new ones there at 1meg each,I also checked the
cap on the 6J5 tube #29 with the resistors out and the 6F5 tube out,I got 220PF befor now it
checks at 125PF so I left it in there.I don,t what happened to make this set work again,
while checking the plate voltage on the 6J5 tube it made a crackling noise and came
back to life,it seems to work fine now ,no crackling noise and comes on just fine
for now,I have tapped every joint and moved every wire but all seems tight no bad
joints,I hate to give this set back to the Lady again only to have it quit
again,do you fellows think I should change that hook up to the way it is on the
schematic or because it is working just leave it alone.It may be like Peter said
that there is moisture deep in the power transformer that is going to to take
time to get rid of,the post from the other day has a photo of the way that .05UF
is hooked up.I am going to run that set for 3 or 4 hours tonight and see how it
goes,thanks fellows for your time and help all the very best Rick

[Rick D]

Hello Fellows
Just an update on the radio,seems after I changed resistors #52 & #53 & #46 and #44 the voltage
on the 6F6 plates stayed at 280 volts ,befor they were around 358 volts,I also changed resistors
#34 & #35 ,I don,t think there any more than three original resistors left in the set,I also
changed every cap except the mica ones.I am glad to say I have run the set for 3 to 4 hours
non stop for 6 nights now with no problem at all,I think it is done and working fine and will
be for some time.I am sure glad I joined the Canadian Vintage Radio Society,and I would like
to say thank you to all for the input and help,I had all but given up,and without the help
I would have.This set will run forever thanks to the help.I read all posts and will be glad
to help in any way I can,thanks again fellows,all the very best Rick
If you would like to see my collection the web site address is
http://www.worldradiocorporation.4t.com there are several photo
galleries on the left side panel,just double click to enlarge

[Author]

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