Philco 84 code 121 no sound
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(11-14-2016, 09:25 PM)Mike L Wrote: Ok I'll give it a try. The few stations received are very very weak, So I feel there is something else going on too. I ordered a set of tubes to see if I might not have an issue there as well.
As far as using the signal generator is concerned, am I measuring output to the speaker with my VTVM? I have the alignment procedure, but It just states adjust for peak signal, but where? I'm also not 100% sure my SG is working properly either. With it connected to the grid cap of the det-osc tube, SG set at 460kc all I get is a low pitched squeal around the 460kc and 1000kc spots on the tuning dial. Nothing anywhere else.
Set radio dial at 550kc. Set sg dial at 460kc. Adjust #11 and 15 for max sound from spkr. Keep sg signal to a minimum as you adjust 11 and 15 for peak.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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City: Springville NY
State, Province, Country: NY
I'm stuck. Adjusting 11 and 15 has minimal effect. I literally have to put my ear next to the speaker to tune or hear a station. Here is what I have done lately:
Replaced all tubes, one at a time with no change.
Re-checked all voltages, all fall in line except that now the 2nd detector plate and screen voltages are "bouncing" around. They are not stable. The plate is around 60 and the screen is around 34. I tried another tube with the same result, slightly different readings but still bouncing. Checked and rechecked all grounds, all were good.
If by chance I re-wound the feedback of the oscillator coil backwards would it receive stations at all?
Before rewinding the coils I had nothing, just low level hum. After rewind I'm receiving a few stations on the low side of the dial, nothing on the high side, but all very very low, barely can hear them. The volume control is always at max.
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Replace 1M resistor and check #20 to make sure that the two caps are wired correctly. When the det 77 and output stage 42 tube are working properly should get a loud buzz when the grid cap of the 77 is touched. Wouldn't sweat the osc coil till we get this sorted.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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City: Springville NY
State, Province, Country: NY
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Joined: Nov 2012
City: Kansas city, MO.
I'm sure Terry will get back to you. It looks to me like what you said about the 0.015 should go to pin 2. The way it is now, it is grounded.
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City: Roslyn Pa
The caps inside 20 are wired incorrectly, only the .001 is grounded. You have two connections from the caps grounded. Please wire as per the schematic and not the Philco p# cause it's the wrong one.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 15,444
Threads: 539
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City: Jackson, NJ
The cap is wired NOT as per sch. The 15nF section is the DC blocking and CANNOT go to GND.
Your problem is, you need to look into
http://www.philcorepairbench.com/bblokcap.htm
here to the original 7762-B. If you have other cap, adjust the pinouts accordingly, the OEU pinout is not gonna work.
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.
(This post was last modified: 11-20-2016, 10:59 AM by morzh.)
Posts: 7,248
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I don't see any 15nf caps anywhere!!!!!![Image: http://philcoradio.com/phorum/images/smi...on_eek.gif] Yes his signal from the detector stage is not connected the the output stage wired in this configuration hence very low volume.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 11-20-2016, 11:00 AM by Radioroslyn.)
Posts: 15,444
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City: Jackson, NJ
(11-20-2016, 10:57 AM)Radioroslyn Wrote: I don't see any 15nf caps anywhere!!!!!![Image: http://philcoradio.com/phorum/images/smi...on_eek.gif]
Oh come on Terry. ![Icon_lol Icon_lol](https://philcoradio.com/phorum/images/smilies/icon_lol.gif) Tell me that you don't know what a Megahertz is. And I am not referring to the verb meaning "it hurts a lot
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: 7,248
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
> Tell me that you don't know what a Megahertz is.
Sure I know!!! Whatda think I'm stoopid er sumptin!!
It's very large rental car![Image: http://philcoradio.com/phorum/images/smi..._crazy.gif][Image: http://philcoradio.com/phorum/images/smi...on_lol.gif]
https://www.youtube.com/watch?v=GLpNmuPQE94
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 11-20-2016, 11:40 AM by Radioroslyn.)
Posts: 64
Threads: 8
Joined: Jul 2016
City: Springville NY
State, Province, Country: NY
That was it!! Lots of volume, finally had to turn it down. Also receiving stations all across the range with just a 3' wire antenna in my basement.
I cant remember where I downloaded that cap block information but it was obviously wrong. I rechecked the others as well against the schematic and those were correct. Now I'm going to have to go back to my 80jr. to make sure that is correct since I used the same information on that one.
Pretty sure my signal generator is not working correctly so I went by ear to adjust 15, 17 and 11. After that project is done I'll come back and do a correct alignment.
THANK YOU Terry and everyone that contributed.
Posts: 7,248
Threads: 266
Joined: Dec 2009
City: Roslyn Pa
Your welcome! Glad you got it sorted and working now your model 80 should be a piece of cake. Pretty much the same set except that it uses tetrodes instead of pentodes for the mixer and detector. I just noticed something the model 81 is the same vintage but it uses pentodes. I've got an 81 in the back room that need servicing. 81 is a two band version of the 80.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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