The PHILCO Phorum
GE 107 wont start up - Printable Version

+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Various and Sundry Categories (https://philcoradio.com/phorum/forumdisplay.php?fid=37)
+--- Forum: Other Radios (Non-Philco) (https://philcoradio.com/phorum/forumdisplay.php?fid=12)
+--- Thread: GE 107 wont start up (/showthread.php?tid=14755)

Pages: 1 2 3

RE: GE 107 wont start up - gregb - 06-11-2016

The tube filaments are all good, that is evident as he has B+. The dial light could be as simple as bad bulb.

Gregb

RE: GE 107 wont start up - morzh - 06-11-2016

If B+ is there then yes, you're right, the filaments are fine.
I would disregard the light for now and concentrate on sound.

He had Plate voltage on 50L6 so his output xfmr is likely good.

Need to check the speaker.

Try to touch pin5 pf 50L6 with a screwdriver (be careful, high voltages around, use one hand only and stand on an insulating mat if in basement), see if you have hum.
If not,
Disconnect the speaker from xfmr secondary and measure across the speaker with ohmmeter. Should be almost short, 0.45 ohm.

RE: GE 107 wont start up - Tgace459 - 06-11-2016

(06-11-2016, 12:54 PM)gregb Wrote:  The tube filaments are all good, that is evident as he has B+. The dial light could be as simple as bad bulb.

Gregb

I can light up the bulb by using a 9 volt and touching the two pins that lead to the light.

RE: GE 107 wont start up - Tgace459 - 06-11-2016

(06-11-2016, 12:15 PM)morzh Wrote:  The simplest check is, put the ohmmeter across the AC plug, while Off. Turn it on. The resistance should be on the order of a few hundred ohms or less . If very high (Kohms, Mohms), your filaments are open or the tube sockets do not make good contact.

Simplest test first...

I have an "auto range" multimeter that automatically sets the range ( I can also set it to manual range if I wish).

If you mean from spade to spade...when I try this it starts out with a 0 reading and when I turn on the power switch, the display cycle up through a series of Mohm readings 18...19...then returns to 0. 

Thing is it doesn't to it every time I turn the switch off then back on again and switching to "manual" and testing various ranges give me 0.

If I test from the + spade to chassis I get 0 when "off" and .474 mohm when "on".
 

RE: GE 107 wont start up - Tgace459 - 06-11-2016

(06-11-2016, 01:00 PM)morzh Wrote:  If B+ is there then yes, you're right, the filaments are fine.
I would disregard the light for now and concentrate on sound.

He had Plate voltage on 50L6 so his output xfmr is likely good.

Need to check the speaker.

Try to touch pin5 pf 50L6 with a screwdriver (be careful, high voltages around, use one hand only and stand on an insulating mat if in basement), see if you have hum.
If not,
Disconnect the speaker from xfmr secondary and measure across the speaker with ohmmeter. Should be almost short, 0.45 ohm.

I'm powered down now and cleaning pins and sockets...but assuming I'm testing from the right points, which are the two terminals on the speaker that have push-on connectors to the transformer, the speaker is testing at 3 ohms.

I can get sound from the speaker if I jump the 2 points with a 9 volt....

RE: GE 107 wont start up - Tgace459 - 06-11-2016

(06-10-2016, 12:22 AM)Arran Wrote:   Check the plate load resistor, 470,000 Ohms, on the 12SQ7 tube, if it's open you won't get any stations coming through. Also if the output transformer has an open primary you won't get any audio at all.
Regards
Arran

While still connected that resistor is at 530,000 ohms....

RE: GE 107 wont start up - morzh - 06-11-2016

(06-11-2016, 01:51 PM)Tgace459 Wrote:  
(06-11-2016, 12:15 PM)morzh Wrote:  The simplest check is, put the ohmmeter across the AC plug, while Off. Turn it on. The resistance should be on the order of a few hundred ohms or less . If very high (Kohms, Mohms), your filaments are open or the tube sockets do not make good contact.

Simplest test first...

I have an "auto range" multimeter that automatically sets the range ( I can also set it to manual range if I wish).

If you mean from spade to spade...when I try this it starts out with a 0 reading and when I turn on the power switch, the display cycle up through a series of Mohm readings 18...19...then returns to 0. 

Thing is it doesn't to it every time I turn the switch off then back on again and switching to "manual" and testing various ranges give me 0.

If I test from the + spade to chassis I get 0 when "off" and .474 mohm when "on".
 

This does not make sense. What you are telling me is you have a short circuit between the plug terminals whether Off or On.

RE: GE 107 wont start up - Tgace459 - 06-11-2016

(06-11-2016, 02:49 PM)morzh Wrote:  
(06-11-2016, 01:51 PM)Tgace459 Wrote:  
(06-11-2016, 12:15 PM)morzh Wrote:  The simplest check is, put the ohmmeter across the AC plug, while Off. Turn it on. The resistance should be on the order of a few hundred ohms or less . If very high (Kohms, Mohms), your filaments are open or the tube sockets do not make good contact.

Simplest test first...

I have an "auto range" multimeter that automatically sets the range ( I can also set it to manual range if I wish).

If you mean from spade to spade...when I try this it starts out with a 0 reading and when I turn on the power switch, the display cycle up through a series of Mohm readings 18...19...then returns to 0. 

Thing is it doesn't to it every time I turn the switch off then back on again and switching to "manual" and testing various ranges give me 0.

If I test from the + spade to chassis I get 0 when "off" and .474 mohm when "on".
 

This does not make sense. What you are telling me is you have a short circuit between the plug terminals whether Off or On.

Yeah. im not sure whats going on there. I thought maybe something was "up with" my meter, but it tests resistors very accurately (when I test new ones out of the package).

And to be accurate. The result is not actually zero, as when I touch the the probes together (0.00). It's going back to the "no read" screen (0.L).

I'm using a salvaged cord from an old computer power-supply (two prong). 

RE: GE 107 wont start up - Tgace459 - 06-11-2016

(06-11-2016, 02:48 PM)Tgace459 Wrote:  
(06-10-2016, 12:22 AM)Arran Wrote:   Check the plate load resistor, 470,000 Ohms, on the 12SQ7 tube, if it's open you won't get any stations coming through. Also if the output transformer has an open primary you won't get any audio at all.
Regards
Arran

While still connected that resistor is at 530,000 ohms....

Well...hold on. There are two resistors coming off that tube. One reads at .531 Mohms, and the other one is reading at 5 MOhms. If Im reading my schematic/product data sheets right I think they are supposed to be 2.2 and 4.7 MOhm resistors respectively.

RE: GE 107 wont start up - morzh - 06-11-2016

I suspected you meant infinity by zero Icon_smile - you need to be accurate with that.


With tubes installed and the switch in ON position according to the schematic you should have a few hundred ohms.
I am not sure how you got the B+ voltage (are you sure of that?) but if you did, your tubes are at least have good filaments and the switch is good too. If not, recheck. Check the switch itself with ohmmeter.

RE: GE 107 wont start up - Tgace459 - 06-11-2016

Gahhh...Im giving up for today.

I cleaned up the pins and sockets and still no joy. Except now I'm only getting millivolt readings on all the DC pins and mostly 126 AC volts on the pins marked for AC.

RE: GE 107 wont start up - gregb - 06-11-2016

Do you have a spare 50L6 tube that you could try in the radio?

Gregb

RE: GE 107 wont start up - Tgace459 - 06-13-2016

I have a resource with a tube tester. I'm going to see if I cant get these tubes tested before I bother ya'll with more questions. Icon_smile

RE: GE 107 wont start up - Tgace459 - 06-13-2016

One stupid question....

This set came with no power cord on it at all (just stubs still soldered on). It looks like someone was going to start a refurbish but then set it aside. I wired the negative blade to pin 2 of the rectifier and the positive blade to the switch. I'm assuming I read the schematic right when I did that?

RE: GE 107 wont start up - Radioroslyn - 06-13-2016

Just as an aside try measuring the resistance 35Z5 out of it's socket, pins 2,3,and 7 should show a low resistance to each other. The pilot lamp get it's power from a tap in the 35Z5 heater (pin3) if there is no resistance from pin 3 to 2 or 7 the lamp won't light but the power supply will make HV. Don't know if an open tap will show on the tube tester. This may solve your pilot lamp issue.

Gl
Terry