Zenith 7-S-240 Eye tube question - 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: Zenith 7-S-240 Eye tube question (/showthread.php?tid=14690)
+- 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: Zenith 7-S-240 Eye tube question (/showthread.php?tid=14690)
Pages:
1
2
RE: Zenith 7-S-240 Eye tube question - Eliot Ness - 06-04-2016
Have you rechecked the 1M (R15) resistor in the eye socket between pins 2 & 4. Also pull the eye tube out and make sure there are no shorts between pins, except for 2 -4. I'd also trace out and verify the 6T5 socket is going everywhere it is supposed to.
Other than the eye tube not closing properly, how does the radio perform? Does it seem to pick up normal stations like it should at a normal volume? Do you have to turn the volume down quite a bit going from a weak to a strong station? Something is keeping your AVC voltage too low.
I hate to say it, but I'd double check any capacitors, resistors, or anything else you may have changed against the schematic for wiring errors (it happens to the best of us).
Hopefully Terry will take a break from his 42-854 and offer some more insights.
RE: Zenith 7-S-240 Eye tube question - Radioroslyn - 06-04-2016
Just for grins try hooking a 9V battery to the grid, + to the chassis - to the grid. If all is well with the tube (6E5) should close it up.
Terry
RE: Zenith 7-S-240 Eye tube question - Eric - 06-05-2016
Traced out all 6 pins and they go where they are supposed to.
also re-verified Resistors 5, 6, 7, 14, 15 and C7
Radio receives stations good (what I'm used to) have about 15-20' of antenna Vol is good across the stations
Ran all my eye tubes through the tube tester Knight 600A all were good also did the 6T5 again and it is better than I remembered so I'm going to use it
Hooked up a 9v with the + to chassis and the - to the 3 pin of the 6T5 it closes the eye about 15% from full open and drops the station vol by 30% also voltage goes from -2.8 to -9.2v with the battery
going to do some more tracing and verifying on what I have done
Nothing else to do on a rainy day down here!....:-)
RE: Zenith 7-S-240 Eye tube question - Eliot Ness - 06-05-2016
(06-05-2016, 12:13 PM)Eric Wrote: ....Hooked up a 9v with the + to chassis and the - to the 3 pin of the 6T5 it closes the eye about 15% from full open and drops the station vol by 30% also voltage goes from -2.8 to -9.2v with the battery....
Try it with the 6E5. The 6T5, like the 6U5 takes ~ -22 volts to close. The 6E5 only takes ~ -8 volts. Instead of hooking it directly to pin 3, hook it to a point under the chassis that goes to pin 3.
Still something is amiss, you should have much more AVC than what you're seeing.
RE: Zenith 7-S-240 Eye tube question - Eric - 06-05-2016
Hooked it to the end of R6 made no dif, Still looking for something I or somebody else might have misconnected.
RE: Zenith 7-S-240 Eye tube question - Eric - 06-06-2016
Ok I have a couple of questions C-21 10mf ceramic and R-16 1K ohms I can't seem to find them? in the print they are located in the upper left corner and in the parts list center bottom. Are they even in the chassis?
RE: Zenith 7-S-240 Eye tube question - Eliot Ness - 06-06-2016
Looks like R16 is part of the#2 coil assembly, so it might be inside that can. C21 is part of the antenna coil assembly. It might be a good idea to ohm out the first two coil assemblies.
RE: Zenith 7-S-240 Eye tube question - Eric - 06-07-2016
RE: Zenith 7-S-240 Eye tube question - Eric - 06-07-2016
Chassis
RE: Zenith 7-S-240 Eye tube question - Radioroslyn - 06-07-2016
Would be a 10mmfd or 10uufd not 10mfd.
Terry
RE: Zenith 7-S-240 Eye tube question - Eric - 06-07-2016
Agreed it's a misprint as the parts list does say 10 mfd, still nothing there
RE: Zenith 7-S-240 Eye tube question - Kenneth F. Besso Jr. - 06-08-2016
Not inside the Tube of the coil ?????
RE: Zenith 7-S-240 Eye tube question - Eric - 06-08-2016
(06-08-2016, 11:35 AM)Kenneth F. Besso Jr. Wrote: Not inside the Tube of the coil ?????
Found C-21 not inside the coil just underneath the chassis they had replaced it with a .02mf and I followed and replaced the paper cap with a new .02mf. traced it out and found it replaced it with a 15mmf. rechecked the alignment and checked the eye still no change.