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Zenith 9-S-262 Alignment Questions - Printable Version

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Zenith 9-S-262 Alignment Questions - Geoff - 10-24-2012

I'll be performing an alignment shortly on my Zenith 9-S-262 and have a few questions.

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153379&g2_serialNumber=2]

Operation #1) It says to connect the signal generator to the 1st Detector Grid. I I looked at the tube compliment and description in the Socket Voltages table:

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153309&g2_serialNumber=2]

I did not see anything listed as the "1st Detector". Is the "1st Detector" the 6K7 RF tube? If so, I believe I would connect the signal generator (through a 0.5 Mfd cap) to the clip on top of the tube. If this is the case do I leave the clip attached or remove it?

Operations #2-4) I guess the term "Dummy Antenna" is throwing me. I always thought a dummy antenna was just a feww feet of wire rolled up with one end connected to the generator. The rolled up wire would then be placed close to the radio, but not connected to it. Sounds like the instructions are telling me to connect the generator to the antenna post through a 200 mmfd cap. Pleae confirm. I'm familiar with the "rock gang" procedure.

Operations #6-7) Am I connecting the generator to the radio through a 400 ohm resistor?

Thanks,
Geoff

RE: Zenith 9-S-262 Alignment Questions - rghines1 - 10-24-2012

The 6L7 is the 1st Detector. Odd this is mistaken on the schematic as the 2nd Detector. Removed the grid cap wire on the 6L7 during the IF alignment, reconnect when complete.

Dummy antenna is kinda odd lingo and can have various meanings depending on context. Connect capacitors or 400 ohm resistor in series with the signal lead as called for on the procedure. You will be connecting to the antenna post.

RE: Zenith 9-S-262 Alignment Questions - Geoff - 10-24-2012

So it looks like I should connect the generator here:

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153315&g2_serialNumber=2]

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153318&g2_serialNumber=2]

Thanks,
Geoff

RE: Zenith 9-S-262 Alignment Questions - Geoff - 10-24-2012

And I assume I am hooking my VTVM up across the voice coil at these two points, correct?

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153321&g2_serialNumber=2]

Thanks,
Geoff

RE: Zenith 9-S-262 Alignment Questions - rghines1 - 10-24-2012

Correct on 6L7.
Prefer to connect meter across voice coil or by ear.

RE: Zenith 9-S-262 Alignment Questions - Geoff - 10-24-2012

Are the 2 spots I have highlighted in red next to the speaker the proper location to connect across the voice coil?

Thanks,
Geoff

RE: Zenith 9-S-262 Alignment Questions - Ron Ramirez - 10-25-2012

No, what you have highlighted is the primary of the audio output transformer. To connect across the speaker voice coil, you would connect on the other side of the iron core - under where it says 13 on your drawing.

RE: Zenith 9-S-262 Alignment Questions - Geoff - 10-25-2012

Thanks Ron. Sounds like these points here:

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153324&g2_serialNumber=2]

What kind of voltage range should I be expecting?

- Geoff

RE: Zenith 9-S-262 Alignment Questions - morzh - 10-25-2012

Units of volts. Or below.
Set it on "AC Volts".

RE: Zenith 9-S-262 Alignment Questions - codefox1 - 10-25-2012

Yes, you have corrrectly identified secondary (voice coil) winding.

You should see only a few volts, surely not more than 15.

If the tone annoys you disconnect the speaker and put an 4 or 8 ohm 10 watt resistor in it's place. Do not run the set without a speaker or resistor attached to voice coil winding. Remember to re-connect speaker when you are finished.

RE: Zenith 9-S-262 Alignment Questions - Geoff - 10-25-2012

Great. Thanks for the advice everyone!

- Geoff

RE: Zenith 9-S-262 Alignment Questions - Geoff - 11-02-2012

I aligned this set last night. I ended up not even using a VTVM to measure the output. I just used the tuning eye as the visual indicator and that worked fine. My setup was a Heathkit IG-102 that I fully refurbished and I verified the output frequencies on an HP frequency counter.

Alignment of the IF's and setting the oscillator to scale (steps 1 & 2) went withought a hitch. Step 3 had some issues though. It says to adjust trimmers G & H. These are both located on the tuning capacitor. When adjusting the screw for G I could not find find a point at which it would peak so I ended up screwing it in all the way and then slowly backing it out. With the screw all the way in the tuning eye was open (the dark pie slice was wide). As I adjusted the screw out the tuning eye started to close a bit but then it stayed at the same level. When peaking the IF's there was the expected sweet spot where the eye would close (the dark pie got very narrow) and if you adjusted any further the eye would open up again. I did not see this happen when adjusting trimmers G or H. I just got to a point where the tuning eye would close a little bit and any further adjustment in the same direction had not affect. No sweet spot. I removed screws for these trimmers and bent the brass? metal plate for each up a little so there would be more range in the adjustment. I then reinstalled the screws and tried to align G again. No change, no sweet spot. However, on trimmer H I was able to find a sweet spot. The rest of the alignment procedure went without a hitch.

Here is the procedure and location of the trimmers:

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153379&g2_serialNumber=2]

[Image: http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=153376&g2_serialNumber=2]

The radio plays fine. Anyone have any ideas on why I cannot peak trimmer G?

Thanks,
Geoff

RE: Zenith 9-S-262 Alignment Questions - morzh - 11-02-2012

I don't remember problems with step 3.

BTW do you use insulated tool to turn the trimmer?
And, the tuning eye still is not the best way. If you have a meter, it will benefit you to use it. I mean, if you are into the old radios, you gotta have some sort of a meter, DMM or such.

RE: Zenith 9-S-262 Alignment Questions - Geoff - 11-02-2012

Yes, I have an insulated tool for the trimmers. I'll try the VTVM way tonight.

Thanks!

- Geoff