Rectifier Question: Zenith 6G001YZX Universal

Hello Radio Friends,

While going over the chassis of my 6G001YZX this weekend, I noticed something immediately; the lack of a 117Z6 rectifier tube and in its place is a selenium rectifier (SR).  The tube socket is replaced with a metal plate, which appears to be factory work, and the SR is bolted to the underside of this plate.  The SR is connected to a wire-wound 3 or 5 watt resistor (that is well cooked and the ceramic is broken, but the wire is not) which is connected to the 40 mfd electrolytic (7A).  Since the resistor no longer bears any markings, I tested it around 155 ohms.  That seems low to me, but I decided to stay in that vicinity and replaced the resistor with a 240 ohm 7 watt resistor.  It immediately came back to life, with only the slightest hum (I have changed nothing else, yet), and a small bit of squealing when I adjust the volume (presumably from the SR).  After 5 or 6 minutes, the new resistor was still cool enough to touch with my finger.

Is anyone familiar with this set and possibly know if this was something common for Zenith to do by 1946?  I did not think selenium rectifiers were widely used on the 1950s?

Any other feedback from the far-more-experienced-group-than-I is also appreciated.

Bob

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Hello Bob,

According to the Zenith Service diagrams depicted on pages 182 and 183 of the 1946 RADIO DIAGRAMS published by Beitman, the 117Z6G/GT rectifier tube is clearly depicted.

There is no mention of a selenium rectifier on either page - on neither the schematic nor the tube and trimmer location illustrations.

I will add as a NOTE: The Beitman published data identifies the Zenith simply as the Model 6G001 and the Chassis as  No. 6C40 - there are no suffixes identified. However, the textual description specifically states it is an "AC, DC, or battery operated superheterodyne. . . "

Respectfully,

Robert

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Hello Robert,

 The Rider's schematic I have lists the rectifier tube as well.  I will take some photos and post them here for everyone to have a look at.  It appears to me to be a factory job, but I could be wrong.  I wasn't sure that since these models included the so-called "experimental" chassis, perhaps this SR was a Zenith engineer's experiment?  Thank you for the reply!  I'll get those photos posted soonest.

Regards,

Bob

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Here are a couple of photos of the SR.  My apologies for the somewhat blurry photo of the underside, I will try again later.  Even through the poor quality of the pic, you can see the square, gray SR, directly behind the orange-drop cap.  The replacement wirewound resistor is at the bottom of the photo; it is connected to the pos terminal on the SR.

• Top side (68 KB)
• Bottome side (blurry) (33 KB)

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OK, thanks to Martin Blankenship, the mystery is solved.  In one of my all-too-common occurances of dyslexia, I transposed the ending of the model number.  This radio is NOT a 6G001YZX, but a 6G001ZYX. The SR is in fact standard equipment on this model.  Also, the "X" denotes a metal case while The "Z" denotes a special modification or revision to the chassis.

My apologies for the error.  Mr Moderator, can you delete my photos from this model? I will request a new model.

• correct model number (21 KB)

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