i just got this radio,instead of the previous owner recapping the power supply he has decapped it and i'm having trouble figuring out the electrolytic connections and polarity,they are all removed from the chassis.any one have some ideas for me?
edd,one of your explicity explained and marked up schematic would be greatly appreciated.
thanks,phil
http://www.nostalgiaair.org/Resources/508/M0025508.htm
:howdy all!
:i just got this radio,instead of the previous owner recapping the power supply he has decapped it and i'm having trouble figuring out the electrolytic connections and polarity,they are all removed from the chassis.any one have some ideas for me?
:edd,one of your explicity explained and marked up schematic would be greatly appreciated.
:thanks,phil
:
:http://www.nostalgiaair.org/Resources/508/M0025508.htm
:
:
:
::howdy all!
::i just got this radio,instead of the previous owner recapping the power supply he has decapped it and i'm having trouble figuring out the electrolytic connections and polarity,they are all removed from the chassis.any one have some ideas for me?
::edd,one of your explicity explained and marked up schematic would be greatly appreciated.
::thanks,phil
::
:
Hi Phil,
I have done a radio similar to this one, Shutter dial with motorized tuning and eye tube, sweet.
Polarity of the filters is like this. Positive goes toward the filament of the 5Y4G or speaker field. The negative goes toward the point closest to the center tap of the transformer.
I hope this helps.
Best Regards,
Bill Grimm
Sir Phil . . . .
Herewith, find one attached Working Schematic and common parts list for " De-capitated " Zenith 9-S-365.
Electrolytics polarities and most failure prone components, additionally marked up.
73's de Edd
ZENITH 9-S-365 Schema Info:  |
got the electros in place and got it powered up to make sure i had a radio and not a doorstopper/wheel chock, it needed a rebuild but otherwise o.k..
then i lost b+,turns out when the last man working on it replaced the power xfmr, he twisted/taped centertap to ground reference wire,corrosion occurred and opened the connection,i found it by wiggling wires and saw b+ return,unwrapped/soldered/retaped and all is well,many thanks for the help,phil
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:Sir Phil . . . .
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:Herewith, find one attached Working Schematic and common parts list for " De-capitated " Zenith 9-S-365.
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:Electrolytics polarities and most failure prone components, additionally marked up.
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:73's de Edd
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: :ZENITH 9-S-365 Schema Info: : : : : : : : |
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Sir Phil. . . .
Certainly glad to hear that the fix was merely a floating HV secondary centertap.
Most people usually get buffaloed by the polarity of electrolytics in that floating derived negative voltage bias supply that is provided by the manner of the lifting that center tap from ACTUAL ground by a dropping resistor or two in the
Candohm section(s).
Seems like Zenith used a slew of different values for Candohms for different chassis, and nowadays, sometimes,you are lucky to be able to find the actual resistive values used in the individual sections, should one open up on you.
In olden days, you would merely use the assigned Zenith "63" number and get a new unit.
Also I had NO idea of what info you might be needing, and its certainly rare that I have not seen other people, thru the decades, mention the quirk of that drafting error on the Red Ryders schematic of this 365 .
Just must not be that many of that rarer units still being serviced.
I did look up and down that 9- series and each is different from yours in the treatment of the candohm values aspect. Consult my referencing and you will see that I did locate a very good reference of the 6-S-27 and it is also utilizing a
250 ohm section to get the AF negative grid voltage supply, along with AF cathode connections on in the two other series taps before finally reaching ground potential.
HOWEVER, there is a variance in the voltage divider aspect of the unit that fills in between ground and the Sub-B+ supply, in the respect that they are taking off a separate voltage level for the plate of the pentode (a variance from the norm) AF pre amp tube, whereas your unit is using the common triode.
IN CONSULTING THE ATTACHED SCHEMATIC THUMBNAIL:
To get everything correct for any future person that might have problems in this area , how's about you looking at the original schematic at the bottom and note the draftsman spec'ing the top section at 11 K and then his dropping down and
filling in the WHOLE section below, down to ground, as an additional 11 K.
In actuality, it really is consisting of 2 sections in that labeled area. He then tacked on the next two values of 35 ohms and 50 ohms on the sections following downward, until reaching the HV CT / Negative grid bias source of AF tubes 1st grids at the very end terminal at the bottom.
See if my correction over to the right [YELLOW box area] is in congruence with your units Candohm unit, if so I will make a corrected schema for archiving and fulfilling anyones need in the future on this special chassis.
I would probably ONLY queston if I got the 35 and 50 values in the correct sequence that he had shown.
That correction, along with the enhancing of wiring union nodes at crossover points of wiring, there's one up above that looks like sub B+ is getting connected to the 1st grid of the AF amp.
Also, one clarified value of an electrolytic.
End
73's de Edd
ZENITH 9-S-365 Schema Thumbnails:  |
phil
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:Sir Phil. . . .
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:Certainly glad to hear that the fix was merely a floating HV secondary centertap.
:
:
:Most people usually get buffaloed by the polarity of electrolytics in that floating derived negative voltage bias supply that is provided by the manner of the lifting that center tap from ACTUAL ground by a dropping resistor or two in the
:Candohm section(s).
:
:
:Seems like Zenith used a slew of different values for Candohms for different chassis, and nowadays, sometimes,you are lucky to be able to find the actual resistive values used in the individual sections, should one open up on you.
:
:
:In olden days, you would merely use the assigned Zenith "63" number and get a new unit.
:
:
:Also I had NO idea of what info you might be needing, and its certainly rare that I have not seen other people, thru the decades, mention the quirk of that drafting error on the Red Ryders schematic of this 365 .
:
:
:Just must not be that many of that rarer units still being serviced.
:
:
:I did look up and down that 9- series and each is different from yours in the treatment of the candohm values aspect. Consult my referencing and you will see that I did locate a very good reference of the 6-S-27 and it is also utilizing a
:250 ohm section to get the AF negative grid voltage supply, along with AF cathode connections on in the two other series taps before finally reaching ground potential.
:
:
:HOWEVER, there is a variance in the voltage divider aspect of the unit that fills in between ground and the Sub-B+ supply, in the respect that they are taking off a separate voltage level for the plate of the pentode (a variance from the norm) AF pre amp tube, whereas your unit is using the common triode.
:
:
:
:
:IN CONSULTING THE ATTACHED SCHEMATIC THUMBNAIL:
:
:
:
:
:To get everything correct for any future person that might have problems in this area , how's about you looking at the original schematic at the bottom and note the draftsman spec'ing the top section at 11 K and then his dropping down and
:filling in the WHOLE section below, down to ground, as an additional 11 K.
:
:
:In actuality, it really is consisting of 2 sections in that labeled area. He then tacked on the next two values of 35 ohms and 50 ohms on the sections following downward, until reaching the HV CT / Negative grid bias source of AF tubes 1st grids at the very end terminal at the bottom.
:
:
:See if my correction over to the right [YELLOW box area] is in congruence with your units Candohm unit, if so I will make a corrected schema for archiving and fulfilling anyones need in the future on this special chassis.
:
:
:I would probably ONLY queston if I got the 35 and 50 values in the correct sequence that he had shown.
:
:
:That correction, along with the enhancing of wiring union nodes at crossover points of wiring, there's one up above that looks like sub B+ is getting connected to the 1st grid of the AF amp.
:
:
:Also, one clarified value of an electrolytic.
:
:
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:End
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:73's de Edd
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:ZENITH 9-S-365 Schema Thumbnails: : : : : : : : : : |
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Sir Phil . . .et al . . . .
This corrected copy of the Zenith 9-S-365 submitted below should now be in compliance for the values of the sections of the Candohm that you found in your units 5906 chassis.
Praise be to you for the time spent in confirming those few resistive sections values info . . . . it just might be invaluable to some one in the future that might be confronted with any problems encountered within that select area.
I’m hosting it as a select item that should remain with time.
73's de Edd
ZENITH 9-S-365 Schema Thumbnails:  |