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ZENITH chassis 1004 - Printable Version

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ZENITH chassis 1004 - theboyzz - 10-26-2008

Hello.I ju8st purchased a zenith 1004 chassis.First i replaced all electrolytics and large caps.Then brought it up on my variac and worked fine.I then cleaned the volume pot and radio still worked.I then replaced the rest of the caps. and one resistor.Turned it back on and can only recieve 1 statio at around 1400 and at low volume.Rechecked all work,then checked tubes,variable cap. for bents plates or ground issues.Any suggestions would be appreciated.ron


Re: ZENITH chassis 1004 - etech - 10-26-2008

Quote:I then replaced the rest of the caps. and one resistor.Turned it back on and can only recieve 1 statio at around 1400 and at low volume.Rechecked all work,then checked tubes,variable cap. for bents plates or ground issues.Any suggestions would be appreciated.ron

Most likely a wiring error. Double check all connections made during cap and resistor replacement. Also, there is a slight possibility that one of the new caps could be a wrong value or bad. It is usually best to try the radio after replacing each capacitor or every two capacitors, so that if something goes wrong, you don't have too far to trackback. Icon_smile

Ed


Re: ZENITH chassis 1004 - exray - 10-28-2008

Just to make sure it has been noted...I think the Wavemagnet MUST be connected for testing. Make sure none of the wires have broken.
Good luck with it. Thats the chassis I have in my chairside (IIRC) and its a decent performer.

-Bill


Re: ZENITH chassis 1004 - Texasrocker - 10-30-2008

My JF Riders vol # 8 lists several notations for "intermittent reception" on the Zenith chassis mod 1004.

If you are using the orig tubes since powerup w/ variac, recheck them to make sure 1 or more may or may not be breaking-down after warmup. Internal tube-shorts etc? Recheck your socket-pin connections to be tight & clean.

Your Zenith chassis 1004 has a old orig style Zenith factory "candohm" type wirewound resistor mounted to chassis. These parts are most usually bad always, intermittent in themselves, and generally overlooked when recapping a set. Check it closely for intermittent operation.

Heres the probs listed by JF Riders vol # 8 (published in 1937)to search for "intermittent reception" probs on the Zenith 1004 chassis:

(1) tubes ( recheck em under load, replace them one at a time if you have spares)
(2) IF trimmer short
(3) dirty variable condenser plates ( can wash-away yrs of debris with spray-can-type of electronics cleaners: "Blue-Shower" or/ "Big Bath" sold at select electronics components stores.
(4) poor ground at "candohm" resistor
(5) loose link wire across Z & G on aerial strip ( check your antenna wires-terminals closely for shorting across these 2 screws)
(6) poor contact on bandswitch. ( see #3 suggestion for electronics spray cleaners) to clean switch contacts. (rotate that switch and make sure contacts are not intermittent from age & debris buildup and it makes secure contacts when engaged)
(7) defective aerial (shorting somewhere internally in the loop, or broken connection internally?) wiggle it when radio is powered up.
(8) defective bypass condenser ( not likely if you already replaced "ALL" them?) Make sure you didnt miss any, I personally dont find many bad "new" caps in my stock, but it can happen.

If your old "candohm" is intermittent, replace it with a close approx suitable ohms-rating, in the 5-10 watt ceramic type wirewound power resistor type(s) using terminal strip(s) in place of the old candohm metal mount assembly. Many of these are "sectional", so you will need a schematic for the data, if you dont have one, I can help provide the data.

Best of luck with your Zenith restoration!! Icon_wink Sincerely, Randal @ TxVintageRadios


Re: ZENITH chassis 1004 - BDM - 10-30-2008

exray Wrote:Just to make sure it has been noted...I think the Wavemagnet MUST be connected for testing. Make sure none of the wires have broken.
Good luck with it. Thats the chassis I have in my chairside (IIRC) and its a decent performer.

-Bill


Bill, this chassis is used in 1937 sets I believe. No wavemagnet.


Re: ZENITH chassis 1004 - exray - 10-30-2008

Ooops, sri. Goofed again. My 10S452 is a 1005 chassis.


Re: ZENITH chassis 1004 - BDM - 10-30-2008

exray Wrote:Ooops, sri. Goofed again. My 10S452 is a 1005 chassis.

That's ok. All will be forgiven if you simply box those Philco's up, and send them my way. Free of charge....Of course Icon_mrgreen


Re: ZENITH chassis 1004 - exray - 10-30-2008

BDM Wrote:
exray Wrote:Ooops, sri. Goofed again. My 10S452 is a 1005 chassis.

That's ok. All will be forgiven if you simply box those Philco's up, and send them my way. Free of charge....Of course Icon_mrgreen

Hey Brian, you are welcome to come down for a visit and you can carry home any big radio that you see in my shack free of charge. YOU ship it Icon_evil


Re: ZENITH chassis 1004 - BDM - 10-30-2008

LOL.....