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 Post subject: What makes a good 1629 magic eye suddenly stop glowing?
PostPosted: Jan Mon 29, 2018 5:39 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3174
Location: Waukegan, IL
I had a real good 1629 in my Eico 950b cap checker. something popped inside the tube, and the green was gone. the filament was still lit. im assuming it was a failure in the tube and not something in the tester, as it was working fine.

Ugh. the other ones i have are dim to needing to be used in a dark room to see,

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 Post subject: Re: What makes a good 1629 magic eye suddenly stop glowing?
PostPosted: Jan Mon 29, 2018 5:43 am 
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Posts: 31916
Location: Maryland 20709, USA
What other symptoms do you have?

I never heard of a tube making a noise when it failed.

I'm thinking you probably blew an electrolytic filter cap.

- Leigh

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 Post subject: Re: What makes a good 1629 magic eye suddenly stop glowing?
PostPosted: Jan Mon 29, 2018 5:57 am 
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Location: Livermore, CA
Agree with Leigh. Look for B+ voltage on pin #4 of the 1629. Should be near 250 volts.

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 Post subject: Re: What makes a good 1629 magic eye suddenly stop glowing?
PostPosted: Jan Mon 29, 2018 6:03 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3174
Location: Waukegan, IL
ok. ill check. but ill add i just got done recapping the unit, and it was working fine. not that any one of the new caps might have gone bad.

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 Post subject: Re: What makes a good 1629 magic eye suddenly stop glowing?
PostPosted: Jan Mon 29, 2018 10:58 am 
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Location: Albuquerque, NM 87123
I recommend resoldering all the pins.


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 Post subject: Re: What makes a good 1629 magic eye suddenly stop glowing?
PostPosted: Jan Mon 29, 2018 11:18 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3174
Location: Waukegan, IL
I do have plate voltage.

this is what i think happened. the end of the Voltage pot is grounded to chassis via a lug under the shaft bushing on my other Eico 950. on the unit in question, the grounded terminal is hardwired to chassis ground using a ground terminal on the rectifier tube socket. well. i think maybe the capacitor discharge of turning the voltage pot down of a cap under test backfed to the plate lead of the 1629. bcause there is the plate lead to the 1629, then via ground to a resisistor. A ground lug on the rectifier socket made a convienent ground. im going to change it to a ground lug under the voltage pot bushing to chassis ike the other one. im guessing someone may have lost the ground lug.

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