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 Post subject: Audio transformer Sentinel 68B
PostPosted: Feb Fri 09, 2018 2:06 am 
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Location: Colorado Springs, CO
I have discovered that the primary to the audio transformer in my Sentinel 68B is open. How do I go about figuring out a suitable replacement? Here are the schematic and relevant tube charts.


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Sentinel 68B.pdf [143.93 KiB]
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19.pdf [40.02 KiB]
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75.pdf [135.39 KiB]
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 Post subject: Re: Audio transformer Sentinel 68B
PostPosted: Feb Fri 09, 2018 11:35 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 93
Location: Colorado Springs, Colorado
How do you find a suitable replacement? Just ask?

I have a couple of those 68B transformers. Two different mounting schemes though.

If you meet me in the Black Forest for pickup, either one is $5.

Need any other 68B parts?

Bob


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 Post subject: Re: Audio transformer Sentinel 68B
PostPosted: Feb Fri 09, 2018 11:52 pm 
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Location: Colorado Springs, CO
I'll PM you.
reb

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 Post subject: Re: Audio transformer Sentinel 68B
PostPosted: Feb Sat 10, 2018 12:11 am 
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Here is what it looks like installed and removed. Not sure where the open is located, no signs of overheating.


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2018-02-09_12-00-45.JPG
2018-02-09_12-00-45.JPG [ 218.72 KiB | Viewed 125 times ]
2018-02-09_16-54-22.JPG
2018-02-09_16-54-22.JPG [ 203.5 KiB | Viewed 125 times ]

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 Post subject: Re: Audio transformer Sentinel 68B
PostPosted: Feb Sat 10, 2018 12:21 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 93
Location: Colorado Springs, Colorado
It is good you posted a picture. I thought you needed the audio output transformer.
I have two interstage transformers too. Have to retrieve them from the barn and check them.
Will get back to you shortly.

Yes, have the interstage transformer just like your picture. Resistance checks OK.
Same terms as above.

Bob


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 Post subject: Re: Audio transformer Sentinel 68B
PostPosted: Feb Sat 10, 2018 1:39 am 
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I was thinking of it as an interstage transformer also, but the schematic labeled it as audio. Old terminology I suppose.

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 Post subject: Re: Audio transformer Sentinel 68B
PostPosted: Feb Sat 10, 2018 2:18 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 93
Location: Colorado Springs, Colorado
Ralph,

In your PM you mentioned the vibrator is noisy, low voltage and unsteady.
I would suspect the vibrator too but just have to ask. Did you replace the buffer
capacitors with correct capacitance and voltage? I know in the 68B power supply
these would be hard to get to but it needs to be done.

Bob


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