Author Topic: Is this a selenium rectifier?  (Read 398 times)

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Offline Steevsee

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Is this a selenium rectifier?
« on: August 22, 2010, 05:13:19 PM »
This rectifier is in a JAL 200 Jukebox power supply(Junction box).
It looks similar to the selenium rectifier shown in Clay's EM repair guide, but I'm not too sure.

I am going to replace the original electrolytic capacitor (since it's almost fifty years old) and would like to replace this rectifier as well.

The old rectifier has the two outer lugs marked in yellow and the centre lug marked red. I'm pretty sure that the yellow are the AC and the red is +, and I guess the body of the rectifier is grounded to the chassis(-)?

Several sites mention the need to add a resistor due to higher output from modern silicon bridge rectifier
Anyone know if this is correct. !@#

Welcome any comments/suggestions. Thanks.

Offline Retropin

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Re: Is this a selenium rectifier?
« Reply #1 on: August 22, 2010, 05:22:46 PM »
No.

If you undo it, it will have 2 large diodes in there, a cap and a resistor somewhere... youve already done the cap?

Had to replace the same on my ROWE 64 model.. had a whopping cap that i replaced with one approx 1/20th of the size.. i stuck it inside the original cap for authenticity

Offline Steevsee

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Re: Is this a selenium rectifier?
« Reply #2 on: August 22, 2010, 05:38:50 PM »
No.

If you undo it, it will have 2 large diodes in there, a cap and a resistor somewhere... youve already done the cap?

Had to replace the same on my ROWE 64 model.. had a whopping cap that i replaced with one approx 1/20th of the size.. i stuck it inside the original cap for authenticity

Thanks Gav. I probably won't replace the rectifier it if it's not selenium.  (or should I still?)

The original cap base is visible under the rectifier in the pic and you can just see a tiny bit of the resistor as well.
I do already have a replacement cap and yes it is much smaller than the original.
Haven't fitted it yet but was just going to bypass the original altogether since plenty of space.

Is it difficult to put it inside the original?  How did you do it?
Thanks again.


Offline beaky

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Re: Is this a selenium rectifier?
« Reply #3 on: August 22, 2010, 06:43:25 PM »
Sorry to disagree with you retropin but It is 2 selenium diodes.(its a Full-wave rectifier but not a full wave bridge rectifier) you can replace it with a silicon bridge rectifier. just connect the 2 yellow wires marked 'Y' to the AC terminals on the new bridge rectifier and the wire marked 'R' to the + on the new bridge. the negitive terminal is not used (it is not grounded in any way)
« Last Edit: August 23, 2010, 02:06:29 AM by beaky »
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Offline Steevsee

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Re: Is this a selenium rectifier?
« Reply #4 on: August 22, 2010, 07:31:30 PM »
It is 2 selenium diodes.(its a Full-wave rectifier but not a full wave bridge rectifier) you can replace it with a silicon bridge rectifier. just connect the 2 yellow wires marked 'Y' to the AC terminals on the new bridge rectifier and the wire marked 'R' to the + on the new bridge. the negitive terminal is not used (it is not grounded in any way)

Thanks Beaky. That should make things nice and simple for me. ^^^
I wasn't real sure what to do about the ground.

Offline beaky

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Re: Is this a selenium rectifier?
« Reply #5 on: August 22, 2010, 07:40:26 PM »
no probs, if you have any problems feel free to ask me any time for some help
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Offline Steevsee

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Re: Is this a selenium rectifier?
« Reply #6 on: August 22, 2010, 08:42:16 PM »
What a fantastic offer. Thanks Beaky.

I'll be recapping both amps next, so might just need to take you up on it.

You gotta love AP and the great people here. @@*

Heres a quick pic of the power amp.  Looks like it should be fun

« Last Edit: August 23, 2010, 09:40:02 AM by Steevsee »

Offline Douggie

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Re: Is this a selenium rectifier?
« Reply #7 on: August 22, 2010, 10:15:22 PM »
As already stated its 2 selenium diodes, these were used exstensivly in British made equipment in the late 50's, early 60's.

I once restored an "Eddystone" receiver for someone who wanted it 100% original and easily sourced a couple of these from ebay UK

(Just on the off chance you wanted originality but obviously silicon devices are more effecient and reliable)