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 Post subject: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 12:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Sterling Heights, Michigan 48314, USA
I'm working on a Telefunken Opus Studio 5650.

The Full wave bridge is shorted out. I'm wondering about the 5 pin array on the bridge. I've never come across a full wave bridge with more than 4 pins. The two outboard pins on the part (see image below) are marked as negatives on the casing. The schematic (also shown below) does not indicate the extra negative connection. There is no continuity between the two negative pins. I've looked up the datasheet online for a B250C100 bridge and all the sheets I've checked show the usual 4-pin array.

Anyone have any input ?

Image


Image

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 12:59 am 
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Location: Toledo, Ohio
The negatives are most likely a common point in the bridge, my best guess. I too have never seen a 5 pin bridge rectifier before.

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 1:07 am 
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Location: Livermore, CA
Diodes are in a row and may require two negatives to be connected together? If 4 diodes are wired together in a bridge diodes at each end need to be connected together. With an external connection no internal wiring will cross.

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 4:28 am 
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Joined: Sep Thu 23, 2010 6:37 am
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Location: Powell River BC Canada
As per what Norm said, here are two five wire bridges.

Attachment:
five wire bridges.jpg
five wire bridges.jpg [ 87.31 KiB | Viewed 1645 times ]

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 5:52 am 
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Posts: 3342
Location: Sterling Heights, Michigan 48314, USA
Here is a photo of the original installation connections of the 5 pin bridge in the Telefunken. There was an exterior jumper wire connecting the two negative pins (yellow wire).

I would be interested in seeing a schematic diagram of the 5 pin bridge.

I'm also curious as to why the manufacturer would even use such a component as opposed to a standard 4 pin bridge (which is what I plan to replace the shorted bridge with).


Image

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 5:59 am 
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Location: Maryland 20709, USA
Dennis Wess wrote:
I'm also curious as to why the manufacturer would even use such a component as opposed to a standard 4 pin bridge
I expect procurement got a good deal on these, possibly surplus from some other company.

The two separate negative outputs probably result from lack of space inside the package to connect the two ends.

- Leigh

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 6:09 am 
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Those are not uncommon, I have seen a number of them over the years in various devices. I think the earlier comment is correct, it was just easier for them to manufacture the bridge with two separate negative terminals. They are always jumpered together upon installation.

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 7:44 am 
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Joined: Sep Thu 23, 2010 6:37 am
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Location: Powell River BC Canada
Dennis Wess wrote:
Here is a photo of the original installation connections of the 5 pin bridge in the Telefunken. There was an exterior jumper wire connecting the two negative pins (yellow wire).

I would be interested in seeing a schematic diagram of the 5 pin bridge.

I'm also curious as to why the manufacturer would even use such a component as opposed to a standard 4 pin bridge (which is what I plan to replace the shorted bridge with).


Image


Attachment:
five wire bridge  VE7ASO.jpg
five wire bridge VE7ASO.jpg [ 101.28 KiB | Viewed 1627 times ]

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de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 8:01 am 
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Steve,

The two diodes on the left in your drawing are shorted. :eek: :D

- Leigh

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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 5:41 pm 
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Location: Santa Rosa, CA
I believe the 5 lead issue has to do with internal construction. Most bridges are made by connecting the leads of separate diodes, like 1N400x series.

If you make the bridge such that the leads emerge from one of the large flat faces of the housing, you need only solder the connections and use the excess lead length as the bridge's external "pins." If the package is "in-line" (that is leads emerging from one of the small faces), then an internal jumper is needed so that the diode leads can be used as pins. To save money, maybe Siemens decided to let the customer provide the external jumper?

At least, this is how we made molded bridges at Westinghouse.

Larger bridges that use "fast-on" lugs could be made with all the lugs facing up and the separate chips soldered between internal metal tabs. These are much better for current-handling and heatsinking, but not as cheap to make as just twisting and potting 1N400x or 1N540x individual diodes.
Rich


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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 5:51 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 9770
Location: Santa Rosa, CA
Try building a bridge out of 1N400x diodes. Your first tendency is to solder the diodes in a square, just like the schematic:

Image

Now, bend the extra lead length to make the 4 pins of the bridge. Bend all the wires in one direction. You discover a couple of things:

1. One of the leads is too short to make the needed pin. (DC - minus in the sketch above).

2. Even if it were longer, it would come out in the same place as the pin on the opposite side of the square (DC plus). Can't have two pins in the same place, so the "far" pin needs to be offset. So you add some wire and bend it around the rest of the structure.

If you leave one end of the bridge un-connected, you can put all the diodes in a nice side-by-side arrangement, but now you need to either internally or externally connect that open leg.

Rich


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 Post subject: Re: 5 pin Full Wave Bridge ?
PostPosted: Feb Thu 28, 2013 7:15 pm 
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You can get silicon diodes nowadays for a few pennies each. Why guess?


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