muskie

[muskieslayer]

i just aquired an old sip migmate, does not have a model on it. it is orange in color. anyhow it has a shorted diode pressed into the aluminum rectifier heat sink. there are 4 diodes pressed into the heat sink. the three other diodes have the cathode pressed into the heat sink. should i press in a new cathode press in diode or is this a bridge circuit where it would be 2 anode and 2 cathode press in diodes. the 3 good diodes all test as cathode press in diodes. I would appreciate some help muskieslayer

 

[Mick - Ford Focus]

muskie

Welcome To The Forum.

Is Your "Name" An Email Address !

Mick

 

[muskieslayer]

yes a mistake

 

[Shedendman]

No lie,thats my dogs name Muskie

 

[Mick - Ford Focus]

muskie

Yes - Advise You To Change It As You May Get Spammed By "The Bots"

Sorry But No Idea With The Diode Thing An Expert Shall Be Along Later.

Mick

 

[Robotstar5]

Convention would be 2 & 2. Can you see any sign of the blown diode been changed before?, maybe put in the wrong way round to give half wave rectification but not sure if that's used in welders?.

 

[mike 109444]

Welcome Muskie.
As Mr Robotstar5 says 4 diodes would imply a full wave bridge.
Did you disconnect the cables (inc any linking from one diode to another) from all the diodes when testing because if not you will get a reading back through one of the other diodes.

 

[mike 109444]

PS what are you using to test (what setting on your meter) does it have a "Diode test" position?

 

[muskieslayer]

i tested the diodes with simpson volt ohmeter

 

[Robotstar5]

yes a mistake

Send a PM to admin/mods and they can change it for you.

 

[muskieslayer]

it does not look like it has been worked on, I have the diodes isolated from each other

 

[muskieslayer]

the diode are isolated from each other,

 

[mike 109444]

I take it there are no other components strung off the diods namely any small capacitors or suchlike?. If you can begg or borrow a meter with basic diode test on it, it might give a clearer indication of the state of the "belived good" diodes. If you look around at circuits from other welders where 4 diodes are fitted they tend to be arranged as a full wave bridge. If all the diodes are fitted in the same way into the heat sink ie pressed in then if there are any codes or markings or even colour coding I would expect to see 2 marked one way and 2 marked the other. If there are any markings it might be possible to look them up to get the specs.

 

[muskieslayer]

there are no other components strung off the diodes, they are pressed into a heat sink ans i have it on my bench. The the heat sink and the diodes are from sip part numberCF-4/1/140. they call it the rectfier. Is there any way to find out from sip what kind of diodes are in it?

 

[muskieslayer]

i am trying to find out the polarity of the diodes are on the sip part number CF-4/1/140, which is a aluminum heat sink with 4 diodes pressed in and is called the recifier. can anybody help please.

 

[Wedg1e]

No numbers on the diodes themselves?

 

[the snooper]

polarity on a diode is easy they will only conduct in one direction

 

[muskieslayer]

no numbers or color codes on the diodes, one is shorted and the 3 others have the cathodes pressed into the heat sink, which does not make sense if it is a bridge.

 

[mike 109444]

Muskieslayer I googled that part number and one of the hits is sipuk and give a price of £23.96 (a lot cheeper than I would have expected!) Ok that is a uk site so cost to ship to usa may make it pricey. Might be worth looking in usa for supplier? failing that search for high power, low voltage diodes and find spec sheets for suitable replacement. It still does seam strange the reading you are getting.

 

[mike 109444]

Having gone through several circuit diagrams on the sipuk site they show most of the welders with only 2 diodes! several list that part "CF 4/1/140" as being the rectifier used and only show as 2 diodes in diagram. Could it be that they double up the diodes (still does not explane your reading).