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Looking for replacement Transformer

Pslade

Jul 14, 2017
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So my Tenma 72-6345 Rework and desoldering station blew. I immediately suspected the transformer. I go in take it out read it and test it. It's blown on the primary side and finished inspecting the unit. Go to find a replacement and I realize it's an overseas can't be found part number or on a shotty site. Can anyone help me find a replacement to this one Chun-Shin PT-025(SL-30) It's
for the soldering portion. Any help is appreciated.

Image attached

http://imgur.com/a/u1M2G
 

Pslade

Jul 14, 2017
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Image if it didn't show uploaded
 

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ramussons

Jun 10, 2014
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A single transformer with those specs may not be easily available.

A 110 V to 12 - 0 - 12 V @ 2A with an additional 6 V @1 A maybe available.

Else you may have to go in for 2 transformers with secondaries of 12-0-12 V @ 2A and 6v @ 1A.
 

Pslade

Jul 14, 2017
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You're absolutely right. I had two in mind on mouser's site because there's just none spec'd that way anywhere. Probably something made in house or on the spot. Thank you for the reply. You gave me closure so now I can proceed with the repair.
 

73's de Edd

Aug 21, 2015
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Sir Pslade . . . . .

Looking at the pristine coloration of your viewable magnet wire windings and the lack of any time related discoloration of the bobbin form . . . .I do fully believe that you just were being the recipient of one SOLID WHACK of line voltage or a lightning hit at your pole.

Are you up to resolution by inspection ?

Do a surgical uncovering of the wrap over on the primary side where the BLACK wires make entry into the transformer.

Let us know what you find, and it would be permissible to use an external 1A fast blow fuse for the blown unit for an initial evaluation of the transformer proper in the interim.
Also . . . give us the total wattage spec on the power labelling on the Tenma case.

HOWTODOITTOIT . . . . .

Tformer_Thermal_Fuses.png




73’s de Edd
 
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Pslade

Jul 14, 2017
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73’s de Edd I've unwound the the primary and secondary sides after measuring resistance discovering that the primary was burned. There is charred and discoloring on that side as well. Sadly there were no internal fuses in the winding. The station is rated for Power requirements : 120 V ac, 60 Hz, 100 W (24V 48W for each the soldering and de-soldering). Here are some more pictures linked with a shot of the windings and coloration: http://imgur.com/a/q6z9p
 

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kellys_eye

Jun 25, 2010
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That's one fried transformer!

Clearly the system is 'under-designed' and the lack of circuit protection is deplorable.

I'd be inclined to find the aforementioned 12-0-12 transformer AND a separate 6V/1A transformer and fit them in an external case and use a wire/plug to power the station.

I guess the 6V/1A eventually provide the internal 5V DC for the control circuitry and the 12-0-12 delivers AC to the heating element - clearly UNDERSIZED for a 48W output. You should source a 12-0-12 transformer of at least 3A to prevent a repeat performance - and fit suitable circuit protection whilst at it.
 

Pslade

Jul 14, 2017
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I assumed that Tenma was a huge brand as I seen so many of them in various workshops I worked in of course Hakko being the main brand. But yeah I looked at it and I was just surprised at the design. There are two transformers actually. The one that's blown is to the Soldering iron half and the other is to the desoldering iron and pump. That transformer is fine(for now) and has an additional 25V output. .Image:http://imgur.com/a/kPYHT
 

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kellys_eye

Jun 25, 2010
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If you could find out whether the AC is used 'as is' or is converted to DC you could then replace the whole transformer/rectifier/regulator section with an SMPS DC supply instead. It may well fit in the case!
 

Pslade

Jul 14, 2017
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The transformer outputs AC voltage which is fed to a board with some regs.
 
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