Help Finding Core/Bobbin for SMPS Repair

crazifunguy

New member
Among the many projects that I have going on is the repair of a SMPS transformer that I ruined dismantling while looking for a short. Turns out the transformer was perfectly fine. After being upset I now have to re-create this thing in hopes that I can salvage this power supply. I am about 95% sure that the core is an EER35. I am trying to locate a core and 14 pin vertical bobbin but have had no success. Any help is appreciated. Thanks!!!!
 

MicrosiM

Administrator
Staff member
Are you looking for a CORE?

Or trying to confirm, that the core you have is ER35?

I think I have ER35 transformers, will check and get back to you! :)
 

crazifunguy

New member
Quesion?? What tape do you use for winding insulation? I can't seem to figure out what the thin yellow stuff is on the origional transformer. I see that kapton is available on ebay. Is that suitable or even better than whats origionally used?
 

MicrosiM

Administrator
Staff member
Quesion?? What tape do you use for winding insulation? I can't seem to figure out what the thin yellow stuff is on the origional transformer. I see that kapton is available on ebay. Is that suitable or even better than whats origionally used?

Kapton, Craft paper both is a standard
 

crazifunguy

New member
OK thank you. I see alot of sites refer to yellow mylar film tape wich i also found on ebay. Just want to make sure this bad boy will work.
 

crazifunguy

New member
Well my ETD34 bobbin came in the mail today. I compared to the ER35L origional. The stack is shorter but the windings should fit without using creepage tape. The origional core appeared to be ungapped. Should I just wind this like the origional leaving out the creepage and see what happens? Are there any calculations that I need to make or just keeping the turns identical will be good enough?
 

MicrosiM

Administrator
Staff member
Formula

Well my ETD34 bobbin came in the mail today. I compared to the ER35L origional. The stack is shorter but the windings should fit without using creepage tape. The origional core appeared to be ungapped. Should I just wind this like the origional leaving out the creepage and see what happens? Are there any calculations that I need to make or just keeping the turns identical will be good enough?

I would recommend you to use formula here, and compare it to original design.

http://www.diysmps.com/forums/showthread.php?77-SMPS-Transformer-Primary-Turns-Calculations

download last version of formula, enter frequency in HZ

Lets enjoy this tasks!
 
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