[Solved] JBC CD-1BE Soldering Station Repair questions.

[jinny143]

Hello,

I'm writing because I need your help.
I have a JBC CD-1BE model and the fuse blew, so I replaced it, and it also blew.
My first question here is.
Where should I start checking?

I took it apart and it looks like one of the elements with the transformer is broken.
It's labeled "BFP 7EIEP" and it looks like a diode, but I'm wondering what it does. Could that be what's causing the fuse to blow?

I compared a recent model of JBC CD-1E and there is no "BFP 7EIEP" on the transformer.

Would replacing that element solve the problem? Or is it possible that the transistor is the problem?

I can't find it on the internet, so I'm asking for help here.

Thank you in advance for your help.

[xrunner]

Did you try to test the "BFP" as a diode with a DMM?

[jinny143]

Thanks for the reply.
I tested the diode and it seems to be broken.
I tried reversing the polarity on both sides and got 0 volts.
How do I find out the specifications of the diode?

Maybe the transformer isn't broken?

Is this the same diode as the one I found?
https://www.eevblog.com/forum/repair/jbc-cd-2bb/msg5243928/#msg5243928

[xrunner]

It's looks to be a transient suppression diode. You can remove it for now and then see if the unit works, and if not keep troubleshooting the circuit. There may be other components damaged. Later you need to replace it with a similar transient suppression diode.

[jinny143]

I have a blown fuse and will test it after purchase, thanks.
I'll let you know the results as soon as I check.

[selcuk]

I didn't have any issues with JBC soldering station but I repaired its hot air station which had the same repeated fuse blown issue. It had a shorted bridge rectifier around the transformer. I replaced the rectifier along with the fuse to fix. There was no damage to TVS diodes. So I recommend to check rectifier diodes if any as well.

And don't forget to measure that TVS after removing it from the transformer. Transformer can make it to look like shorted.

[gamalot]

SMCJ36CA from LittelFuse:

https://www.littelfuse.com/media?resourcetype=datasheets&itemid=37388813-0d6d-4329-969b-1aa8b7614ac1&filename=littelfuse-tvs-diode-smcj-datasheet

[jinny143]

@gamalot - Yes, I have placed an order with this element and am waiting for it. Thank you.

[jinny143]

@selcuk - Thank you for your response.  I'll check it out. 

[JimKnopf]

@jinny143 Don't worry if your DMM show you no reading on your brand new BFP Bi-TVS diode.

You need  a DY294 to check breakdown voltage and a AC powersupply (up to 40 V) together with an oscilloscope to test this TVS diode. I used an EA-STT 2000 as AC PSU in my test setup.

[jinny143]

@JimKnopf - Wow thank you so much.
For explaining it in such detail.
But I don't have the equipment to test it.
I think the Bi-TVS diode is broken, because I checked it with a microscope and there is a crack in it.
I will replace the Bi-TVS diode and Fuse and check it and let you know the result.

Thanks again for the detailed explanation.

[jinny143]

hello.
Thanks to your help I was able to fix my JBC station. Thank you very much.

I replaced the Bi-TVS diode and Fuse as you suggested.
After fixing the two, it works like the attached picture. Nothing else seems to be wrong.