Metcal MX-5000 repaired for not heating up

[gregpl]

Didn't see this posted anywhere so thought it might help someone one day.
Was using my metcal mx-5000 and turned it off to replace tip then it wouldn't
heat up anymore. Everything else would work. When I picked up the iron to use
the bar graph did nothing and of course would not heat up.

Took it apart and found SMD diode D12 bad. SK16 -  https://media.digikey.com/pdf/Data%20Sheets/Diodes%20PDFs/SK12-SK16.pdf

Replaced the diode and its working again. Almost bought a new one. Glad I took it apart.

[Zucca]

Thanks gregpl, great job!

[memed]

Hi.
I have same issue with my MX-5200.
Did Q4 MOSFET was heating up that time?
Diode  D12 was shorted?
Thanks

[gregpl]

I used an IR camera and could see D12 getting hot. It read shorted. Replaced it and its working now.
I didn't check any voltages or anything else. Just used the IR to see if anything was getting hot.

[helpmerepair777]

Hi , im new around here ! ehhe 

i was going to check this link https://media.digikey.com/pdf/Data%20Sheets/Diodes%20PDFs/SK12-SK16.pdf EDIT : the link is expired

its for the D12 diode , but the link is expired , and I wanted to know what SK12 diode to choose , im getting a used metcal mx-5000 and ordering come stuff from mouser so I told myself , why not get some spare parts , im gonna order thursday so let me know if you have any other spec for this SK12 diode

THANKS ALOT !

[Sajjad khan]

Hi i am new here, having MX500 not heating up, My lm2576hvt get US repeatedly whether there is some short at output line which i don't find anywhere, i have checked Q1, Q2, Q3, Q4, U4, C4, C24, and many other components all measure good, i got reference from a Serviceable where i found difference of voltages at nagative sense point i.e  cathode of D8 they should be 7.5v but i measure 2.5 and at cathode of D20 it should be 3.5v but i found 1.5v.
Mention that these values are in stanby mode no hand piece connected, can any body help.