... and just as I'm about to solder the last two wires on the front panel of said equipment, the iron goes cold ...
The soldering iron in question is the very, very wonderful Metcal MX-PS5000 system. I used to think Weller made the rolls-royce of soldering irons, but these things are just in a different league!
They heat the element by RF induction heating. 13.560 MHz to be precise. It's got all manner of error detecting, it'll put itself to sleep when not in use, and also has outputs for two irons. It's also expensive.
So I think, it's probably gone to sleep ... nope.
Perhaps the tip has failed? No... (takes two seconds to change too!!)
Damn ... the emergency iron is flagged into service, and the job finished...
A new MX-PS5200 is ordered (at about £500!.. ouch). We simply can't be without it.
But let's see if we can't do anything about the old one...
Firstly, remove the retaining nuts from each of the F-connectors.
Flip the unit over, and remove the 4 security torx screws, one in each corner.
First thing was to check the presence of the +48V and +24V supplies from the switched mode mounted in the rear third of the enclosure.. all present and correct... damn.. out goes any ideas of a blown fuse and a quick-fix! There's no hope of getting a schematic, so it's down to the poke-and-hope method of fault-finding....
It's an LM2576-ADJ (not that you'd know from the photo) .... and replacing that restores the supply to the second stage of the drive amp, but not all of it .... damn.
The final piece of the jigsaw is D12 in the small switched mode buck converter .... it too was dead short ... lord knows what the original is, there's no circuit anywhere on the web, so I selected a 1N5819HW for the job, based on the datasheet for U3. It's physically smaller than the diode it replaced, but it seems to work! I've got a hot iron!Excellent ! We now have a spare in the workshop.
Not sure I like Metcal's new logo much ...
Hi (from france),
ReplyDeleteMany thanks for your blog, i have successfully repair my MX-PS5000 with your guidelines.
My MX5000 see 'power' with output power to 0, and i found the U3 very hot , without any signal output signal to D12/L4...
D12 is a SK16 (https://image.noelshack.com/fichiers/2018/12/5/1521800572-20180323-104452.jpg).
I have replace it by a SK36B witch have the same direct and reverse voltage , but 3A (SK16 is only 1A).
All works well !
some pictures after repair:
https://image.noelshack.com/fichiers/2018/12/5/1521800580-20180323-111602.jpg
https://image.noelshack.com/fichiers/2018/12/5/1521800587-20180323-111639.jpg
Très bien! Nice to know the article has been of help. My smaller D12 is still working well!
ReplyDeleteHi.
ReplyDeleteI have same issue with my MX-5000.
Diode D12 shorted!
Thanks
Also I found bad soldering joints around the trough hole components (inductors).
ReplyDeleteI just bought a Metcal MX-PS5000 on ebay that does not work, I did not know this manufacturer, and I was looking for a more professional soldering station than the one I have, I got one and ended up on your blog, you help me repair it and, I tell you which diode is D12, in my
ReplyDeleteboard is a SK38B, but mine is in good condition, the damaged component in mine at the moment is the IXFH12N50F, do tests and I will comment on the news, thanks for sharing
Good luck. I still haven't used a better iron.
DeleteHi.
ReplyDeletevery interesting this page. Very well Doz.
i have a broken Mx5200 that when i power it don't heat the element.
i find in short circuit the 12n50 mosfet. i replace it but nothing. i check the lm2574 and lm2576 voltage.in the 2574 is correct, but in the 2576 i have always 48V in output and i don't see the frequency before the inductor output, i alredy see the 48v. i think it i broken. now i try to replace it.
then i check the output of 74hc04, is correct that i find a sinusoid wave at 13.56MHz? i think that i must find a square wave at 13.56Mhz.
then is correct that in the parallel capacitor of the inductor output i measure 3kohm of impedence. i think it is too low.
many thank Luca
you then found the reason for the low resistance of 3 kilo-ohms on the active channel 1 or 2. At the workstation it is almost 4.2 kilo-ohms.
DeleteHi.
ReplyDeleteGot the same fail with my MX-PS5000.
Diode D12 was shorted. I replaced it with MBRS190T3 and now all works as should.
Many thanks for shared info!
I also found D12 shorted at Metcal MX5000. Thanks it’s good information.
ReplyDeleteI had the same problem "open error", the D12 diode had gone open circuit. I replaced it with an SS12 and it seems to work. This page is gold, many many thanks. /Magnus
ReplyDeleteI too have the 0 output issue. I checked the D12 and it appears to be good. Not shorted or open. I removed it to check it.
ReplyDeleteWhat I did notice is the capacitor C73 is missing. It looks like someone has been in this unit before me. I was given this power supply. My working unit is a 500. I was able to use the tweezers on that one to remove the D12 for testing. I’ve tried resetting and nothing happens. Something else I’ve noticed is the nicad memory battery is bad and starting to leak. Is it possible that’s causing issues with the cpu?
Thanks everyone for your notes and experience with these units.
Can anyone tell me the value of C73? It is located to the lower left of the D12 board it is the bottom cap in a column of 5. Mine is missing.
ReplyDeleteCan anyone tell me the part number for Y3? It is glued to the nicad battery on the front board, upper left when looking from the rear.
ReplyDeleteI forgot to check during last repair, but it can be 32,768 KhZ used for RTC
DeleteDo anyone know what value R1 is?, next to U4 and R3 looks like it is connected to that small trasistor ztx 951 with a heat sink. My ztx951 is blown..
ReplyDeleteI got it working again.I found that R1 is 100 ohm, Q2 ZTX951(the heat paste on this one was dry) deliver power to the IRFZ540 that drives the switching transistor. U3 and D12(working but it had crack in it, so replaced) gives 5,7V to the oscillator 74HC04. Beware: The inductor(22uH 5800-220-RC) close to J2 broke off, resulted in an "open error"
DeleteImportant to mention that U4 is a LM2576HVT-ADJ/LF03 it can handle 60V Max input, the other ones can only handle 40V. R1 is 100 ohm. Beware of a inductor just beside J2, if it breaks off the board you will get: "open error".
ReplyDeleteHELLO, DOES ANYONE KNOW WHERE I FIND THE DIAGRAM OF THE MX-PS5000, WHEN I CHANGED THE LCD SCREEN BY CARELESS I MADE A SHORT AND I LOST IT; ZTX 951 Q2 SHOWING GROUND FAILURE, REPLACE AND IN THE SAME SITUATION, RAISING TEMPERATURE R1, ANY HELP IN SOME WAY
ReplyDeletethere is still no diagram, but there is experience with the 5000 or 5200 series.
DeleteYou can use the Metcal ps500 a guide. Q2 delivers power to the driver IRFZ 540, when Q2 blows is was the isolating pad on IRFZ540 that defective, check that can on IRFZ540 does not conduct to GND/Chassis . Also check the NPN transistor that drives Q2 ztx 649. The display runs on 5v. Check VCC pin. And pray the CPU is okay. The display seems to be a standard 16x2 LCD.
ReplyDelete