Metcal MX500P Soldering Station?

[stbaratheon]

Hello everyone,

This is my first post here, so sorry if this is the wrong forum for this.

I am trying to fix a Metcal MX500P soldering station power supply. I have 3 old broken power supplies to choose from, each with their own issues, and can only choose one. They are as follows:

1) Doesn't turn on, even with adequate connector.
2) Turns on, but doesn't recognize when a working wand is connected.
3) Turns on, recognizes the wand but green light flickers and tip doesn't heat up.

I've just started my journey into fixing electronics and would love to resurrect this treasure. I've read the previous related forums and understand that there are various errors that can the cause the issues listed above.

So from your experience, which Metcal supply would you advise I start with (eg. blown fuse or transistor)?

I would appreciate any feedback, even if it about a similar piece.

Thank you,
Danny

[MosherIV]

Try searching youtube for metcal repair.

There is a video with the same symptoms as 3.

Guy did not find actual source of the problem, just unkown dry joint some where.

Ps. Welcome to the forum.

[BurningTantalum]

Hi there. These units are very complicated for a first attempt at a repair. Having said that the schematic is available online and there is info on EEVblog on various faults and repairs. The main starting point is to identify a working RM3E wand with a working tip so that the MX500P can be tested. The wands are not impossible to repair and/or fault find, and if faulty will likely have break(s) in the coax inner near the handle. The only external indication that the unit is working is when the top switch is switched and a good wand gives a green LED or bad gives orange (from memory.)  Post any progress or questions.
Regards, BT

[benj38]

If it were me I would go with option #2 without hesitation.

This would be either some bad connection to or in the wand, or some fault in the wand detection circuit. Both should not be hard to fix. In particular, the wand contains no electronic components, and the detection circuit is a simple DC circuit with the main players being two transistors (2N3904, 2N3906) and a comparator (LM393).

The other two faults may involve the RF circuit and/or the buck converter circuit, both of which can be easy or very hard to fix, depending on how (un)lucky you are.

That said, if you have very little experience in electronics repair, even option #2 may not be a walk in the park.