{"id":3131,"date":"2018-06-30T23:56:17","date_gmt":"2018-07-01T06:56:17","guid":{"rendered":"http:\/\/www.stevenrhine.com\/?p=3131"},"modified":"2021-03-10T16:36:28","modified_gmt":"2021-03-11T00:36:28","slug":"next-project-miller-375-plasma-cutter","status":"publish","type":"post","link":"https:\/\/www.stevenrhine.com\/?p=3131","title":{"rendered":"Miller Spectrum 375 X-treme Plasma Cutter.. Teardown \/ Repair Complete!! & Schematics!!"},"content":{"rendered":"

Miller Spectrum 375 X-treme Plasma Cutter.. Teardown \/ Repair Complete!! & Schematics!!<\/p>\n

Yep, this one Let The Smoke Out.. Link To Miller Product Page<\/a> This one is a bit older it has the ICE-27C\/T Torch.<\/p>\n

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\nBasic Wiring Schematic Under The Cover..
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I Support The Right To Repair https:\/\/repair.org\/stand-up\/<\/a> #RightToRepair<\/p>\n

Your PCB Revision Will Be On The Secondary Side Of The PCB at The Bottom..<\/p>\n

Download the Miller 375 Plasma Cutter Schematic For Board # 224975 rev 224982H With 24V Relay<\/a>
\nDownload the Miller 375 Plasma Cutter Schematic For Board # 224975 rev 231540B With 18V Relay<\/a><\/p>\n

Miller 375 Schematic Images Extracted Form PDF. (Edited For Rotation Only) Click to Enlarge, Then Right Click Save As to Save!!<\/p>\n

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Visual Where the Smoke Got Released From.
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Rest looks OK..
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Big Mess..
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Need to Get the Value of R123 a Ceramic Power Resistor.<\/p>\n

Will be digging further but just removed the parts that had a visible catastrophic failure \/ damage<\/p>\n

Will Still need to find the failure that caused the Resistor to Go Nuclear!<\/p>\n

So Far My Parts List
\n2 X 1500UF 250V Caps
\n1 X Relay TE Part No. T9AS1D12-24<\/a>
\n1 X AVX FFB16J0395K 3.9uf 525v Capacitor
\n1 X Unknown Ceramic Power Resistor (Replace With PTC Miller Part No. 200656 Or Vishay Part Number PTCTL8NR100HBE<\/a>)<\/p>\n

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\nCeramic Power Resistor After Some Clean Up.. Back Side Totally Blown Out.
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I was messaged by a member on the miller forum that relay NT90RHAS24CB in the Hobart Variant Plasma and Welders is Obsolete and has been superseded by a Tyco Brand Because if it having issues \/ failing as well.<\/p>\n

Looking at the data sheets..
\nTYCO or TE Part No. T9AS1D12-24<\/a> is a Direct Replacement.<\/p>\n

As Soon as I find my larger nozzles \/ solder wick or if kimco delivers my new ones which ever occurs first I will pull the 2X DSP 45-12A<\/a> Rectifier Diodes that are on the resistor power circuit and check them.<\/p>\n

I Need to remove the Plastic Cover So Removing & Checking The Transistors..<\/p>\n

Waiting On Larger Nozzles for My Desoldring Gun.. Wish I had a Hakko Stocking dealer here.. Seems Like Motion Industries has Purchased all the cool stores and nixed all the good stuff!<\/p>\n

But the Rework Equipment Is All Unpacked Not 100% Setup.. Yet Just Enough to do some Basic Work..<\/p>\n

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All the IGBT’s Seemed to Check Out With Multi Meter.<\/p>\n

Negative Lead on Collector Posotive On Emitter Open.. Touch Gate With Posotive Lead Will Tone ON Emitter\/Collector, Short Emitter and Gate = Collector and Emitter is Open Again.<\/p>\n

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Data Sheets For IGBT’s
\nMiller Part # 219156 X 4 https:\/\/www.mouser.com\/datasheet\/2\/196\/auirgp35b60pd-1225850.pdf<\/a>
\nMiller Part # X 1 https:\/\/www.mouser.com\/datasheet\/2\/196\/irg4pc40udpbf-1227630.pdf<\/a>
\nMiller Part # 225480 X 2 https:\/\/www.mouser.com\/datasheet\/2\/196\/auirgp50b60pd1-1225219.pdf<\/a><\/p>\n

Diodes Are Next… Need Larger Nozzle.
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Diode Data Sheets
\nMiller Part # 225523 X 2 APT30D60BHB<\/span> http:\/\/www.microsemi.com\/existing-parts\/parts\/60540
\nMiller Part # 225481 X 2 APT75DQ120BG http:\/\/www.microsemi.com\/existing-parts\/parts\/60739<\/p>\n

There is 1 More Resistor in a TO247 Package MP9100-50.0-1%<\/a><\/p>\n

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Proprietary Miller 218760.. Looks Like a Custom Rolled Phsae-leg IGBT or Dual IGBT
\nIf anyone Knows Of a Replacement Please let me know.<\/p>\n

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Schematic Data:
\nTO247AC 5P DWN FLIP Listed as IRF130_5 Pinout: Emitter1 Gate1 Emitter2 Gate2<\/p>\n

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Busy Day.. Got My Desoldering Tips In..
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\nLit the Solder\/Desoldering Machines Up..
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Removed Some More Parts..
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Whats Under The Hood of the Miller 375.. Plasma Cutter!!
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Digikey Mouser & Miller Order Totaling Less Than $40 Right Now + Ship.<\/p>\n

All IGBT, Resistors, & Diodes Checked Again and All are Good.. The Leads Cleaned Aligned Ready For Reinstall When The Repair Parts Arrive.
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PCB Prepared Ready For Reassembly..
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December 31st 2018<\/p>\n

“Not a Trick” But a Treat!! What You See In The Photo is Real.. More Parts are Arriving!! I know it been a long time!!<\/p>\n

Another Big Thanks to Miller Electric for Providing the PTC Update Miller Part No. 200656 Is a Vishay Part Number PTCTL8NR100HBE<\/a> I will be Reassembling it tonight or this weekend I hope.<\/p>\n

A Big + to Arrow Electronics<\/a> For Having These Parts In stock and Shipping Them So Fast.<\/p>\n

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Some New Parts Installed I did Not Install the HX 50-P as it is still on order\/transit but it looks like it only has some slight cosmetic damage..
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The Long Process of Soldering & Heat Sinking the The transistors. “Diodes, Resistors, and IGBT’s”<\/p>\n

I Found it Simpler to Install the Transistors, Install Heat Sinks,\u00a0 Solder Transistors, Remove heat sink and verify thru hole penetration on soldering, Apply heat sink compound and reinstall.<\/p>\n

You can see There is 1 heat sink tab broken on a resistor near the botton but it looks like it will hold a good contact.
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More Assembly…
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And More Assembly.. and Power On Test With 110V and 240V so the Switching Circuit Is Working.
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I know it looks bad with the conformal coating stripped in the solder area’s but I will apply a new conformal coating the the pcb asap and I also had to make an insulator to go between the PCB and the Case.
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All Assembled Now Will She Work??? Not With My Air Chuck So\u00a0 I had to make an Adapter..
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Ultimate Test Yea, it is a Poor Video But Proof it Works. I Need that third arm out of the chest or remote camera.
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