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Power feed circuit board blew

Redneck_Sophistication

Redneck_Sophistication

Super User
I was setting up cut in aluminum abs engaged the power feed not realizing how fast it was set to.

I stopped it as quick as I could, but it shut off as I was throwing the switch.
The built in circuit breaker didn’t trip, nor did the branch circuit breaker.

I opened it up to find a small burn mark, and oddly it blew traces right off the board without burning. There were little ribbons of copper in a couple spots.

Being an expert in electronicals (I even know what end of the soldering iron to hold!) I repaired the traces, and replaced a cooked resistor. But no joy.

I’d like to maybe try to get a replacement board but I don’t know the manufacture I remember the guy I bought from saying it was from Taiwan or was it Thailand?

Does anyone recognize this label?

Every power feed I’ve seen looks exactly the same what’s the chances another board from another manufacturer would work?

If I was dishonest I guess I could order a new one and return with the bad board. But I don’t like that.

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Sure can, thought I did

You can see the missing trace between the blue things (caps) there was a little copper ribbon hanging off. I replaced it with a tiny insulated wire on the back of the board to the pin of that first plug

The cluster of four resistors had one burned I replaced it with a smaller one of same lines.

Oddly enough after I repaired the traces the little “power” light would turn on but nothing would work. After I replaced the resistor it wouldn’t light up.
 

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Have a good look at the solder joints on the high amperage components on the board.
I see a couple that look like they were poorly done.
 

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Looks like an old power feed. Probably will not get parts for these anymore. You can play around with the board if you wish, but if it was me, after some play time I would just get new power feed. They are cheap. I know, throw away society.

Me and my dad did repair some Chinese electronics recently - they had blown thermal relays - good luck.
 
I just went through this my power feed (luckily the cnc conversion was almost complete so some a little work and cnc was up and running).

Yes I did trace (and replace) the offending component. First test the next component blew along with the first. Dissection shows that that these power feeds are built using old school components and have finite life when used (used hard like I did, less than 2 yrs) but for a normal hobby usage can be 5-10 years.
 
Could have burned out of those ic's on the board, they don't always show signs of being burnt out, I imagine they are simple discrete ic's probabaly like a voltage reg and a couple 555's, that stuff is still available through like digikey
 
@Tom Kitta i don’t know the age, the millwright I got the mill from never had it running after the rebuild. I’ve only used it lightly 6 months or so.

@phaxtris I don’t really know what that stuff is. I can see a burned component and if I know what it is solder in a new one that’s about it.

My multi meter is more of a construction type, to test a component for ohm’s wouldn’t you want to do so off the board? Why I was hoping someone would recognize the name of the company to maybe find a whole new part.


Where’s the best place to buy a new feed in Canada?
 
Typically, I have found, in those applications, the IC's are usually OK. Hard to test in or out of the circuit so typically, if our troubleshooting lead us to believe that an ic was nfg, if we were to pull it out to test it, then we just put a new one in. We can and have built test circuits but it more out a want to know scenario.

As to what @terry_g says, exactly. That joint caught my eye too. Touch up any joint that looks suspicious, but don't do that unless you are comfortable with circuit board repair. Too much heat can cause foil lifts and or damaging the semiconductor itself.

I have tried to find the thyristors shown (S600bls2) as I would go to or suspect those first, but the only ones I can find with that number, close, are surface mount technology (SMT). The through hole are either long discontinued or made for that circuit board vendor so not available to the general public. With a good look at the board, we might be able to find a generic replacement. If it was on my bench, I could do more for you. Sorry. If you are stuck, you can send it to me but it sounds like that board is available so probably not worth mailing. And I can't guarantee anything even if I get my hands on it.

I think the large blue discs might me MOV's (Metal Oxide Varistor) and those could be the issue. They can fail without exploding, often do. You can test them with an ohmmeter. They are a surge suppression device and with the collision, and resuting fault, a surge might have taken one out. If you can take a better look at the lettering, maybe post a pic. They could be capacitors, but, MOV's come in similar packages so people sometimes confuse them till the number is taken off of them. I can't tell from the camera angle. Diodes can all be tested in circuit but it is often a definitely gone or might be gone scenario. So, sometimes helpful. You should have about 650 ohms one direction, and open circuit the other. The problem when in circuit is that the other components might influence your results. If you feel comfortable, you can unsolder and lift one end then test it. But, if you get those two readings in circuit, most of the time, that diode will be OK.
 
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How to Test a Metal Oxide Varistor

A Metal Oxide Varistor (MOV) is an electronic device that protects an appliance's power supply from voltage spikes and surges in the AC power line. Normally, the MOV has very high electrical resistance. If lightning strikes a nearby power line, the high voltage causes the MOV to become a shunt...
ourpastimes.com ourpastimes.com
 
I took a better look. Check this component. I think it is a fuse
 

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Is it a multilayer board? By that I mean the board could have runs embedded in different layers of the board.
I see where the resistor was mounted the pad is blown off, it should have an eyelet and if it is a multilayer board there may be internal runs that would need to be connected to the eyelet.
Agree with above on the quality (or lack of) of the soldering, you could resolder the joints and see if that helps.
I just looked at Amazon and have the prices ever gone up. I think the cheapest one is over $300 now so it's worth trying to fix.
 
Here is the fuse if you need one, I think. Confirm lead spacing first and pop a pigtail in to confirm it is the fuse before ordering one

37321000410 Littelfuse Inc. | Circuit Protection | DigiKey

Order today, ships today. 37321000410 – 10 A 250 V AC DC Fuse Board Mount (Cartridge Style Excluded) Through Hole Radial, Can, Vertical from Littelfuse Inc.. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
www.digikey.ca www.digikey.ca
 
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