Can anyone who has experience with electronics identify what is the component labeled SG356? Someone who had it burn on their board is telling me it's a thermistor but I don't think that's right.
Electronic Component Identification
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Can anyone who has experience with electronics identify what is the component labeled SG356? Someone who had it burn on their board is telling me it's a thermistor but I don't think that's right.
hotpoint9534
Well-known member
Looks like a thermistor to me: http://www.rhopointcomponents.com/surge-gard-inrush-current-limiters-sg-series.html
Tom
Tom
magic_clean
Well-known member
Glenn
it looks like a varistor. Meant to absorb voltage spikes.
it looks like a varistor. Meant to absorb voltage spikes.
Glenn,
As Tom said above. Its a NTC Thermistor meant to limit inrush current. It appears to be made by API and is called a Surge-Gard Here is another web resource:
http://www.rtie.com/category-s/48.htm
Not sure why I can't find the 356 model though...
Just from the matte appearance of the finish I'd say its meant to run hot. Its not a Metal Oxide Varistor MOV
As Tom said above. Its a NTC Thermistor meant to limit inrush current. It appears to be made by API and is called a Surge-Gard Here is another web resource:
http://www.rtie.com/category-s/48.htm
Not sure why I can't find the 356 model though...
Just from the matte appearance of the finish I'd say its meant to run hot. Its not a Metal Oxide Varistor MOV
I agree wit the others posted here-the device is a thermistor.And they will run hot while doing their jobs.They should cool down when they change from higher resistence to lower.Some McIntosh tube power amps used these to control inrush charge current on the rectifiers.When the amp "dosn't work" the thermistor was the first thing to check.Was wired in the primary circuit to the amp power transformer.Remember when you could get these from Radio Shack!Another way to tell if the device is a thermistor-is it wired in series to the circuit being protected-MOV devices go from "hot" to ground.
That all makes sense, the component is located on the board next to the incoming AC connection point. It's a motor controller board for an F&P GWL08, which is NLA. I'm in contact with someone whose board (not mine!) burned the item of note. She has an electronics tech willing to attempt repair on the board if they can identify the component and find a replacement (and assuming nothing else on it is fried). I sent a pic of my board to her but stupidly didn't check the resistance reading (which may or may not help her situation), which would require another 72-miles round trip to do so ... my GWL08 is being used by my sister. F&P of course does not publish specs for their boards.
I could also investigate whether the (different from GWL08) board in the other two F&P washers in my possession have the same component ...
I will send Phil's info and link, maybe that'll be of some benefit to them.
Thanks, everyone!
<blockquote>I could also investigate whether the (different from GWL08) board in the other two F&P washers in my possession have the same component ...</blockquote> Yeah, no ... different board has different components. There's an NTC thermistor mounted in a similar position, presumably for the same function, but it's not an SG356.
I have an earlier board - a green casing board from a series 3 machine. Circuit is very similar to your mustard board.
My Thermistor is a SG319. My board is from a 240 volt machine of course.
Kb0nes link above is a match to the devices, a "surge gard". That's what the SG stands for.
The prognosis isn't good. I have never successfully repaired one of these boards with a power supply fault. I've replaced fuses and diodes, but there is always something else further down the chain that blows the fuse as soon as I add power.
For what it's worth, my SG319 shows about 8 ohms resistance. (in circuit.)
I have successfully repaired F&P boards with damaged PCB tracks (corrosion from water ingress) and with damaged microswitches on the display board, but these power supply faults have always been a dead board, or even a dead pair of boards. Not to say they aren't repairable, but beyond my ability to diagnose...
F&P seem to like using obscure electronic components that google hasn't heard of...
Good luck with it.
Chris.
My Thermistor is a SG319. My board is from a 240 volt machine of course.
Kb0nes link above is a match to the devices, a "surge gard". That's what the SG stands for.
The prognosis isn't good. I have never successfully repaired one of these boards with a power supply fault. I've replaced fuses and diodes, but there is always something else further down the chain that blows the fuse as soon as I add power.
For what it's worth, my SG319 shows about 8 ohms resistance. (in circuit.)
I have successfully repaired F&P boards with damaged PCB tracks (corrosion from water ingress) and with damaged microswitches on the display board, but these power supply faults have always been a dead board, or even a dead pair of boards. Not to say they aren't repairable, but beyond my ability to diagnose...
F&P seem to like using obscure electronic components that google hasn't heard of...
Good luck with it.
Chris.
Overall that thermistor is likely the least critical component on that board. One could almost just bus it out for testing. Its only there to limit inrush current when the board is first energized and those big reservoir capacitors charge up. As long as it is sized to drop to the required resistance during operation then any NTC part could go there.
Odds are a typical failure that these boards might have is one of the pass transistors failing. If they short they will just pop the fuse. A motor controller like this is pretty straight forward, well at least the high power parts, so they should be pretty repairable. If the proprietary logic IC's fail then the board is likely doomed. The left most 3/4ths of the board shown should be reasonably repairable should the fault lie in the high power bits of the circuit.
Fingers crossed for a rescue!
Odds are a typical failure that these boards might have is one of the pass transistors failing. If they short they will just pop the fuse. A motor controller like this is pretty straight forward, well at least the high power parts, so they should be pretty repairable. If the proprietary logic IC's fail then the board is likely doomed. The left most 3/4ths of the board shown should be reasonably repairable should the fault lie in the high power bits of the circuit.
Fingers crossed for a rescue!
Found this link on another thread on the super forum...
They don't list F&P boards by number but say in the text that fp boards are repairable so it is worth a call...
They don't list F&P boards by number but say in the text that fp boards are repairable so it is worth a call...
Gizmo, I directed the woman having the problem to contact FixYourBoard.com and CoreCentricSolutions.com ... they declined to repair her board.
Interestingly, her last communication to me advised that her electronics guy "repaired F&P boards for 15 years until he went into business for himself" (presumably doing electronics repairs other than F&P boards). So that brings up the point of why was she questioning me about the board if he has knowledge of them ... apparently he doesn't have experience with the GWL08 board. She was ecstatic to get the info I was able to provide, thinks they'll be successful.
A follow-up on this case: She advised that the board is successfully repaired but did not provide details as to what exactly was done.
