Lincoln SP175T DOA????

[Pipeliner]

Crazy, now there's 2 posts within a week on here about SP175T's.

I haven't used it in a while - maybe a year. When I go to use it yesterday it would not turn on. I haven't left it plugged in, so don't suspect a lightning strike or anything like that, but I could've left it plugged in at some point and forgot.

Anyway, when I turn it on it does absolutely nothing. No fan, no wire feed, not so much as even a click. I have power in and out of the switch. I have power to the circuit breaker and it is not popped out. I'm stumped.....

[Pipeliner]

Code is 10985. The circuit breaker is on the back panel vs the earlier codes that had the circuit breaker reset under the wire feed / spool panel.

[ccawgc]

see if you have 230 volts at LS1 to H2 on the pcb. this is the supply voltage to the fan motor. with out the fan powered you do not have 24 volts to run the pcb and the gun trigger. Remember that when measuring a 230 volts, do not measure to ground.
only HOT wire to HOT wire. Your problem is most likely the line switch and one side is not making connection. A bad switch can measure good if you measure to ground for 120 volts. one side closed and the other open you will read the closed side voltage on both sides, because it sneaks around through the fan motor.
use the diagram pasted inside the welder or the one in the owners manual.
H2 on the pcb is a common HOT connection. the other HOT connection is N.O.
either on the relay or beside it. Look at the diagram and follow the wires from the plug through the line switch and circuit breaker to the pcb. From the pcb to the fan motor and you will find your problem. have to get 230 volts to the fan motor or nothing happens. Fan motor has 4 wires to it. 230 in and 24 vac out.
wires 213 and 214 at J1 plug. there are thermostats in the 211 to 213 line.

[Pipeliner]

see if you have 230 volts at LS1 to H2 on the pcb.

I do have 230v at LS1 to H2 on the PCB. And I have 230v in and out of the switch. That is as far as I got for now.

[Pipeliner]

Diagram inside cover

[Pipeliner]

[Pipeliner]

I can positively say the line switch is good. And LS1 & H2 read 230v.

[Pipeliner]

If I measure #211 and #214 I should get 24vdc correct? If nothing there, then this would indicate the fan mounted 24v transformer has pooped the bed or am I missing something?

[Pipeliner]

And if it is a dead fan / transformer is there a superseded part number for # 9SM15787-2 because I’m not finding that anywhere?

[ccawgc]

That part number is listed as obsolete whit no cross. which leaves us with a problem.
we need to find a 230v fan motor that is the same size and also a small 208/230 transformer with a 24 volt secondary to make the welder work.
The 115 volt fan motor is still available. If you can figure out a way to power it.
you could use it. may be another 115 volt device in series with it. that will drop half the 230 volts. 9SM15787-1 about $67.

[ronsii]

How about rewinding the fan motor? what design are the windings on it??

[Pipeliner]

The 115 volt fan motor is still available. If you can figure out a way to power it.
you could use it. may be another 115 volt device in series with it. that will drop half the 230 volts. 9SM15787-1 about $67.

Does the 115v fan have the 24v transformer needed?

[Pipeliner]

How about rewinding the fan motor? what design are the windings on it??

I don’t know anything about that. It has a 24vdc transformer attached to it like this.

[leightrepairs]

If I understand correctly you have 230 V measured between LS1 and H2 and the fan does not run and you do not have 24 VAC between 211 and 214? If this is true I would start by checking the wiring from LS1 and H2 to the fan/transformer. If the wiring is good all the way to the fan/transformer, I would disconnect 211 and 214 from the transformer and use an external power supply 24 VAC to to 211 and 214 and see if every thing then functions. If everything then works I would find a fan and separate transformer to replace the existing fan/transformer. If this temporary set up does allow everything to operate do not use the welder in this configuration as you will not have any cooling to the unit. Not knowing how the fan and transformer are wired together and seeing that from what you have checked makes me think that there is a broken wire since both the fan and transformer appear to have failed at the same time.

[Pipeliner]

Not knowing how the fan and transformer are wired together and seeing that from what you have checked makes me think that there is a broken wire since both the fan and transformer appear to have failed at the same time.

I have considered doing everything like you've mentioned. There are no broken / loose wires to the fan. I have found an old thread or two on here saying this is a know problem and either the fan fails and takes out the xformer or vice versa.

[Pipeliner]

Well good news - it’s alive! Just not as intended, but it still welds. I found an old doorbell transformer that puts out 18vac or 28vac. So I hooked it up the 18vac side to #211 & #214 to power up the board and it worked. So now for a permanent fix since it won’t be going in the dumpster.

If I get the 115v Lincoln fan with the 24vac transformer, what kind of “device” as ccawg referred to above would be required in series to drop the 230vac to half? Will a light bulb work or is there a minimum amount of amp draw needed on the second device to reduce the voltage?

Still can’t believe Lincoln would give up on this critical part.

[ronsii]

When it comes to AC and stepping down voltages... my first thought is always transformers... as I don't know how just basically putting a resistor in series with a reactive load would do??? but... they do make 'travel transformers' for knocking 240 to 120... I know... it's another 'kludge' but depending on how much power the fan uses it would probably work easy


https://www.ebay.com/itm/TRAVEL-VOLT...Cclp%3A2334524

[ccawgc]

simple ohm test on both the 230v primary or the 24v secondary will tell you which failed. Lincoln is discontinuing most of the parts for the SP line of welders.
As they run out of parts. The 115 volt fan I listed the part number for is from the sp135 and with 115 on its primary the secondary will have 24 volts.
Another option that just came to mind is mount a 230 to 24 transformer where the fan lives and mount a 230 muffin fan on the out side of the case blowing in.

[Pipeliner]

What if I get the 115vac fan for the sp135 you mentioned and mount a 230vac to 115vac transformer in the wire spool compartment. I could run 230vac from the power switch to the transformer then 115vac to the new fan and hook the 24vac out of the new fan back up to #211 & #214 like it should be?

If the sp135 fan fits the same mounting as the original 230v fan this would be a cleaner looking work around for $20 more. What VA size would I need?

[Pipeliner]

Before I go to the workaround, Lincoln says the original 9SM15787-2 FAN MOTOR superseded to 9SM15787-4.

Welding Mart show to have it in stock. I placed an order and am holding my breath....

[Pipeliner]

Ok, that was quick - order cancelled. Figured - back on with plan A.

[rexcormack]

Just wire one side of the 115 fan motor to LS1 or H2 (doesn't matter) and the other side to case ground.

[Dan]

You might consider looking in to whether or not there is enough room to fit a fan for a Hobart Handler 190 inside the machine. It would give you the 230 volt input fan and 24 volt AC output too.

[Pipeliner]

Snatched the guilty party from the little beast. Holy cow some disassembly required!

[ronsii]

Just wire one side of the 115 fan motor to LS1 or H2 (doesn't matter) and the other side to case ground.

I can't believe I didn't think of that