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chrismac
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1. you are correct it must be a metal plunger as there is continuity through the chain!! I just went and checked dash it... I will modify that for testing.
2. I will
3. I was going to but talked myself out it.
4. I did consider the lamp test I will also report back,
I'll try and get these checks done tomorrow, I am away for the wkend then.
2. I will
3. I was going to but talked myself out it.
4. I did consider the lamp test I will also report back,
I'll try and get these checks done tomorrow, I am away for the wkend then.
chrismac
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well spotted, unfortunately its just my poor photography angle and a leg from the heat sink.
Untitled by chrismac2012, on Flickr
prepman
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Think it's just punctuation....that's blurring me. Got PDF now ...eyesight issues need to zoom in.
Off in caravan to Devon will mull it over whilst away. Diesel welder/generator and problem is only in weld mode?
chrismac
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Yes correct thanks
chrismac
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Okay then, let me try and get this into words,
first set of tests,
Battery connected, solenoid pulls and releases when connections made,
lying on ground weld and auto mode selected, nothing happens
lying on ground weld and auto off selected, solenoid pulls
lamp test showed the same,
Then I had a thought, set in weld mode auto idle and struck an arc, revs pick up (read on though as more test carried out)
weld in auto mode, solenoid pulls but drops off after approx 5 sec
weld with auto off, solenoid pulls on for 5 secs and off for approx 18 secs, repeats this cycle.
Solenoid fitted with insulation, only insulated until wires connected, with + or - connected there is a reading.
With the solenoid having the pull and hold facility I guess there is a lower current when its being held down than when it is actually pulling down, is this what has changed with the body of the solenoid not grounding, the machine is unusable in this state due to the solenoid not holding down as it should when auto idle is off.
I think I have found some interesting features out tonight, I dont understand why yet, (maybe never will)
Appreciate the time you guys are taking to mull over this.
That sounds like it working as expected? To be really clear though - does it hold for the entire time the battery remains connected?
These are expected. Auto mode does not need to pull in for more revs if not welding.
Weld + auto-off has the solenoid across the battery via those 2 switches.
Before I dive into the rest, can you clarify where the solenoid was and its insulation status for the following comments:
chrismac
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Yes it holds for as long as I dare hold it, not wanting to roast it, I believe there is a lower hold current?
Sorry, I should have been clearer, solenoid refitted, insulated as much as possible as there is some continuity once the wires are connected giving a reading.
The second tests were striking an arc to engage the circuit, or try to, apart from when in auto off mode no arc was needed for the welder to cycle the way it was.
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It's my understanding that the solenoid has an internal switch that disconnects the powerful coil once it's been pulled in and just leaves the hold coil energised.
That, I think, is to be expected as you're now measuring the path back down the negative wire through the auto switch to ground (and various other paths too). The important point here is that with the insulation in place, we get to choose when that negative solenoid terminal get connected to ground and that'll be either
* Through the auto switch when in the auto-off position
* Through the SCR in the idle control board when the auto-idle position
The weird behaviour starts when you compare these 2:
So the only thing that changed here was it was refitted back on the engine but it was still fully insulated. So electrically the 2 situations are the same. Which makes me think there's extra mechanical force needed when it's on the engine and the circuit is not supplying enough current to hold open the valve now we removed its direct path back to chassis ground via the fixings.
The fact that it repeats every 20seconds or so is odd though and will need some more testing to fully diagnose...
At a guess though, something in the chain of solenoid negative to auto switch to chassis ground is broken or poor connection. The repeating cycle might be heating/cooling, or it might be the SCR helping out every 20seconds.
To try and diagnose one thing at a time, I'd take the idle board out of the picture by removing the wires from C. That way the only thing that provides that path to ground is via the auto switch.
I can't tell from the photo, but I assume the blue wire on C comes from the solenoid negative and the dark wire goes to the auto switch? If so they need to remain joined together when you pull them off C.
Photos of the wiring from C to the switch and from the switch to ground would be useful to make sure I'm not leading you astray in my assumptions.
I'd do a visual inspection of that path from C to switch to ground, make sure there are no crusty connections, and even test the switch in isolation.
Once happy retest. If it still won't hold (or even pull) you can try a chunky jumper wire across the various segments of that ground path to see which segment needs jumping to make it hold. (not using that thin black wire from the photos that's going to burn up or introduce more problems).
So the only thing that changed here was it was refitted back on the engine but it was still fully insulated. So electrically the 2 situations are the same. Which makes me think there's extra mechanical force needed when it's on the engine and the circuit is not supplying enough current to hold open the valve now we removed its direct path back to chassis ground via the fixings.
The fact that it repeats every 20seconds or so is odd though and will need some more testing to fully diagnose...
At a guess though, something in the chain of solenoid negative to auto switch to chassis ground is broken or poor connection. The repeating cycle might be heating/cooling, or it might be the SCR helping out every 20seconds.
To try and diagnose one thing at a time, I'd take the idle board out of the picture by removing the wires from C. That way the only thing that provides that path to ground is via the auto switch.
I can't tell from the photo, but I assume the blue wire on C comes from the solenoid negative and the dark wire goes to the auto switch? If so they need to remain joined together when you pull them off C.
Photos of the wiring from C to the switch and from the switch to ground would be useful to make sure I'm not leading you astray in my assumptions.
I'd do a visual inspection of that path from C to switch to ground, make sure there are no crusty connections, and even test the switch in isolation.
Once happy retest. If it still won't hold (or even pull) you can try a chunky jumper wire across the various segments of that ground path to see which segment needs jumping to make it hold. (not using that thin black wire from the photos that's going to burn up or introduce more problems).
chrismac
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Yes correct the blue wire on C and the black are numbered 41, I have checked their connections, all function as expected, switch also works fine.
I can get photos when I get back home on Tuesday.
its interesting how it cycles when nothing is being done to activate the cycles, no arc needs struck for this to happen.
Yes that thin wire was just a bit I had lying about with a clips on either end.
chrismac
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Not quite sure what your wanting me to ground out here. J and ground from S4 are good,
chrismac
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I refitted the solenoid as it was previously when it was working, no change, same as when isolated, revs on a cycle, regardless of auto idle switch position, this is a backwards step as it used to go into high revs when weld mode was selected, auto idle switch on permanent continuity to ground regardless of position, with coil wired in, obviously the could is grounding the circuit, removed neg wire and auto idle switch makes and breaks continuity, is it possible the coil has failed to give this scenario, I will re-isolate the coil over the weekend, this makes no sense,
I removed wire from C no change, I will recheck this with coil isolated,
The coil is getting warm, and does a strange delayed pull twice when the engine is stopped, see videos, one shows the engine cycling the other stopping/stopped, hopefully the videos work or take you to my flickr page.
Not getting 12v at the coil only getting 10v ish , lamp test now shows a dim lamp, battery is 12.5v
I'll update over the weekend when I get a chance to check some more.
Untitled by chrismac2012, on Flickr
Untitled by chrismac2012, on Flickr
I removed wire from C no change, I will recheck this with coil isolated,
The coil is getting warm, and does a strange delayed pull twice when the engine is stopped, see videos, one shows the engine cycling the other stopping/stopped, hopefully the videos work or take you to my flickr page.
Not getting 12v at the coil only getting 10v ish , lamp test now shows a dim lamp, battery is 12.5v
I'll update over the weekend when I get a chance to check some more.
Untitled by chrismac2012, on FlickrUntitled by chrismac2012, on Flickr
chrismac
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this should read; obviously the "coil" is grounding the circuit
chrismac
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Have not managed to get long at it this weekend but I have noticed now after the lack of 12v to the idle board, it is intermittent, it is intermittent due to the CB1 being overloaded and cutting in and out, I have replaced this as the original was not working, I also have a second which also gave the same symptoms, both used to work fine previously, the only reason I changed to the second was it was tidier not like a fuse type, this will be the reason for the solenoid is now pulling and releasing, not sure why the circuit breaker is overloading though or what could be giving this issue.
chrismac
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Cycling issue sorted out, the solenoid was sticky when getting pulled down, it was not getting its full travel meaning the 20amp pull was not letting go and the less than 5 amp hold part taking over, I have lubricated it with some PTFE spray, now the minor issue is the plunger comes flying up past its retractable travel so I have temporarily rigged up a travel stop for the plunger and its working now as it should in weld mode as the circuit breaker is not getting over loaded. It now holds on less than 1 amp.
Back to the idle circuit board now.
Back to the idle circuit board now.
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chrismac
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Okay, I isolated the solenoid flick the weld power switch, works as it should, leave switch in weld mode, auto idle switch to auto, the rev's drop to low idle speed, auto idle switch off rev's pick up,
Only issue now is when in auto idle when the arc is struck the machine senses this (as the CT1 test confirmed) revs pick up but the revs drop off after approx 5s, the scr's should be 8.5 amp I could only get 8amp, I tried ordering 25amp but they did not test out as they should or scrapped that idea.
Would I be right in thinking these are highly possible at fault, I have already replaced one of the replacements due to it failing the mutli meter test.
Only issue now is when in auto idle when the arc is struck the machine senses this (as the CT1 test confirmed) revs pick up but the revs drop off after approx 5s, the scr's should be 8.5 amp I could only get 8amp, I tried ordering 25amp but they did not test out as they should or scrapped that idea.
Would I be right in thinking these are highly possible at fault, I have already replaced one of the replacements due to it failing the mutli meter test.
Sorry, been off for a while... It's good progress that you've got everything working outside of that auto-idle board, so can now focus on that board as the remaining fault. The fact that the revs pick up in when an arc is struck, suggests that at least the main SCR that switches the solenoid is probably working. I see you've started a SCR test thread, so worth checking them all for sure.
Did you resolve the fact that you were only getting 10V to the coil - or did that go away after sorting out the travel issue so it isn't drawing 20A continuously?
Did you resolve the fact that you were only getting 10V to the coil - or did that go away after sorting out the travel issue so it isn't drawing 20A continuously?
chrismac
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Welcome back! yes we now have 12v at the coil.
Yes I started thinking it could be highly likely it was a SCR at fault, as you'll maybe have read, I am a little confused by the testing of the uprated ones. I found a post somewhere on the web where a guy changed them out to 25amp 400v.
