Fujitsu-General Fault

[airefresco]

Got called out today to General Inverter system (AOH36LNAWL). Basically it tripped the breaker, and since the breaker has been reset has shown a communications fault. I checked the outdoor boards and the red LED on the main board is not lit (or flashing). Checked out all the fuses and they are all fine. There´s 230V on to the filter board and 230v across the two wires on the yellow plug on the main PCB. I assume this the power to the main PCB. One thing I did notice is that there are two wires which go onto the main PCB (W601 and W600, see picture below, grey and black wires.) both of these have 230v to nuetral, is that correct? Should one be a nuetral?

I don´t have any documentation or anything on these units, but i´m thinking that the filter board is dead. I don´t really want to replace it until im sure it´s definitely that. It going to be such a nightmare new one.

Any help would be greatly appreiciated.



paul..

[SUBCONTRACTOR]

three month i was changing pcb after pcb on the same unit like yours and finally it worked when i changed all of them except indoor pcb.
On your picture i noticed the same gray wires :the correct voltage is each wire to N is supposed to give 240V( in my case only one was live)
As for the main pcb - yes the red led is supposed to be off

You have to take a DC voltage at the red and black wires entering ACPower module.
If you have only a few volts 7-8 then the inverter is gone....
Take readings after the active power module incase it is working....

[airefresco]

Right, thanks for that. We only have a 230v mains supply here. So it´s right then that both the grey and black should be 230v (240v in your case) to N?

I need to check the ACPM tomorrow.

Don´t suppose you happen to have a service manual, or wiring diagram or anything?

cheers
paul..

[paul_h]

I don't have a manual for that unit. But check the posistor, two small orange wires from the main PCB. If that's open circuit when the unit is powered up, then it's in protection mode and odds are there's nothing wrong with that PCB.
If there's a short on the compressor, afm, fan motor etc, it goes open circuit to protect the system.
If that's the case, cut power, start disconnecting things one at a time until the posistor closes circuit and the the o/u powers up. (by listening to the TX valve, or when tx valve disconnected, by measuring the comms line voltage)
Try condenser fan, then TX valve, then compressor, then IPM, then AFM etc. Plugging back in whatever you tested previously of course. When disconnecting afm, you are checking whether the input plugs you disconnect have 240v DC. When disconnecting the IPM, you are checking whether the AFM output plugs you disconnected have 330vDC

If it's still dead, one of those things is going to be faulty anyway (which is why the c/b tripped) and the filter pcb is dead.

[nike123]

Got called out today to General Inverter system (AOH36LNAWL). Basically it tripped the breaker, and since the breaker has been reset has shown a communications fault.

paul..

What communication error you got?
What is voltage between W19 and W20, also between W23 and W24 at outdoor unit POWER SUPPLY PCB ASSEMBLY
K05CW-0501HUE-FL0?
W9 and W21 should have simmilar voltage against W2!

[airefresco]

error code 0:01E

I was reading through other threads last night, and someone mentioned something about a condenser fan motor that gave similar symptoms to what I have. While I was there yesterday I did actually notice that the fan wasn´t spinning in the wind. Anyone who´s ever been here will know it´s quite a windy place. The units (all different makes) to each side of it, their fans were spinning with the wind, not fast just a little bit, and the one I was working on was dead still. So I think I´ll look at the fan first.

thanks for the help so far.

[airefresco]

Progress report: Just been back to site. Checked the fan first. With the fan connected and power on (nothing runs because the unit is in fault) the condenser fan won´t turn freely by hand. With the fan disconnected from the PCB, then it will spin freely. Took ohms reading from all the wires,

Black-Brown 62K
Black-Yellow 50K
Black-White 58K
Black-Red 130K
Red-White 190K
Red-Yellow 116K
Red-Brown 130K

The orange wires (posistor) Have 230v AC (one´s live the other is neutral) between them, is that correct? Should this not act as a switch? I have nothing going to the smaller board behind the main board (I assume this is the IPM) It has 4 wires a brown and orange (that come from the filter board) nothing on them in DC or AC and the Black and Red ones also have nothing, but I assume that´s because there´s nothing on the Orange/brown? By the way, it ******* to get to.

I´m still leaning towards a faulty Filter board. There are 3 chokes on there one of them is a shiny copper colour, the other two are a dark brown colour, like they have been hot or something. Is that normal?

[paul_h]

No, the posistor should be a circuit. If it's closed, there should be no voltage difference across it, there's no active and neutral across it, it's like either side of a circuit breaker, both sides should be live to another neutral. If you put you multimeter across it, you should get 0v as there's 230v on both sides. It's part of the ac circuit and if that has power, the filter PCB should be good.
So the posistor is activating as a protection device.

The fan you need to test by diode testing, red wire to black wire should be around 0.9v when reversed (mulitmeter (MM) red to motor black, MM black to motor red) and open circuit the other way, MM red to motor red etc,
Also motor black to motor white should be about 0.7 volts one way, 1.5v the other way

[nike123]

The orange wires (posistor) Have 230v AC (one´s live the other is neutral) between them, is that correct? Should this not act as a switch? I have nothing going to the smaller board behind the main board (I assume this is the IPM) It has 4 wires a brown and orange (that come from the filter board) nothing on them in DC or AC and the Black and Red ones also have nothing, but I assume that´s because there´s nothing on the Orange/brown? By the way, it ******* to get to.

I´m still leaning towards a faulty Filter board. There are 3 chokes on there one of them is a shiny copper colour, the other two are a dark brown colour, like they have been hot or something. Is that normal?

I sent to your mail service manual for that unit.
You did not answered to my questions regarding voltages at power supply board.
Electronics troubleshooting require methodical approach. First establish that voltage is present and that is as required at these points I asked, then go further.

Fan motor is DC type and by your description it could be his PWM driver faulty, so disconnect the fan motor jack during initial testing.

[SUBCONTRACTOR]

Nike ,can i get a manual as well. Thanx

[nike123]

Nike ,can i get a manual as well. Thanx

Manual is sent to your mail!

Fujitsu has two type of manuals, one is service manual without service instructions (only schematics and part lists) and other is service instructions. This second is pretty big (90 MB) so If you need something I will sent to you only part of your interest.

[SUBCONTRACTOR]

Manual is sent to your mail!

Fujitsu has two type of manuals, one is service manual without service instructions (only schematics and part lists) and other is service instructions. This second is pretty big (90 MB) so If you need something I will sent to you only part of your interest.

I am keen to learn ore and more electronic stuff ...how to troubleshoot it....i got a basic understanding of the components but i am a quick learner and hope to advance...

[nike123]

I am keen to learn ore and more electronic stuff ...how to troubleshoot it....i got a basic understanding of the components but i am a quick learner and hope to advance...

Ok, for that purpose I will upload service instruction to server and then sent to your mail link and password for download. Please, don't distribute this instruction because that would be violation of my agreement with Fujitsu.

[paul_h]

Hey what's the difference between a lnawl and a lmawl. I've only got the latter, which did not have the w600 and w601 connections the OP posted, which is why I couldn't offer any specific advice.

[airefresco]

Nike123 -I didn´t get your email. I´ve sent you a PM

Paul - I think I get what your saying. So the reason I got 230v across the posistor is because it´s activated, so there´s something else holding it off? One of the things you mentioned earlier, like the compressor or fan motor, to name a few?

The only bit I don´t quite understand is bit about the testing the fan motor. I assume I have to test the motor while it is connected? Does it matter that the unit is in fault (fan not working) when I test it? Should I still get voltage then?

[paul_h]

Nike123 -I didn´t get your email. I´ve sent you a PM

Paul - I think I get what your saying. So the reason I got 230v across the posistor is because it´s activated, so there´s something else holding it off? One of the things you mentioned earlier, like the compressor or fan motor, to name a few?

The only bit I don´t quite understand is bit about the testing the fan motor. I assume I have to test the motor while it is connected? Does it matter that the unit is in fault (fan not working) when I test it? Should I still get voltage then?

There should be 0 volts across the posistor, both sides shoudl be 230v, so the multimeter should read 0v as there's no difference between each side.
You got 230v across it because it's open circuit, it's cutting power to the control circuit, that's what is giving the comms error.
You have something that's failed enough to trip the c/b, that's a worry. The fan motor seems faulty, that's a given, but it should have blown a fuse on the inverter PCB (normally marked 'F2'). If that's not blown, I'm going to guess the PCB that the fan plugs into, or the inverter PCB had taken the damage, so that's faulty. Knowing that the fan is faulty, I'd start there, seeing if the unit works without the fan plugged in, (it should for a few minutes). Making sure a fuse isn't blown at the fan side PCB (F2), and then disconnecting the AFM outputs, If there's 330V DC at the AFM outputs, the main PCB (where the condenser fan plugs into) is gone. Give the compressor a quick megger test just to be sure as well.
edit:
All fan motor voltages are with the mains turned off and the fn motor unplugged, the voltages are attained using the diode testing of your multimeter.

[nike123]

Hey what's the difference between a lnawl and a lmawl. I've only got the latter, which did not have the w600 and w601 connections the OP posted, which is why I couldn't offer any specific advice.

I think that difference is in used compressor manufacturer or type!
I don't have in hand new model name identification scheme but designation on that place is usually used for compressor manufacturer (M-Matsu s h i ta, N-I don't remember)!

[airefresco]

ahhh, with you now on the fan motor stuff. I understand exactly what you saying now. Got a bit confused before.

Going back to the posisitor, I didn´t have what you said I should have. I had 230v between 1 wire and the main neutral terminal, and 0v between the other and neutral, then 230v between the two wires to the posistor.

[paul_h]

ahhh, with you now on the fan motor stuff. I understand exactly what you saying now. Got a bit confused before.

Going back to the posisitor, I didn´t have what you said I should have. I had 230v between 1 wire and the main neutral terminal, and 0v between the other and neutral, then 230v between the two wires to the posistor.

Yep, sound like a short on one component or PCB and the posistor is doing it's job.
You need to find the fault. BTW I've edited my last post trying to explain it more. It's 3.30am here and I'm thinking slowly

[nike123]

Nike123 -I didn´t get your email. I´ve sent you a PM

Now it is sent!

[airefresco]

What communication error you got?
What is voltage between W19 and W20, also between W23 and W24 at outdoor unit POWER SUPPLY PCB ASSEMBLY
K05CW-0501HUE-FL0?
W9 and W21 should have simmilar voltage against W2!

Now I have the drawing (thanks) I can tell you the voltages.

W19 - W20 = 230v
W23 - W24 = I couldn´t find these on the drawing
W9 and W21 both have 230V to neutral (W2)

Thanks for the help, it is appreciated

[nike123]

Now I have the drawing (thanks) I can tell you the voltages.

W19 - W20 = 230v
W23 - W24 = I couldn´t find these on the drawing
W9 and W21 both have 230V to neutral (W2)

Thanks for the help, it is appreciated

Ok. You then could measure voltage between W28 and W29 (it is the same if L102 is OK).

[airefresco]

There is no voltage between W28 and W29.

[nike123]

There is no voltage between W28 and W29.

Do you have 12V DC at CN100?

[airefresco]

I haven´t checked that yet, i´ll get back to you.

thanks

[nike123]

I haven´t checked that yet, i´ll get back to you.

thanks

Ok, check this also!







Maybe resistance of windings will not be same as here but you got general idea if fan windigsa are OK or not.

[paul_h]

Where did you get that stuff? I've only seen basic service manuals with operation, diagrams and part numbers. All the troubleshooting was learnt in the field and nothing was documented here.
Also down here we were taught to disregard any measurements of resistance, as they can't be relied on, only diode testing, or live voltage testing was told to us. Even comms signal was only done with a testing diode on you multimeter probe, looking for DC voltage from indoor or outdoor, not combined AC signal.

[nike123]

Fujitsu has two type of manuals, one is service manual without service instructions (only schematics and part lists) and other is service instructions. This second is pretty big (90 MB) so If you need something I will sent to you only part of your interest.

This is from official service instructions. I have access at Fujitsu intranet.

[nike123]

Also down here we were taught to disregard any measurements of resistance, as they can't be relied on, only diode testing, or live voltage testing was told to us. Even comms signal was only done with a testing diode on you multimeter probe, looking for DC voltage from indoor or outdoor, not combined AC signal.

As I have some knowledge in troubleshooting electronics, I could say that any type of measurement is good if you know what are you measuring and how defective part should behave during that measuring.

Disregarding resistance measurements or combined AC signal measurement is not wise in field service.
With that measurements you simply establish that part is defective or out of boundaries and then replace that part, but when you work in lab or service shop you then could measure all values.

Also these manuals are written for field service and they only instruct you to find what part is wrong and not what is wrong with that part.

Older manuals have been much more descriptive and communication testing as been accompanied with oscilloscope pictures of signals.

P.S.
When you measuring resistance of active parts (diodes, transistors, thyristors etc..) their resistance is depending on applied instrument voltage and internal resistance of instrument, therefore it is better to measure voltages drop at these parts. As you see at active filter module troubleshooting instruction, resistance measurement is different with different instrument used and their test voltages. Therefore is approach you learned good for that type of measurements, but there is lot of parts who could give repeatability at any instrument used.

[paul_h]

Yeah we went with ignoring resistances because it could still pass that, but be faulty due to multi meter used etc. ie, measuring condenser fan motors for resistance, which seem good, but they blow PCBs and fail diode tests. Just like thermistors (fuji air or samsung refrig) can pass resistance tests, but read the wrong voltage and be faulty.
So I was taught voltage or diode tests only, and I don't see any manuals similar to the one your referencing.
Wasn't my choice, just how I learnt field repairs. fuji au thought it was more reliable that way I guess so never used those diagnostic manuals, just told us how to test in other ways.

edit: Anyway, my way is definitely faster, c'mon airefresco, I would have diagnosed this air con 15min after arriving on site!

[airefresco]

Well if it turns to be the filter board in the end than I did :P

I´m going back on Monday, armed with the info Nike sent me. I reckon we´ll have an answer by then.

I really wish I got to do this kind of stuff more often.

[airefresco]

Ok been back. I got mucho info.

Serial Signal Test (First diagram posted by Nike)
Between terminal 1-3 170-200V. I think this is too high as the diagram says 70-130V.

AFM Test: (As the second diagram posted by Nike)
+ - 360KΩ (correct)
- N1 0.3Ω
P + 330KΩ
L1 L2 361KΩ
P N1 0.3Ω
L1L2 Control ∞
L2 N2 ??? (I could not find the N2 terminal)
L2 P 0.3Ω
p L2 0.3Ω

All these bar the first and test to the control box are nowhere near what they should be
As a side note, I tested the leads on the multi-meter and they read 0.3Ω.

Finally the fan motor. The motor is not the same as the one posted by Nike. I posted the winding readings earlier in this thread.
This is what I have.


So after all this I think the AFM is screewed. Do we all agree?

[nike123]

So after all this I think the AFM is screewed. Do we all agree?

Agree! ....

[multisync]

This is from official service instructions. I have access at Fujitsu intranet.

The FS-cs.co.jp one?

Multisync
London

[nike123]

The FS-cs.co.jp one?

Multisync
London

This one:
http://www.fg-cs.co.jp/int/

[multisync]

This one:
http://www.fg-cs.co.jp/int/

I too have access but I can't find a 90 meg file anywhere

Multisync
London

[nike123]

I too have access but I can't find a 90 meg file anywhere

Multisync
London

It is not 90, it is 68 actually. Does that have any difference?

[multisync]

It is not 90, it is 68 actually. Does that have any difference?

No it was where to look. I went back and read your first email about service v service instructions

It was hiding behind 'new window'

Multisync
London

[airefresco]

Those manuals are really handy in one respect, where as you can see from my troubles in this thread. The manual (or Nike in this instance) showed what to check how to find it and what value to expect, which is great. But then there´s other side where if you don´t have these manuals you need to be able to diagnose faults. Paul proved this as he was using his experience to diagnose the problems I was having. Even with me using this manual, Paul pretty much diagnosed the problem before I did, and he had never seen the unit. I guess the key word there is experience, and like I said earlier I never get to do this kind of stuff anymore, so I don´t get a lot of practise at it, so in that respect, the manual was great for me, next time I have a fault with a Fujitsu or General unit I probably will look at the info Nike posted again to refresh what I did this time. But I would much prefer to be able to just know this sort of stuff.

So anyway. I was asking in the wholesalers today about the AFM and the other boards and the good news is that are available here. The bad news is that I was told they are really expensive and there may not be a huge difference between the new boards and a new outdoor unit. It depends on which boards I order. Which brings me on to my next point. I really don´t want to go through all the hassle of getting a new AFM to find that it blows again. I´m in two minds as to what to change. Paul mentioned earlier that fan looks screewed so I´m thinking about just changing the fan motor and the AFM. Do you think this will suffice?

[paul_h]

I haven't worked on any for about 9 months. They are under a 5yr warranty here, and as they only started selling inverters about 7 years ago, most are still under warranty.
Inverters didn't get popular till 4 or 5 years ago, so I don't come across many inverters out of warranty, anyway, they're normally cheaper to replace when they're over 5 years old as parts are hard to get and pricey.
edit: Under 5 years old, they are all repaired by warranty service agents. I used to work for one, which is where I learnt how to repair them, but I'm out on my own now, repairing older conventional splits and not seeing many inverters.

[airefresco]

Heard something today which may add a twist to this. Apparently the guy who installed the system is to keen on vac pumps. Been to another job of his today. Two Samsung units a little over 2 years. Both units with dead compresors. After a few phone calls, it turns out he wasn´t keen on lugging the vac pump around. I might just go for a new outdoor unit now knowing this, or least give the client the option to do so. Great eh.

[ozairman]

Hey what's the difference between a lnawl and a lmawl. I've only got the latter, which did not have the w600 and w601 connections the OP posted, which is why I couldn't offer any specific advice.

Paul have a look at the AOTR30LCT manual

LMAWL has AO(H,T,Y) LJAYL/LJBYL style inverter chassis, ie IPM section on main inverter controller pcb but as a smaller machine diode bridge on actual inverter controller pcb. Thats what the cut out is in the back left hand corner of the pcb.

LNAWL is a cassette type outdoor unit but based on AO(H,T,Y)R30LCT inverter chassis, the triangular one with: power filter pcb, TR pcb containing IPM and Diode Bridge, ACTPM and then controller pcb.

[ozairman]

Paul is on the right track, before you go throwing parts at it left right and centre diagnose what is actually preventing the machine from powering up. It may only be one part of the inverter or it could be more.

1st question if you suspect a dodgy install have you actually tested the compressor for shorts to earth with a megger?

1st suggestion
Go to an electronics shop and buy yourself a 1000V 1A rectifier diode, then do some googling on how to test electronic components such as transistors using the "diode check" function of your multimeter. Learn how to test the diode and see what readings you get when you test it in one direction and then the other. Over time this skill will become your new best friend when it comes to diagnosing shorted components which are stopping the machine from powering up.

Also if you are unable to read the detailed electronic circuit diagrams in the manuals (pcb diagrams) then do some more googling on how to do it. The printed circuit board diagrams are like roadmaps for fault finding these machines.

There are other uses for the 1000V 1A rectifier diode as well, but too much information too soon causes too much confusion

Sorry if some of this sounds a bit arrogant or cryptic but I work on these things day in and day out and a basic understanding of electronic components being able to read a detailed board diagram is big help. The service instructions are good but sometimes lack things as well. The ACTPM module is the only inverter component that resistance type measurements actually provide reliable results for (actually the last part of that test L2-P gives a more conclusive reading as it is actually testing the internal diode). Static tests of IPM, diode bridges and DC fan motors are much more conclusive than resistances measurements on these components.

paul_h your previous employer had many of these manuals on their PC's they maybe just did not want to print out all the 100 or so pages for you! also serial signal testing with a diode in series with your multimeter lead is pretty easy to remember and works on any Fujitsu type unit with communication between indoor and outdoor.

[airefresco]

No, it´s OK. I understand exactly what you mean and I actually agree with you. I have a basic understanding how most electrical components work and I can read circuit diagrams.

I only found out about the vac pump issue and i´ve not been to site since, so no I´ve tested the compressor. Everything that I have done I have wrote in this thread.

The thing with this particular job is I really don´t want to frig it up, so I´m just being really cautious. You probably don´t know, but Lanzarote is only a small island and we have to import everything, which can take an eternity and cost the Earth. The only thing I can get parts for at a reasonable timescale is Daikin, as they have a main dealer over here. So if order the boards for this and it turns out to be wrong, then I have go through the whole process again and before I know it, a year has passed and I have one pissed off client.

We don´t have anywhere here to buy electrical components, but I´m actually doing a search at the minute for a relay that I need, so I´ll order a diode at the same time. Like I said though, this is going to take a while to sort. I don´t want the client to go to someone else and they just fit a new outdoor unit, which is what will happen. What would you do in my situation?

[nike123]

I don´t want the client to go to someone else and they just fit a new outdoor unit, which is what will happen. What would you do in my situation?

Fit the new unit before someone else do, because, if you are going to learn "basics" on that unit, customer will probably feel what is going on, and find another more overweening guy for that job.

Of course, if he have choice!

[paul_h]

The thing with this particular job is I really don´t want to frig it up, so I´m just being really cautious. You probably don´t know, but Lanzarote is only a small island and we have to import everything, which can take an eternity and cost the Earth. The only thing I can get parts for at a reasonable timescale is Daikin, as they have a main dealer over here. So if order the boards for this and it turns out to be wrong, then I have go through the whole process again and before I know it, a year has passed and I have one pissed off client.

We don´t have anywhere here to buy electrical components, but I´m actually doing a search at the minute for a relay that I need, so I´ll order a diode at the same time. Like I said though, this is going to take a while to sort. I don´t want the client to go to someone else and they just fit a new outdoor unit, which is what will happen. What would you do in my situation?

In that case, replace the unit, edit: especially if it was your 'friend' that installed it.
I tried to help diagnose, but if you have to wait so long for fuji parts, it's probably not worth it. Even now after this stage of diagnostics, the main inverter PCB and comrpessor have not been verified. I don't know how many visits you've taken already, but I think the customer will think you've been mucking about if you go there for more checking. My concern is the fan motor, you've said that is 'locked up' when the unit is powered up. That could be a faulty motor, or it could be a dead main (inverter) PCB along with the AFM.
edit:
I hope the info given here by nike123 will help you to immediately diagnose another fujitsu the first time you come across it, and can confidently quote the customer after the first service call. But with this unit if you think it will take so long for parts, it's not worth the risk of further diagnostics on a return visit, possibly making the customer think you are wasting their time.

[airefresco]

Well thanks to everybody who has helped me with this. I´ve been quite lucky on this in the respect that i´ve been there a few times to do other things, so i´ve been able to carry out checks while i´ve already been there. I have learned a lot about inverters, and I think i´ve got my head around it now. At least I now know what all the parts do and why. Obviously, there´s still a lot to learn, but next time, like Paul said, I should have a much better indication as to what is going on the first visit.

Once again, thanks to everybody who help me. It is appreciated.

[bangoman]

hi mate send me the fujistu manual ,minbango@gmail.com the one with t/shootin procedures.Thanxs heaps.

[nike123]

hi mate send me the fujistu manual ,minbango@gmail.com the one with t/shootin procedures.Thanxs heaps.

As far as I know, I already gave you procedure for your case in my reply to your thread here.

[airefresco]

There´s a great ending to this little tale.

When I went to see the client to give them options of either replacing the AFM, (explaining that there is a good chance the new board may blow straight away) or replacing the whole OD unit there was a guy repairing one of the fridges. Anyway, he overheard the conversation and told the client (after I left) that there was no need to replace the OD unit, and he could replace the AFM cheaper than me (he was 10€ cheaper than me). So the client gave him the order and he fitted the board on Monday. System came back on line and worked fine. Until this morning when the breaker tripped, and when reset, the controller now displays the same fault as before.

I found all this out from a friend of mine who works in the place. So i´m really glad I didn´t just change the AFM now, although that was the fault, there is obviously something else taking it out.

I don´t really want to get involved in this anymore ( I lost out on the original install by 50€) and now this, it´s just not worth the hassle.