Fujitsu AOU30CLX

[Tomwhite]

People seem to be willing to share valuable knowledge on this site. Grateful for any I might receive. AC had not been used about a month and breaker tripped at some point.Reset breaker, pressed remote, red operation light flashed briefly and rapidly, then only green timer light flashed two times,pause,two times pause,....Wall unit(ASU30CLX) fan started blowing but did not get cool.Observed outside unit fan not working Removed cover from outside unit AOU30CLX and saw dried up gekko across main terminals. Removed gekko, checked incoming voltage, good,235V. From another discussion on this site about Fujitsu's I started some voltage checks and right off discovered no voltage going out of power supply at terminals W28 and W29. Have I found the problem? A bad power supply PCB? Thanks in advance for any and all comments

[frank]

Have a look here to see the fault code sequence fits your unit. http://errorcodeairconditioning.blog...ror-codes.html

[Tomwhite]

Yes, thank you, the flashing sequence,green timer only, two flash, pause two flash, pause...... appears to be Reverse comms fail at startup or another table called it Serial reverse transfer error at startup and directed me to check voltage at outdoor unit terminals which I did(235VAC) and then suggested perform serial signal diagnosis which was checking voltage between terminals N and 3 on outdoor terminals. With multimeter set for DCV I got a fluctuating reading of 20 to 50 ?

[Tomwhite]

Disconnected brown and orange wires at TM102 and Tm101. 235vac at least up to there.Reconnected brown and orange. Disconnected red and black wires at ACTPM + and - and only got 5vdc. Now I'm thinking the problem is in the IPM PWB

[install monkey]

http://johnstonesupply9.com/TechDocs...SU30-36CLX.pdf
link to service manual

[Tomwhite]

Yes, thank you, circuit diagrams are very helpful. Now if someone could tell me how to trace the voltage through the system.What voltage should I find across the red and black leads from IBM PWB when disconnected from ACTPM + and - ? I measured 5vdc. What voltage should I get when reading terminals N-3 on outdoor unit per Serial signal diagnosis? Reverse comms fail at startup or Serial reverse transfer error at startup I guess is a very broad question, but if there is a troubleshooting procedure of following the voltage through a Fujitsu inverter that someone has used it would be greatly appreciated.

[install monkey]

Andy's Inverter Testing Guide.pdfAndy's Inverter Testing Guide.pdf
tayters inverter check guide

[Tayters]

Yes, thank you, circuit diagrams are very helpful. Now if someone could tell me how to trace the voltage through the system.What voltage should I find across the red and black leads from IBM PWB when disconnected from ACTPM + and - ? I measured 5vdc. What voltage should I get when reading terminals N-3 on outdoor unit per Serial signal diagnosis? Reverse comms fail at startup or Serial reverse transfer error at startup I guess is a very broad question, but if there is a troubleshooting procedure of following the voltage through a Fujitsu inverter that someone has used it would be greatly appreciated.

Hi Tom,

If you look in the manual page 9 the brown and orange is 240AC, these go into the IPM to a bridge rectifier and come straight out on the red and black around 300VDC. From your testing it looks like the rectifier is goosed (probably shorting on the AC input side) and the posistor is then going open circuit to protect the system.

This DC goes to ACTPM, voltage on red goes out on a white wire, through the choke coil and back on the other white wire back into ACTPM. ACTPM monkeys about with this DC voltage and it comes out on P and N (white and violet) at around 340VDC. This then goes to the capacitor PCB and comes out at the same voltage on W7 and W8 (yellow and blue) back to IPM. Here it goes to the Inverter chip and also out on W306 and W307 (black and white) to the controller PCB. This is used as the supply for fan motors and is also whittled down to provide low voltage DC for probes, other IC's on PCB.

Testing is as I suspect the way you've started. Disconnect the cables from the start and plug them in bit by bit until you find the voltage disappear (posistor doing it's thing). Bit hard to check further on for you as you need the DC voltage there for further testing. Power down for a few mins before unplugging and high voltage DC as it can spark across when unplugging causing major grief.

Voltage between N-3 fluctuates up to around 100V. Use your meter on AC to check. If your reading is around the 50V then generally this means only one side of the system is giving out a comms signal. This logic doesn't quite work on newer systems as but is a fair guide.

Got a file somewhere for general checks of the ACTPM. Will dig I out and post it when I get a chance.

Cheers,
Andy.

[Tayters]

Andy's Inverter Testing Guide.pdfAndy's Inverter Testing Guide.pdf
tayters inverter check guide

Top man!
Gonna have to have a chat about your commission.

[install monkey]

last resort - i'll post your moby number!

[Tomwhite]

Many thanks. Gold info. Yesterday I dug into the unit and removed the IPM PWB which had a lizard stuck behind the diode rectifier? ( I'm just an old maintenance electrician, don't know electronics ) Serious burn damage obvious and rectifier tested open. Next stop is the Fujitsu parts dealer. They don't sell to homeowners usually but my son is in his second year at U of Hawaii community college in the Refrigeration, A.C. program and he has an in. I'll post the results. Thanks

[install monkey]

how was the lizard?
every post now where a unit isnt working, my first post will be - any animals on your circuit boards

[Tayters]

Tough life for a lizard out there. One minute you're crawling in a box keeping out the sun, next minute, BOOM! Gonna be an endangered species at this rate.

Got the ACTPM checking here. Not for your specific model but should be similar. I've measured brand new (working!) ones and they don't quite match these figures sometimes so just use these figures as a guide. Some go pop (bit like the Geko) and you can see some scorch marks on the grey paint stuff.

Happy checking!

[Tomwhite]

The lizard had become jerky. Fujitsu is going to have to add lizards to the list of gods they pray to for all the business they create. I replaced the IPM and things got marginally better. Now I get 215 VDC across the red and black leads from W16 and W17. If I ruined the new IPM my wife will speed dial the Fujitsu repairman. Closer inspection shows the ACTPM board also has some burning. Tomorrow I'll check with the tables I got from Andy and many thanks.

[Tomwhite]

AC is working. I had the white and violet wires crossed on the ACTPM. Like I've always suspected, it's better to be lucky than good. To my brothers in the UK, thank you and aloha.