Troubleshooting Daikin Inverter PCB Pt1

Attempting to find out whats wrong with this board without a schematic.

There is a good possibility that the control supply voltage is supposed to be 110 - 120V and something else is dragging the control voltage down on the inverter board.

They are 'throw away' items and I don't think Daikin publishes repair schematics for them.

Category:

Science & Technology

Tags:

• PCB
• Daikin
• Inverter
• Electronic
• repair
• circuit
• board
• inverter
• AC
• DC
• Current
• transformer
• rectifier
• solder
• multimeter
• DMM
• troubleshooting

[sjbrewy]

HI Aussie50, I have a Daikin exactly like this one and is doing the same thing, it wont work and those Led lights dont work. I got a fault from the remote control that is a u4- incorrect interunit wiring (interunit). outside not communicating with inside. Ive checked all wiring connections and plugs on power in/out and on the boards, but still not worky to make shore of good contact. Would it be that first PCB board stuffed, can it be fixed. is it worth fixn.Thanks

[Aussie50]

@sjbrewy I never bothered fixing the unit in the vid, jsut too hard.

I would suggest getting a Daikin tec to look at it. it could be a board in the outdoor unit or indoor.

[spuddly01]

Do an ohms test from chassis to the 5 & 12V negative. If they one and the same then so be it - at least it will be easier to fault find.

I suspect the designer was US based or failed to understand the PSU spec sheets when designing. The spec sheets usually show a 110V mains due to the US based semiconductor market.

I'd be very surprised to learn they are using a ceramic resistor to drop the 240 to 110. Then again - built to a price...

The unload voltage is just due to design

sPuDd..

[Aussie50]

thanks mate!

I figured the control boards were a generic thing for all markets, powered with 110v. and the AC boards were dropped in at the factory to suit the market the unit was being shipped to, I'E 240 to 110 step down for our marked, and no step down for the US market.

I'll pull the board again and go anotehr video at some stage, right now I got other things to tackle.

[spuddly01]

Also you say "...I'm testing to ground..." in reference to your multimeter leads. I'm assuming you mean your meter -ve lead is connected to mains neutral or the chassis/electrical earth? Im wondering if this is upsetting your measurements. I would check and see if the 5 & 12V PSU negative is connected to earth/chassis. Most are not, they are floating secondary with a 2.2nF 3Kv ceramic cap holding it to half mains. (Except PC PSU's). Have a look around a modern VCR PSU. Same as the inverter PSU.

[Aussie50]

I'm testing to chassis ground, the PSU is earthed to the AC units chassis too..

I will do a test of the DC 5 and 12V rails to the PCB ground too..

Theres no step down trans, just the ceramic caps and high wattage resisters to limit current and voltage. its been ages since i did VCR PSU's but you are right about the design of the system!.

the fault is on the control board. when I remove the power lead from the main AC board, the voltage on the pins (yellow plug) goes up to 140v AC.

[ultimateinfinite]

Spider? Fuck. That. Shit.

[krisachar]

Nice video !

[mrjunior41]

this means when i want to repair my a/c i have to bring it first to a man ho can check the circuit board if not the circuit board i have to bring it to a man who can repair the gas leak or change the compressor.

[mrjunior41]

i thinking this thing of inverter a/c is making repairing of a/c more difficulty , it is not resulting as it should the board will die faster than the compressor & with out a board the compressor can't work