FIXED Samsung Mini Split Air Conditioner not working

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
15
Location
Hawaii
Model Number
AS18A6RC
Brand
Samsung
Age
More than 10 years
This air conditioner has two model numbers.
The indoor unit is AS18A6RC.
The outdoor unit is US18A6RC.
The air conditioner is completely unresponsive to the remote or to the on/off button on the indoor unit.
The display board does not light at all when you press the on/off button, and nothing happens.
Last time it was used a few weeks ago it worked fine.
In the meanwhile we have had an electric storm several miles away which led to a 10 hour power outage, I don't know if this was a factor.
I have checked both units are receiving 220 volt power.
I have checked the fuse on the main pc board in the indoor unit and it is good.
I have a multimeter and could check voltage from the main pc board to the display board if I knew where to check and what it should be.
I have a copy of the installation and operation manual, but it does not go into the detail I need.
Can you help?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,035
Location
Murray, Utah 84107, United States
Nothing comes up with either one of those numbers. If it's one unit it will have one model number. Read it from the tag on the machine. Click here: http://www.repairclinic.com/ then follow the link “Help me find my model number”.
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
15
Location
Hawaii
Thanks for your prompt reply.
This is a mini split system.
That means there are 2 main components which you have to buy separately.
The components are the indoor unit (evaporator) and the outdoor unit (condenser).
You have to connect them together with a copper coil (two pipes, one large for the liquid supply and one small for the gas return) which you also have to buy separately.
The model numbers I gave are correct for sure.
On Repair Clinic if I put in AS18A6RC this comes up for the inside unit: https://www.repairclinic.com/Shop-For-Parts/a16b160d1066792/Model-AS18A6RC-Samsung-Air-Conditioner-Parts
Similarly if I put in US18A6RC this comes up for the outside unit: https://www.repairclinic.com/Shop-For-Parts/a16b160d1068745/Model-US18A6RC-Samsung-Air-Conditioner-Parts
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
15
Location
Hawaii
Sorry, got that backwards.
It should have been: "(two pipes, one small for the liquid supply and one large for the gas return)".
I also found this: manualslib.com/download/145734/Samsung-Digimax-A6.html
From which I got this Samsung Technical Manual: ftp://samsungehs.pl/Samsung Manuals/Others/AD 18 19 24 26 B1 Technical Manual.pdf
It has information for many of Samsung's air conditioners including mine, with electrical diagrams at the end.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,035
Location
Murray, Utah 84107, United States
Check the fuse on the main board for continuity. If it checks good the main board is bad. The main board has been discontinued by the manufacturer and is no longer available. Part number for the board is: PD-TQ24A1R-01
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,035
Location
Murray, Utah 84107, United States
It's possible however, it too has been discontinued. I checked several parts sites and it was listed as no longer available or out of stock. When the last one was sold the computer updated the part availability as "out of stock" by default. You can call RepairClinic and check with them but I went through this once before where the person pointed out that there is an expected ship date under out of stock. RepairClinic told them it would be in by the expected ship date but four weeks later they were informed it was no longer available and issued a refund.

You can confirm the board is bad by checking the fuse on the board and measuring the voltage on the board. The fuse is located at F702. Measure the input voltage (12 VDC) and the output voltage (4.5-5VDC) at IC02. I'll see if I can find a diagram that shows the location for you.
Samsung AC.jpg
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
15
Location
Hawaii
Thank you, you have been extremely helpful, especially with the picture of the board as I had a circuit diagram only.
I removed the board and found a dead gecko on the back of the board in the area covered by a plastic shield.
It had died long ago, but it had corroded the board. It had removed the lacquer and exposed the copper and then continued to corrode.
The fuse F702 is a PCB type MST T1A/250V and it is blown, it is open circuit.
BTW, there are 2 fuses on the board, the fuse I referred to earlier is F701 which is good. It is a glass tube type and I found out the blob means it is a slow blow type.
I cleaned up the corrosion, and found evidence of a recent arc between the copper on the board across capacitor C101.
I have ordered a replacement for fuse F702.
I will report back when it is installed.

I have a repair order from the previous owner which shows part number PD-TQ24A1R-01 was installed in 2003.
However, the board itself has part number PD-SH30ZC-01 on it (and not PD-TQ24A1R-01).
The original PD-TQ24A1R-00, replacement PD-TQ24A1R-01, newer PD-TQ24A1R-02, substitute DB93-01984A (according to SearsPartsDirect) and PD-SH30ZC-01 that I have all come up as no longer available, and I can't find used boards either.
I'm not impressed by Samsung support.
So I am hoping I can repair this one.
BTW I misspelled Samsung as Sumsung in the title when I started this thread. Can you correct it to help others?
 

Daddyfix

Premium Member
Joined
Nov 26, 2015
Messages
15
Location
Hawaii
Success! The air conditioner is working fine now.
I cleaned up the copper surface where it had corroded, and lacquered that part of the board.
I then desoldered the blown fuse F702 and soldered in the replacement.
I reinstalled the board with some bubble wrap between the back of the board and the plastic shield so that a gecko can't get there again.
By the way, you were right, PD-TQ24A1R-02 is discontinued and no longer available.
So repair was the only option other than replacing the complete air conditioner.
Thanks so much again for the great help that you gave.
 
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