Fridge not cooling - a case study with no happy ending

During this 2026 Spring Festival/Chinese New Year,
the fridge stopped cooling - a test icecube melted.

In a bizarre event, the wall socket energizing the fridge
ceased to work. I cannot replace it yet since the wires
were daisy chained at the socket.
I needed a Wago type device which I recently purchased.

BUT after a week or so, water turned into ice and it
was normal again . . . until it wasn't.

THEN my test icecube/chunk - in those coleslaw containers
you get from fast food outlets - melted again.

Bummer.

So I studied



How to Test & Replace a Defrost Timer in a Refrigerator | Repair & Replace

The rest of the videos in this series cover other failures.

In my case



HVACR: How A Refrigerator/Freezer Defrost Timer Works/Defrost Timer Troubleshooting/Sequence/Testing

Wow. My fridge, a National/Panasonic NR-B29T does not
use an electromechanical timer so it is good to know that
the 6 to 8 hour compressor/cooling period is interrupted
by 20 mins of defrost/heating. Were you aware of this?
I certainly didn't. The videos I watched never mentioned
this fact. So if my defrost cycles are too close together,
something is wrong.

These are the only two circuits exclusively energized.
And within each period, the defrost thermostat turns off the
heater when the ice is gone while the compressor shuts off once
the desired temperature is reached. So two circuits and 4 distinct
phases. Thus an idle period can follow a defrost if the thermostat
cuts out earlier because there is no more ice to melt.

Here are the readings I have taken with comments on what I did
or observed. I don't have the service manual so the behaviour
of the electronics has to be treated like a black box.

If I witnessed a recovery, chances are the fridge sensor
is still working although that does not rule out contact
corrosion or a marginal supply to the electronics interpreting
the sensor wrongly.

It is even more difficult when I don't have a baseline to
compare with BUT I challenge you, does anyone on this planet
have a baseline for their fridge?

Power meter shows normal current readings for
cooling, idle and defrost.
EXCEPT that the compressor now draws 512 mA
instead of 489 mA. The reading also depends on
the mains voltage. We are currently experiencing
a heat wave.

The power meter has been connected for ages and
I can tell the state the fridge is in. When
defrosting, the phase angle is zero.

When idle, it is 11 mA.

Water from freezer compartment does not flow
into the drain tube. It wets the floor.
I can't figure this out yet.
Now I know. The guide was not fully inserted
by the previous repairman. Now the defrost water
collects in the tray as expected.

13:49 19/04/2026 sick, cooling -1.5 12,0
15:51 19/04/2026 sick, cooling  1.3 11.4
21:25 19/04/2026 sick, cooling  3.8 12.5

14:26 20/04/2026       defrost  2.7 11.9
18:41 20/04/2026 sick, cooling  3.1 12.0

01:46 21/04/2026 sick, cooling  2.9 10.8
06:29 21/04/2026 sick, cooling  5.0 10.9
17:33 21/04/2026       defrost  5.6 13.9
20:48 21/04/2026 sick, cooling  4.4 13.0

08:01 22/04/2026 sick, cooling 11.1 13.6
10:08 22/04/2026 sick, cooling 11.1 14.0
15:19 22/04/2026 sick, cooling  3.7 12.1
16:34 22/04/2026 sick, cooling  2.9 12.0
22:28 22/04/2026 sick, cooling  6.1 12.3

06:59 23/04/2026 sick, cooling -0.7 11.0
08:58 23/04/2026 sick, cooling -0.6 12.0
19:34 23/04/2026 sick, cooling  0.6 11.0
21:04 23/04/2026 sick, cooling -1.4 10.9
21:29 23/04/2026       defrost  7.5 11.0

03:01 24/04/2026 sick, cooling -2.0 10.6
07:27 24/04/2026 sick, cooling -0.9 10.5
09:43 24/04/2026 sick, cooling -1.1 10.6
11:00 24/04/2026 sick, cooling -2.1 10.4
11:52 24/04/2026 sick, cooling  0.9 10.4
14:42 24/04/2026 sick, cooling -2.5 10.4
16:29 24/04/2026 sick, cooling -3.8  9.9
16:48 24/04/2026       defrost 11.3 10.4
21:43 24/04/2026 sick, cooling -2.6 11.0
23:20 24/04/2026       defrost 12.9 11.2

07:20 25/04/2026 sick, cooling -2.5 10.5
09:04 25/04/2026 sick, cooling -0.4 12.8
13:59 25/04/2026 sick, cooling  9.0 11.0
18:30 25/04/2026 sick, cooling -0.5 10.9
20:22 25/04/2026         idle  12.6 11.1

04:54 26/04/2026 sick, cooling -2.0 10.3
08:34 26/04/2026 sick, cooling  0.7 10.8
12:12 26/04/2026       defrost  0.9 10.2
13:39 26/04/2026 sick, cooling  2.3 11.0
15:09 26/04/2026 sick, cooling -0.6 10.9
18:17 26/04/2026 sick, cooling -1.4 11.8
22:25 26/04/2026 sick, cooling -0.8 11.8

04:30 27/04/2026       defrost  6.5 10.1
07:58 27/04/2026 sick, cooling -2.1 10.8
10:03 27/04/2026 sick, cooling -2.1 10.5
12:35 27/04/2026 sick, cooling -3.4 10.2
13:59 27/04/2026 sick, cooling -3.9 10.5
17:42 27/04/2026 sick, cooling  0.2 12.5

02:27 28/04/2026 sick, cooling -0.1 10.6
07:28 28/04/2026 sick, cooling -4.3  9.5
08:54 28/04/2026       defrost -1.1  9.3
10:42 28/04/2026 sick, cooling 11.3 10.4 no ice at freezer evaporator
13:43 28/04/2026 remove fridge control flap
14:24 28/04/2026 sick, cooling  2.2  8.2
14:35 28/04/2026 sick, cooling  1.9  7.5
15:33 28/04/2026 sick, cooling  1.4  7.0
17:20 28/04/2026 sick, cooling  0.0  5.1
17:38 28/04/2026 sick, cooling -0.3  4.9
19:23 28/04/2026 sick, cooling -1.9  3.2 ***
20:22 28/04/2026 sick, cooling -0.3  4.3
22:39 28/04/2026       defrost  2.9  5.1

02:44 29/04/2026 sick, cooling -0.9  3.4 ***
08:03 29/04/2026 sick, cooling  9.4  7.3
08:20 29/04/2026 sick, cooling -0.4  4.0 ***
09:32 29/04/2026 sick, cooling -0.8  3.7 ***
10:52 29/04/2026 sick, cooling -1.8  3.1 ***
defrost ?
12:47 29/04/2026 sick, cooling  1.8  5.6
13:29 29/04/2026 sick, cooling -2.8  2.3 ***
14:45 29/04/2026 sick, cooling -2.8  2.3 ***
16:10 29/04/2026 sick, cooling -3.2  2.0 ***
16:46 29/04/2026          idle 11.6  6.5
17:45 29/04/2026 sick, cooling -0.9  2.7 ***
defrost 20min
18:04 29/04/2026 sick, cooling  8.4  7.9
18:14 29/04/2026 sick, cooling  0.4  5.2
18:45 29/04/2026 sick, cooling -2.7  2.6 ***
20:35 29/04/2026 sick, cooling 11.1  7.3

02:18 30/04/2026 sick, cooling -3.3  2.0 ***
07:xx 30/04/2026       defrost  0.5  3.3
07:36 30/04/2026 sick, cooling  8.1  7.0
07:45 30/04/2026 sick, cooling -0.1  4.4
09:34 30/04/2026       defrost  0.0  3.7 ***
10:00 30/04/2026 sick, cooling  0.1  4.6
10:16 30/04/2026 sick, cooling -1.4  3.4 ***
11:24 30/04/2026 sick, cooling -1.3  3.4 ***
13:00 30/04/2026 sick, cooling -2.5  2.5 ***
16:21 30/04/2026 sick, cooling -0.4  4.6
18:15 30/04/2026 sick, cooling -3.5  1.6 ***
19:24 30/04/2026 sick, cooling -3.6  1.5 ***
19:39 30/04/2026 in defrost
19:48 30/04/2026 sick, cooling 11.9  7.6
20:55 30/04/2026       defrost  3.3  4.9
21:08 30/04/2026 sick, cooling  8.5  9.5
22:22 30/04/2026       defrost  7.3  6.1
23:52 30/04/2026 sick, cooling  1.7  5.3

06:40 01/05/2026 sick, cooling -2.3  2.6 ***
07:01 01/05/2026 sick, cooling -3.7  1.5 ***
09:45 01/05/2026 sick, cooling  0.3  4.7
11:14 01/05/2026 sick, cooling -2.3  2.6 ***
12:12 01/05/2026 sick, cooling -1.3  3.3 ***
13:07 01/05/2026 sick, cooling  4.0  6.5
15:11 01/05/2026 sick, cooling -2.6  2.8 ***
16:05 01/05/2026 sick, cooling -0.3  4.4
16:39 01/05/2026 sick, cooling -2.4  2.9 ***
18:04 01/05/2026       defrost  9.4  7.1
18:29 01/05/2026 sick, cooling -0.5  4.1
19:50 01/05/2026       defrost  2.1  5.1
20:24 01/05/2026 sick, cooling  0.5  5.9
22:42 01/05/2026       defrost  1.8  4.9

defrost
05:37 02/05/2026 sick, cooling 10.4  7.4
06:12 02/05/2026 sick, cooling -1.5  3.4 ***
07:25 02/05/2026 sick, cooling  4.1  7.0
09:12 02/05/2026 sick, cooling  3.1  7.4
09:42 02/05/2026       defrost  4.1  6.9
12:04 02/05/2026       defrost  1.3  5,1 getting more defrosts
13:11 02/05/2026       defrost  6.8  7.5
13:53 02/05/2026 sick, cooling -0.7  4.1
15:30 02/05/2026 sick, cooling  1.5  6.0
16:14 02/05/2026 sick, cooling -1.5  3.5 ***
17:32 02/05/2026       defrost  2.8  5.5
18:10 02/05/2026 sick, cooling  0.5  6.3
23:15 02/05/2026 sick, cooling -2.7  2.5 ***

05:23 03/05/2026 sick, cooling -0.8  3.6 ***
05:53 03/05/2026 sick, cooling -2.3  2.5 ***
05:54 03/05/2026       defrost
06:49 03/05/2026       defrost  1.8  4.5
08:04 03/05/2026 sick, cooling  2.4  6.1
08:30 03/05/2026 sick, cooling -2.0  3.0 ***
12:17 03/05/2026 sick, cooling -1.6  3.4 ***
13:08 03/05/2026 sick, cooling -0.1  4.6
13:57 03/05/2026       defrost  3.0  5.0
15:45 03/05/2026 sick, cooling  2.5  6.6
18:12 03/05/2026 sick, cooling  5.1  8.8

03:16 04/05/2026 sick, cooling  7.5  9.1
first time noticing a climb from 489 to 512 mA
05:41 04/05/2026 sick, cooling  2.8  7.2

06:20 04/05/2026 sick, cooling  7.3  8.8
09:12 04/05/2026 idle 11.3 5.0 something wrong with these numbers
09:13 04/05/2026 sick, cooling 11.4  9.2
10:30 04/05/2026 sick, cooling  0.1  5.1
13:45 04/05/2026 sick, cooling  1.6  6.3
14:13 04/05/2026       defrost  1.4  5.1
14:49 04/05/2026 sick, cooling -1.0  4.0 ***
15:59 04/05/2026          idle 11.5  8.3
16:32 04/05/2026          idle 11.8  8.3
19:26 04/05/2026 sick, cooling 12.2  9.4
20:39 04/05/2026 sick, cooling  0.4  5.3

00:14 05/05/2026 sick, cooling -0.2  5.0
06:10 05/05/2026       defrost  3.9  6.5
06:22 05/05/2026          idle 11.4  8.1 no cooling phase?
06:24 05/05/2026 sick, cooling 10.4  8.3
06:53 05/05/2026 sick, cooling -0.1  4.5
07:01 05/05/2026       defrost  6.0  7.4 haywire !
07:24 05/05/2026 sick, cooling  0.7  5.3
12:23 05/05/2026 sick, cooling  2.8  7.3
12:41 05/05/2026 sick, cooling  0.5  5.3
14:37 05/05/2026 sick, cooling  0.4  5.8
14:43 05/05/2026       defrost  3.6  9.8
17:45 05/05/2026 sick, cooling  0.6  5.4
20:17 05/05/2026       defrost  5.8  8.4
22:26 05/05/2026 sick, cooling  1.8  6.7

01:37 06/05/2026       defrost  0.0  5.3
06:57 06/05/2026          idle 11.9  9.0
10:27 06/05/2026 sick, cooling  2.4  6.8
11:18 06/05/2026 sick, cooling  2.7  7.0
12:01 06/05/2026 12.9  9.9
DISCONNECTED. No Happy Ending.

Hisense open-close door
0.7  7.8
1.0 15.4
3.7  6.7
2.8  8.9
6.7 10.8
5.2  9.5
4.3 10.3
5.1 11.9
4.2 10.6
4.2  9.7

So, where to start?

Firstly the FIRST reading of the day. This gives the fridge
all night long to reach the lowest temperature.

Most readings taken here allow for at least 30 mins after the door
has been opened. The temperature probes are placed just
inside the door which make for wild readings once the
door is opened because of the lack of thermal mass and the
condensation from the outside air. But they are placed
to be out of the way of accidental strikes and lack of
cable restraints and the length of the cable.
It is what it is.

And then there are those blips which indicate a defrost
happened but I cannot be sure.

I mark "***" at those readings which meet the requirements
for both the freezer and fridge compartments IE 0C or below
for the freezer and less than 4C for the fridge.

The barrier happens at:

"13:43 28/04/2026 remove fridge control flap"

This opens the passage of freezer air directly into
the freezer. This is also when I reseated the drain
thingy connecting the Freezer Compartment to the
manifold in the fridge compartment leading outside to
the drain hose. No blockage found by sticking in a
cable tie.

It used to be that at the maximum settings, lettuce
would ice up in the fridge.

It is clear that before, there are no *** while
after removal of the flap, I now get ***.

The fridge can clearly do no better and is just
limping home.

When we moved into this house end-1972, we brought
along the Kelvinator and my wife recalls we switched to
this smaller fridge between 1995 and 2003.
So about 2 decades of continuous use.

The current draw increase and the poor reading at the
freezer vent (my car air-conditioner was pumping out
at least -10C) leads me to conclude that the compressor
needs to be replaced at the very minimum for food safety.

The fridge failed exactly this way a few years ago and
replacing the board fixed it. I don't think the sensors
or the board are at fault this time.

Perhaps it is a failing run capacitor. The second hand
unit we saw advertised has apparently been sold so
there is nothing to compare.

So we bought a Mitsubishi. The radiator runs along the
body shell just like the National. We waited 3 hours after
delivery before powering on. Is seemed sluggish but
overnight it cooled to expectations. Water froze in the
freezer. No hurry to place a stone in the plastic cup
with a chunk of frost from the Hisense icebox.

One day I will improve the Hisense by placing a PC fan
inside to circulate the air.  

Before we chose the replacement, we asked for a photo
of the circuit diagram. I bet no other consumer does that.