Thanks Huckleberry for always being there for me!
That page was helpful but confusing at the same time partly because I was
hoping that I could jump 120 volts to two of the three terminals of the
compressor to see if it runs. If it runs, that would be proof that the
compressor is fine - which - after all - is the only part that would kill
the frig if it wasn't working.
The page talked about various letters stamped on the relay, and a magnetic
switch but mine has no letters on it and there is no magnetic switch.
Anyway, I think I'll just replace both the cap and the overload/start relay
combo, and if that works - you guys are heros. If not. Well then, you're
Went to a great appliance store in San Jose where the guy behind the
counter tested the cap and said it was good.
He said the compressor not working could be three things:
1. Bad compressor
2. Bad relay
3. Restriction in the freon lines
He strongly suggested I not buy his relay from him before testing it, and
he explained how the relay works (the white part is the thermal switch by
He said to plug in the power to the relay (two spades) and check that the
backside of the relay (3 pins) has power to common.
To do this, he told me to create a test jig where I can put 120 volts to
the Start and Main/Run pins of the compressor, with the neutral on the
common pin, and then pull off the start once the compressor starts.
He said if the compressor doesn't start - then that's it for the frig.
So I went home empty handed and then picked up some alligator clips,
spades, and butt connectors and am slapping together a test jig as we type.
The wife and sister were very unhappy that I came home, essentially, empty
handed. But the guy was right that I didn't do enough diagnostics.
The test jig will have two spades on the incoming end, which will plug into
the existing power cable (hot and neutral), and then it will have three
outputs which will be tube-connectors (two hots and one neutral).
The procedure will be:
1. Unplug power
2. Hook two male spades to female spades in power cord
3. Hook a butt plug to Start (hot) and to Run/Main (hot) and to neutral
4. Plug it in
5. Yank off the start wire as soon as the compressor starts
If the compressor starts, then it's good.
If not ...
There's something missing here & that is the cap. As I understand it,
the cap is wired in series with the start winding in order to phase
shift its current and get the motor started in the right direction.
Without the cap, I don't think that the motor will start.
Also, now knowing what the output terminals of the relay are, one can
diagnose it directly. Its circuit follows:
120 <----OVERLOAD----.---RELAY---| |-----< Start
Neu <----------------------------------------< neutral
The relay & cap could be in reversed order.
If you jumper the cap terminals, there should be zero resistance between
the 120 input and the Start output. If you can't tell which input is
120 & which is neutral, try them both.
On Sat, 09 Jul 2016 20:23:14 -0400, Bob Engelhardt wrote:
Thank you Bob for suggesting jumping the capacitor terminals to short them
out, as that gave me some additional connectivity diagnostic information
when I checked continuity:
The relay has only two wires going into it, and three holes coming out.
Disconnected from power, and with the capacitor terminals shorted:
a. Red power input terminal went directly to the relay top output pin
b. White neutral input terminal went directly to *both* lower output pins
If I remove the short between the capacitor pins, it changes to:
a. Red power input still went directly to the relay top output pin
b. White neutral input still went directly to the rearward lower output pin
c. White neutral input no longer innervates the forward lower output pin
Unfortunately, it appears that the relay & cap are working.
Do you interpret this the same as I do?
Yes, I think that's right.
Except that it's standard to switch the "hot" line, not the neutral.
Are you sure that the white input wires are neutral? White is the usual
color for neutral, but inside an appliance they could do otherwise.
On Sat, 09 Jul 2016 20:00:22 -0400, Bob Engelhardt wrote:
By gathering clues, I figured out which is the neutral on the compressor
and which was the always powered pin, and which was the sometimes powered
Then I created a test jig and hooked it up, without a capacitor.
When I powered it up, the compressor still didn't run.
On Sat, 09 Jul 2016 22:31:42 -0400, Bob Engelhardt wrote:
I will make any jumper cable we need to debug this darn thing.
Since it appears (to me anyway) that both the cap and the relay are
working, that leaves mainly the compressor to test (which is critical).
If my prior tests of the relay were accurate, they seem to indicate a
working relay, since there is 120VAC across the two lower terminals to the
upper power terminal.
I wish the motor had a marking for the Start terminal versus the Mark/Run
terminal and common, but there is nothing marked I can decipher.
A. POWER TERMINAL
B. RUN TERMINAL (aka MARK terminal)
C. START TERMINAL
So these are just my guesses for the three terminals:
Given that, is this your suggestion for wiring the cap in series:
1. From the power cord (red) hot wire to the top POWER terminal of the
2. From the power cord (white) neutral wire split into two wires:
2a. From the power cord (white) neutral to the MARK/RUN rearward lower pin
on the compressor.
2b. From the power cord (white) neutral to the cap in series and from the
cap to the START forward lower pin on the compressor.
Is that what you are suggesting I test?
On Sunday, July 10, 2016 at 12:26:44 AM UTC-4, Danny D. wrote:
I don't see why you need any test jig. You say that you've had the
cap tested and it's good and the relay is working. If you have
120V showing up at the two winding leads going into the compressor
and it doesn't start, then the compressor is screwed. If it starts,
but shuts down after running for a brief time, then I guess it could
be something blocking the flow in a line. In either case it's likely
it's done anyway, depending on the cost of a new fridge.
3. I guess that these are the motor terminals:
4. Here is the suggested test jig with the cap in series with the terminal
that I "think" is the START terminal:
5. I accidentally hooked it up backward the first time, with the HOT wire
splitting into two, one of which went through the capacitor and then to
what I think is the compressor START terminal - and the other hot went to
what I think is the compressor RUN terminal.
6. Then I labeled the wires, and hooked it up the opposite way - with the
HOT wire going only to what I think is the compressor topward COMMON
terminal. One neutral wire went to the capacitor and then to what I think
is the compressor bottom-forward-facing START terminal and the other
neutral went to what I think is the compressor bottom-rearward facing RUN
In both tests, the motor just hummed but did not appear to start.
When I pulled what I think is the start wire neutral off, the hum didn't
What do you make of this?
What are my options?
(PS: Money is tight).
Actually, with AC, it's all the same. Functionally, that is - there is
a safety difference.
You've already determined that there is continuity on the start winding,
so no difference when pulling it does not indicate an open winding.
The no-difference is due to the cap-in-series which limits the start
current to about 1/2 amp (its impedance is 220 ohms), while the run
current is likely 6, 8, or more amps. I.e., the start current is too
small to notice when it's removed.
I can't think of anything else to try. It seems pretty conclusive that
the compressor is shot. Oh ... somebody said that the "Freon" line
could be plugged. That could be, but diagnosing and fixing that would
be just as expensive.
I suppose, for the hell of it, you could try reversing the start & run
leads. Can't hurt & maybe there was a brain fart that got their
On Mon, 11 Jul 2016 19:43:35 -0400, Bob Engelhardt wrote:
I hadn't thought of that. I did avoid touching the chassis. :)
Thanks for explaining that the start current is much less than the run
current, so the motor "sounds" wouldn't be easily discerned.
I don't know how to test for a plugged freon line either. :(
Thanks for that idea.
I just reversed the START and RUN terminals, and there was no difference.
It hummed but didn't kick on.
One problem is that I can't tell what's going on from the sound, but when I
hooked all the old parts back, it kicked off again as it did when I started
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