GE Monogram Fridge MN ZISS48DYS Stopped Running

[SLSNUT]

Hi Jeff, I'm a 56 year old Navy Mechanical Engineer and did my thesis on refrigeration, so I am somewhat familiar with these units and have performed other repairs (not on this unit): just short of servicing sealed compressors. My unit died while I was away and along with losing 140 lbs of frozen salmon and halibut from an Alaskan trip I went on in Aug all my beer and Champaign is warm!

Here are my symptoms: I have AC power to compressor (all terminals of Relay and Overload Kit 4387913 show 115 VAC to ground). Lights on inside, compressor, condenser and evap fans are not running. Refrigerator spaces are obviously at room temp. Compressor is cool to the touch but shows some substantial rust coming through its black coating on it's underside. What do you think? Steve

[jeff1]

Hi,


all terminals of Relay and Overload Kit 4387913 show 115 VAC to ground

Don't test to ground, that can just confuse. Only volt test across something.


Lights on inside, compressor, condenser and evap fans are not running.

Stuck in defrost timer or open temp control will certainly shut off the compressor and all fans....but the lights would still work. Since they don't work something may be up with the main power ( house fuse, loose wire, plug outlet, chewed wire, burnt male-female wire connector ). Find where the main plug wires comes in and start testing there.

jeff.

[SLSNUT]

Hi,



Don't test to ground, that can just confuse. Only volt test across something.



Stuck in defrost timer or open temp control will certainly shut off the compressor and all fans....but the lights would still work. Since they don't work something may be up with the main power ( house fuse, loose wire, plug outlet, chewed wire, burnt male-female wire connector ). Find where the main plug wires comes in and start testing there.

jeff.

Thanks for quick reply Jeff,

House uses breakers and none are tripped. Measured across relay and got no voltage. Measured from each terminal to overload terminal and still no voltage. I did get as I said 115 VAC from each terminal to gnd. I am assuming the black box with large blk leads is the start capacitor correct?

[SLSNUT]

Thank you Jeff for you quick reply this evening!

Ok I tested across the terminals of the relay and got no voltage and across each relay terminal and the overload terminal with same result. Voltage tested from each of those terminals to ground does measure, as I said before, 115 VAC. I am assuming black plastic box screwed to chassis with heavy leads is the start capacitor correct? Forgot to say earlier this unit was manufactured in July 1998.

[jeff1]

Measured across relay and got no voltage

No power then.....looks like the neutral may be open since you can get a reading from line to ground.


I am assuming black plastic box screwed to chassis with heavy leads is the start capacitor correct?

Sounds like it.


House uses breakers and none are tripped.

So far sounds more like the nuetral is open.

jeff.

[SLSNUT]

445Jeff,

Not being an electrical engineer I'm gonna guess that this means the hot side is connected at the wall plug and going to the relay but the neutral somehow has a break in it? Should I get 115 across the relay if the neutral is properly connected? Without moving the fridge to unplug and check the outlet to which it is connected which is difficult at this point, I should be able to verify this by testing the leads that come from the power cord that has a plastic clipped connector at the bulkhead by the compressor correct? I just checked it with my FLUKE and got 116VAC at the power cord between neutral and the hot lead, hot and gnd tested same. Will send picks of compressor and relay in a min. [ATTACH=CONFIG]

Ok across the two terminals on brown relay in pic I get no voltage. I get 116 VAC on terminals from wall socket that attach to that connector on lower left side that has orange black and green ground wires.

In looking at other posts on several sites the motherboard seems to be a common culprit for symptoms like min, ie, lights on inside but all fans and compressor inop with compressor cool. BTW my compressor relay (another suspect part in other threads) shows no sign of overheating or burns on the connectors or compressor prongs. Where is the mother board on my unit or does it even have one?

steve

Steve

[SLSNUT]

Spending the better part of today troubleshooting this problem... pulled the fridge out to see if I could find an access panel on back to locate the motherboard. No luck. All sheet metal backing riveted to perimeter. Only hole was square for condenser fan suction... Duplex plug intact with good contact with hospital grade plug I installed years ago on power cord. Does this fridge even use a motherboard? If so where is it hiding? In pic below I am holding some type of electrical component that hums steadily when fridge is plugged in. Don't know exactly what it is but it's not hot to the touch. Posted other pics to give you more info and perspective on my fridge.

Still in need of some guidance Jeff. What do you think? The fridge is in excellent physical condition. Steve

[jeff1]

Does this fridge even use a motherboard?

Nope.



Not being an electrical engineer I'm gonna guess that this means the hot side is connected at the wall plug and going to the relay but the neutral somehow has a break in it?

That appears to be so yes.

On your compressor pic, the red and orange are power....should read 110-120 volts AC across those.....the 2 blacks are run capacitor.


I just checked it with my FLUKE and got 116VAC at the power cord between neutral and the hot lead, hot and gnd tested same.

What is unplugged in your bottom pic?

jeff.

[SLSNUT]

Nope.



That appears to be so yes.

On your compressor pic, the red and orange are power....should read 110-120 volts AC across those.....the 2 blacks are run capacitor.

OK the red is the spade connector on the top prong of the compressor and the orang is the spade connector on the right side of the relay correct? I get no voltage across these leads. What does that indicate?

What is unplugged in your bottom pic?

That is the power cord lead, I have it unplugged to keep doors open but plug it in when I take VOM readings.

jeff.

Thank you,

Steve

[jeff1]

OK the red is the spade connector on the top prong of the compressor and the orang is the spade connector on the right side of the relay correct? I get no voltage across these leads. What does that indicate?

If you read power across the power cord ( looks like top two terminals ) but not at the compressor, somewhere in between the power is lost.

jeff.

[SLSNUT]

Can't see where I'm losing the power unless the relay is bad. Does it also control power to the fans? I ordered a Relay and Overload Kit (4387913) fm Amazon this evening along with a run capacitor. Cheap enough $33 total. BTW The overload (switch?) the unit that attaches to the upper prong of the compressor rattles when I shake it. Don't know if that means it's bad or not. I've run out of ideas. You?

steve

[jeff1]

Can't see where I'm losing the power unless the relay is bad

The relay is for the compressor only....won't effect the fans, lights.

Post a copy of the wire diagram that came with the unit.

jeff.

[SLSNUT]

Did not buy this thing new so I don't have that diagram. Not at home now so cant check the chassis. Where are the schematics usually secured on the chassis? Any chance a short in one of the fans might be cause of power interuption? How many volts should I measure at the condenser fan?

Steve

[jeff1]

Where are the schematics usually secured on the chassis?

Often in an envelope in the upper area.


Any chance a short in one of the fans might be cause of power interuption?

A short would normally blow a fuse/breaker.


How many volts should I measure at the condenser fan?

Normally 110-120 volts AC.

jeff.

[SLSNUT]

Ok found the electrical schematic.

446

After looking at the schematic, problem traced to the defrost timer I was holding in the pic posted on previous page. It was humming but when I advanced the timer manually with my thumb slightly, the fridge compressor and fans came back to life. Guess it was stuck on defrost. I ordered another one on Amazon for $9.56 shipped, to be on safe side.

Your thoughts Jeff?

[jeff1]

Did the compressor come on? Are the lights on ( earlier you mentioned they where not working either )?
Stuck in defrots will shut off the compressor and fans but will leave the light(s) working.

jeff.

[SLSNUT]

Jeff in quotation marks below is what I wrote in posts #1 & 6 of this thread.

"Here are my symptoms: I have AC power to compressor (all terminals of Relay and Overload Kit 4387913 show 115 VAC to ground). Lights on inside, compressor, condenser and evap fans are not running."

"...symptoms like mine, ie, lights on inside but all fans and compressor inop with compressor cool."

In hindsight I should have looked at the defrost timer when you suggested it back then I guess. However, there is somthing to be said for noodling it out myself. Thank you for your assistance regardless.

steve

[jeff1]

I have AC power to compressor (all terminals of Relay and Overload Kit 4387913 show 115 VAC to ground).

Power to ground is not really power....need power accross something, not to ground.
DId the compressor come on when the fans did?
Lights on or still out?

jeff.

[SLSNUT]

Lights were always on as I indicated in all of my posts and yes the compressor came on with the fans when I manually advanced the defrost timer.

steve

[jeff1]

Lights on inside, compressor, condenser and evap fans are not running

I took this as lights on the inside, compressor, fans are not running.


yes the compressor came on with the fans when I manually advanced the defrost timer.

Great :)
Should be just a bad defrost timer.
4-6 hours back to temp and 24 hours back into an on and off routine.

jeff.