Rick and company,
I too wish to thank you for the diagram which ought to be pasted to the back of every one of these fridges.
Two questions on these GE SxS. How can you tell if you have the new board. assume the relay might be obvious or . . . date code or?
I've been through two boards in two years on one of these SxS and now its down again. seems like defrost symptoms but could be evap fan, i.e. freezer is refrigerator, refrigerator is oven . . .
fixyourboard.com has a pretty good logic schematic for the defrost circuithttp://www.fixyourboard.com/techzone/refrigerators/ge_fridge_nodefrost/defrostflow.html
but calls for ohming the "bimetal switch". i don't thing these have bimetal switches. I thought they have thermistors which vary resistance with temperature. maybe they are still bimetal, and maybe the reading they are looking for - under 10 ohms - indicates a range, e.g. 0 to 10 that is within appropriate operating characteristics.
first problem is, identifying the "bimetal switch" which I assume from your diagram is the evaporator thermistor which is also used to terminate the defrost cycle. (I'm a little hazy on that terminology relative to good old analog defrost operation because the defrost cycle was operated by a timer and the bimetal switch turned the element on and off to prevent overheating during that timed cycle but did not terminate the cycle.) Assuming I have the right thing to test you show ohming J1 pin 5 to J1 pin 4 and then I'd refer to the thermistor values to see if the ohms vaguely correspond to current evap temp. One thing not mentioned, is such a test reliable if the junction is still plugged in? if so, maybe this is a slight advantage to the PC board control as in most analog versions you had to unplug everything and test it on its own - although that also highly logically confirmed what was working and what wasn't. no black box to deal with.
And , I'm still black box as to whether the new and disimproved model responds to the thermister by reentering refrigeration mode or it simply turns off heater and the processor is running a timer (and if all this utter nonsense overcomplicating fridges in order to cost people money and grief is actually aimed at some miniscule energy savings and I can blame this whole disaster on EPA - who are pretty much singlehandedly responsible for most problems I encounter in life - you'd think they would have a relative humidity sensor as well to change the cycle timing rather than a knife edge algorithm of how fast the evap warms but maybe that is a reasonable surrogate for it being iced out and I'm only complicating what is already too complicated, but I digress).
As to the evap fan, I'm not clear what the real benefits are of two or three speed operation. you list 12V high 8 V for low although then I see a listing of 4V low, 8V med, 12V high. I've generally found good ole fashioned AC evap fans to be virtually bomb proof. I'll come across them completely iced up or gummed up with locked rotor. clean em up, little lube on the shaft and back in business. water don't hurt 'em, ice don't hurt 'em, food gunk don't hurt 'em.
If I read your first diagram right, after observing resistor condition and checking for open or short condition J2 pin 3 to J2 pin 8 and then following up at motor if either is observed, I would test for voltage between J2 pin 3 and J2 pin 4 during operation. And if I'm not getting voltage at all to J2 pin 8 this is an indication of damage to the board possibly resulting from some misoperation or misapprehension of the evap fan. Now, you say this should be less likely with new boards because of relay style operation, although I'm wondering if these guys every heard of a fuse. We used to used those to protect DC control circuits as well as mains, just sayin . . .
I guess in the bigger picture while I'm thanking you for your extensive work to help crack the black box a little bit - what is the point. I've got plenty of work without these headaches. I suppose if we are trying to cure unemployment by turning 30 million more people into appliance repairmen it would be more efficient to keep writing unemployment checks and not have all our food spoil - maybe that explains the increase in food stamps.
Maybe I can ask if there is another thread to discuss what manufacturers have actually got this figured out best and will move the the bottom of this post there, but can't avoid asking when I'm on the 3rd go round in 3 years for this fridge whether there are better options. Can I still buy an analog controlled fridge or one with minimal printed circuit work, or small circuits devoted just to the icemaker for instance which have been prevalent for years but if the icemaker goes, you don't lose all you food.
I will certainly plead guilty to not having cracked the depths of the problems the way that rick has and maybe once you really understand a board, the GE isn't any worse than anybody else's - or perish the thought, maybe it is better. (although fixyourboard.com also identifies their 13.5 volt power supply as fluky. http://www.fixyourboard.com/techzone/refrigerators/ge_fridge_testload/ge_fridge_testload.html
don't know if they fixed that on the 'new' versions.)
and fixyourboard warranties their repairs for 2 years which is nice but to me the gold standard is 22 years not 2 years. I've got an analog SxS Estate brand (think I once figured out it is a whirlpool but not sure) fridge I bought from Sam's club 22 years ago for 500 bucks and done nothing but clean the condenser grid a couple times prophylactically.
if there is a modern manufacturer who can take those guts and wrap some stainless steel around 'em and sell 'em for a grand they'd be in the money from my perspective. I'd tell everybody I know to buy one.
And I'm now faced with the decision whether to fix this GE again (maybe better than I did before by buying a new board without really knowing why the old one failed, maybe Rick's work will help me to know why it failed) or to throw in the towel and choose another manufacturer or different GE control strategy because counter-depth would be better in this setting anyway. If so, what manufacturer should I choose?
if you made it to the end of this post you were able to suspend the ADD that has you being an independent entrepeneurial serivce person (e.g., for extreme example see my screen name) long enough in favor of ARD - (i.e the retentive disorder) when it comes to appliance repair. thanx for playing. thanks for any service ideas and any observations on brands which seem to have more analog or better worked out or separated digital control regimens.
aka- the man who refuses to buy a washing machine with a digital main controller.