Resistor Failed to Short

[apostolakisl]

My Bosch Freezer just shut off Saturday night.  Still had power, but the control panel was off and the thing was just doing nothing except turning the light on when you opened the door.  So, being me, I tore into it.  Found the control board which they conveniently mounted where it is basically impossible to remove unless you take the compressor out.  With a little love (ie I destroyed the mounting bracket, it only cost $10 for a new one, but I have no idea how I'm going to put the new one in . .  that is a problem for another day) I got it out.  On inspection, I see only one obvious sign of issue.  A resistor which is split.  I removed the resistor and discovered it to basically be shorted (3 ohms instead of 4700).  I thought resistors failed to open circuit, not short.  This seems very odd.  I was thinking I would replace the resistor, but when I saw it was shorted I figured there is no way that something else on the board  didn't get ruined.  So, I ordered a new board for it. Thoughts?

[Brian H]

That is interesting.

All the failed resistors I have seen either have gone way up in value or opened up. Since you read it out of circuit. It was not a reading thorough anything else in the circuit.

Looks like it may have carried a fair amount of current. Its leads look like they are turning black or they had some type of insulation painted on them.

[apostolakisl]

1 minute ago, Brian H said:

That is interesting.

All the failed resistors I have seen either have gone way up in value or opened up. Since you read it out of circuit. It was not a reading thorough anything else in the circuit.

Looks like it may have carried a fair amount of current. Its leads look like they are turning black or they had some type of insulation painted on them.

Just a picture illusion.  The leads are regular.  The resistor is physically big, not sure what ratings it has aside from reading the color bands.

[larryllix]

The control board for my upright freezer went a few years ago. I maintained it by splicing the compressor leads to a plug and plugged it into an On Off Linc module with a program cycling the compressor about 50%. Colder is OK and shouldn't hurt the compressor. 

I was working on a weather temperature algorithm (freezer is in the garage with semi-outside temperatures ) to alter the cycle ratio but the new board came in to the supplier within a few days.

[apostolakisl]

4 hours ago, larryllix said:

The control board for my upright freezer went a few years ago. I maintained it by splicing the compressor leads to a plug and plugged it into an On Off Linc module with a program cycling the compressor about 50%. Colder is OK and shouldn't hurt the compressor. 

I was working on a weather temperature algorithm (freezer is in the garage with semi-outside temperatures ) to alter the cycle ratio but the new board came in to the supplier within a few days.

This freezer is pretty complicated for that.  I would have to find the fan leads to power them on.  Then without the defrost cycle with its heaters and compressor off time running per their specs it would freeze up.  If I knew the replacement board were only a couple days out, I might try it.  But, sadly, I don't expect the replacement for at least 1 week.  I was able to put a chest freezer back into service to keep my stuff frozen, but finding anything in a chest freezer is a major PITA.

[larryllix]

17 minutes ago, apostolakisl said:

This freezer is pretty complicated for that.  I would have to find the fan leads to power them on.  Then without the defrost cycle with its heaters and compressor off time running per their specs it would freeze up.  If I knew the replacement board were only a couple days out, I might try it.  But, sadly, I don't expect the replacement for at least 1 week.  I was able to put a chest freezer back into service to keep my stuff frozen, but finding anything in a chest freezer is a major PITA.

I  don't think this upright has any defrost cycle. I just cut into the two wires and the compressor ran, along with the fans. The air enters the bottom, drops it's moisture as it cools into the bottom pan and the chilled air enters the freezer  space from the top vent. We have had the unit frost right over when we left the door open but when closed again it sublimates all the frost and clears right out. There is no defrost timer. The combo fridges have defrost cycles, but AFAIK this freezer only doesn't need it. We have had the pan overflow in the garage with extreme humidity outside. Maytag unit, made by Whirlpool, as they all are now.

[apostolakisl]

2 minutes ago, larryllix said:

I  don't think this upright has any defrost cycle. I just cut into the two wires and the compressor ran, along with the fans. The air enters the bottom, drops it's moisture as it cools into the bottom pan and the chilled air enters the freezer  space from the top vent. We have had the unit frost right over when we left the door open but when closed again it sublimates all the frost and clears right out. There is no defrost timer. The combo fridges have defrost cycles, but AFAIK this freezer only doesn't need it. We have had the pan overflow in the garage with extreme humidity outside. Maytag unit, made by Whirlpool, as they all are now.

This is a built-in counter depth freezer.  It wouldn't have much of any tolerance for ice on the evaporator.  https://www.ajmadison.com/cgi-bin/ajmadison/B30IF70NSP.html  Plus, to work on the guts which are located under the unit, you have to have the door open.  That doesn't work out well if you have 30 minutes worth of work to do!  Anyway, good news is we took the opportunity to clean the freezer which we have never done in the 10 years we have owned it.  We have the matching fridge, and really like them . . .except for this.  Only other issue was when the start relay went out on it, but that was cheap and easy.  Though they do not spec the relay as a part, the Bosch customer service said I needed to buy a new compressor.  I was like, suuuuure, then got a generic start relay and changed out the connectors to make it plug in.  I really wouldn't expect the control board to fail, but all it takes is one cheaply made 10 cent part to cause havoc.  I was surprised that the control module was only $100.  I thought for sure they would try to extort massive cash for that proprietary part.  Seeing as how they kind of have you by the cahonas when considering the cost and PITA of replacing a built-in with custom panel freezer.

[larryllix]

20 minutes ago, apostolakisl said:

This is a built-in counter depth freezer.  It wouldn't have much of any tolerance for ice on the evaporator.  https://www.ajmadison.com/cgi-bin/ajmadison/B30IF70NSP.html  Plus, to work on the guts which are located under the unit, you have to have the door open.  That doesn't work out well if you have 30 minutes worth of work to do!  Anyway, good news is we took the opportunity to clean the freezer which we have never done in the 10 years we have owned it.  We have the matching fridge, and really like them . . .except for this.  Only other issue was when the start relay went out on it, but that was cheap and easy.  Though they do not spec the relay as a part, the Bosch customer service said I needed to buy a new compressor.  I was like, suuuuure, then got a generic start relay and changed out the connectors to make it plug in.  I really wouldn't expect the control board to fail, but all it takes is one cheaply made 10 cent part to cause havoc.  I was surprised that the control module was only $100.  I thought for sure they would try to extort massive cash for that proprietary part.  Seeing as how they kind of have you by the cahonas when considering the cost and PITA of replacing a built-in with custom panel freezer.

Yeah, I have found that also. They always want to convince you the compressor, immersed in an oil bath and sealed needs replacing and when you consider the cost of parts and the technology and equipment to replace the compressor...guess what? They get the commission of a new fridge/freezer sale again.  IIRC, Bosch is the only appliance that isn't made by Whirlpool now.

Much to my delight, my control board snapped in to the front pocket where the readout is. A simple connector and snap it into place. I thought the whole door liner/panel would have to come apart. whewww! It was a 30 second replacement. It took me longer the reconnect the compressor to the original wires. LOL

[apostolakisl]

The new board came a while back, I installed it and it works.  The plastic cover just came today (back ordered), so now the fun of trying to screw it in with the 1/2 inch of space between it and the back end of the compressor 18 inches deep from the front of the unit.  I have half a mind to just let it just keep hanging.  It isn't like it is being moved anywhere.