Bad Indicator Lamp?

[dsquire]

Since I'm too cheap to throw out my deep fat fryer I'm trying to fix it. 

My first thought was the element or switch but they both check out OK for continuity and so does everything else except for the small red indicator light. Should there be continuity across the terminals of this light. I believe that it is what was called a neon indicator. It is not a LED. This unit is probably 12 to 15 years old and still has a lot more french fries and doughnuts to cook.
I believe in repair as a first option, not last. 

Anybody with any comments on this good or bad gladly accepted. I know I'm going to hear from Bernd on this one.

Cheers 

Don

[John Rudd]

Most neon lamps have a small resistor in series with them to limit the strike up current...If it fails to light, try changing the small series resistor...For 110/120 vac its likely to be around 100K...

[dsquire]

John

Thanks.

I don't see any resistor unless it is internal. Would all the electricity for the heating element have to pass thru this indicator light or does the indicator light only indicate that the heating element is drawing current? 

cheers 

Don

[CrewCab]

Would all the electricity for the heating element have to pass thru this indicator light

I would doubt it Don, I suspect the indicator will be in parallel to the main circuit ......... however someone who really knows what they are talking about will be along soon 

CC

[John Rudd]

The neon lamp isnt a load carrying device...it doesnt have the capabilities to carry load currents such as an electric element...

The neon will be in parallel with.....

Try your local Radioshack place and see if they have a replacement neon indicator

[Bernd]

Anybody with any comments on this good or bad gladly accepted. I know I'm going to hear from Bernd on this one.

Cheers 

Don

Well it looks like I got beat to the answer already. They have given go advice Don. 


I do have to say one thing tough, those deep fried foods will surely end your machining carer in a hurry if it plugs up the pipes.

Oh, one thing does come to mind. I don't believe that a neon bulb like that would burn out. So check for a broken or loose wire in the circuit. Does the light just show that the power is on or does it go out when the oil is up to temprature?

I need to check in these bulbs a bit more. I used to play with them when I made flash circuits such as used in camera flashes.

Bernd

[dsquire]

Thanks John and CrewCab for your comments, they all help.

Well it wasn't the neon lamp. As John, Crew Cab and Bernd pointed out that is in parallel and only indicates power on or off when the oil is up to temperature. As it turns out, it is OK but dosen't have any function with the pot heating up other than to tell you the power is on.

I did find one other piece hidden inside a woven insulating sleeve that is in series. I am not sure what it is called but my guess is a thermosistor (sp). It is about 4mm dia x 10mm long and is a shiny metal case. On one end of this is a blue cone shaped nose. The wire leads running into the ends are both about 1mm dia. The writing on this baby is as follows.

PAT     K
MICROTEMP
4372 A
AJBSU 192C

When I put the Ohm meter across the leads with it out of the circuit there is no reading one way and just the smallest needle deflection when reversed. I believe that this is where the problem lies. I had a coffee percolator many years ago that had the same problem and worked like new when I replaced the thermosistor.

While trying to get this thermosistor out of the circuit I tried to remove a nut that was on a steel stud that was spot welded to the aluminum pot. Yes Aluminum to Steel. I checked it with a magnet. Anyway, the stud broke off and that is where the switch was mounted. Since part of the switch is a bi-metal contact it has to be mounted that close to the aluminum pot to work properly.

So at the end of the day I have to table littered with pots and pieces and tools and don't have a pot to put chips in. I guess I'll just have to break down and buy one of the new ones.

I tried last night to take a picture of the small part that I have just been talking about and no luck whatsoever. I finally had to quit that before I put the camera into orbit. I'm going to have to find my camera manuals and figure that out. Here I am telling all the new members that we need pictures and I can't even produce one myself.

Bernd
I'm hoping that eating deep fried foods won't do me in. So far heart and arteries all seem to check out OK. Now the lungs, thats another story. I have COPD and my best friend and allways close companion is 6mm dia air line hooked to an oxygen tank or concentrator 24/7.
   
Thanks for all the help guys, it is appreciated.   

Cheers 

Don

[Bluechip]

Don

That little doins is probably a thermal fuse ....

192C ? Maybe 192 deg. Celsius ?

In Derbyshire speak ... worrabirtthissun then ?

http://cpc.farnell.com/thermodisc/g4a01192c/fuse-thermal-w-e-192c/dp/FF01031

Happy sizzlin ..

EDIT If it is one, and you replace it .. it is a THERMAL fuse  er ... not to be SOLDERED, usually crimped  ...

Thought I'd mention it ... 

Dave BC

[dsquire]

Dave

Thanks for the comeback. I went and looked at the picture of the thermodisk and it is exactly like the one in my unit that I described in my last post above. 

Cheers Dave 

Don

[Bluechip]

Don

Have a quick look at the edit   ... I've seen it done !

Lots of 'em used in power electronics, often on heatsinks ..

Also verify current rating for your kit, some only carry lowish currents ie 3A or so. Others up to about 20A IIRC

Dave BC

[dsquire]

Dave

Yes, the old one was crimped on, not soldered on and that is how I would have replaced it. As I mentioned in my reply to John, CrewCab and Bernd, I am now going to replace it seeing as I broke the mounting post off that holds the switch. I thank you for the help with this Dave.

Cheers 

Don

[Bernd]

Ok Don. Glad to be of some help.

Next time you fry up a couple of chicken wings and have a beer with them, think of me. I love that combo. Trying to plug up my pipes a third time. 

Bernd

[Comp]

Sorry, caught this post late,  yep, its a thermal fuse,  they are non-resettable,   {when they go, they go!!!}  it is possible it is just a thermal fuse failure,... ( I would say 1 in 4 chance,...) and you pop in a new one, away you will go,.....   BUT!!  they are a protection device,...   often the element is breaking down to ground, and the fuse does its job, and cuts out... .....  sometimes this happens as the element heats up, so the fault is intermittent,....   DO NOT BYPASS THE THERMAL FUSE!!!!    Sorry to shout, but I have seen it done!!!!  They are crimped on, by the way, cos they can get hot enough to melt the solder!!


Good luck, (& Good frying!! )   Cheers,    Fred

[John Rudd]

Sorry, caught this post late,  yep, its a thermal fuse,  they are non-resettable,   {when they go, they go!!!}  it is possible it is just a thermal fuse failure,... ( I would say 1 in 4 chance,...) and you pop in a new one, away you will go,.....   BUT!!  they are a protection device,...   often the element is breaking down to ground, and the fuse does its job, and cuts out... .....  sometimes this happens as the element heats up, so the fault is intermittent,....   DO NOT BYPASS THE THERMAL FUSE!!!!    Sorry to shout, but I have seen it done!!!!  They are crimped on, by the way, cos they can get hot enough to melt the solder!!


Good luck, (& Good frying!! )   Cheers,    Fred

Difference of opinion here I'm afraid...They are crimped rather than soldered...

The heat from soldering can destroy the fuse....

Lifted from a manufactures site...."A range of thermal fuses which will protect equipment from excessive temperature rises. They are not resettable and must be replaced if ‘blown’. NOTE: when installing any of these devices, never solder directly to the wire leads – you must use screw terminals, terminal blocks or crimped on connectors."

[dsquire]

Fred
John

Thanks for the comebacks. That is what I like about this forum. When you need help you can call on people around the world and get advise. Sometimes there are conflicting opinions but that always gets straightened out in the end.   

As I mentioned in an earlier post.

"While trying to get this thermosistor out of the circuit I tried to remove a nut that was on a steel stud that was spot welded to the aluminum pot. Yes Aluminum to Steel. I checked it with a magnet. Anyway, the stud broke off and that is where the switch was mounted. Since part of the switch is a bi-metal contact it has to be mounted that close to the aluminum pot to work properly."

I have never seen steel spot welded to aluminum before. Is this an acceptable practice? With this in mind I am going to retire the cooker and recycle the bits for some other use someday. 

Thanks to all who have read and responded to this thread.

Cheers

Don

[75Plus]

I have never seen steel spot welded to aluminum before. Is this an acceptable practice? With this in mind I am going to retire the cooker and recycle the bits for some other use someday. 



Don

Don, Sunbeam has been welding steel studs to aluminum pot and skillet bottoms for at least 50 years. We got a Sunbeam electric skillet for a wedding gift in 1960 that had stainless steel studs to hold the legs welded to the aluminum bottom which was attached to the stainless steel skillet to improve heat distribution.

Joe