Disabling Auto-Off on a Sunbeam Health at Home Heating Pad

About: Just a dude who reads a lot of Instructables.

Statement of Empiricism
I have used this heating pad for several years now (I wrote these instructions in December 2007, it's now February 2011).  I have had exactly ZERO issues with it - it works perfectly and the hedgehog is fat and happy.  YOUR MILEAGE MAY VARY!  PLEASE USE EXTREME CAUTION IF YOU FOLLOW THESE STEPS.  If you do this, closely observe the pad for at least a few days to make sure it's not overheating or catching on fire.  See the obnoxious red text below:


WARNING! DONT BURN DOWN YOUR HOUSE!
USE CAUTION! TRY AT YOUR OWN RISK!
YOU WILL VOID YOUR WARRANTY!

So, I got this heating pad at the store a while back to use as a hedgehog heating pad. I found out that the 2-hour auto-off timer was hardcoded into the circuit, and they didnt even bother to put a switch on the casing to disable it. Typical overprotection of the consumer - this wouldnt exist if our country was a bit less litigious.

African hedgehogs need at least 72F to be happy, so a heating pad under the cage is recommended. I mean, how could you say no to his face?

So, to disable it, I decided to take it apart and find the culprit like this guy did. Its too bad that for some reason they decided to make it even harder to change this feature.

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Step 1: Surveying the Situation

Here, we can see the circuit board and outer casing.  It’s an Eagle LOPP4, and apparently it was made on Christmas of 2006 (2006-12-25)! It also bears a marking of 07.28, and I have no idea what that means.

Step 2: Doing the Modification

So, the deal is that after a lot of trial and error, I finally found which single pin on the IC you have to cut. I’ve circled the IC in the picture below.

It’s PIN #2!

OK, it actually isn’t #2 on the schematic, but in the picture it makes sense. Just take a soldering iron and a sharp pointy object (I used a thumbtack), melt the solder, and pry the pin from the board. Be careful not to touch pin #1 - if you disconnect it, it will turn off every 5 minutes! Then, put the entire thing back together and celebrate!

I used the datasheet for the IC chip to figure out what pins to screw with. I can’t find the number of the chip right now without tearing the whole thing apart again. Basically, the chip is just a counter, and you cut one of the pins that makes it increment. So simple.

Step 3:

Now I have a happy hedgehog. He’ll never be cold again.

Step 4: Also, the Sunbeam Model 836

Nick V has modified his Sunbeam Model 836. For those interested, here’s his description of the mod:

The chip is a CD4060 (14 stage ripple counter) on mine. They use it as count up timer to turn the ac to the heater coils off after two hours. I wired in a 10k resistor pullup to Vdd to pin 12 (master reset). This disables the counter function, and voila, no auto off!

I went ahead and found the datasheet for all you kids looking to try this. I extracted the one piece of information you probably need, which is in the attached picture.

Nice job, Nick! Hats off to you!

4 People Made This Project!

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28 Discussions

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SteveDay72

Tip 2 months ago

After making sure you have correctly identified the pin you can simply cut the PCB trace that it connects to. Cut it in a place that can always be patched with a wire/solder-blob later, just in case you want to reverse the hack.

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SteveDay72

2 months ago

My heating pad was a newer version. The PCB was marked "LOPP4 NEW". The design is tidied up a little, but otherwise the same. It still uses a 4060 14-stage binary ripple counter (mine uses an HEF4060BT which is pin compatible with the 74HC4060 ic).

I didn't bother desoldering and lifting Pin 2. Instead I opted to simply cut the PCB trace to that pin instead. Much quicker!

FYI: the mod works because Pin 2 is the oscillator input, which *appears to get a half-wave rectified input from the AC 60Hz power input (* I have not reverse engineered the board, but that's my "gut feeling" based on the components around that pin). By cutting the oscillator input you are preventing the counter chip from counting - a pretty clever trick.

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deb1ie

Question 6 months ago on Introduction

I have a Sunbeam heated throw/lap blanket with a 3-hour shutoff. Do you think this modification would be about the same as with the heating pad? How’s a girl supposed to keep her totally outdoor cat warm at night? She sleeps on the outdoor back porch at night, which is her choice, not mine.

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JonathanM116

3 years ago

I have a new Walgreens heating pad the board number is 109375N the chip is 18 pin and reads SONIX N8P2602BSB 102QNKB14 I have reptiles and I am trying to disable the two hour shut off

20151208_181435.jpg
4 replies
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dsamualJonathanM116

Reply 1 year ago

here is the 18 pin Sonix IC pinout. JohnathonM116 and myself have same pad.

Can anyone PLEASE help me? I also have the data sheet which had more info

temp_-962599086.jpg
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dsamualJonathanM116

Reply 1 year ago

after some digging on Internet, I've found datasheet for IC. Can anyone PLEASE help me with which pin?
I've currently got 3 different heating pads all doing the flashing red light.
one is the same as yours, other is HP215
I have IC pinout for sonix 18 pin IC but it won't let me post

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dsamualJonathanM116

Reply 1 year ago

I know this is old, but I'm having red blinking light. Hold power and plug in, see green light for a second then back to red blinking. Did you ever find out how to fix this?

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Omnotohm

3 years ago

Hey, thanks for posting your project. I'm wanting to do the same as you, however, the IC on my heating pad is not as identifiable as I'd like. Info is: Softheat Heating pad, the marking on the chip says only "184-00098" and "*F41FJG" it is an 18 pin chip. I'm no slouch with regard to tech but I don't look at chips every day either so naming convention may be eluding me on this one. I'm reluctant to just hope pin out is the same as others on this forum and start cutting willy nilly. Try as I have to find a pinout on google, nothing has popped up. Any advice would be much appreciated!

BTW, I greatly appreciate that you don't get all preachy about safety. I get it. yes, yes, I am modifying a heating pad. yada yada.. I'm not here for a lecture or finger wagging, I simply want to know about ... whatever'. More often than not when I look up how to do X or find Y all you see in posts are people that a) don't answer the question(s),and b) want to start preaching about whatever rule, guideline, or safety, you might be in breach of. It was refreshing to not have to endure this here.

magnifying_2016-01-01_13-00-39.jpg
2 replies
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Davidson CruseOmnotohm

Reply 2 years ago

I have the same exact heating pad w/ same chip. Did you ever find out which pin to cut?

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Omnotohm Davidson Cruse

Reply 2 years ago

sorry bro, I got tired of looking. I just couldn't find a pin out. Magne you could figure it out w an o-scope but who has the time or patience? I've since found a heating pad that stays on so kinda gave up on it.

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Snavile

2 years ago

Hi I decided to break open my softheat controller and stumbled on this forum. I am dealing with Ic after 25 years so not following from which end I should count the pin # 2 see my board with tc25B1-04 I couldn't open datasheet as the domain no longer exists granted this thread is 5 years old in 2016 btw there are some faint letters on the ic can't read now but will revisit if needed for diagnosis

IMG_0032.JPGIMG_0033.JPG
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SteveJ87

3 years ago

I just did this to a 720-905. IC is oriented differently, but it is the same pin that needs to be cut. Thanks for documenting this! (I'm using mine for plant germination, not hegehogs :) ).

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StephanV1

3 years ago

I have a brand called "soft touch" .. it has the type of screws I will have to drill out. I don't wanna bother if I have no clue what PIN to dismantle .. any body know the brand? possibly bought at wall mart by my ex.. thanks in advance.. :-)

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jjtwins2

3 years ago

I have a Dunlap Auto shut-off heating pad which has worked great for many years until a couple of nights ago. The auto-shut off light was flickering in the morning and and won't shut-off unless the unit is unplugged. The pad is not working and I was hoping if I could shut off the auto setting that the pad would still work, any thoughts or sugguestions would be much appreciated. thanks

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Omnotohm

3 years ago

upon flipping the PCB over I found what I thought would give me an answer but I've yet to find a pinout for the chip.. picture is attached but the new information is:

TS100S-A / V - 02

HJX 94V-0 FR-4

E333641

TC25B1-04

I'm going to keep looking but I'd appreciate any insight you, or anyone, has! Thx, happy new year.

IMAG3656.jpg
1 reply
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hardwarehankOmnotohm

Reply 3 years ago

I haven't found anything other than the 184-000 PDF which isn't helpful, and might not be applicable. Good luck!

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Ftshooter

4 years ago

? - while I've got my controller open I'm curious if you have any ideas on how I might be able to boost the max heat output by like 5-10 degrees?

1 reply
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hardwarehankFtshooter

Reply 4 years ago

Without changing the chip or the heating element I don't think this is possible. I'm pretty sure on the high setting it's at the maximum output. If you figure out how to do this without starting a fire, that might be interesting, but I don't advise it :).

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michele.free

4 years ago on Step 4

HI. I have a LOPP4 NEW board on mine. (I also need it for my animals.) It looks a bit different than yours, but not much. The case says EA SAL104. Made in China, of course. Does anyone know which pin on this one I should cut? Thanks so much! I want to jailbreak my hot pad. I'm so high tech! I've attached a picture of mine.

sunbeam hot pad.jpg