Disabling auto-off on a Sunbeam Health at Home heating pad
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 didn’t even bother to put a switch on the casing to disable it. Typical overprotection of the consumer – this wouldn’t 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 not help this face?:
So, to disable it, I decided to take it apart and find the culprit like this guy did. It’s too bad that for some reason they decided to make it even harder to change this “feature.” Here’s the outer casing:
Here is an overview of the circuit board:
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.
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 here:
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.
Now I have a happy hedgehog. He’ll never be cold again.
Update (1/2009)
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:
Nice job, Nick! Hats off to you!
bishop
December 13, 2007 at 1:29 AM
won’t be cold again, but when you come home to find Hedgehog Toast, what will you say then Mr. "I Hacked My Heating Pad to torch my pet"?
I bet trpik will not make you cheese toast then. no sir.
no cheese toast for you.
none
RD
December 13, 2007 at 1:29 AM
Nice hack. I’d have just cut and hardwired, your’s is more elegant.
Just an FYI. These timers are there because if you fall asleep on a heating pad it can cause neurological damage, like Bell’s Palsy. I don’t think Sunbeam ever came up with a use case that included hedgehogs, so I forgive them.
ArEuDum?
December 13, 2007 at 1:29 AM
Why? Just why? What do you think are the possible reasons for this "safety feature"? Is it there for something to bypass when bored? Is it there so SunBeam can charge twice as much for Hedgehog Heaters as they do for heating pads? Is it there so if I fall asleep with it under my leg I won’t bleed brain fluid from my eyes? Is it there so you don’t burn your house down?
Dumb Ass! Get a heat lamp.
Hank
December 13, 2007 at 1:29 AM
Are U Dum?:
You obviously know nothing about hedgehogs. Heat lamps are a very bad idea, use WAY more electricity than the heating pad, and are way more of a fire hazard. Also, burning my house down isn’t an issue, and I put that at the top to warn people who didn’t look at the datasheet not to screw it up. I happen to know how integrated circuits work, especially when they are as simplistic as a timer – maybe you don’t.
The heating pad has been running for a week, like I thought it would, and the hedgehog is very happy (and warm of course). There are no heating pads currently sold that do not have this "safety feature," so I had no choice. I’m just letting others know since they should be able to disable it if they would like to in return for voiding their warranty and chances for legal action against Sunbeam,
I’m sorry that you don’t like reverse-engineering. I hope you live a nice life full of safety and trust in corporations, since they’re just looking out for our health interests and not protecting themselves from being sued. Oh, and I hope you don’t have a laptop, because I hear those [burn down like mad...](http://www.youtube.com/watch?v=WeWq6rWzChw&feature=related)
Bill
December 13, 2007 at 1:29 AM
Awesome Chacos dude.
jebus zeus
December 13, 2007 at 1:29 AM
cute hedgehog, happy heating, forget those guys…
TDub
December 13, 2007 at 1:29 AM
I too have a hedgehog, and she’s got a heating pad…we just so happened to have a pad back from before they had the auto-off feature! Though, if it ever poops out on me, this will come in handy! Thanks!
Bill
December 13, 2007 at 1:29 AM
We bought a heating pad for our cat from the local pet store. She’s 17 and likes to be warm. The pad is designed to stay on all the time and we have a happy kitty.
Ben
December 13, 2007 at 1:29 AM
If the heat pad is underneath the hedgehog, won’t he just go on it and get it dirty? Why wouldn’t you just use a space heater or heat lamp?
Hank
December 13, 2007 at 1:29 AM
Ben: It’s under his cage on low, heating by conduction. Good question, though. This way, it heats the plastic surface under him, in turn heating his bedding, and we never have to clean it.
Space heaters and heat lamps use much more electricity. I don’t want to pay $30/month to heat my pet.
John
December 13, 2007 at 1:29 AM
I have a Sunbeam model 734-5 and the circuit board doesn’t look like that. Any ideas? Anyone get this to work for that version?
How’d you look up what to cut/ etc?
Hank
December 13, 2007 at 1:29 AM
John,
I looked up the datasheet for my chip. If you can find the model number of the IC chip, I could probably figure out which one to cut, or at least attempt to, provided you would free me from any liability for any consequences… :)
[Here](http://www.national.com/mpf/LM/LM555.html) is an example datasheet. They’re usually PDFs. On the right is basically the only diagram you need. If I remember right, I simply disconnected the **OUTPUT** pin from my chip, so when the timer went off, it didn’t trigger the relay that would shut the heating off. Good luck!
Scott
December 13, 2007 at 1:29 AM
Hi. Thanks for posting this info on disabling the auto shut off on your heating pad. I need to bypass my Sunbeam 536 auto shut off for different reasons, but still necessary. I am getting supplies to make Kombucha Tea. This is a fermented health drink that needs to remain at a temperature of about 84 degrees for 2 weeks. Sitting the bottles of cultured tea on a heating pad is the desired method.
Can you guide me with this model if I send you a digital picture of it? I would really appreciate. I’ve been searching all morning for postings on this matter.
Scott G.
cathy
December 13, 2007 at 1:29 AM
hi hank! wow! you are so detailed-i love what you did here and it’s exactly what i have been searching for! i can’t stand those auto shut-off heating pads….my old heating pad that did NOT have that feature lasted for years and the new ones don’t last nearly as long. i am very impressed with your research! thank you for taking the time to help people like me who are looking to solve the same problem. BUT i must say….i am going to ask my general contractor husband to hard wire the darn thing just like one of your other readers suggested! the who circuit board thing is way over my head and if hubby hardwires it….i’ll get it done much, much quicker! lol! thank you again. cathy
Lisa
December 13, 2007 at 1:29 AM
Hi Hank!!! Thank you so very much for accomplishing this feat! I’m a wildlife rehabilitator and like your darling hegehog – my orphans need continual heat – so I get the picture – problem is, I’m trying to disconnect on a Dunlap – I have the culprit circled, but how will I know which one to disconnect??? Where would I get the datasheet and model number??? I promise not to hold you to any damages – I figure, I can’t use the darn thing like it is, so if it works great, if not, well, it’s back to yard sales and estate sales cuz that’s where I found all the other OlDER HEAT PAD that don’t have this feature.
Looking forward to your answers -
thanks again, Lisa
NickV
December 13, 2007 at 1:29 AM
Nice hack. You inspired me to mod mine, but it is a model 836 – a little different. 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 am am using it as heater for seed starting in the garden. $11 at Walmart versus $32 for their so called seedling heater…….
Kristin
December 13, 2007 at 1:29 AM
Dude! You rock!! Like NickV, I’m also using my heat pad as a cheapie way to start seeds without shelling out $50 for a couple of seedling heaters. I will be starting on this new project this afternoon, here’s hoping i don’t burn my house down! (I fully acknowledge your waiver of all responsibility of those who try this hack, btw.) And yay for a happy hedgehog! He’s a cute little dude.
JJ
December 13, 2007 at 1:29 AM
Hank,
As Kristin said before me, You ROCK.
I am elated to have found your site to tell me how to disable the ‘auto-shutoff’ on the sunbeam 836. I have not done it yet, but it is 4 am in Ca. and it will wait another day. I was just about to shut down the pc after searching for over an hour for a clue about how the switches even worked.
Not only are you bright (to figure it out), articulate (able to communicate it to someone like myself), caring (to take the time to share it and respond to others in order to help out critters or whatever) and unpretensious (thats just obvious by your responses or lack thereof to the people that wrote to you about it). … you are kind & loving or you would not be caring for that little guy as you are. This is nearly two years later, is s/he back to the wild or still with you? Precious little face.
My indoor elderly cats and a couple of outdoor ferral cats depend on the heating pads.
I also foster abandonded (usually, well … always resulting from human stupidity) kittens, opposums, or whatever orphaned critter that needs help.
Heating pads are the only way to keep them alive in most instances. I just bought 4 of those sunbeams at Walmart @ approx. 11.00 dollars/, thinking they were the old kind without the auto-shutoff. The package states 2 hr. Auto shutoff but it but I missed it. As I was looking for the receipt, it occured to me that there has to be a way to disconnect that feature. I had intentions to open the control, but I don’t believe I could have figured it out. You saved me alot. Thank you.
If you ever need any legal assist. you got it. Glad you took the time and that you figured out what that little guy needs. Best Regards, Jay
Hank
December 13, 2007 at 1:29 AM
Jay:
Thanks for the comment! I’m glad you found the article useful. It sounds like some pretty cool stuff you do for the animals. I didn’t take the hedgehog in, though. I bought him for money. He’s my pet. And he’s still happy and warm after all this time. Let me know if the 836 instructions work if you decide to try ‘em. They’re pretty new. Thanks for the offer of legal assistance. I’ll let you know if I need it ;).
Hank
December 13, 2007 at 1:29 AM
Cathy,
Glad I could be a help to you. Our pad has been running constantly on low for over a year now with zero problems. I hope yours will get the same mileage!