Honeywell LCD fail and repair - no background music
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- Опубліковано 30 вер 2024
- The LCD screen of my Honeywell CMS927 thermostat mostly stopped working.
See here how I fixed the display using a toaster.
(Also applies to the CM927 - the S indicates it was sold with the receiver. The 921 is the 1 day rather than 7 day version.)
Inspiration from:
• Honeywell cm901 Thermo...
The site for user manuals:
heatingcontrol...
By popular demand this is a re-upload of • Honeywell LCD fail and... without background music, the clicking and whining is the camera auto focus.
Brilliant instructions however still didn’t work on first 2 attempts. Third time I pressed centre of screen as well as the bulldog clips and now fully repaired with all digits showing
CM927 buzzing when has a broken screen
Thank you so much. This has fixed mine too and I am so happy not to have to pay out £80 for a new one. Also, I'm so glad you did another video without the music. I couldn't concentrate on the other one and I couldn't hear what you were saying, so all in all, thank you for taking the time to post this one, without the loud music. Thank you.
Glad it helped
Thank you so much for not putting background music. THANK YOU
You're welcome!
The more comments on this video the more youtube will promote it over the version with music.
Very nice work 🙏🏻
If you have access to a small soldering iron, set it to 200℃ and go a bit back and forth over the glued areas on the flat flex cable while applying moderate pressure.
0:21 Buzzing
Why didn't you explain more about the packing and what it's purpose is and what it is made of?
There’s not much more satisfying than getting something working that was previously broken
This was so helpful managed to fix mine, from zero display to about 90% display. Thanks so much.
Thank you. Clear and precise instructions. I tried the toaster 3 times, in the end I had to use a hair dryer.
This 'trick' only works for a few weeks / months, and then the LCD completely fails . Don't waste your time with this scam.
Yes but you can do it again and again. That is what I do.
I’ve done this a couple of times now. Only takes a few minutes and saves £+135 every time. 👍
I can’t thank you enough or in fact believe how effective this is. I try to mend everything I can but was at a loss with this. Following your demo to the letter (I also thought I had over done it having held it over for 1 full minute) it has re-laminated the lcd and has saved me money I could I’ll afford. Thank you again, your a hero!
PERFECT! Fixed first time, £100 for a new controller saved and one less thing in landfill/recycling. Many, many thanks for posting this video. I owe you a beer. :)
Excellent. I'd love to take you up on that offer, but it's going to be sometime off!
Thank You that worked a treat, had to give it two goes but it went from unreadable to fully functioning! You saved me £70+
Finally got round to this just now and it worked perfectly. I waved the lcd side slowly back and forth in a flat position about three inches above the toaster for about two or three minutes. I did it until the screen colour darkened a bit and I don't think it got very hot. I let it cool and repeated the process.
I put a narrow wooden stick into the gap that was just the right size to compress the contacts without crushing the gap when the clip was on it. The stick came nowhere near to burning. I now have both controllers working good as new and the operation is quick and easy enough to do again in the future if necessary. I have seen new controllers advertised for over 200 quid so this is a very satisfying fix.
Many thanks!
I have just done it… it works. Brilliant! Many thanks!
1min first time (marked improvement). Then, additional 90 seconds; just perfect!
I cannot believe it was so easy. You need a very small screwdriver.
Excellent!
Your method worked like a charm for me. It turned out there's no need to cook the hole assembly - I ended up heating up my clamp above the toaster and, once moderately hot, putting it on for 30-60 seconds and checking the display afterwards. It took three iterations.
My thermostat looks as new. Thank you very-very much!
Good to know :)
@@mygrandadsshed I did wonder about a pair of hair straighteners...
It’s not connected
Hi, what wires are you using to connect the batteries and circuit board? What were you using at 7:06, and how does the screen hold up long term after the heat treatment?
The blue packing is an offcut of 2.5mm T+E mains cable I had laying around, trimmed to give two flats. It can be anything that will not melt at 300°C during the cooking phase. It presses the flexi back onto the glass and PCB.
Can't say long term, my display is still good today so 3 months so far.
Thank you so much ! Just followed this video to fix 2x CM901 (upstairs/downstairs), used a hairdryer for 3.5 minutes on each and both worked first time.
Nice work!
I was so nervous pulling this apart. I was expecting it to be completely broken when putting it back together. But somehow it's like new. I'm proper chuffed with myself. Thankyou for sharing this video.. i only hovered above toaster for one minute tho as I was nervous about leaving it longer....and for all the women that say they cant do it. Its pretty simple. If I can do it, so can u!!!
My view was, it's broken already - can I save buying another. If I can that's good, otherwise I can say that I tried.
Mine stopped working again today and done the same trick. It didn't work 1st time round, so I done it for a second time and back working. Deffo my fave video on UA-cam. Thankyou!!
Wish you had shown at normal speed how to open the damn thing.
Just seen this - probably a bit late now, but you can slow down the playback in youtube with the gear icon.
This has worked for me before, but this time I think I might have melted the LCD screen... Just waiting for it to cool down so I can put it back together and see!
I'm amazed, I thought I'd cooked it, but apart from saying "FOOM TEMP" the rest of it is legible. More importantly, I can actually turn the heating on!! Thank you so much :-)
Thanks for reporting back. :)
Since I did mine 18months ago I have since lost a few of the characters, but I can still read the time and temperature which is what matters.
While I agree with some comments this fix is not 'permanent'; it's accessible to people who would otherwise buy a new controller.
Thanks so much for that. You just saved me £100. Your fix worked perfectly.
hi to all,
can anyone send me correct part number for the lcd? i've the same problem but i don't know what lcd i've to buy
In the comments of my video that has the annoyingly loud music @jwstolk posted a suggestion of a part number: CMT907G1003
@@mygrandadsshed Note that that's the part number for a complete thermostat, but it's the cheapest and most basic version, and in my case the LCD module worked with my much more expensive wireless/modulating version of the thermostat.
Yes, this worked for me.. thank you! I have another method if you have the tools available. Cable tie (3.6mm wide) + hot air re-work gun (for electronics - link below*) + one bulldog clip.
I used a 3.6 x 250mm cable tie as "packing" ie. slid vertically in the gap behind the green ribbon connector. It slides in a few cms then stops. It is the perfect height and will apply pressure on the adhesive of the connector/PCB junction from above (which seems to be where the problem lies).
1. Pre-warm the underside of the pcb near the ribbon connector using a hot air gun set to 220 C/Fan 50% for 1-2 mins.
2. Clip a single bulldog clip on to the edge of the glass over the ribbon and heat the bulldog clip until hot to the touch (both sides - but mainly the underneath) for 1-2 mins.
3. Move the bulldog clip slightly so it is only over the ribbon on the top side (and pressing down on the cable tie packing inside) and heat the general area and bulldog clip for 1-2 mins on both sides till hot to the touch. The edge of the screen slightly discoloured near the edge but faded quickly on cooling.
4. (Optional) After cooling, I clamped the glass screen gently (!) in the centre using one of the clamps linked below also then warmed the glass front of the whole screen for 1-2 minutes using the heat gun set to 220 C until it slightly discoloured. I saw something similar on another vid and I'm not sure this is necessary but I include it for completeness.
Optional Mini-woodworking clamps:
www.amazon.co.uk/Silverline-250108-Mini-Clamps-100/dp/B001C7LTSW/ref=sr_1_1?keywords=silverline+250108+mini+clamps+2pk+100mm&qid=1662932632&sr=8-1
5. I tested it by placing it back on the mainboard, plugging in the connector and testing using a lab power supply at 3V before re-assembly (positive lead goes to top right contact if you have the power contacts uppermost - as shown in the video by MGS).
It seems to have completely solved the problem - all digits working :) Thanks again.
* www.amazon.co.uk/Desoldering-Station-Rework-Welder-Anti-Static/dp/B09MZ4T37W/ref=sr_1_10?crid=BMGV1EJMGJ7O&keywords=hot+air+gun+for+electronics+959D&qid=1662935838&sprefix=hot+air+gun+for+electronics+959d%2Caps%2C74&sr=8-10
I wonder how the heat not melted the lcd film ?
It needs to withstand the heat level of molten solder during manufacturing.
And it gradually failed recently, but I’ve repeated it with success! Great result, thank you.
Worked perfectly! Just took 1:30-2:00min for 5cm above the toaster on higher level! Great, Thanks!
Four strong bull-nose clips along very edge of the screen, carefully inserted a small straw from a spray can to press down the ribbon at the top edge, heated the screen side downwards for 2 minutes over a toaster [screen turned blue throughout], placed to cool to room temperature, removed the straw from pressing onto the ribbon. Assembled and used electrical cleaner spray on all pin connections. Screen fully working! EXCELLENT.
This is so helpful - thank you. Rested mine on top of the toaster. Bit nervous about it over heating, so started with 30 seconds (tad better), then tried 1 min (better again) before going for 1 min 30 which gave me a 100% display. Gave it about 5 minutes to cool in the kitchen, then put it in the fridge for another 5 before reassembly. For the packing, I cut one of the pointy ends off a cocktail stick and shaved two adjacent sides flat with a scalpel, sliding it carefully in blunt (cut off) end first after I'd put the bulldog clip on that side. Flat sides downwards and to the front. Very grateful.
Thank you! This fix worked brilliantly. Most impressed.
Absolute genius! Thanks - worked a charm.
Thanks so much for this amazing fix
Worked for me, using a hair dryer to heat the LCD module instead of a toaster. Will see how long the display continues to work. Thanks for the video !
It's been a couple of years now - this winter I've lost enough segments to make it annoying. Redoing it will be on the summer jobs list. If time permits I'll record that process and post a new video. The more likes the higher up my jobs list it will get :)
Thank you for the video, it is very educational.
However, I did not manage to recover the display despite 3 attempts. Could you tell me why? Is there another solution? Thank you.
Sadly I don't know. There are several reasons why the display might stop working, but the connection to the glass is a weak link due to differing coefficients of thermal expansion.
Tried this way previously with some success, but after a while the LCD problem would return. The last time I tried, not all the display came back. Then I saw another UA-cam video, where a piece of wire insulated mains wire is inserted under the length of the ribbon, between the LCD and circuit board. The paperclips to squeeze everything together. I used a hairdryer to provide heat, concentrated on the ribbon area both sides. That did the trick. LCD was black, then returned to normal as everything cooled down. Once assembled LCD worked properly this time. The ambient temperature was showing as high for a while, then gradually returned to normal after nearly an hour.
Will hope this fix lasts a lot longer than previous attempts.
Hi, glad that it worked for you. As others have commented the packer between the glass and PCB to sandwich the flexi connector is important to remake the connection when heated.
I tried this fix using a hair dryer instead of a toaster, I got all but a few bits of numbers back but it is readable and usable and definitely cheaper than the replacement costs (£100+) so well worth it. I appreciated the easy to follow breakdown and fixed mine for the time being. Thanks
I'm not sure how long, but the display will turn black from the heat. The clips are important as they supply pressure to keep the assembly together.
THIS WORKS. The first time I tried, I didn't leave the screen over the heat long enough, so made no difference. I tried again until the glue holding the screen and backing melted enough to separate the two, and when it cooled down the screen worked again. Thank you, and saved me £100 buying a replacement.
And you saved the environment by sparing your controller going to recycling. :)
I had the exact same problem and thanks to you it is now fixed and up for sale as a complete, working unit. For all those who have a FAN assisted oven: 150C. 2 mins, middle shelf on an upside-down baking tray.
Nice to know another method - especially with better temperature control.
It works! Display was almost blank, couple of minutes over the toaster, working again. It looks & smells like you've completely trashed it, but the LCD clears after a few minutes. Hopefully it will last some time. To the manufacturer's credit the device is really easy to dismantle with no gotchas. The only negative is that flimsy ribbon cable fixed under the backlight so you can't see it
Since recording the video over a year ago, I have now lost two elements from the word "room", but the important numbers are still good.
I found this similar fixes on a few different sites and tried it with no success until I tried this method of stripping the unit right down to the screen itself. It worked on the second attempt after I left it on the toaster for almost 2 mins then put it in the freezer to cool off before moving the bulldog clips. The screen went very dark but recovered when it cooled off.
A great fix that saves £100! Many thanks.
Glad that it worked for you :)
I'd day to others, let it cool naturally back to room temperature, a cold freezer plunge might thermally shock components on the board or the display.
I did one of these and it worked a treat, ent to do my second one and didn't realise there was a plastic film over the screen which melted, the screen now has a black part which usually disappears after cooling but hasn't, is the screen now ruined or is there a way to solve this? Even if its broke I'm glad I got one fixed!
Goo news for 1 :)
Being glass the screen with the melted plastic should be recoverable. Reheating, gentle scraping and then a cleaner like IPA or acetone (nail polish remover) should clean it up. Just take care not to stress the flexi and damage the connection while it's demounted. Good luck.
Very clever. Are we to deduce that the heat from the toaster sorted the failing LCD screen?
The heat from the toaster, along with the pressure of the buldog clip (and packer) softens solder and remakes the connection of the flexi to the main PCB and the glass.
Amazing, worked well for me! I love it how cooking your electronics is now a standard repair procedure!
I'd also recommend thoroughly cleaning the surface of the button contacts with an alcohol wipe. This helped me fix my malfunctioning buttons.
yep good shout, finger grease can mess up those sliding & button contacts.
Thank you so much for that, I thought I'd have to buy a new one but it worked!
You are welcome!
Nice to see another unit saved from landfill.
This is astonishing. I have never played inside electronics before, and it worked! Almost perfect, second time. First time 20 secs on the toaster. But it hadn't worked. Then used a hairdryer and a cooking thermometer to monitor the temperature. Took it to around 70° as in another comment, re-assembled, and hey presto! Thank you so much.
If only all electronics was this easy to fix :)
btw how black did the screen look at 70°C?
@@mygrandadsshed 6 on a scale of 1 - blackness to 10 jet black. Rather a guess of course. How on earth was this discovered? Not the sort of item that inadvertently gets left over the toaster. Presumably there is some theory behind it?
Thanks for this. I was looking for help with the LCD on my ravenheat boiler...would the heat trick (hairdryer) work with the LCD in situ? I don't know how to/if the LCD can be removed on my boiler.
Hi. The heat required will probably damage the surrounding plastic or components like buttons.
You also need to be able to add pressure onto the LCD connections, so the heat can remake the joint.
@@mygrandadsshed thank you for your reply
That piece of "padding" seemed to play an important role but it looked like plastic-covered wire which would have made a molten mess at 200 degrees C. A bit more detail about it and where you placed it would have been very welcome.
When I filmed, to be honest, I did not appreciate how important the packing was/is.
I used a short section of mains wire, it's 1 core from a twin and earth cable.
To make it the right size I used a knife to make it a bit thinner.
I guess something like a wooden lollipop stick would also work, crafted to the right size.
It is there to support the flexible connector between the main circuit board and the screen, so as it heats up the pressure squashes the contacts back firmly.
@@mygrandadsshed OK.... I see that the contacts need to be compressed from inside and outside to re-establish the connection.
I'm just a bit hesitant about what material to use if the temperature is going to get so high. A wooden strip sounds a bit risky as well.
Or is mains wire safe to use at that temperature?
The duration over the toaster is not long enough to burn wood. Most insulation cable should not smoke before 200°C - you can try heating it before putting it between the glass and circuit board to check the behaviour.
Hay alguien que sepa el valor ohmmico del sensor y si es ntc o ptc?
Sorry I don't know what technology the temperature sensor is using
Many Thanks! it worked for me as well on CM901 model, only difference I used a hairdryer to heat it.
Excellent!
Tried this but display still sporadic. You think I should concentrate on the ribbon which attaches to the screen?
This is a really helpful video. Still too scared to do it myself but at least I now know what the problem is. Many thanks.
Once you decide it's so unreadable and a new one is required you might as well have a go, as at that point you have nothing to lose.
I managed, as long as you have heat source, a screwdriver - and I found a mounted pin very helpful to undo the four clips. They look as if they are designed to be pushed back by something like that. It's a doddle, I've never fixed anything remotely like this before.
That is excellent, thank you so much.
You're very welcome!
I'm not sure why UA-cam keeps pushing the original one. It gets many more views on the channel. Apparently it's due to likes/comments/engagement. I don't want to take it down as it helping people, but I did link the new one in the description.
@@mygrandadsshed it's a shame yt doesn't let you edit the old video and replace it with the new one, but then if it is different which it will be I can understand why they couldn't keep the statistics, number of likes views etc. Nevermind the new vid is great, thanks for the update.
Just buy a new unit.... Costs more but takes seconds to install and you get a guarantee on the unit come on