GHD 4.2b Repair of thermal fuse and thermistor

Today we repair a ghd 4.2b which we initaly think its just a thermal fuse issue but after tests we find out this is a thermistor replacement also.
My KZbin setup
Microphone Blue Yetti
Camera setup
Camera 1 SJCAM SJ4000
Camera 2 SJCAM SJ4000+
Camera 3 Ipad mini2
Camera 4 JVC JVC TK-C1381
Camera 5 Kodak Pixpro SP360 4K
Camera 6 Kodak Pixpro SP360 4K
Microscope setup
Navitar 1-60123
Navitar 1-6010 Adaptor
Camera JVC TK-C1381
Capture card Easycap DC60 Composite Video
Sharp Aquos S-video monitor
Soldering Equipment
Iron + desoldering CSI 701A
Hot Air Blackjack BK4050

[@IsrarNomiHussain]

Very good video I have ghd 4.2b, suddenly stoped working and changed the normal fuse plug to start with no joy. Than I tested the thermal fuse reading was coming 3 to 5 ohms, heater element reading was 70 ohm when disconnected from pcb as they in parallel. Changed thermal fuse it come to life again, so happy thank you Kev

[@lukewithey6548]

Kev thanks I have used this video 4 times in the last 5 years to fix multiple straighteners.

[@JMRolfe]

Excellent video. Love that you show all the components that are worth checking. Thanks!

[@sebastianmoonsamy5276]

Great video I managed to fix the my wife's straightener but I can't seem to get the plates to heat the same...one plate is warm while the other is hot

[@KevsElectricalWorkshop]

check connections are correct and both heaters are bonded to plates correctly.

[@Jj-il9cz]

Thank you video was easy for following for beginners.Awesome thanks Kev.

[@joebeeston1995]

Thanks for the video, strangely (or maybe not) my 4.2b PCB has a slightly different layout to the one on the video. What would a good reading be for the thermistor?

[@KevsElectricalWorkshop]

approx. 100k at 25 deg c, you will need to disconnect to measure

[@mark.e.p]

This is great video. Could it be a dodgy switch as when you flick it on sometimes it comes on for split second then goes off?

[@katherinesequeiros2644]

Hello, I have the same issue with the glass thermistor MF58, I didn't hear quite well in the video. could you please tell me which was the recommended thermistor's value?

[@KevsElectricalWorkshop]

100k at 25c

[@ylmazcevirme8365]

I received a straightener, it is the same as the straightener you repaired, I just want to ask, how many kiloms or ohms is the thermal resistance? I measured it as an open circuit and the values ​​above it were deleted.

[@KevsElectricalWorkshop]

thermal fuse (brown wires) as close to zero as possible, heaters are around 70 ohms each disconnected, thermistor 100k at 25 deg c disconnected

[@javicivic-xx9826]

Thanks you. You are the BEST. Your video is perfect . ,

[@marletegoncalvesdonascimen3213]

Olá kelvs Meu nome é Nilton Estou aprendendo concertos mas fico perdido em algumas coisas Trocar fusível Indentificar componentes em curto Mas sou calmo devagar eu consigo Parabéns por seu trabalho 🙏

[@KevsElectricalWorkshop]

Congratulations you will get there slowly.

[@singhres]

Thanks for the video. Regarding the thermal fuse. What value should a working thermal fuse provide at room temperature? Mine is reading 0 ohm. Not sure whether to replace.

[@KevsElectricalWorkshop]

dosnt mater if its a thermal fuse or a fuse it should be as low as possible to be good so 0 ohms is good

[@mrj1518]

Few questions please. 1. Can i use regular tool box solder to solder the cables of the thermistor to the circuit board? 2. What Ohm should be showing when testing the thermistor? 3. Can i use regular computer CPU thermal paste when fitting back the plates?

[@KevsElectricalWorkshop]

1..you can use normal solder for any of the PCB connections as its outside the hot zone. 2..100Kohms Approx at room temperature measured while disconnected. 3..I use HY410 which is a cheap cpu grease but its rated at to 280C

[@mrj1518]

Kevs Electrical Workshop thanks for the quick info. I'm trying to work out what's wrong with mine. It started to stop working in some plug sockets (odd) now doesn't work in any at all. I've stripped it down and the measurements are.... R8 and r11 52ohm Thermal fuse 000.1ohm Heat plate 066.8ohm 105 components all 102.4ohm Other heat plate 066.8ohm Thermal resistor unsoldered showed 0.82.2k ohm steady. I tested again and showed 94.6ohm but slowly went down to 84k ohm when I stopped checking it. Wonder what else it could be?

[@KevsElectricalWorkshop]

Proberly a intermitant lead or bad swivel connector

[@patrick_carnimeo]

Io ho su 2 piastre uguali il fusibile rotto e il termistore che misura 100kohm circa e che varia resistenza al valore della temperatura deduco che sia sano, perchè allora si è bruciato il fusibile????

[@jolivierb]

Hello Bravo. Great job. I saved a lot of money Thank you I am French

[@marcoc6793]

Hello Kev and many thanks for this excellent video, I have read (or at least I think I did) all the comments and answer but I can't find where get the thermal fuse, do you have a specific of this? i.e. at what temperature should it break. Ebay would be nice, thanks a lot

[@joseluiscolado]

Thank you from Spain. good job

[@meghanjohnson1175]

Any tips on how to fix a flat iron that gets WAY too hot? Its a chi and it has a temp gauge button that goes from 330° F to 410°. Ive had it for a year i think and suddenly it gets so hot that i cant touch the outside of it

[@KevsElectricalWorkshop]

sorry not come across them so cant give any advice

[@Skeptic-Professor]

Hi wonder if you could help never used an ometer before. what setting do I put it on. Thanks in advance.

[@KevsElectricalWorkshop]

what meter do you have

[@thomasleerecruitment]

Is it just worth replacing the replacing both the thermal fuse and thermistor to be on the safe side? I've got my wife to repair...

[@KevsElectricalWorkshop]

The thermistor is a lot more complex to replace so if in measures good when disconnected from board dont replace it unless needed.

[@thomasleerecruitment]

@@KevsElectricalWorkshop thanks mate!

[@charnevanderlinde7645]

Hi can you please help me ... I have a ghd Mk5 model I replaced the thermal fuse and it's still not switching on I tested the resistors R8 and R11 they were fine i tested the plates they were fine i tested the main cable that's fine so i can't see what else can be the problem .. Will you please be so kind to give me advice at what else might be the cause cos now currently it's not switching on no beeping sound nothing I checked everything that are usually the problems PLEASE HELP ME.Thank you for your videos 😄🥰

[@TheRobot1968]

hi and thankyou for the great video! i followed your advice and went into the thermal fuse compartment, found out that a white thin cable is loose. where do i attach it please? sorry total newbie here! how can i send you a photo please to advice me?

[@KevsElectricalWorkshop]

email in the about section of my channel

[@davesage9190]

Welcome back. Nice watching you do that repair. I missed ordering stuff from Banggood based on what you ordered for your various construction projects. :-) Will you be buying and using some goodies again soon in your videos?ThanksSage

[@KevsElectricalWorkshop]

Hi Dave, life has been a bit hectic the last couple of months but i do plan too.

[@sham1234567891]

Could you please help me solve the following? I got a Remington hair iron model 9509. It starts and then stops after mild heating. Thanks.

[@KevsElectricalWorkshop]

Sorry never touched remington so cant help

[@charnevanderlinde7645]

Hi when putting back the heater plate when applying thermal paste do you need to apply heat to it in order to set or do you leave it just like that ?

[@KevsElectricalWorkshop]

just leave it like that the thermal paste dosnt set.

[@muhaahaloa941]

How can i make my silicone adhesive soft i tried heating it in a pan, i want to be able to put a blob over the thermistor and have it run down the sides itself, im onto my 8th attempt even purchased the same stuff you have ?Please if any one has any ideas i want it more like a pouring type silicone, it just sits like a blob LOL..

[@KevsElectricalWorkshop]

The runniest it will be is when in comes out of the tube, heating ect will just make it set faster. if you want to pour it you need flowable silicon but then you get the problem it runs away.

[@MooosivBalls]

Hi Kev, great video thank you!, I bought a kit, replaced fuse and thermistor (thermistor came attached to a heat plate. Heat pad works on fuse side but not thermistor side. I connected original heat plate and new heat plate from kit with new thermistor and neither of those heat up either. Any tips to resolve this would be much appreciated.

[@KevsElectricalWorkshop]

do you have a meter to measure the heater plates?

[@MooosivBalls]

@@KevsElectricalWorkshop yeah, I did actually measure voltage yesterday which was at approximately 44v. I think, please correct me as I'm completely noob and trying to grasp an understanding. I think, the new heatplate with new thermistor is not working, so what's happened is the working heat plate has overheated and now blown the new thermal fuse and I'm back to square one. Have ordered a new kit. Does 44V at the heater sound right?

[@MooosivBalls]

@@KevsElectricalWorkshop Second kit arrived today. The thermistor side heats up but is way behind the switch side in terms of temperature, so the switch side gets to about 230c before it beeps and turns off. I've resoldered the thermistor and made sure heatplate contacts are good - I put plenty of thermal compound in - I'm stumped - any advice please?

[@KevsElectricalWorkshop]

are you measuring each plate separately or both clamped together? what are the resistance reading of each heater while disconnected?

[@ellieokeefe2931]

hi kev great vid by the way what is the name of the mega board you used to make your chip tester?

[@KevsElectricalWorkshop]

Arduino mega 2560

[@LouiseG-my3dg]

Very helpful video. On my 4.2B straighteners it appears the thermal fuse failed due to the thermistor debonding from the heater. The thermistor measures just under 100Kohms - can this just be stuck back down or safer with a new thermistor? Also do you recommend a specific type/brand of thermal fuse? Thank you

[@KevsElectricalWorkshop]

what shape is your thermistor?

[@LouiseG-my3dg]

Kevs Electrical Workshop Hi Kev, thanks for replying. The thermistor is exactly the same as your faulty one in this video, little black oval shaped one.

[@KevsElectricalWorkshop]

ok there are the best and never go wrong, look at the mating surface of the thermistor you will see a ring, remove it by flicking with nail or small knife this will give you a fresh bonding step, use high temperature RTV silicon in this step (none in middle) and clamp to heater until set. feel free to add a bit extra rtv in top edges. I use Technicqll red available on ebay for a few pounds. must be rated 250 or 300 C Sometimes if lucky and the thermistor blob size is small you can use the heater clip to retain the thermistor.

[@LHKleyn]

@@KevsElectricalWorkshop Hi Kev, I need to replace my elements on both sides, can I use RTV silicon instead of thermal paste?

[@valectronica]

@@KevsElectricalWorkshop Hello. Good information, but can you explain how to join the cable with wire? Because I think tin melts Regards.

[@tonyrobinson8610]

Great Vid Kev. Checking my non-working GHD 4.2B shows that the thermal fuse is us and will be replaced but, checking heating elements shows that the heating elements on each side is 71 ohms and not half of that value as shown in your vid. Is this ok? or, does it suggest an additional fault? Keep up these helpful vids - we amatuers would be lost without them

[@KevsElectricalWorkshop]

Hi Tony, disconect both heaters and measure them you will most proberly find the one on the thermistor is broken.

[@tonyrobinson8610]

Kevs Electrical Workshop Bingo!, Got it in one. Thanks a bunch. Able now to move on with the repair. Cheers mate.

[@littlebbastard]

@@KevsElectricalWorkshop can i send a set of ghd 5.0 to you for repair please cheer's

[@paradisehereicome5902]

Hi Kev thanks for the tutorial a quick question what is the past called that you put under the heat plate?

[@KevsElectricalWorkshop]

its called thermal grease, i use HY410

[@paradisehereicome5902]

cool thanks for the quick reply

[@marcoc6793]

It's me again Kev, I temporary bypassed the thermal fuse just to see if it was turning on and it did. Unfortunately I see the led blinking and a sound coming from the buzzer at regular interval. I've disconnected from 1 side the thermistor and it says 110K (seems ok). I hope is not the PIC. Is the thermal fuse working like a normal fuse but with temperature? I mean, the bypass I did could perfectly simulate the TR? Many thanks

[@KevsElectricalWorkshop]

Sorry for the delay, its the PIC's A/D gone faulty

[@sweetdata3974]

Thanks for this video ! I have got an issue with replacing the heater- switch side on Mk5. In fact, for the 2nd Time, when I replace it and test it, it breaks, it seems there is a short circuit somewhere ( black burn trace localized at the breakeage zone) , an idea please? Thank you

[@KevsElectricalWorkshop]

Sometimes the control board can over drive a heater but this is rare and breaks both normally, main cause is the heater is to tight to the plate with little or no thermal grease, the heater and plate expand at different rates when heated and if the cant move the plate will break the heater.

[@sweetdata3974]

@@KevsElectricalWorkshop Thank you very much,for the answer, I think my case is the rare case, because I put another heater with grease, same problem on the other side. what piece is faulty in this case please?

[@KevsElectricalWorkshop]

remove r10,r5,r1 from board and measure them, they are all 1M ohm, one of these normally causes the rare over power issue.

[@howtodo1518]

Great thank you! I'm looking to buy a thermistor for ghd 5.0, I didn't understand very well which one should I buy, could you help me please?

[@KevsElectricalWorkshop]

buy one from ebay already mounted on a heater it will save a lot of work.

[@howtodo1518]

@@KevsElectricalWorkshop I would like to mount it my self on the heater ;)

[@KevsElectricalWorkshop]

ok here are some ebay buzwords "100K Ohm B3950 1% NTC Thermistor Temperature Sensor 3D Printer Reprap" they normaly have white cable attached just cut to size.

[@howtodo1518]

@@KevsElectricalWorkshop OK ! thank you very much

[@ks6902]

Could it be the thermal fuse that's causing it to cut off after a few seconds? My wife's ghd 4.2b stopped working so I took them apart, cleaned contacts and it worked for a few seconds then packed in again

[@KevsElectricalWorkshop]

it could be, i have had a few do this on me but only on revisions with a square buzzer

[@ks6902]

@@KevsElectricalWorkshop wife ordered some new ones, literally 30 seconds after realising they broke (women and their straighteners 😅) going to order some spares online and have a go at fixing.

[@alancarrick7645]

While changing the fuse I broke the silver clip, can you buy a replacement silver bracket model 4.2B?

[@KevsElectricalWorkshop]

ebay is your best bet

[@beautifulsmall]

you can reset some thermal fuses with freezer spray.

[@KevsElectricalWorkshop]

no didnt work possibly needs to ne colder

[@gr0nis]

Hi, I have a v5 and trying to figure out what is wrong. I have checked everything in this video (the fuse, the heaters, thermistor, and resistors). Everything seems ok. Nothing looks burnt. If i turn it on, everything seam to work, but the heaters don't get warm. Not sure what I should test next. Any ideas?

[@gr0nis]

Rechecked everything and It was the R11 resistor that was dead (1.4M ohms measured). Ordered now from China. I guess I have to wait 4 months for the resistors to arrive before I see if it works! Wish me luck :)

[@KevsElectricalWorkshop]

a few £ from ebay and would be local, just search for R11 or R8

[@gr0nis]

@@KevsElectricalWorkshop I live in Sweden and here electronics are rarely local. All sellers I found on eBay ships from overseas (US or China). Sometimes I can find components through some local online shop. Most of the time it’s import from Germany, and the worst case you have to order from China.

[@salvsena]

hi, i have GHD 5.0, have replaced thermal fuse because it was broken, but now when turn on i listen beep and only one resistor is warm, the resistor near termistor is cool. What i can check ?

[@KevsElectricalWorkshop]

sounds like you have a broken heater that needs replacing

[@salvsena]

​@@KevsElectricalWorkshop thanks for your reply, after 10 seconds also the new thermal fuse is broken. Why this ?

[@KevsElectricalWorkshop]

if the broken heater is on the temperature sensor side it will overheat the other side and blow the thermal fuse.

[@andy7146]

hi Kev another great video. I have tried to replace the thermistor on a 4.0 and 4.2b after heater plate and fuse blow but when switched back on temp shot up to over 200 degrees C is this the chip or is it something I did wrong? can you advise. Thanks andy

[@KevsElectricalWorkshop]

normaly bonding to the plate causes the issue, what thermistor are you using.

[@andy7146]

hi kev I am using TKS DHT0B104F4003SY 100K 4000k 1% Axial Glass NTC Thermistor from rapid electronics.

[@KevsElectricalWorkshop]

Should get away with it, does it go over 200 and then drops back?

[@andy7146]

it goes to 205, 210 then drops down to mid 195 ish

[@KevsElectricalWorkshop]

Its not too bad, there is quite often a overshoot with replacement thermistors think its due to the responce time. if you replace R3 from 4K3 to 5K6 this will take off 10 deg on the readings

[@ethnicartisanmarket5745]

Hello. Can you repair FHI HEAT flat irons as well?

[@KevsElectricalWorkshop]

possibly

[@hadiqariaz7772]

Hi I have a ghd platinum that doesn't heat up and there is a red light that just flashes, what do you think is wrong with it and can I fix it?

[@KevsElectricalWorkshop]

Proberly a broken heater, if under 2 years old contact GHD. Dont know of anyone who repairs them just cant get the parts.

[@vsolomonidesable]

Vic Hi Kev my granddaughter has a GHD 4.2b and when she plugs in it beeps . I managed to open it and found that R11 is burnt out could you please supply me the one and could you tell me what other component I would need to check to get it working or if you give me your address I could send it to you for repair.

[@KevsElectricalWorkshop]

Hi Victor, You can find our repair service at www.webinfusion.co.uk, the resistors you can find on ebay search for "ghd R11" and to be honist that is possibly the only fault

[@JGMGM6950]

Thank You 🍺

[@vickybin3077]

Great Job! by the way, I supply the heating element for hair straighteners, welcome inquiries!

[@littlebbastard]

Hi kev can i send a set of ghd 5.0 to you for repair cheer's

[@KevsElectricalWorkshop]

yes our repair service is available at www.webinfusion.co.uk

[@muhaahaloa941]

Bk again sorry i hope you don't mind me asking what is the arduino setup you created to test the 8 pin pic or ic actually doing ??And do you know what thermistors are in the original GHD using are they glass or smd or even the glass type ?

[@KevsElectricalWorkshop]

The Arduino supplies power to the PIC and toggles the interupt line at 50hz, it then calculates the thermistor ohmage via measuring the thermistor input voltage and using a bit of ohms law. if you have ever tried to measure the thermistor in-circuit you know you cant. The thermistors are 100k @25c beta value approx 4100

[@muhaahaloa941]

Kev i love the videos mate, having lots of fun the closest i could find is NTC 100k B3950 its the glass type, like a small bulb.

[@KevsElectricalWorkshop]

The B3950 is close and often gets used but is not ideal and possibly the best fit unless you want to spend £10 per thermistor, Pics are protected they wont give up there code. thats a new fault on the SS5 proberly the pic or C1.

[@muhaahaloa941]

Hi kev still working with the pic :D..Few friends are looking at decap, i used to do a lot of exploit development so we will see, replaced C5 mate properly attached the 100k B3950 bulb type thermistor with 350 deg silicone and it went to 230 deg and did not look like it was coming down, so i had to unplug it as it started to smoke a little LOL and i did not want to kill the thermal fuse,what hurt is i burnt my really finger in the process..I don't understand why the thermistor is reading 60 ohms at 25 deg..

[@KevsElectricalWorkshop]

LOL all fun, good luck with the decaping of the pic aparently the die inside is created such that even a decaped pic still dosnt give direct access to the protection fuses......write the code from scratch far easier, its only 1K of code. Think that thermistor you had was a bit faulty should be 100K at 25

[@davidapartment8349]

hi i have mk5 , it don't turned on, then i changed the PCB , but i think is the fuse the problem, i have a question, if one fuse ore i don't plug the fuses , the led will turn on or i need to plug the fuses too for see the led on? cause the led don't turn on anyway i changed the pcb , the cable is ok, thanks

[@KevsElectricalWorkshop]

Can you explain more didnt quite understand

[@davidapartment8349]

sorry my english is bad ^^ i discover that the fuse give no power with the tester, so i need to change it. i changed the pcb before discover it, thinking it was the problem, but the light didn't turn on anyway, and after i discover it was the fuse. my question is, if the fuse is the problem, the light don't turn on? do i need to change the fuse to see the light indicator turn on? hope u understand now ^^

[@KevsElectricalWorkshop]

For anything to happen all fuses need to be good.

[@davidapartment8349]

ah ok thanks! so if 1 fuse do not works or for example disconnected, the light will not turn on. thanks for the info ^^

[@geirmyklebust]

Have identical Straightener, one side not working. But, to much work, not worth it, I got a new better one, second hand ceramic GHD, for about 25 bucks incl. shipping.

[@gordonfisher9226]

Would a reading of 0.04 ohms across the thermal fuse show a faulty fuse?

[@ellieokeefe2931]

hi kev whats the board underneath this one Arduino mega 2560 called?

[@KevsElectricalWorkshop]

display/keyboard shield

[@ellieokeefe2931]

thank you

[@maxastuto]

hi, I have a hair straightener GHD 4.2 B Jemella European version at 230Volt. The problem is that it doesn't turn on. I have text all, the 2 resistors of the plates, the fuse, the NTC thermistor marks 140Kohm at room temperature, the switch, the rotatable connector of the cable, the two 70 ohm minimelf smd resistors, the diodes, etc. etc. everything is OK. The T4D 560 triac has on one pin the voltage to supply the plates, while on the other pin, it has nothing. Could it be that IC 12F675 does not send the signal to the triac because it is faulty or should be reprogrammed ??

[@KevsElectricalWorkshop]

PIC dead, clean your switch and change the PIC

[@maxastuto]

@@KevsElectricalWorkshop many thank for your information! replaced the new pic, the pic must be reprogrammed? Where can I find the firmware for the pic?

[@florencedieu8529]

Can't hear too well

[@ellieokeefe2931]

also what is a 100k beater?

[@KevsElectricalWorkshop]

100k 4100 beta, 100k is ohms at 25 deg C the beta is the curve characteristics