GHD hair straightener repair - Page 1
Forum section: electronics / repair

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 04:40:55 pm
content: A colleague has asked me to look at his daughters GHD hair straighteners. They just don't come on.I think the problem may be the resistors. See attached photo. starting from bottom 1st is 50R and that matches colour codes. 2nd is 1M, 3rd and 4th are 460K although there is 300K between the two non connected ends so probably other circuitry. Right had one is 855Kblack brown green is 015 or 0100000 (100K ?). Are thse conventional colour codes ?

author: Andy Watson
author_rank: Super Contributor
timestamp: August 24, 2014, 04:48:21 pm
content: Quote from: Simon on August 24, 2014, 04:40:55 pmEither 500 ohms or 1M. Given that there are two in series that appear to be across the mains, I would suspect the latter value.Edit: Hang on a mo, R8 and R11 have a different colour scheme! I would say they were 51 ohms.

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 04:51:33 pm
content: Well then they seem to be at fault, if the bands spell 51R and it measure 1M, turning the values over is 500K in a very weird way

author: Andy Watson
author_rank: Super Contributor
timestamp: August 24, 2014, 04:57:12 pm
content: Try again:Brown black green = 1MGreen black brown = 500R, Not a preferred value, so I would suspect these are 1MBlack brown green , doesn't make senseGreen brown black would be 51 R. So presumably these are not across the mains!

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 05:00:56 pm
content: Well the second must be 500 because the other way it starts with 0 which is pointless, it measure 1M. Yes these are directly connected to mains, I think they are being used as mains droppers for the control chip that is a custom GHD, I'm only getting around 2V on the chip.

author: Andy Watson
author_rank: Super Contributor
timestamp: August 24, 2014, 05:05:07 pm
content: Any use ?http://www.ghd-repair.co.uk/4.0B.html

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 05:12:14 pm
content: Thanks, seems like I'm not the first to have to fix one then.

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 05:20:48 pm
content: Their PCB references and values are slightly different but they are saying that what I'm calling my 2nd resistor (R8on my PCB) fails open circuit often, it should be 100 ohm, but then they have 1 I have two so looks like they know the fault and tried to cure by splitting the resistors but still one has gone unless it's a soldering fault.

author: SeanB
author_rank: Super Contributor
timestamp: August 24, 2014, 05:28:17 pm
content: There is a thermal fuse inside by the element that goes open circuit. Easy to change and you probably would look at the videos by Televisionmagforum on the GHD and the assorted fakes on how to repair them.https://www.youtube.com/channel/UCFTnQHvgadDIbSlP7qLmBkgand look down for the GHD videos.

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 05:30:13 pm
content: This one is genuine i think and very well made

author: Andy Watson
author_rank: Super Contributor
timestamp: August 24, 2014, 05:31:52 pm
content: Well R8 and R11 are the same. So assuming there's nothing connected to the mid-point you should get the same (more or less) reading for both of them.

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 05:32:51 pm
content: I get 50R and 1M so one has gone practically open circuit.

author: SeanB
author_rank: Super Contributor
timestamp: August 24, 2014, 05:42:11 pm
content: So slap in a 51R 1/4W resistor and try it, then if it works get the right MELF resistor or simply close it up again.

author: Andy Watson
author_rank: Super Contributor
timestamp: August 24, 2014, 05:44:01 pm
content: Have you checked for continuity through the heating element (as somebody has mentioned above - there's usually a series thermal fuse in-line).Don't discount the possibility that the wrong components have been fitted at the factory - very easy to mis-read those 51/1M markings (as I did). Try to compare the circuit with those given on the GHD site.To be honest, unless you see this as a challenge, I would be telling your colleague, with as much authority as I could muster, "Beyond economic repair", irrespective of the truthConsumer electronics - blargh!

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 05:47:31 pm
content: Quote from: Andy Watson on August 24, 2014, 05:44:01 pmTo be honest I have done that on everything he has asked me to look at so far which usually comes in the form of TVs for his kids bedroom and either it is too hard to find a fault or I don't want to take the risk that it catches fire while the children are asleep and it's on standby.In this case it seems an easy fix and i owe it to him, i mean i need to do something for all that sheet metal stuff he does for me

author: Andy Watson
author_rank: Super Contributor
timestamp: August 24, 2014, 06:00:59 pm
content: From the GHD site:QuoteIf either R8 or R11 is reading more than 51R - you've found the fault.

author: Simon
author_rank: Unknown
timestamp: August 24, 2014, 06:02:57 pm
content: indeed that is what I have, i'll assume the cap came away from the resistor body as it now reads 1M not 51R, it's the type that almost loks like a little fuse