"Hakko 191" sensor leads too short? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: January 28, 2018, 06:02:21 pm
content: I suppose you get what you pay for, but I just bought a $12 Hakko 191 thermometer from ebay and I'm having the hardest time fitting one of the supplied sensors.Even when using the push button to bring the center post closer to the other two, it just seems that the sensor arms are too short.Is the quality control on these sensors really bad, or am I missing something?The only thing I can think of doing is untwisting one of the sensor arms and then reforming it to lengthen it by about 2mm.Oh - and I only got 5 sensors even though the ebay listing said it came with 10.

author: wraper
author_rank: Unknown
timestamp: January 28, 2018, 06:09:41 pm
content: QuoteDunno about that but I'm pretty sure you bought counterfeit.

author: ledtester
author_rank: Super Contributor
timestamp: January 28, 2018, 06:36:47 pm
content: I'm pretty sure it's not a real Hakko, and I knew that when I ordered it, but shouldn't they supply sensors which fit?Attached is a pic of what I got.

author: wraper
author_rank: Unknown
timestamp: January 28, 2018, 07:05:01 pm
content: Quote from: ledtester on January 28, 2018, 06:36:47 pmThey should not anything. Say thanks if it shows temperature within +/- 10oC, not +/- 50oC

author: amyk
author_rank: Super Contributor
timestamp: January 28, 2018, 10:08:41 pm
content: Quote from: wraper on January 28, 2018, 07:05:01 pmIt's a thermocouple sensor. It's either going to work or not.Are you sure you're fitting the sensor arms correctly? You might also want to check to make sure the movable pin is not caught in something:

author: wraper
author_rank: Unknown
timestamp: January 28, 2018, 11:06:51 pm
content: Quote from: amyk on January 28, 2018, 10:08:41 pmAnd thermocouple is supposed to work by itself, without any circuit and calibration of that circuit? I wouldn't be surprised if there is no cold junction compensation like in crappy reflow ovens. BTW it's only one variant of such counterfeits on the video, others are completely different inside. And Big Clive paid several times more for it.

author: stevelup
author_rank: Regular Contributor
timestamp: January 29, 2018, 01:48:41 pm
content: Love the logo on the sensor packaging!

author: ledtester
author_rank: Super Contributor
timestamp: January 29, 2018, 06:50:29 pm
content: Here are some pics showing how far the center post can move:

author: mikerj
author_rank: Super Contributor
timestamp: January 30, 2018, 03:56:12 pm
content: Take the tensioner mechanism apart and find out if something is limiting it's movement e.g. plastic flashing that needs to be trimmed. If nothing obvious then bend the hooked end so the thermocouples fit. When you buy this kind of cheap counterfeit crap, never assume it will work out of the box without some level of 'improvement'.

author: ledtester
author_rank: Super Contributor
timestamp: February 04, 2018, 12:50:55 am
content: Unfortunately I don't think I can increase the travel of the center post - it's being limited by the case itself. The 4th picture in my previous post shows that the slot in the case has more room for travel (next the red and black wires), but the problem seems to be that the button well at the other end isn't deep enough.After a lot of work I was finally able to get two of the sensors mounted.

author: wraper
author_rank: Unknown
timestamp: February 04, 2018, 01:28:09 am
content: Frankly, after seeing the video it looks more like you have problems with hour hands, not sensor.

author: ledtester
author_rank: Super Contributor
timestamp: February 06, 2018, 07:22:50 pm
content: I sent the video to my ebay vendor, and they gave me enough of a refund to buy 10 sensors from another vendor.