Home |
Search |
Today's Posts |
![]() |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
|
LinkBack | Thread Tools | Display Modes |
#1
![]() |
|||
|
|||
![]()
Gentlemen,
I refer to you this photo of the internals of a typical modern cheap and nasty blanket controller. All the components it uses are shown on this board: just 5 diodes, 3 resistors and some 'mystery component' whose function is presumably to sense overheating from the two resistors it's between and cut-back the mains voltage to the blanket itself if needed. https://tinyurl.com/t7s6og8 Question is, what is the correct name for this 'mystery component' and what should it read resistance-wise when cold? Thanks! -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
#2
![]() |
|||
|
|||
![]() Question is, what is the correct name for this 'mystery component' and what should it read resistance-wise when cold? .... and (I forgot first time around)... why have they put a couple of turns in each of the leads? -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
#3
![]() |
|||
|
|||
![]()
Cursitor Doom wrote:
https://tinyurl.com/t7s6og8 Question is, what is the correct name for this 'mystery component' PTC thermistor? thermal fuse? http://www.aolittel.com/sale-10973142-aupo-p3-f-pico-subminiature-pellet-ceramic-thermal-fuse-tf-cutoff-125c-250v-2a-axial-leaded-for-air-.html |
#5
![]() |
|||
|
|||
![]()
On Fri, 22 Nov 2019 20:17:25 +0000, Andy Burns wrote:
PTC thermistor? thermal fuse? http://www.aolittel.com/sale-1097314...-subminiature- pellet-ceramic-thermal-fuse-tf-cutoff-125c-250v-2a-axial-leaded-for- air-.html Bingo, Andy! Good call. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
#6
![]() |
|||
|
|||
![]()
On Fri, 22 Nov 2019 16:11:31 -0500, Ralph Mowery wrote:
It might be a simple fuse. See if the resistance is zero/near zero when warm and cold. Can not tell from the photo, but looks tohave a 7A over the 120 volt. It's actually 2A in this case. Andy's suggestion was correct. But like you say, the resistance should be pretty low whereas it's actually infinite, so looks like it's blown. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
#7
![]() |
|||
|
|||
![]()
On 11/22/19 2:50 PM, Cursitor Doom wrote:
Gentlemen, I refer to you this photo of the internals of a typical modern cheap and nasty blanket controller. All the components it uses are shown on this board: just 5 diodes, 3 resistors and some 'mystery component' whose function is presumably to sense overheating from the two resistors it's between and cut-back the mains voltage to the blanket itself if needed. https://tinyurl.com/t7s6og8 Question is, what is the correct name for this 'mystery component' and what should it read resistance-wise when cold? Thanks! Not sure about the name of the component, but I will say that today's electric blankets are awfully poor made. Years ago, when I had one while growing up, it lasted for at least 10 years before someone threw it away during cleaning. As an adult, I purchased a Sunbeam brand about five years ago and I've never had one last more than 6-8 weeks! The only type of heating blanket I've found in recent times that does last are electric throws. I have two, purchased about 5 years ago, and with heavy use, they still work fine. Problem is that they are a bit too small for bed use although I make them work that way. |
#8
![]() |
|||
|
|||
![]()
On Friday, November 22, 2019 at 11:50:53 AM UTC-8, Cursitor Doom wrote:
I refer to you this photo of the internals... Question is, what is the correct name for this 'mystery component' and what should it read resistance-wise when cold? It's either an energency overtemperature cutoff (like a fuse), or a thermal switch that repeatedly time-cycles according to the heating/cooling time constant of its companion resistors. It has a '2A' rating, not a temperature rating, so probably NOT the emergency cutoff. Maybe a PTC resistor (solid state 'switch'). The diodes presumably send current to heating element A on positive half-cycles, and heating element B on negative half-cycles (so as to retain some function if one element fails open-circuit). |
#9
![]() |
|||
|
|||
![]()
On 23/11/19 5:34 pm, whit3rd wrote:
On Friday, November 22, 2019 at 11:50:53 AM UTC-8, Cursitor Doom wrote: I refer to you this photo of the internals... Question is, what is the correct name for this 'mystery component' and what should it read resistance-wise when cold? It's either an energency overtemperature cutoff (like a fuse), or a thermal switch that repeatedly time-cycles according to the heating/cooling time constant of its companion resistors. It has a '2A' rating, not a temperature rating, so probably NOT the emergency cutoff. Maybe a PTC resistor (solid state 'switch'). The diodes presumably send current to heating element A on positive half-cycles, and heating element B on negative half-cycles (so as to retain some function if one element fails open-circuit). It's cactus, throw the thing out. |
#10
![]() |
|||
|
|||
![]()
On Friday, 22 November 2019 23:49:28 UTC, Starfella wrote:
On 11/22/19 2:50 PM, Cursitor Doom wrote: Gentlemen, I refer to you this photo of the internals of a typical modern cheap and nasty blanket controller. All the components it uses are shown on this board: just 5 diodes, 3 resistors and some 'mystery component' whose function is presumably to sense overheating from the two resistors it's between and cut-back the mains voltage to the blanket itself if needed. https://tinyurl.com/t7s6og8 Question is, what is the correct name for this 'mystery component' and what should it read resistance-wise when cold? Thanks! Not sure about the name of the component, but I will say that today's electric blankets are awfully poor made. Years ago, when I had one while growing up, it lasted for at least 10 years before someone threw it away during cleaning. As an adult, I purchased a Sunbeam brand about five years ago and I've never had one last more than 6-8 weeks! The only type of heating blanket I've found in recent times that does last are electric throws. I have two, purchased about 5 years ago, and with heavy use, they still work fine. Problem is that they are a bit too small for bed use although I make them work that way. 10 years? I grew up with one several times that old. NT |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Sunbeam heated blanket controller | Electronics Repair | |||
Shure M610 Feedmack controller Shure Feedback controller M610.pdf [1/2] | Electronic Schematics | |||
blanket chest - blanket chest 003.JPG | Woodworking Plans and Photos | |||
blanket chest - blanket chest 002.JPG | Woodworking Plans and Photos | |||
blanket chest - blanket chest 001.JPG | Woodworking Plans and Photos |