Blown heated blanker controller. Trying to figure out these smd resistors

[petehall347]

at 225 ohms i calculate about 250w .. but the resistance will change as it heats up so cant really calculate it easy
your tester knows what it is so its maybe good .

[Widget]

how many watts is the blanket supposed to be ?

100w.

I put it into my new(ish) component tester. Didn't tell me much I don't think.

[petehall347]

how many watts is the blanket supposed to be ?

[petehall347]

this is how it should be

[Widget]

f1 looks like a thermal fuse
the wonky display might not be helping things

True. though doesn't look like any legs were broken.

see what resistance between black and white and blue and brown .

Blue/Brown = 225ohms
Black/white = 944ohms

Check the resistances of the blanket and compare it with the good one before you turn to the controller. Some blankets have a sense wire in addition to the heating one, and if that is damaged the controller responds by effectively committing suicide. The blown resistors may be a symptom of a dead blanket.

Will do, though looks like we might have a receipt here for warranty, so might try getting refund/exchange.

are there any more components under those elevated displays?

none

There is a three pin triac near display, but when I see fault like this, where a few resistor disappear and where these was directly connected to controller... first disconnect that leg of ic, and see if you have diode junction reading to any other. .

i didn't notice that triac .

You see on bottom pcb trace signature, and on top is black package, combined with 220v heater what else could be...

https://www.eevblog.com/forum/beginn...=2302253;image

Thyristor... 2P4M
Op is lazy... (:-

Sorry, only saw that components this afternoon & had to Google it.

someone broke its heatsink off .

-

No heat-sink on it. No heat-sink on the working one either. Perhaps there meant to be & without one, it overheating causing as overload of some sort?

[petehall347]

someone broke its heatsink off .

[harp]

You see on bottom pcb trace signature, and on top is black package, combined with 220v heater what else could be...

https://www.eevblog.com/forum/beginn...=2302253;image

Thyristor... 2P4M
Op is lazy... (:

[petehall347]

i didn't notice that triac .

[harp]

There is a three pin triac near display, but when I see fault like this, where a few resistor disapear and where these was directly connected to controller... first disconnect that leg of ic, and see if you have diode junction reading to any other. Probably not, and thats is end of story designed to serve newnormal ideas of light green eco ic suicide.
It is sadly to say in this modern time - make your ovvn controler with discrete riggid parts which you can repair if you need.

[stj]

are there any more components under those elevated displays?

[CG2]

Check the resistances of the blanket and compare it with the good one before you turn to the controller. Some blankets have a sense wire in addition to the heating one, and if that is damaged the controller responds by effectively committing suicide. The blown resistors may be a symptom of a dead blanket.

[petehall347]

see what resistance between black and white and blue and brown .

[petehall347]

f1 looks like a thermal fuse
the wonky display might not be helping things

[Widget]

i cant see any mains switching devices,
i'm wondering if the numbers are just a display rather than a control.
and if both fuses are good it may just be a shorted display chip
it looks like it has a big switch so maybe it just has full power and half power (half wave rectified) to the heater

Oh, I didn't see/test the white (ceramic) fuse (F1), iirc the glass fuse (F2) tested ok.

The big (0-1) switch is on/off. The temperature & timer go up to 9 I think via the soft-press gray buttons

here is a different repair on the same controller . https://jestineyong.com/homemaker-el...ow-rug-repair/
and here is a pic of how it looks on the front .

Saw that one, pitty it wasn't the same repair I need lol.

am guessing the middle contacts black and white wires go to a thermistor in the blanket .

I'm not sure how the wires in the blanket work. There's 4 wires that run into the blanket but none seem to be linked to each when I did a cont test.

[petehall347]

am guessing the middle contacts black and white wires go to a thermistor in the blanket .

[petehall347]

here is a different repair on the same controller . https://jestineyong.com/homemaker-el...ow-rug-repair/
and here is a pic of how it looks on the front .

[stj]

i cant see any mains switching devices,
i'm wondering if the numbers are just a display rather than a control.
and if both fuses are good it may just be a shorted display chip
it looks like it has a big switch so maybe it just has full power and half power (half wave rectified) to the heater

[Widget]

OP said it was likely a short between mains and the thermistor, he binned it.

No, Kurets said that, not me (op) lol. but yes, I'll probably have to bin it.

[redwire]

OP said it was likely a short between mains and the thermistor, he binned it.

[Widget]

so it doesnt have a thermostatic switch, just a teperature disply/timer?

Not sure to be honest. I only know of the on/off switch & buttons to control temperature & timer (s2 & s3).