What Are These Resistor Looking Componenets?

[jostewcrew]

Thought these were resistors, however they dont match any color coding to be as such. Ceramic Caps? Chokes? Inductor? Thought inductor but i thought inductors were 4 band. Need help Please. Anyone ever seen before?

[budm]

Re: What Are These Resistor Looking Componenets?

They are MOX Flame proof resistors.

The one with (counting from the bottom) Brown - Red - silver - Yellow - Brown is 0.12 Ohms 4% with temp co of 100ppm/c.

The other one I cannot really tell what the color bands are.

What do they show on your Ohm meter?

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

the bands are as follows for each:

black, black, gold, black, black

black, red, silver, yellow, brown

i tried using many color chart calcs and they wont allow these colors. any link to a page with a chart?

they both show .3 ohms on the meter. the black and gold one is on a circuit that blew the main cap and mosfet. im changing the other circuit components for good measure.

[budm]

Re: What Are These Resistor Looking Componenets?

So the resistors are not blown then.
Are they connected in parallel?
It looks like they are current sensing resistor connected to the Source pin of the MOSFET so if too much current flow it will shutdown the drive to the Gate of the MOSFET.

BTW, when measuring very low Ohms resistor, you need to deduct your probe leads resistance from the reading since you probe leads are no 0 Ohms.

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

Not in parallel. you are correct with the layout. both are on the source pins of the fets on separate circuits. both resistors meet to chat on a circuit that seems to lead to a 14 pin ic.

so if they are good, ill just replace the one cap and the fet. everything else tests fine. just wanted to be safe...but was becoming a headache tracking down the resistors.

[budm]

Re: What Are These Resistor Looking Componenets?

Not in parallel. you are correct with the layout. both are on the source pins of the fets on separate circuits. both resistors meet to chat on a circuit that seems to lead to a 14 pin ic.

so if they are good, ill just replace the one cap and the fet. everything else tests fine. just wanted to be safe...but was becoming a headache tracking down the resistors.

Between what pin and what pin of the MOSFET are shorted?
When that MOSFET shorted out, it can damage the IC that drive the Gate of the MOSFET, so the new MOSFET will be damaged if the IC is bad.

What is this board any way?
Can we see the whole board?

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

Uploaded front side and backside of board. Back side orientation is flipping front side over from top down.

this is a control box for an old liftbox, hidden tv in furniture type deal...out of business for like 6 or 7 years...no service man or schematics i could find. it controls a tv stand that sits in a dresser...this box is the power source for the lift motor and the relays for the ir remote and such. the box had power, 120v in and out for the tv plug. but no function of lift. open up the box and see the cap and the black fet.

so, the fet on the bottom right (starting far right pin at edge of board g,d,s) drain and source are shorted. this fet leads to the charred looking resistor (b,b,g,b,b) ,still on the source line and connects to line heading toward ic. underneath the aforementioned resistor , is the other fet that is testing good, has the other resistor (b,r,s,y,b) in line with its source pin, that ties in with the other resistor that leads to the ic.

if the other fet is good and both resistors are good....then i think it was limited to the fet blowing?

The main filter cap was blown on the anode side. I tested the components in this circuit. all diodes are good.

I was thinking the transformer blew.... still testing

[budm]

Re: What Are These Resistor Looking Componenets?

Uploaded front side and backside of board. Back side orientation is flipping front side over from top down.

this is a control box for an old liftbox, hidden tv in furniture type deal...out of business for like 6 or 7 years...no service man or schematics i could find. it controls a tv stand that sits in a dresser...this box is the power source for the lift motor and the relays for the ir remote and such. the box had power, 120v in and out for the tv plug. but no function of lift. open up the box and see the cap and the black fet.

so, the fet on the bottom right (starting far right pin at edge of board g,d,s) drain and source are shorted. this fet leads to the charred looking resistor (b,b,g,b,b) ,still on the source line and connects to line heading toward ic. underneath the aforementioned resistor , is the other fet that is testing good, has the other resistor (b,r,s,y,b) in line with its source pin, that ties in with the other resistor that leads to the ic.

if the other fet is good and both resistors are good....then i think it was limited to the fet blowing?

The main filter cap was blown on the anode side. I tested the components in this circuit. all diodes are good.

I was thinking the transformer blew.... still testing

I cannot tell from the pictures as to what and where the resistors (b,b,g,b,b) and (b,r,s,y,b) are.
It sounds like the main filter cap has failed so the circuit is fed with pulsing DC instead of steady DC so the circuit is damaged.
I cannot really trace out the board using the pictures due to density of the board.
The only only thing you can do is to replace the damaged parts, then power up the board by putting 75W incandescent in place of the fuse then power up without activating any thing, if the lamp comes on full bright and stay that way it means you still have short circuit.

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

yeah, i didnt expect to be able to get any tracing done...thats all on me, though i appreciate the thought. i just wanted to figure out what and what value those resistors were. still even with searching for nox color codes, they dont match what it is showing me.

im probably going to just order what i can and then find another box for parts and test between the two. im sure i can get a working control out of the two. thanks for the light bulb trick... ill make sure to utilize it

[budm]

Re: What Are These Resistor Looking Componenets?

MOX = Metal Oxide type resistor, no relationship to color band.

The 5-band color band used on this resistor is not the same as normal 5-band coding (https://www.digikey.com/en/resources...or-code-5-band).
For this resistor:
The 4th band is the Tolerance band, 5th band is for the Temperature Coefficient.

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

MOX = Metal Oxide type resistor, no relationship to color band.

The 5-band color band used on this resistor is not the same as normal 5-band coding (https://www.digikey.com/en/resources...or-code-5-band).
For this resistor:
The 4th band is the Tolerance band, 5th band is for the Temperature Coefficient.

right, i got that its not the same, however ive yet to find a chart that lists gold or siver, (third band on these) that gives any value. calcs wont accept it so i need a chart, but it refuses to give values for these colors other than multipliers.

so if its black, black, gold, black, black
or
black, red, silver, yellow, black ...
im still lost in values other than knowing that the 4th is tolerance and the 5th is temperature coefficient. or am i still not understanding something?

i think i got it, correct me if im wrong.

black= 0 ohm, black = 0 ohm, gold = x.1 ohm, black= no tolerance ,black = 250c ... so it will be 0 ohm +/- 0 ohm resistor with a temperature coefficient of 250c?

black =0 ohm, red = 2ohm, silver = x.01 ohm, yellow = no tolerance, black = 250c ... so it will be 2.02 ohm +/- 0ohm with a temperature coefficient of 250c?

the internet isnt being kind to me on this one...im trying lol

[budm]

Re: What Are These Resistor Looking Componenets?

right, i got that its not the same, however ive yet to find a chart that lists gold or siver, (third band on these) that gives any value. calcs wont accept it so i need a chart, but it refuses to give values for these colors other than multipliers.

so if its black, black, gold, black, black
or
black, red, silver, yellow, black ...
im still lost in values other than knowing that the 4th is tolerance and the 5th is temperature coefficient. or am i still not understanding something?

i think i got it, correct me if im wrong.

black= 0 ohm, black = 0 ohm, gold = x.1 ohm, black= no tolerance ,black = 250c ... so it will be 0 ohm +/- 0 ohm resistor with a temperature coefficient of 250c?

black =0 ohm, red = 2ohm, silver = x.01 ohm, yellow = no tolerance, black = 250c ... so it will be 2.02 ohm +/- 0ohm with a temperature coefficient of 250c?

the internet isnt being kind to me on this one...im trying lol

This typical color band scheme is not applied to these resistors.
https://forum.digikey.com/t/when-you...-resistor/1501
As noted, the fifth band if it is Black it can mean Non-inductive resistor.

black, black, gold, black, black Are you sure one end is not Brown?

Also when you check both of them with your Ohm meter using lowest Ohm scale, I.E. 20 or 200, to get better display resolution then deduct the meter probes resistance from the reading, what do you get?

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

again, i realize i cant use the standard color code for bands, but since i have no data on what these bands mean... im trying to make sense of it. where are you getting your denotations from? ive searched google for hours and it just keeps coming up with the same standard crap. how do i find out what the bands mean for these...

im 100 percent sure on the color schemes ive listed for the one with red and yellow. the all black one may actually be black,black,gold,brown, black. they measure .3 ohms a peice even though theyre different bands....may not make a difference because i dont know what they mean anyway. my leads shorted are .3 so deducting that i guess their 0 ohm

[budm]

Re: What Are These Resistor Looking Componenets?

See the link to Digikey on my last post.
If they want 0 Ohm resistor then it will only have 1 Black Band in the middle, or use large gauge jumper wire to handle the curent.

[budm]

Re: What Are These Resistor Looking Componenets?

BTW, you can see the resistance element wrapped around the core of the resistor.

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

thank you!!!

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

finally wrapped my head around what i was reading, from help here and online. the color body means nothing (manufacturers use different body colors depending on whatever theyre trying to notate within their own realm of components)

with what ive gathered, these are modified, four band , wire wound, high precision resistors with a fifth band notating the energy coefficient.

thank you budm for your insight and assistance.
shout out to R M MARSTON for a great guide and publish in the world of passives.

reference on where i found my answers:

Passive and Discrete Circuits: Newnes Electronics Circuits Pocket Book, Volume 2

[redwire]

Re: What Are These Resistor Looking Componenets?

Pink body usually means fusible, but not all manufacturers follow that.
more about it here: https://www.badcaps.net/forum/showthread.php?t=63662

[jostewcrew]

Re: What Are These Resistor Looking Componenets?

Pink body usually means fusible, but not all manufacturers follow that.
more about it here: https://www.badcaps.net/forum/showthread.php?t=63662

that makes perfect sense... thank you. so this is in fact a wire wound fusible resistor. i was pretty sure from earlier but this was the icing on the cake. thank you good sir.

initially, i also thought it was a current sensing resistor as there are two separate circuits , fet followed by these resistors, that only combine on a line leading to an ic. (only the one end of the resistors meet on this ic line) but i realized although this was possible, it was more likely a fusible, low ohm resistor for protection for over current for the ic if one of the lines failed and crossed. the two circuits were output lines 1 and 2 from a transformer. the fuse still reads through, so in my mind the ic is still good and it was limited to the fet failing and not actually having a short to ground on a line or from the transformer failing.

[budm]

Re: What Are These Resistor Looking Componenets?

Is one end of these two resistors have one end connected to Source and another connected to the Negative leg of the main filter cap?
What is connected to the drain of the MOSFET, I see the terminal next to it with (+) label.
The large Wattage of the resistors of the resistors are to big to be used to protect IC that draws so little current, it would be 1/4 W or so of fusiible resistor for protecting the IC.

If you can read the part number of the IC that drives the Gate of the MOSFET then you can look up spec sheet and may be application circuit for the IC.