Component detection help

[conan981]

Hi to all, and sorry if i put my post here since i couldn't find any other place that could be better. i am sure that here someone can help me to recognize a component from a soldering station board i have.
It is a protection component, in first pictures is marked with a red circle, and is put in parallel with a diode rectifier BYR29F-600 (Rectifier diode ultrafastge)

Component is broken It is quite all burnt and i couldn't find nothing with that marking.
Soldering station is working the same, but without protection so i prefer to wait..
here are some photos ..
thanks in advance for any help
Sincerly

[vinceroger69]

Re: Component detection help

Please ignore i thought it read 1802 which is sometimes capacitor markings which would of possible made it a
18 pf capacitor but not 100% sure

[conan981]

Re: Component detection help

i supposed from his position it was some type of metal oxide varistor. (on the board near the other varistor is marked G1, and near my component is marked G2)
the first line seems to be written 180Z
if it was a capacitor shouldn't be written something else?
btw thanks for you suggestion

[stj]

Re: Component detection help

make & model of the equipment?
maybe there is a schematic.
that looks more like a MOV btw.

[conan981]

Re: Component detection help

should be a Mov indeed.. but i would like to know the properties.. to buy something equivalent. Known that is used to protect diode rectifier BYR29F-600 there is no considerations we can do?
SOldering station is old and couldn't find any schematic .. btw model is AC-DC 250 TIG

[stj]

Re: Component detection help

what make?

and the mov,
maybe i'm reading it wrong, does it say:
180z
38i1
??

and what is the diameter??

[conan981]

Re: Component detection help

diameter is 7mm
i read 180Z
on second line 3811 (third char is 1 for sure)

[stj]

Re: Component detection help

then i think it's a v180za1 or equiv

[conan981]

Re: Component detection help

Great
Thanks mate, i'm going to try

[eccerr0r]

Re: Component detection help

I don't know why a MOV would be placed in parallel with a diode...
Is it really in parallel with the diode?

[stj]

Re: Component detection help

or why it's rated at 115v running - i would expect that in u.s. or canadian stuff.

[budm]

Re: Component detection help

The cap is put in parallel with the Diode is for snubbing, looks to be 180pF and it should be rated at about 1KV. Most of the time they will put cap in series with the resistor to form RC snubber network and connected in parallel with the diode.

[conan981]

Re: Component detection help

So do you think it is not a varistor?

[budm]

Re: Component detection help

I cannot see why they will put MOV in parallel with diode.
Just think about it: If the MOV conducts when breakdown Voltage reached then the diode will be bypassed by the MOV which then the load will be fed with AC!

[vinceroger69]

Re: Component detection help

its odd i first thought it maybe be capacitor(post 2) but when you said the board id started with a G it made me question myself as all the capacitors i can see start with board id of C so yes does make you question things

[budm]

Re: Component detection help

I would like to see the straight shot pictures of the top and bottom side to verify the connection of that G2 device.

[stj]

Re: Component detection help

G used to be used as a designation for spark-gaps in the past.

[petehall347]

Re: Component detection help

G used to be used as a designation for spark-gaps in the past.

yep .have seen that recently in a philips tv .

[conan981]

Re: Component detection help

Thanks to all
Here are photos of front and bottom of pcb. if some other detail is needed let me know.

[stj]

Re: Component detection help

it looks like one pin is connected to the diode, but the other looks isolated.
check with a meter

also
the blue cap behind the diode is bad.


is this a welder??