Need to replace resistor 900 ohms / % Tolerance

The original resistor doesn't look like 900R to me. It looks like Black, White, Red which is 1900 ohms.

It looks as if it has got hot, but how do you know it has failed ?

What resistance does it measure ?

Do you have the schematic and parts list with values  for the board - without those thingsmay go badly wrong.

MK

The original resistor doesn't look like 900R to me. It looks like Black, White, Red which is 1900 ohms.

It looks as if it has got hot, but how do you know it has failed ?

What resistance does it measure ?

Do you have the schematic and parts list with values  for the board - without those thingsmay go badly wrong.

MK

thx for your reply, I don't have the schematic and parts list unfortunately.

about the ohms,don't you see 4 rings ? why do you think there is only 3?

Eh, isn't a black band a zero? Brown would be 1. But then I've not seen resistors start with Black bands (unless they're zero-ohm) as the first band should be the first significant digit.

Perhaps it is discoloured or marked in some way that is a little different.

Sorry, Brain Fart on my part.

I think we don't know the value of that resistor !

092 with a silver tolerance band !

Measure it would be best.

Or tell us what the baord does and show a picture of more of it  - might be possible to work out what its for and thus waht value makes most sense.

MK

Here is the picture of the entire board. It allows to vary the speed (power) of electrical pump. There is a timer attached to it but that on the front panel.

Hmm. Looks like part of a relay R-C snubber ... I wonder if the capacitor is on the rear-side of the board ... there are probably a range of values that could work. It would be there to avoid the relay contacts from arcing/welding together.

That being said, michaelkellett is right - you should measure the resistor and see what value it measures at the moment. It certainly looks like it's been hot, but not hot enough to cook to death just yet ...

- Gough

Ok, will do, thanks for all the information. 

Rear side nothing special.

Maybe it's for switch-on surge protection (i.e. before the motor starts fully spinning, it could be for providing less power to the motor, and then the relay kicks in). In any case, based on no further information, I too would not automatically assume it is faulty, because a bit of discoloration can be normal in such boards.

I posted a similar conclusion, but Verint ate it !

The tracks to the resistor and the relay contacts are quite chunky and augmented by a soldered on wire, so I think the designer expected large currents.

I agree that the resistor may well be OK.

Any replacement should be of similar size and surge (or short term overload) capacity.

MK

yes something I should have mentioned first is that a current surge from wires arc effect have conducted to dysfunction of the box and a strong smell of burn and resistor was hot.