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Electronics => Repair => Topic started by: ..... on November 05, 2019, 08:08:01 pm

Title: New resistor bigger than old
Post by: ..... on November 05, 2019, 08:08:01 pm

Hi thanks for looking.

i am currently trouble shooting a power supply and the -12v rail is only measuring around -2v.

i was looking at the board for anything obviously broken, i saw that a resistor was exploded so that i could not read the colour bands.

i looked at the schematic and it says 10r for the restore so i orders some 10 ohm restistors from eBay, they have arrived but they are significantly bigger.

i measured them with my multi meter and they are 11 ohms.

is there a problem with them bring bigger.

here are the resistors i bought: https://www.ebay.co.uk/itm/0-1-100ohm-Various-Value-Resistors-In-1W-2W-Power-5-Pack-of-5/231188853221?ssPageName=STRK%3AMEBIDX%3AIT&var=530403143436&_trksid=p2057872.m2749.l2649 (https://www.ebay.co.uk/itm/0-1-100ohm-Various-Value-Resistors-In-1W-2W-Power-5-Pack-of-5/231188853221?ssPageName=STRK%3AMEBIDX%3AIT&var=530403143436&_trksid=p2057872.m2749.l2649)

thanks for any help
JAck 

Title: Re: New resistor bigger than old
Post by: DaJMasta on November 05, 2019, 09:03:39 pm

Resistors rated for higher power will be larger to be able to dissipate the heat, the ones you bought are suitable replacements so long as they fit in the space.  The original probably wasn't a 2W rated resistor.



That said, resistors are straightforward parts that don't often fail on their own - there's a good chance that replacing the resistor isn't the only thing that needs doing.

Title: Re: New resistor bigger than old
Post by: ..... on November 05, 2019, 09:43:43 pm

Thanks for the reply

good to know the resitors i bought will work.

im working my way back through the -12v rail and the resitor is the first broken part ive found

thanks
jack