Glow Worm Ultimate PCB fault - require resistor colours

[paulsydsmith]

Hi, I have a Glow Worm Ultimate 40FF which has Stopped...it's quite obvious from the PCB what the fault is:

I have a 2 Fuse PCB, and the resistor R11 next to fuse F1 is all burnt up and gone open circuit.

Rather than buy a complete new PCB, I'd like to replace the resistor (I work for an electronic company), but I don't know the value to replace it with.

If anybody has to hand one of these, could you please post the resistor colours, then I can do my bit for the environment and repair rather than discard.

Thanks.

 

[Agile]

You need a little more knowledge than just the resistor value!

Resistors dont just burn up!

They only overheat when subjected to a current overload.

To repair your PCB you will need to see what the function of the resistor is and find the real fault that caused it to overheat.

Tony

 

[paulsydsmith]

The real fault was a couple of "dry joints" on the board, which have caused more current to flow through this resistor than it was designed for.

Over a period of time (possibly since new:9 years) it has just been running this resistor a little warmer than it would normally. Eventually it has just given up the ghost.

The company I work for can get the part for pennies, but Glow-Worm have told me that it's not repairable and they can't give me the information I require....hence they want me to pay a large sum for a new PCB.

What ever happened to the age of repairing something rather than just throwing stuff away and getting new?

 

[londonboy]

http://www.kpsec.freeuk.com/components/resist.htm

 

[Agile]

If anyone can post a close colour picture of the area of the PCB with the R11 then I can decode the colour.

Tony

 

[Biggles..]

as the guy works for an electronics company as an engineer i'm sure he knows his own resistor colour band and their values.

Try emailing a guy called geoff at a company called CET they repair boards and he'll deffinately know the R value.

 

[paulsydsmith]

FIXED!!
It's 27K ... the band I couldn't read turned out to be orange...

So I removed the resistor and forensically analysed it using a USB microscope...kinda guessed it was orange, then did a Google search for photographs of the PCB (thanks to all those out there selling PCB's!!), which confirmed my thoughts.

Touching a few dry joints on the board, and replacing the resistor with a 27K one means I have now had hot water again since Sunday !

Thanks to everyone who replied with hints and tips regarding resistor colours.

 

[Agile]

I suspect this may be a mains dropper resistor with a power disipation of 5-10 watts which will run hot.

Its better to mount these on a longer lead length thus spacing them further from the substrate and thus critically further from their own solder connections. Even spirialing the lead will improve the heat loss further.

Tony

 

[paulsydsmith]

All,
just to let you know that three years on and the bopiler is still running smoothly.....all for half an hours work and a component costing less than 10p!!

 

[Agile]

What is a "bopiler" ?

 

[paulsydsmith]

What is a "bopiler" ?

Obviously it's a Boiler with a spare 'P' ...

 

[strahl]

Hello Paul

Just to let you and the others here in the forum know, at our Glowworm Ultimate 60FF the exact same thing happened last week: the resistor R11 after the fuse burnt and the PCB was scorched around it. The fuse didn't blow.

stefan

 

[paulsydsmith]

....for those looking at this thread - my original fix made back in 2009 is still going strong - the boiler has behaved perfectly since my replacement of the resistor.