Fuses blowing in pcb's

[Vic Spanner]

Wont it vary from boiler to boiler?

Maybe but remerber a lot of manufactures use common parts across the range

Surely youre not meant to memorise the resistance of every component on every boiler?

No you write it down in your little book, In the summer when your servicing boilers spend some time and take some readings of good components

 

[newcomers]

Wont it vary from boiler to boiler?

Maybe but remerber a lot of manufactures use common parts across the range

Surely youre not meant to memorise the resistance of every component on every boiler?

No you write it down in your little book, In the summer when your servicing boilers spend some time and take some readings of good components

Good idea........do you boys really do things like that then? Any other handy little tips?

Ideally Id like to spend every Saturday with one of you boys, showing me little extras and tips. Id even pay you £50 a day for the privelige

 

[Vic Spanner]

Ideally Id like to spend every Saturday with one of you boys, showing me little extras and tips. Id even pay you £50 a day for the privelige

See we do like you

 

[ricicle]

Individual parts on a boiler such as fans, pumps etc will vary slightly from model to model but individual electronic components such as resistors, capacitors, diodes and transistors etc will usually be standard components.If you find an old PCB somewhere that you know worked take some components off and test them so you learn what their readings should be.Testing with components still soldered on the board can be misleading as there can be parallel readings.
Some favourites are burn't out resistors or capacitors, faulty diodes especially in rectifiers and the old favourites dry joints and shorted wires

 

[newcomers]

Individual parts on a boiler such as fans, pumps etc will vary slightly from model to model but individual electronic components such as resistors, capacitors, diodes and transistors etc will usually be standard components.If you find an old PCB somewhere that you know worked take some components off and test them so you learn what their readings should be.Testing with components still soldered on the board can be misleading as there can be parallel readings.
Some favourites are burn't out resistors or capacitors, faulty diodes especially in rectifiers and the old favourites dry joints and shorted wires

Jeez.............I have got a lot to learn.......


But seriously, if you had everything disconnected and it was still blowing, surely you'd just replace the pcb. Would you really waste all of that time trying to figure out which resistor or capacitor had blown.......or would you?

 

[Rob]

newcomers, you need to go on a couple of courses. not sure who mentioned dartford but ive done a couple of baxi courses there.

Worth doing, and remember courses are as good as you wanna make them.
I remember reading one of PaulBarkers' posts about courses and reminded me of own experience. Dont be the cocky one making jokes about everything
just sit there listen and ask as many questions as you can.

 

[newcomers]

newcomers, you need to go on a couple of courses. not sure who mentioned dartford but ive done a couple of baxi courses there.

Worth doing, and remember courses are as good as you wanna make them.
I remember reading one of PaulBarkers' posts about courses and reminded me of own experience. Dont be the cocky one making jokes about everything
just sit there listen and ask as many questions as you can.

Thats what Im like anyway, im forever asking people questions, I can never know enough!!!

 

[ricicle]

[quote="newcomers
But seriously, if you had everything disconnected and it was still blowing, surely you'd just replace the pcb. Would you really waste all of that time trying to figure out which resistor or capacitor had blown.......or would you?[/quote]

Depends on how fast your fault finding skills are, offset your hourly rate to the customer on a new PCB.There can be great satisfation from finding a faulty component on a board but did something else cause the component to fail???
By the way I'm an industrial sparky not a boiler engineer

 

[newcomers]

[quote="newcomers
But seriously, if you had everything disconnected and it was still blowing, surely you'd just replace the pcb. Would you really waste all of that time trying to figure out which resistor or capacitor had blown.......or would you?

Depends on how fast your fault finding skills are, offset your hourly rate to the customer on a new PCB.There can be great satisfation from finding a faulty component on a board but did something else cause the component to fail???
By the way I'm an industrial sparky not a boiler engineer [/quote]

Yeah but even if the component on the pcb was faulty, you would still have to get a new pcb!!

 

[ricicle]

[quote="newcomers]Yeah but even if the component on the pcb was faulty, you would still have to get a new pcb!![/quote]

Not necessarily if you had a spare component and your soldering skills are good

 

[newcomers]

[quote="newcomers]Yeah but even if the component on the pcb was faulty, you would still have to get a new pcb!!

Not necessarily if you had a spare component and your soldering skills are good[/quote]

In my case, that would mean a new pcb!!

 

[ricicle]

Another skill to practise then!

 

[Soggy_weetabix]

I am not trying to annoy you. Basic electrical checks will lead you to the fault.

How do you test for reverse polarity?

This is a basic question I was asked by a customer who was an electrician, when I told him his boiler was faulty after changing a plug to his programmer!!!

David

 

[newcomers]

I am not trying to annoy you. Basic electrical checks will lead you to the fault.

How do you test for reverse polarity?

This is a basic question I was asked by a customer who was an electrician, when I told him his boiler was faulty after changing a plug to his programmer!!!

David

Test the neutral and make sure the reading isnt 240V

 

[Paul Barker]

Sometimes whole house is wired reverese polarity, and if it was a TT earth it would never show up, but a pme earth would carry a hell of a lot of current.

Earth and Neutral should be similar dc potential apply meter to phase and to boards earth should be 230v (nominally, which of course is a Euro untruth, look for 240v) neutral to boards earth (tns strapped to armour or tncs attached to neutral emerges from cut out) should be 0 to 5v.

Then the boiler supply alone could be falseley polarised.