Bush LY1911WCW Blowing Mains Fuse

[anotherdude]

Picked this up free a few weeks ago and as it kept blowing mains fuses I didn't go any further

but have some time now so thought i'd take another look

nothing obvious from what i can tell maybe 1 part on the back on the secondary side (f1 near the main board power connector, looks whitr but with tinges of brown round the sides) but assuming this is irrelevant as if it's blowing main fuses it has to be a problem primary side?

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

check the bridge rectifier & the fet on the heatsink for shorts between any of the pins.

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

check the bridge rectifier & the fet on the heatsink for shorts between any of the pins.

thanks just been googline ad seen about a rectifier

am i right to assume if the rectifier or fet has blown it'll of took out the diodes and resistors surrounding them?

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

no.
btw, you said it blew the fuse?
what fuse.
the brown box near the power connector is a fuse!

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

no.
btw, you said it blew the fuse?
what fuse.
the brown box near the power connector is a fuse!

ye seen that labelled F2 on the board

seems to check out fine, fuse blowing is at the wall going into the socket, 3 pin plug going into a 3 pin socket (uk plug)

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

meter across the power connector on the board to see if it's really shorted.

it's unlikely, but it could be a bad power switch or damaged mains cable - i'v seen that once.

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

meter across the power connector on the board to see if it's really shorted.

it's unlikely, but it could be a bad power switch or damaged mains cable - i'v seen that once.

seems you could be correct

removed the mains cable and used another and it's now no longer blowing the mains fuse but i'm seeing little to no voltage across the power supply

[Alastair E]

Re: Bush LY1911WCW Blowing Mains Fuse

As in--No 240V getting To the PSU board?

Set Mains power-switch, or fuse on any mains-filter boards? Fuse in the replacement power-lead? Is there power to the wall-socket, after you blew out the fuse earlier, coulda taken the trip for that ring-main out in the house-breaker....

The latter, I'm often falling foul of with the supply-fuse to my isolating-transformer--I go round head scratching for a while--before penny drops....

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

that's why you can never have too many led's & neon lights

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

As in--No 240V getting To the PSU board?

Set Mains power-switch, or fuse on any mains-filter boards? Fuse in the replacement power-lead? Is there power to the wall-socket, after you blew out the fuse earlier, coulda taken the trip for that ring-main out in the house-breaker....

The latter, I'm often falling foul of with the supply-fuse to my isolating-transformer--I go round head scratching for a while--before penny drops....

that's it well kind of, theres no voltage at where the voltage comes in, but the fuse is good and so is the socket, tested the toaster with both

not sure whats happened tbh, even disconnected from the power board and measuring the output from the wall to the output I get nothing

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

so socket good.

plug & fuse presumed tested.
check the cable for continuity on both conductors.

is it a molded plug?
and is there a chassis switch on the tv? all the tv's i'v got with built-in cable have a rocker switch on the back.

[Alastair E]

Re: Bush LY1911WCW Blowing Mains Fuse

Ive had a couple of IEC type mains-leads go faulty, on one--the moulded in fuse-holder in the plug was loose, not making connection....

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

so socket good.

plug & fuse presumed tested.
check the cable for continuity on both conductors.

is it a molded plug?
and is there a chassis switch on the tv? all the tv's i'v got with built-in cable have a rocker switch on the back.

it is a moulded plug, there is a rocker switch but I bypassed that as I think that was what was causing the fuses to blow

fuse tests good as does the cable

[Alastair E]

Re: Bush LY1911WCW Blowing Mains Fuse

Have you Tried the cable--say in the kettle....?

Check continuity with DMM from the set power-socket to the PSU plug and onto the PSU board...

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

in the kettle?
tv's use 3amp cable!

just puting a 60w lamp on the end will be enough.

[Alastair E]

Re: Bush LY1911WCW Blowing Mains Fuse

In The UK......
We use those leads with 13A fuse--to power elect kettles!

First thing that came to mind to test the lead with. TV's in the UK seem mostly to have 10 and 13A fuses fitted in the IEC lead plugs....

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

i'v not seen many tv's wih IEC, mostly captive cable.
probably because it's cheaper.

that said, IEC should not fit a kettle.
kettles use HOT-IEC with a notch in the connector and a blocking piece in the kettle.
so you cant use a cable that isnt rated for high temperatures.

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

so pinched a cable from a 22 inch lcd whats smashed, same connector tested the smashed one first to double check the fuse and i get a standby light (can't lay my hands on the remote) so that cable does work,

so plugged it into this bush psu, no standby light and voltage jumping at the ac in pin

tested the previous cables on the smashed lcd I had tried on this bush and all work fine, so still a short somewhere maybe?

no idea what was going on earlier with the previous cables

now seeing high resistance at the f2 fuse and no continuity when off, guess my MM is playing silly beggers


also it's not that typle of lead, it's just the straight 2 pin connector you'd see coming from the mains connector to the power board (if that makes sense brown and blue wire only)

[stj]

Re: Bush LY1911WCW Blowing Mains Fuse

o.k.
put a new battery in your meter.
then check the bridge rectifier & fet for shorted pins.

[anotherdude]

Re: Bush LY1911WCW Blowing Mains Fuse

realised what i'd done earlier now, as I was using a different cable to test i must of inserted it the wrong way (blue to brown/brown to blue)

how stupid of me

DMM is fine as far as I can tell measured a few batteries and got the right readings, ordered another f2 fuse and the rectifier and fet anyway just in case

high resistance at the f2 would mean it's blown? and the reason i'm seeing no other voltages anywhere?