pace 2000 power fault

mentholflash01

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#1
hi everyone
wat would cause this can anyone tell me
ive gone thruo 3 power leads so far
thanks
 

fatblerk

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#2
mentholflash01 said:
hi everyone
wat would cause this can anyone tell me
ive gone thruo 3 power leads so far
thanks
I've successfully changed a couples of those along with the SMD cap underneath with good results on 'dead boards' but haven't seen one as damaged as that though?

Unless somebody can tell you different it may be worth changing it along with the cap and see what happens? ....... just stand back when you switch it on ...lol

About 4 quid from RS .....
 

TBC

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#3
looks like a s/c diode mate - when the transistor switches of from the transformer there is a back surge - normally this would be diverted back into the coil and protect the transistor. check D1 and D2 just behind it.
find the faulty component before you restart the supply - you could be causing more problems by letting the chopper blow up like that LOL
 

mentholflash01

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#4
if i leave itin the box and add a power cable with a new fuse it will bang and spark then blolw the fuse again
why isnt the fuse on the board stoppin it gettin to this
or the varsiter
thanks for the reply
 

fatblerk

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#5
TWOBEERCANS said:
looks like a s/c diode mate - when the transistor switches of from the transformer there is a back surge - normally this would be diverted back into the coil and protect the transistor. check D1 and D2 just behind it.
find the faulty component before you restart the supply - you could be causing more problems by letting the chopper blow up like that LOL
Thank feck you told mentholflash01 different ....... lol
 

mentholflash01

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#6
thanks for thereply 2 beers i will do that ,do you know wat settings i need to set a multi meter toso i can test for knackered components
cheers
 

TBC

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#7
metholflash your not takin in what i said.
the force that is blowing the transistor up is coming from the transformer.
when a coil is charged with power/energy it generates a magnetic field.
when this field collapses energy is made in the form a electricity.
what stops this electricity from running back into the chopper transistor is usually a diode (only allows electricity to flow one way) i.e away from the transistor.
since the primary side of the chopper transformer is the path of least resistance - when the diodes fails it will all flow back to the chopper very very quickly producing very large voltages. it is thuis effect that is causing you the problem. not what is coming from the mains lead.
hence the reason the posistor and fuse cannot stop it.
 

mentholflash01

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#8
hi
took fatblerks advise replaced the item readded power and burnt down my house anybody have any ideas how to fix it only joking thanks for the replies
 

TBC

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#10
just set your meter to continuity (the buzz when the probes touch) then if you get a tone both ways round on d1 and d2 then remove them and test again.
what is more troubling is why would the thing have happened in the first place. the power supply on the box is very reliable and not prone to this sort of thing.
 

mentholflash01

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#11
hi mate
ive been lookin for components d1 and d2 and cant findem mate
sorry can you help ive tried the blue things in front but 1 doesent give a beep eitherway and 1 will give a single beep 1 way then another beep
 

TBC

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#12
D1 AND 2 should be local to the transistor mate. look between the heatsink and the transformer
 

chookey

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#13
It might be worth checking C2504 as well. If this were to go short, a direct short would be present across the power supply and the drain and source of the TOP 223Y.
Note that the TOP 223Y isn't a normal transistor type.
View attachment 14513
For free pdf datasheets on thousands of different semiconductors, try these.
http://alldatasheet.com/
Regards......Chookey​
 
Last edited:

chookey

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#14
Just took a look at a 2000 I have open on the bench. C2504 has been omitted from this one so may not be present in yours. The 2 diodes that TWOBEERCANS mentioned are in front of the 2 blue capacitors that you checked and right behind the transformer.

Regards......Chookey​
 

mentholflash01

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#15
hi guys thanks for your help
heres wat i got
in the board i didnt et a reading
are theses the right compponents
only get a reading the 1 way round
thanks
 

TBC

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#16
ok check the 2 blue decoupling caps are working - also check the low voltage elctrolytic and the mains smoothing cap. since the supply is a basic one it really has to be one of those. in more complex power supplies the optocoupler can cause runaway but i think you can exclude it from this problem.
 

TBC

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#18
it is necessary to scope(oscilliscope) the electrolytics to make sure they are working. from reading above it seems you are not technically minded<i mean no disrespect at all. a switching mode power supply can be very dangerous.
with all that in mind i would suggest a repair by substitution.

this means that you must change all the parts on the primary side of the power supply from a working power supply. there are only about 10 parts if i remember correctly. excluding smd's under the board.

in most cases in this kind of power supply the item that has exploded is unlikely to be the cause of a problem - more likely an effect.
 

mentholflash01

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#19
hi mate do you think it would be possible to give me a shopping list for the offending items
i found the transister at farnell in one as i asume that would definatly need replaceing
minimum order is 20 quid the transister is only £2.60 so i could do with making up my order
i will transplant by sight
thanks a lot
phil
 

mentholflash01

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#20
hi
can anyone give me a shopping list for all power items on a 2000
thanks
 
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