Electronics help
 

On Sat, 3 Feb 2018 21:28:03 +0000, ss wrote:

snip
Mechanical is my thing mostly, like just
started watch repairing which wont be a problem for me as I can
physically see whats wrong, unlike electronics.

Whilst I get what you are saying (and given limitations like the cost
of some diagnostic equipment), you can sorta 'see' what's going on
with some electronics by using a simple DMM or even an oscilloscope
(and you can get PC based / USB jobbies quite cheap these days) or
even just an LED and resistor. ;-)

DIY I will always give something a go before binning.(with safety in mind)

As has been mentioned elsewhere, the 'problem' with diy fixing SMPSU's
is the high voltages often flying about, the frequencies and the
closed loop'edness of them.

One of the common problems with them (and PSU's in general) is
capacitors going bad but you can often spot them and if done soon
enough (like if something starts misbehaving rather than failing
outright as such) you can often save something from dying in a more
complicated way. ;-)

Cheers, T i m

Electronics help
 

Update:

I got the other charger working, replaced the fuse and no joy, it turned
out the fuse holder was faulty so replaced that and all ok now.

As for the other I may as well get a replacement for the faulty diode
and see what happens, now out of interest more than anything else due to
the other charger now working.

Thank all for the input and help given.

Electronics help
 

On Sun, 4 Feb 2018 12:30:44 +0000, ss wrote:


Update:

I got the other charger working, replaced the fuse and no joy, it turned
out the fuse holder was faulty so replaced that and all ok now.

As for the other I may as well get a replacement for the faulty diode
and see what happens, now out of interest more than anything else due to
the other charger now working.

Thank all for the input and help given.

If it's not "information overload", I never had a supply blow one
rectifier.

The current that flows in the duff reccy invariably takes the other
out simply because you now have a mains input with a diode across L-N.

The fuse is no protection for the diodes, semiconductor rated fuses
would have no place in a SMPS feed.

I always replaced all four, they were cheap and technically two should
survive and not have sufferred any "trauma", but replacing all four
was a certain way of avoiding the pitfalls of erronious identification
and meter prods that might not have had a good contact.

On a plus point, I bought some reccys from Ebay for my Polaroid TV, I
was amazed at the price, If I were back in the trade I'd be buying
them in in the kg

If you are throwing any PC's out, the PSU's contain four suitable
mains recs. Even if they are cheap, it's not good to spend cash on
something you may have stashed in the shed.




AB

Electronics help
 

On Sunday, 4 February 2018 12:52:34 UTC, Archibald Tarquin Blenkinsopp wrote:

If you are throwing any PC's out, the PSU's contain four suitable
mains recs. Even if they are cheap, it's not good to spend cash on
something you may have stashed in the shed.

lots of PSUs do, and they don't need to be 1N3599s (or whatever they were) but I expect the OP doesn't have suitable junk lying about nor could identify which diodes would be suitable & which not.


NT

Electronics help
 

On 04/02/2018 13:59, wrote:
If you are throwing any PC's out, the PSU's contain four suitable
mains recs. Even if they are cheap, it's not good to spend cash on
something you may have stashed in the shed.

lots of PSUs do, and they don't need to be 1N3599s (or whatever they were) but I expect the OP doesn't have suitable junk lying about nor could identify which diodes would be suitable & which not.

I do have an old PC and monitor was broken but with the help from here
managed to get it repaired so keep as a spare.
Yes I would probably struggle to indentify suitable components. I do
Have loads of junk but mechanical stuff rather than electronic.

The diodes on ebay will cost under £2 for pack of 4 so will just go with
that, easiest option for me.

Electronics help
 

On Sunday, 4 February 2018 14:28:41 UTC, ss wrote:
On 04/02/2018 13:59, tabbypurr wrote:

If you are throwing any PC's out, the PSU's contain four suitable
mains recs. Even if they are cheap, it's not good to spend cash on
something you may have stashed in the shed.

lots of PSUs do, and they don't need to be 1N3599s (or whatever they were) but I expect the OP doesn't have suitable junk lying about nor could identify which diodes would be suitable & which not.

I do have an old PC and monitor was broken but with the help from here
managed to get it repaired so keep as a spare.
Yes I would probably struggle to indentify suitable components. I do
Have loads of junk but mechanical stuff rather than electronic.

The diodes on ebay will cost under £2 for pack of 4 so will just go with
that, easiest option for me.

sounds good.
Maybe this sort of thing will spawn a new market for 100w filament lamps.


NT

Electronics help
 

In article , T i m
scribeth thus
On Sat, 3 Feb 2018 21:28:03 +0000, ss wrote:

snip
Mechanical is my thing mostly, like just
started watch repairing which wont be a problem for me as I can
physically see whats wrong, unlike electronics.

Whilst I get what you are saying (and given limitations like the cost
of some diagnostic equipment), you can sorta 'see' what's going on
with some electronics by using a simple DMM or even an oscilloscope
(and you can get PC based / USB jobbies quite cheap these days) or
even just an LED and resistor. ;-)

DIY I will always give something a go before binning.(with safety in mind)

As has been mentioned elsewhere, the 'problem' with diy fixing SMPSU's
is the high voltages often flying about, the frequencies and the
closed loop'edness of them.

One of the common problems with them (and PSU's in general) is
capacitors going bad but you can often spot them and if done soon
enough (like if something starts misbehaving rather than failing
outright as such) you can often save something from dying in a more
complicated way. ;-)

Agree on that look for swollen ones..

Cheers, T i m


--
Tony Sayer

Electronics help
 

On Sun, 04 Feb 2018 12:30:44 +0000, ss wrote:

As for the other I may as well get a replacement for the faulty diode
and see what happens, now out of interest more than anything else due to
the other charger now working.

Sorry, not read this from the beginning so don't know which diode you're
referring to. Some diodes you can just replace from whatever you find in
your junk box and they'll work just fine. HOWEVER, if your SMPS runs at
(for example) 20khz (some run much faster) then you will NOT fix it by
replacing the diode with another common-or-garden rectifier device. For
these you need a *fast recovery* diode. The low junction capacitance of a
FRD can make all the difference between it working or not. They're not
expensive, but you're highly unlikely to have one lying around. I'm sure
CPC Farnell have them for peanuts, though - order over internet.



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the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

Electronics help
 

On 04/02/18 16:47, Cursitor Doom wrote:
On Sun, 04 Feb 2018 12:30:44 +0000, ss wrote:

As for the other I may as well get a replacement for the faulty diode
and see what happens, now out of interest more than anything else due to
the other charger now working.

Sorry, not read this from the beginning so don't know which diode you're
referring to. Some diodes you can just replace from whatever you find in
your junk box and they'll work just fine. HOWEVER, if your SMPS runs at
(for example) 20khz (some run much faster) then you will NOT fix it by
replacing the diode with another common-or-garden rectifier device. For
these you need a *fast recovery* diode. The low junction capacitance of a
FRD can make all the difference between it working or not. They're not
expensive, but you're highly unlikely to have one lying around. I'm sure
CPC Farnell have them for peanuts, though - order over internet.



Its the mains input side, dear, running at 50Hz


--
I would rather have questions that cannot be answered...
....than to have answers that cannot be questioned

Richard Feynman

Electronics help
 

On Sun, 4 Feb 2018 16:56:31 +0000, The Natural Philosopher
wrote:

On 04/02/18 16:47, Cursitor Doom wrote:
On Sun, 04 Feb 2018 12:30:44 +0000, ss wrote:

As for the other I may as well get a replacement for the faulty diode
and see what happens, now out of interest more than anything else due to
the other charger now working.

Sorry, not read this from the beginning so don't know which diode you're
referring to. Some diodes you can just replace from whatever you find in
your junk box and they'll work just fine. HOWEVER, if your SMPS runs at
(for example) 20khz (some run much faster) then you will NOT fix it by
replacing the diode with another common-or-garden rectifier device. For
these you need a *fast recovery* diode. The low junction capacitance of a
FRD can make all the difference between it working or not. They're not
expensive, but you're highly unlikely to have one lying around. I'm sure
CPC Farnell have them for peanuts, though - order over internet.



Its the mains input side, dear, running at 50Hz


Do you not mean MAINS or maybe *running* at 50Hz


or are his keyboard acrobatics related to the stupidity of the
gibberish :-)

God help any poor soul in the NG that does need assistance :-(


AB

Electronics help
 

On Sunday, 4 February 2018 17:15:59 UTC, Archibald Tarquin Blenkinsopp wrote:
On Sun, 4 Feb 2018 16:56:31 +0000, The Natural Philosopher
wrote:
On 04/02/18 16:47, Cursitor Doom wrote:
On Sun, 04 Feb 2018 12:30:44 +0000, ss wrote:

As for the other I may as well get a replacement for the faulty diode
and see what happens, now out of interest more than anything else due to
the other charger now working.

Sorry, not read this from the beginning so don't know which diode you're
referring to. Some diodes you can just replace from whatever you find in
your junk box and they'll work just fine. HOWEVER, if your SMPS runs at
(for example) 20khz (some run much faster) then you will NOT fix it by
replacing the diode with another common-or-garden rectifier device. For
these you need a *fast recovery* diode. The low junction capacitance of a
FRD can make all the difference between it working or not. They're not
expensive, but you're highly unlikely to have one lying around. I'm sure
CPC Farnell have them for peanuts, though - order over internet.



Its the mains input side, dear, running at 50Hz


Do you not mean MAINS or maybe *running* at 50Hz


or are his keyboard acrobatics related to the stupidity of the
gibberish :-)

God help any poor soul in the NG that does need assistance :-(


AB

What is this guy's issue?
In case there's any question TNP's comment was correct, and any old diode can not be used, though a good many can.


NT