I have a Nikkai QM82 800W inverter (12V DC - 230V AC 50Hz) which has
some severe burning and an exploded chip. It's also sold under the
Skytronic brand name in the UK, and as Power-Up in Europe - I think
they are all made by the same manufacturer in Taiwan. Sold recently by
Maplins in the UK.

Can anyone look inside one and tell me the values for:

U8 (most important! This chip is destroyed!!)

R45
R47
R49
R51
Q17
Q18
Q19
Q20

Any help at all would be appriciated!
TIA

Richard

On Tue, 19 Aug 2003 08:06:37 +0100, MacMan85
wrote:

|
|
| I have a Nikkai QM82 800W inverter (12V DC - 230V AC 50Hz) which has
| some severe burning and an exploded chip. It's also sold under the
| Skytronic brand name in the UK, and as Power-Up in Europe - I think
| they are all made by the same manufacturer in Taiwan. Sold recently by
| Maplins in the UK.
|
| Can anyone look inside one and tell me the values for:
|
| U8 (most important! This chip is destroyed!!)
|
| R45
| R47
| R49
| R51
| Q17
| Q18
| Q19
| Q20
|
| Any help at all would be appriciated!

Sorry to mention this, but if an electronic device has "severe burning and
an exploded chip" It is probably scrap. If you repair one bit, this will
reveal another failed bit. :-(((((((((

Dave Fawthrop Killfile and Anti Troll FAQs
at http://www.hyphenologist.co.uk/killfile.
Agent Korean Spam filter From: {å|¿|¾|®|¥|Â|À|ç|¤|¶|§|±|ª|º}
or Subject: {å|¿|¾|®|¥|Â|À|ç|¤|¶|§|±|ª|º}

On Tue, 19 Aug 2003 08:45:59 +0100, Dave Fawthrop
wrote:

On Tue, 19 Aug 2003 08:06:37 +0100, MacMan85
wrote:

|
|
| I have a Nikkai QM82 800W inverter (12V DC - 230V AC 50Hz) which has
| some severe burning and an exploded chip. It's also sold under the
| Skytronic brand name in the UK, and as Power-Up in Europe - I think
| they are all made by the same manufacturer in Taiwan. Sold recently by
| Maplins in the UK.
|
| Can anyone look inside one and tell me the values for:
|
| U8 (most important! This chip is destroyed!!)
|
| R45
| R47
| R49
| R51
| Q17
| Q18
| Q19
| Q20
|
| Any help at all would be appriciated!

Sorry to mention this, but if an electronic device has "severe burning and
an exploded chip" It is probably scrap. If you repair one bit, this will
reveal another failed bit. :-(((((((((

I agree, my experience of repairing switch-mode power supplies is
that is that if it is more than the two main switching transistors
(and associated resistors) then normally they are not worth repairing.

oops forgot U8 is TC4011BP

You'll spend more money fixing it than you will buying a BETTER one
that DOESN'T explode when overloaded.

May I recommend TrippLite brand which is damned near indestructable
and more reasonably priced than boat dealer inverters costing
thousands for no reason other than greed.
(Tripplite has a $50K insurance policy. If it destroys your load,
they'll buy you a new one, at least in the USA)



On Tue, 19 Aug 2003 08:06:37 +0100, MacMan85
wrote:



I have a Nikkai QM82 800W inverter (12V DC - 230V AC 50Hz) which has
some severe burning and an exploded chip. It's also sold under the
Skytronic brand name in the UK, and as Power-Up in Europe - I think
they are all made by the same manufacturer in Taiwan. Sold recently by
Maplins in the UK.

Can anyone look inside one and tell me the values for:

U8 (most important! This chip is destroyed!!)

R45
R47
R49
R51
Q17
Q18
Q19
Q20

Any help at all would be appriciated!
TIA

Richard



Larry W4CSC

Maybe we could get the power grid fixed if every politician
regulating the power companies wasn't on their payrolls.

Larry Posted Snip----
You'll spend more money fixing it than you will buying a BETTER one
that DOESN'T explode when overloaded.

May I recommend
----End Snip

And I thouroughly recommend the hint hint in Gripper's post

The detail in OP suggests experience, though experience would
suggest that SMPSU in the state reported would most likely not
be worth the time expense and effort required

Good luck either way

Jimbo
--
remove jukebox to reply
http://www.witzend.org.uk
http://www.by-users.co.uk
http://www.by-user.co.uk

If you want a replacement try A.R.D. electronics..they offer a 1000w
inverter for £ 100.00

Runs my fridge a treat despite all this hot weather !

http://www.ardelectronics.com/


Steve

"Jimbo" wrote in message
...
Larry Posted Snip----
You'll spend more money fixing it than you will buying a BETTER one
that DOESN'T explode when overloaded.

May I recommend
----End Snip

And I thouroughly recommend the hint hint in Gripper's post

The detail in OP suggests experience, though experience would
suggest that SMPSU in the state reported would most likely not
be worth the time expense and effort required

Good luck either way

Jimbo
--
remove jukebox to reply
http://www.witzend.org.uk
http://www.by-users.co.uk
http://www.by-user.co.uk

su4704 Posted Snip----
If you want a replacement try A.R.D. electronics..they offer a 1000w
inverter for £ 100.00

Runs my fridge a treat despite all this hot weather !

http://www.ardelectronics.com/

----End Snip
Pardon????

Jimbo


--
remove jukebox to reply
http://www.witzend.org.uk
http://www.by-users.co.uk
http://www.by-user.co.uk

On Tue, 19 Aug 2003 20:34:21 GMT, "Jimbo"
wrote:

Larry Posted Snip----
You'll spend more money fixing it than you will buying a BETTER one
that DOESN'T explode when overloaded.

May I recommend
----End Snip

And I thouroughly recommend the hint hint in Gripper's post

The detail in OP suggests experience, though experience would
suggest that SMPSU in the state reported would most likely not
be worth the time expense and effort required

Good luck either way

Jimbo

Thanks, Neil, for the info - most useful.

To the people who suggested, rightly, that it might be more trouble to
fix than it's worth, you are right - if I was only interested in
getting a working inverter.

As an electronics engineer who's been designing SMPS for 30 years, I'm
interested in this one because of the extent of the failure, and the
failure analysis is every bit as interesting as getting the beast
working again.

It's very rare for a failed SMPS to destroy quite so many components -
and the original failure in this one appears to be a blown electolytic
in the 12V regulated supply, which seems to have short-circuited a
7812 linear regulator and allowed a catastophically high voltage into
the output driver oscillator. Very interesting is the fact that it
hasn't blown any of the input fuses!

As an educational excercise, it's fascinating!

Regards,
Richard

On Wed, 20 Aug 2003 14:55:00 +0100, MacMan85
wrote:

On Tue, 19 Aug 2003 20:34:21 GMT, "Jimbo"
wrote:

Larry Posted Snip----
You'll spend more money fixing it than you will buying a BETTER one
that DOESN'T explode when overloaded.

May I recommend
----End Snip

And I thouroughly recommend the hint hint in Gripper's post

The detail in OP suggests experience, though experience would
suggest that SMPSU in the state reported would most likely not
be worth the time expense and effort required

Good luck either way

Jimbo

Thanks, Neil, for the info - most useful.

To the people who suggested, rightly, that it might be more trouble to
fix than it's worth, you are right - if I was only interested in
getting a working inverter.

As an electronics engineer who's been designing SMPS for 30 years, I'm
interested in this one because of the extent of the failure, and the
failure analysis is every bit as interesting as getting the beast
working again.

It's very rare for a failed SMPS to destroy quite so many components -
and the original failure in this one appears to be a blown electolytic
in the 12V regulated supply, which seems to have short-circuited a
7812 linear regulator and allowed a catastophically high voltage into
the output driver oscillator. Very interesting is the fact that it
hasn't blown any of the input fuses!

As an educational excercise, it's fascinating!

Regards,
Richard

My experience of SMPSU's is that the Switching Transistors Gallantly
lay down their lives in an attempt to save the Fuse, bless them. In
this case it sounds like its taken out the Tranny as well, hands up
all those who have taken out a Tranny?