Nikkai 800W inverter

[MacMan85]

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

 

[Dave Fawthrop]

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

|
|
| 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 <[email protected]> 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}

 

[Mr Mark]

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

|
|
| 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.

 

[Gripper]

oops forgot U8 is TC4011BP

 

[Jimbo]

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

 

[Jimbo]

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

 

[MacMan85]

Larry Posted Snip---->

<----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

 

[Mr Mark]

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?