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How do I hotwire the powersupply's relay in an NEC Plasma monitor?

J

Jack Edin

Yo...

I've chased the on switch's operation all the way onto the powersupply
board. No small feat as it goes through two other boards first...

I'm fairly sure the PS is toast, but there is no good reason that I'm
aware of.

The unit was dropped, and the display destroyed. Upon the Plasma
display's replacement a working set was expected, but no action...

It was noticed the ribbon cable from the front panel was kinked, and the
board on the besel appeared damaged. Both were replaced.

Still no action.

I determined the ribbon cable was installed incorrectly on the besel
board's side. I reversed this, and with great hope I pressed the button...

So I'm writing 'cause it didn't work, of course.

There isn't a stand-by light on the front...

I never hear the relay click.

Is there an easy way for a service tech to bypass the soft-on circuit,
and make it freakin turn on? Hot-wire the relay??

The problem is I can't get to the bottom of the PS's PCB easily. It is
bolted to a pan, and all of it's transisters use this pan as a heatsink.

I'm tempted to pull it apart, and look for fractured solder joints; cold
solder joints; whatever. I figure a digital picture taken before I start
may just be the trail of breadcrumbs that gets it back together again...
All the specialized brackets, and insulators too. Better not forget one
of those!

Anybody have any better suggestions?

The model is an NEC PX-42VP1A 42" Plasma Monitor.

The powersupply is a Rubycon RPS-9281, part#: 79646681

All my searches for info seem to turn up messages whose replys are -
better leave this to the qualified technicians, etc... And Board swap
only...

Isn't there an old-school technician hanging out in this newsgroup?

Any of you old-school tech's understand these high-tech toys?

It's a switching powersupply that happens to have 6 or 7 secondaries...

Any help would be appreciated, including a lead on where I can buy a
replacement used - cheap!

Thanks, in advance.

Jack
:)
 
A

Art

As you already know NEC recommends board only service for these products.
Old "Black Box" troubleshooting and repair, I.E. keep on changing each
"Black Box" in sequence until the item functions. Totally doubtful that you
will find any kind of print for the item nor definitive support from the
manufacturer. If you know the theory and operational charactristicts of the
power supply then you should have no problem checking for lousy solder
connections or cracks, and detrmining how to defeat the protective circuts
to power it up. Suggest that you at least obtain the servicing manual and
training manual for the item befor going much further.
 
T

tbrentnewman

Jack,

I'm curious to know if you were able to find a supplier for the powe
supply. If so, where, and what was the price of the supply?

Thanks in advance,

Bren
 
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