I got a Dex Monitor, it's a Daewoo CMC-531X Chassie. It's really a difficult
chassi. The problem was the hor deflection. I tried to unconnect the 50v
rectifier diode and the monitor then goes out of safe-mode. I discovered
later that removing one leg of a big inductor in the deflection can make go
away the protection. I tried to change all the resistor in this part, i
changed the Mosfet IRF640 with a IRF630A but it won't work . Probably the
HOT is fried. This circuit part powers the primary winding of the LOPT. It's
a deflection problem, none of the outputs of the trafo were shorted or
overloaded. With a Digital Multimeter i tested the resistance between the
pins of the (removed) trafo and i discovered that a winding, from pin 8 to
10, is open. I think that because this winding is shorted the rest of the
deflection is shut off. It's really the LOPT ? What may it cost ? I tried to
insert the reference to HR-Diemen, but it don't recognize it. More data :
LOPT Transformer :
DAEWOO FFA73515U 1B0210 S
Monitor :
Dex 2450+ (Dex is a small Italian company who solds remarked Micronica
computer equipment)(This monitor is made by Daewoo in korea.)
FCC ID = ??????????? (i' ve forgot it)

(excuses for my poor english )

--
Intiglietta Mino
VeroFalso Inc.
A volte c'e' a volte non c'e' :-)

I have the schematic on this one in front of me. If your HOT is shorted,
replace it. Resolder the pins on the FBT. I show it as Loc: T500, Part No.
CF1656, probably Crosses over to the FFA73515U you mentioned.

If you replaced the Mosfet (Q507) then I recommend you change C556
(1uF/200V) and D510 (HER124). I would use a High-ESR Cap for C556, and make
it a 22F / 250V. You can probably sub a MUR460 (On-semi) or an STTH306 (ST
Micro) for D510. D510 is a fast switch diode that boosts the B+ for
resolution at high scan rates, say above 800-600 or so resolution. So if the
monitor was ran at that rate for long periods of time, it accelerates the
life of C556, and places more stress on D510 and Q507. C556 ideally ought to
be a high ESR as installed at the factory , but not all mfr's shoose to do
so because of cost. D510 would likely check good with a bench DMM, but its
switch speed probably is degraded enough to cause a problem, so replace it
anyway.

If you cannot locate these parts, there is a repair kit online where you can
purchase he http://www.technotronic-dimensions.com/Products.html
Part no = TD772-G. It contains an IRF632A for Q507, because its based on the
proview chassis...but you probably dont need the mosfet anyway.

If you are certain the flyback is bad, the same site can probably supply the
flyback too. But Pins 8 and 10 on my Schematic are connected internally, so
that part of the FBT is ok.


"Stan®" wrote in message
...
|I got a Dex Monitor, it's a Daewoo CMC-531X Chassie. It's really a
difficult
| chassi. The problem was the hor deflection. I tried to unconnect the 50v
| rectifier diode and the monitor then goes out of safe-mode. I discovered
| later that removing one leg of a big inductor in the deflection can make
go
| away the protection. I tried to change all the resistor in this part, i
| changed the Mosfet IRF640 with a IRF630A but it won't work . Probably
the
| HOT is fried. This circuit part powers the primary winding of the LOPT.
It's
| a deflection problem, none of the outputs of the trafo were shorted or
| overloaded. With a Digital Multimeter i tested the resistance between the
| pins of the (removed) trafo and i discovered that a winding, from pin 8 to
| 10, is open. I think that because this winding is shorted the rest of the
| deflection is shut off. It's really the LOPT ? What may it cost ? I tried
to
| insert the reference to HR-Diemen, but it don't recognize it. More data :
| LOPT Transformer :
| DAEWOO FFA73515U 1B0210 S
| Monitor :
| Dex 2450+ (Dex is a small Italian company who solds remarked Micronica
| computer equipment)(This monitor is made by Daewoo in korea.)
| FCC ID = ??????????? (i' ve forgot it)
|
| (excuses for my poor english )
|
| --
| Intiglietta Mino
| VeroFalso Inc.
| A volte c'e' a volte non c'e' :-)
|
|

"Techforce" wrote in message
...
I have the schematic on this one in front of me. If your HOT is shorted,
replace it. Resolder the pins on the FBT. I show it as Loc: T500, Part No.
CF1656, probably Crosses over to the FFA73515U you mentioned.
Hr Diemen doesn't have the CF1656 neither FFA73515U (?)

[CUT]
Thanks for the substitutions(hope i can do them in this week), but i've
changed a big electrolytic cap who filters the psu, it was in point of
explosion.i slightly changed his value.

If you cannot locate these parts, there is a repair kit online where you
can
purchase he http://www.technotronic-dimensions.com/Products.html

I can't order it, i'm not in America and i don't want to spent away $25, i
can buy the single parts

If you are certain the flyback is bad, the same site can probably supply
the
flyback too. But Pins 8 and 10 on my Schematic are connected internally,
so
that part of the FBT is ok.
The windings in the trafo must have a resistance, if it reveals open, there
is a trouble
1. In the schematics (can you send me your copy? )
2. In the winding who generates "600V" as schematics.