Problem with DM7025 Power Supply

[nings]

Hello,

I have take a lot of time on this power supply but I'm lost

I have try to repair this power supply but during a test, I have removed power and move the power supply but when moving I have shortcut 2 components create a sound like "clac" and now seem totally death

Before the backlight was ON now all stay OFF

Some screens about the power supply :

http://*************/photo/my-images/689/part1l.jpg/
http://*************/photo/my-images/849/part2z.jpg/

http://*************/photo/my-images/684/under1i.jpg/
http://*************/photo/my-images/857/under2.jpg/


I have shortcut the resistor R46 and the diode D16.
Picture here : http://*************/photo/my-images/830/disasterlocation.jpg/

Tested :

Look picture here for number : http://*************/photo/my-images/687/disasterexplain.jpg/

For the first hit :

R46 = Have the right resistance value compared to colour code
C24 = tested the capacity it's ok
D12 = block in one side, ok in other
C3 = 217v and -105V (possible? here it's 240v)
R3 = Have the right resistance value compared to colour code
D1-5-6-3 = block in one side, ok in other


For the second hit :

L4 = ? It's a resistor or not ?
D16 = block in one side, ok in other
R50 = I have changed this resistor by another SMD 100. Number code = 10ohm mesured 2.2kohm
R51 and R47 = show 0.6M ohm both should be 1Mohm it's the problem ?
D19 = block in one side, ok in other
R70 = 0.05 ohm may be the multimeter which it's not 100% accurate
R44 = 4.7kohm the right value from SMD number.


Someone can help me to repair this problem ?
Or it's directly my mainboard which have burn and don't anymore power on the power supply ? (Because I have of course hit the metal box with power supply when I have try to power my dreambox )


Thx in advance for your help !

[Per Hansson]

Re: Problem with DM7025 Power Supply

Sorry to hear about your Dreambox

I can't provide much help in the fault diagnostic.
But just a little mention that we prefer if posts are attached using this site's image attachment function... (Links often go dead or load very slowly on external sites)
Keeping them as close to 2000px wide/high (whichever applies)

It is of course possible to buy a new Dreambox 7025 PSU, but they are quite expensive
http://www.satpro.se/default.asp?id=...t_nr=107&div=0

[nings]

Re: Problem with DM7025 Power Supply

OK

It's for not overload forum DB
Yes I know that picture doesn't stay a lot of time.

But no problem, I can upload on the forum DB directly.


Yes but buy another is too much expensive
It's probably a little thing which have burn but don't know what ... And if it's the power supply or the mainboard...
I try to look the mainboard today if I see something which have burn.

But I don't think because I have the metal part in the hand when the power supply have touch that. And it was 220v and I'm still alive


Thx for your reply !

[Per Hansson]

Re: Problem with DM7025 Power Supply

Does the DM7025 support soft start?
On my 7000 "turning off" simply means to turn the LCD off, CPU and all still running...

If it is the same on yours then you should be able to power up the PSU without the Dreambox (Attach a HDD for load)
That way you will be able to test it and make sure it works before you connect it to the Dreambox...

/etc/init.d/rcK
#!/bin/sh

PATH=/sbin:/bin
echo "system shutdown..."

if [ -e /var/etc/uinit ] ; then
    . /var/etc/uinit
fi

#set environment variable (mID)
. /proc/bus/dbox.sh

#DM7000
if [ $mID -eq 05 ] ; then
    killall -9 smbd
    killall -9 nmbd
fi

#Turn off swapspace
if [ -r /proc/swaps ]; then
    sync
    cat /proc/swaps | \
    while read SWAPSPACE remainder ; do
        [ "$SWAPSPACE" = "Filename" ] && continue
        swapoff $SWAPSPACE
    done
fi

umount -a > /dev/null 2> /dev/null
umount /mnt > /dev/null 2> /dev/null
umount /var > /dev/null 2> /dev/null

#DM7000
if [ $mID -eq 05 ] ; then
    /sbin/hdparm -y /dev/ide/host0/bus0/target0/lun0/disc
    /sbin/hdparm -y /dev/ide/host0/bus0/target1/lun0/disc
    /bin/lcdoff
fi

[b700029]

Re: Problem with DM7025 Power Supply

I see 4 diodes and a Molex. Maybe a Flex ATX PSU could be substituted?

[nings]

Re: Problem with DM7025 Power Supply

If it is the same on yours then you should be able to power up the PSU without the Dreambox (Attach a HDD for load)
That way you will be able to test it and make sure it works before you connect it to the Dreambox...

The first problem : LCD backlight start but with nothing on it and have some volts on the molex cable. may be 1V on 5V and 3V on 12V.

After my shortcut, LCD doesn't start anymore and I have no power on molex 0.01V (probably the multimeter which it's not really accurate)

And I doesn't found a way for start manually the power supply without plug to the Dreambox and doesn't know if start or not... No way for check

I see 4 diodes and a Molex. Maybe a Flex ATX PSU could be substituted?

Not ... I have found something like that for the pinout :

DM7025 Dm7025+

1 +12v-sb +15v-sb
2 power on Ground
3 +15v +6v8
4 Ground power on
5 +12v +12v
6 +12v +12v
7 Ground Ground
8 +5v +5v
9 Ground Ground
10 +3v3 +3v3
11 Ground Ground
12 +2v5 +2v5
13 +2v5 +2v5
14 Ground Ground

It's not really standard

[nings]

Re: Problem with DM7025 Power Supply

It's possible thats the problem can come from somes resistors ?

I have found a lot of errors from the colour code or smd number...
0.6Mohm instead of 1Mohm, 270kohm instead of 470kohm...

I have found one other with 1.2ohm and from colour code should be 15ohm ..
But when a resistor burn, should be have an unlimited ohm value and not decrease his resistance no ?

[nings]

Re: Problem with DM7025 Power Supply

It's probably not resistor because are in //

I have change another capacitor without any change
Nobody can help me ? And try to give me a solution for check the power supply ?

How it's possible to measure this power supply ?
Some parts are AC and other DC and change the result

I have +230V on one side and -104V on the other side ... The radiator is at -104V and the other 0. I really doesn't understand how this result can be right.

And I have -104V on the majority of the components ... I try to understandy and follow the 230V but it's really hard

230V on one side of the transformers but nothing on other side ??? I shouldn't have something on other side ?