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Thread: DM7020s Power supply

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    Default DM7020s Power supply

    I've got a friend who has got a 'dead' 7020s - he does not know what happend - he loaned the unit to someone and suspects that they (being total wallies) pluged it into a cable outlet and not a LNB on sat dish.

    Would this be sufficient to kill the PSU?

    If so - whats the starting point - the diodes? - or does it 'blow' a lot more?

    The internal fuze seems to be OK - so it must be something 'transient' related - again pointing to some semiconductors.

    Since the PSU is a descrete PCB - its easy to service it - but before breaking it apart - perhaps someone here has some guidelines and experiance in 'fix' as far as the most common things to check?

    Any information would be most welcome

    Bottom line is to send it back under warranty - but that's a long process - so if a 'fix' is possible is a better solution ...

    Thanks for any help

    Cheers



Look Here ->
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    Quote Originally Posted by eyesee View Post
    I've got a friend who has got a 'dead' 7020s - he does not know what happend - he loaned the unit to someone and suspects that they (being total wallies) pluged it into a cable outlet and not a LNB on sat dish.

    Would this be sufficient to kill the PSU?

    If so - whats the starting point - the diodes? - or does it 'blow' a lot more?

    The internal fuze seems to be OK - so it must be something 'transient' related - again pointing to some semiconductors.

    Since the PSU is a descrete PCB - its easy to service it - but before breaking it apart - perhaps someone here has some guidelines and experiance in 'fix' as far as the most common things to check?

    Any information would be most welcome

    Bottom line is to send it back under warranty - but that's a long process - so if a 'fix' is possible is a better solution ...

    Thanks for any help

    Cheers
    I don't know if the psu would blow. I'd be a bit concerned abou the tuner module though. Contact z80 as he has spare PSU's.

    Leroy

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    .. thanks for the speedy response ..

    I would have though that plugging-in cable would not kill PSU - but transient - could do it ...

    Tes the Tuner could be dead also - but at the moment - there is NO volts going to the main PCB - because the PSU is not outputting anything

    If z does have spare PSU for sale that great (please PM) ... its the easiest option - to replace complete PSU

    Cheers

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    I have all the bits to fix a 7020.

    The power supplies, the tuner module, and the daughter board for the ALPS tuner module.

    I also have the LNBP21 IC that blows on the main board.
    I have the switching regulator that mates to the LNBP21 ic also.

    Good enough support?

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    Of course if you dont look closely when plugging in the lnb cable on a 7020 you will plug it in the cascade instead of primary.....

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    Quote Originally Posted by z80 View Post
    Of course if you dont look closely when plugging in the lnb cable on a 7020 you will plug it in the cascade instead of primary.....
    I wouldn't think that would smoke the PSU?

    Leroy

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    Quote Originally Posted by z80 View Post
    I have all the bits to fix a 7020.

    The power supplies, the tuner module, and the daughter board for the ALPS tuner module.

    I also have the LNBP21 IC that blows on the main board.
    I have the switching regulator that mates to the LNBP21 ic also.

    Good enough support?
    Dear z80
    Dy dreambox show only two paralel lines in the screen and don't boot!
    Please can you help me?
    May be a Power supply problem or what?

    Thanks

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    Quote Originally Posted by bledis View Post
    Dear z80
    Dy dreambox show only two paralel lines in the screen and don't boot!
    Please can you help me?
    May be a Power supply problem or what?

    Thanks
    I don't think its your PSU - you are getting someting out of the video ... but since it does not boot and the fact that you are getting 'parallel' lines - gives a strong indication that you have some sort of memory problem.

    You video memory has got a 'patten' - this implies some sort of memory leak / corruption with you addressing. A memory addressing / corruption problem - will render your DM not to boot - again confirmation of a 'memory' and not PSU problem.

    Memory corruption can be caused by many things.

    1. Faulty memory.

    2. Faulty controller circuitry.

    3. A transient in your power.

    Before you start ripping your 'hair' in trying to fix this problem with H/W parts - there is a good chance that a simple image reload should bring your DM back to life. Reloading the image will 'force' new data into your memory - if it was a simple power transinet that caused this problem - then this will fix it

    Just use Dreamup and a null modem cable connected to your PC and the DM's serial port.

    1. Power-down the DM
    2. Disconnect LNB cable from DM
    3. Connect one end of null modem cable to the RS-232 port on the rear of the DM
    4. Connect the other end of the null modem cable to the serial COM port on the PC
    5. Start Dreamup on the PC - and follow the 'prompts'

    If you are able to perform a succesful 'dreamup' then this is a VERY good indication that your DM will most likely 'fix itself' when you reinstall the new image.

    If dreamup does not 'work' - in the sence it cannot connect to your DM - this would indicate that you do indeed have some form of hardware failure.

    If this was the case - I would attempt to reload the boot loader with a Jtag cable (other posts here describe how and have link to loader) - just in case you 'memory problem' wiped the loader also. If you manage to succesfuly Jtag the DM - this is once again a good indication things will 'fix' themselves.

    After you reload the boot loader - then go through the above process - to once again install the new image with dreamup and the null modem.

    If succesful - your DM will be back to life

    Hope the above information is useful to you

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    Thanks for your reply eyesse

    The problem is that I can't connect my dream 7020 neither with dreamup neither LAN.

    BR

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    Quote Originally Posted by bledis View Post
    ... The problem is that I can't connect my dream 7020 neither with dreamup neither LAN.

    BR
    .. do you get a consistent pattern on the TV screen every time you power-up the DM?

    If you do then there is definately a memory problem - but this could be caused by several things - including a PSU problem.

    If you are a technical person - you may wish to measure the voltage on the HDD power connector - you should have +5v and +12V - this is a good indicator that PSU is still delivering the correct voltage to the mainboard...

    I would then try to Jtag the DM with a new loader - if this does not work - then there may be 'real' hardware issues..

    the fact that you cannot dreamup or connect to LAN indicates that there is nothing 'running' in yor DM ... a Jtag is the most appropriate next step - if your power to the mainboard checks out ok ...

    Are the LED's working (on) and the front pannel showing anything?

    If it does then this indicates the PSU seems to be ok ...

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    Many many thanks for your help mate!
    I don't know how to use Jtag in 7020 and I dont have bootloader for it!
    I have measure the PSU and I think is OK (anyway I didn't have any scheme for it)
    Last edited by bledis; 30-04-08 at 10:25 PM. Reason: image add

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    Quote Originally Posted by bledis View Post
    Many many thanks for your help mate!
    I don't know how to use Jtag in 7020 and I dont have bootloader for it!
    I have measure the PSU and I think is OK (anyway I didn't have any scheme for it)
    ... there is a good post here on how to use the Jtag - as well as how to make the cable - its simple if you can solder ...

    Someone posted the bootloader binary here - just do a search - if you can't find it - I'm sure someone will point you in the right direction

    Glad to hear the PSU is giving the correct volts ...

    ... the image you posted is 'tiny' - can hardly see what it is ... but since its orange ... I presume its your front panel - its 'glowing' which is good .. but what's the message - if any?

    Cheers

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    I think no Jtag for DM7020 mate!

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    Quote Originally Posted by bledis View Post
    I think no Jtag for DM7020 mate!
    ... here are the steps you can do to flash a new image ... if you current DM functions enough for you to do this - then go ahead and try to load a fresh image ...

    BTW - I asked my friend (google) to for this information as I did not know ..

    1. Power down the Dreambox, either using "shutdown" (to enter the deep-standby mode) or by using the power-switch. Standby is not enough!
    2. Press and hold the lower frontpanel button.
    3. Switch on the dreambox, either by using the powerswitch or, in deep-standby mode, press the power button. Still, hold the lower button.
    4. The text "*** STOP ***" should appear. If something like "/flash".. appears, you didn't hold the right button.
    5. Now you can release the button. The bootloader entered the "waiting" mode.
    6. Above the "*** STOP ***" text, there should appear an IP-address (four decimal values with a dot in between). If there appears the string "dhcp" instead, the box still searches for a DHCP server. Wait a bit. If it doesn't change, something doesn't work with the DHCP server. Check whether network cable is plugged in etc. If it just doesn't work, set an IP using the serial terminal)
    7. Now, open a browser on your PC. enter in the address line "http://ip/" (where ip must be replaced with the value in the LCD).
    8. On the bottom of the page, there's a link called "firmware upgrade". Click it.
    9. On the next page, you can select the flash image you want to flash. be sure that it has the ".nfi" extension. You can't flash other images (like .img)!
    10. Click on "FLASH!" and wait. It might take some time to upload and flash the image.
    11. Switch the box off again, and on again. The new image should be flashed and working.

    EDIT: if you want to know more ... here is a good link ...

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    I know the procedure my friend, but the problem is that I can't connect it neither throught LAN neither by rs232!

    BR

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    Quote Originally Posted by bledis View Post
    I know the procedure my friend, but the problem is that I can't connect it neither throught LAN neither by rs232!

    BR
    ... sorry - forgot your LAN is dead also

    ... there is till one more option - so I hope this works for you ..

    On the DM7020, there is a loader called "first-stage" in the bootrom.

    1. First, it will look for a answer for the serial "dreamup" protocol
    THIS DOES NOT WORK ON YOUR SYSTEM
    2. Then, it will look in the NAND flash for a valid 2nd stage loader. When found, the loader will be decompressed (gzip) and executed.
    THIS DOES NOT WORK ON YOUR SYSTEM
    3. If no second stage loader was found, the loader will try to boot from a recovery compact flash image.
    THIS IS YOU ONLY HOPE

    I am not sure of the format of the files you need to put on your CF ... but here is some more info that might be helpful ... if not - google

    Different Boot sources
    The Secondstage loader has the following boot sources: source argument prefix for autoexec.bat
    flash path into the first boot partition, usually starting with a /. example: "/autoexec.bat" for "/boot/autoexec.bat". /flash/
    cf path into the first FAT[12|16|32] partition on the compact flash card /cf/
    none not used. used to temporary disable boot sources -
    stop not used. Used to enter the bootloader, for example for using the bootloader's web interface -
    tftp [server:][bootfile] - server and bootfile will be taken from dhcp when not available (but can be overridden). /tftp/


    Prerun
    Prerun means that "/cf/autorun.bat" (sic!) will be executed before anything else. This can be useful if you, for example, want to put a flash upgrade app onto a CF card for upgrading a firmware without any other interaction.

    Try Default Boot Sources
    ..just means that, when everything else failed, "/flash/zImage.elf" will be tried again. This is useful when you messed with your autoexec.bat...

    Primary/secondary/Alternate boot sources
    The "Primary bootsource" is the tried first (exception is "prerun", which comes even before). If this fails, the "secondary boot source" will be tried. (This can be useful to mimic the dbox2's boot behaviour: first try tftp, then flash. The reason for not defaulting to this is that the network init, including auto negotiation and DHCP timeouting takes several seconds.). The alternate boot sources can be enabled by pressing a key on bootup, either the "up" or the "down" key. "up" is alternative boot source 1, "down" the alternative source 2.


    I really hope that you can somehow reload your image - otherwise we just ran out of 'easy' options

    Let us know how you go ...

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    Senior Member z80's Avatar
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    I reckon the power supply is broken.

    Just one of the rails is down, that's why there is SOME activity.

    And I reckon it's the 12v which is controlled by a 7812 regulator in the diametrically opposite corner to the on/off switch, in a T0-220 package.

    and i reckon plugging a cable modem cable in did it....


    but my avatar says it all.....

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    reckon I'd blow my power supply after plugging your avatar

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    Quote Originally Posted by z80 View Post
    I reckon the power supply is broken.

    Just one of the rails is down, that's why there is SOME activity.

    And I reckon it's the 12v which is controlled by a 7812 regulator in the diametrically opposite corner to the on/off switch, in a T0-220 package.

    and i reckon plugging a cable modem cable in did it....


    but my avatar says it all.....
    Thank for your help mate but please can you excplain exzactly what can I do in order to give a try ? Many thanks. BR

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    Senior Member z80's Avatar
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    Quote Originally Posted by bledis View Post
    Thank for your help mate but please can you excplain exzactly what can I do in order to give a try ? Many thanks. BR


    You need a new power supply to diagnose the fault by substitution.

    they are only a hundred bucks RRP.

    I would offer to fix it for you but you haven't been around long enough.
    (and you didn't buy it from me).

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