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PLAKNER'S DRD420 PIN #15
HARDWARE MODIFICATION

 

THE WINK SYSTEM

Actually, DirecTV made an comercial agreement with Wink company. It was done to provide interactive control by the DirecTV customer over certain commercials.

The Wink system allows the user to click a button at the remote control when he wants to receive more information (via regular mail) from the product being announced at screen commercial.

From time to time, the receiver connects to DirecTV toll free phone number and transmit the selected commercials / products by the customer, then, DirecTV send that request directly to Wink that will contact the responsible company to send the junk mail.

THE SOFTWARE UPDATE

This receiver function was not previously designed, so the receiver software needed to be updated.  Only 4.5th generation receivers, like DRD420/440/480 are able to receive this software upgrade via the datastream, at least for a while, and acording to what DTV and Wink explain at their website.

NDS, Thomson and DTV used the opportunity to include an extra feature at the upgrade software, the ability to block completely the use of H card at the receiver after it receives the upgrade.

Receivers produced after December 12 2000 are receiving the software upgrade at the factory, so they will not accept to work anymore with the H card.

Receivers produced before December 12 2000 were produced with the old software upgrade, the DRD420RE upgrade number was 380105.

Apparently by some not explained well reasons, receivers exposed to datastream are open to receive the upgrade automatically.  The upgrade is not done immediately, it schedule the upgrade for at least some hours in advance, so you will know when it will happens. You should see the "Future Upgrades" screen to make notice of it.

Nothing you can do to avoid the upgrade, except for unplugging power cord and hope for the schedule upgrade to be erased.

THE SPECIAL UPGRADE SETUP

The first thought about the Special Upgrade Setup at service screen does not block in any way this auto-upgrade.  Many friends did it and received the upgrade "with no mercy".

WHAT IS POSSIBLE TO DO?

These receivers technology use a Flash Memory, something that can be reprogrammed on board, this was done basically to accept online upgrades like the Wink. Of course this is a well accepted thing, since you can correct software failures and bugs, even receive new features as Wink and so on.   The actual upgrade on datastream is not very welcome for testers that want to keep using the H card.  So, at this time, this software upgrade is not very welcome for some people.

The only possibility is a "Hardware Rework".  Something that at the end will not allow the flash memory to be programmed.

Looking at the Flash Memory datasheet, it was found that this chip pin #15 needs to receive +5Volts power Voltage to supply energy to the internal chip circuitry.  So, whenever the processor wants to program or reprogram the chip, it needs to control a power circuit to feed +5V to pin#15.

So it is easy, everything that needs to be done is avoid the processor to control power to pin #15.

This can be done in two ways, first)  cut off the communication from the processor to the power circuitry, in real two transistors, and second) isolate completely pin #15 and solder it to ground.

The second option was considered for many friends, even some modifications like that were done.  Some old suggestion was a cannibalistic one, just saying to lift pin #15 from the board and soldering a wire directly to the pin and to ground.  Ok, it works, but the pin is very, very small and almost impossible to be soldered by a normal person with a 40W solder iron and a shaking hand.  Lots of people just ended with broken pin #15. Ok, the receiver will not do the upgrade even with broken pin 15, but I would not recommend to do that kind of barbarian action.

Yet at the second choice, some people used to isolate pin #15 at the continuity of its board traces, doing a simple sharp razor blade cut to isolate the trace, then scratching a bit over the isolated trace (pin #15 side), solder a small wire to any ground place around.  This solutions also works, since it isolates and ground pin #15, but again, there is not an easy spot to do that, and the trace width to scratch is tinny and very difficult.

MY CHOICE.

Then I look forward and found the two transistors, the ones that power +5V to Flash Chip pin #15 upon the processor request.  I considered the possibility to rework the transistors, remove them or something like that. The problem is that the transistors are located below the card slot, difficult to access and to work.

Looking forward, I found out the trace that goes from the processor to the transistors, that would be the last possible place to install a rework.  Then I found a nice cutting point, indicated by the red circle at the figure. Some point where there were no other very close board traces to cut by accident, and an easy spot to work, even without removing the board from the receiver.  Once the cut is done, the processor will not be able to control the transistors anymore.  

Now it is necessary to make sure the transistors would be quiet and will never switch +5V to the Flash pin #15.

Analyzing the electronic circuit involved, when wanting to reprogram the Flash Chip, the processor feds positive level to the base of the NPN transistor, this transistor will turn ON, and will fed negative level to the base of the PNP transistor, this one also turns on and feed +5V to the Flash pin #15.

Now there is no more connection from processor to the base of the NPN transistor, but this transistor base is floating and it can trigger +5V to flash at anytime.  So, we need to just apply a definitive ground (low level) to this transistor base.

Following the traces, it was found that the FP (large dot spot) close to the green LED is an electric connection exactly the NPN transistor base, so soldering a wire from FP to Ground will lock the NPN transistor inactive forever.  FP means Flash Programming, and that point is the factory test point, so it should be located at an easy spot, easy also to solder the wire.

It means, that cutting the trace as indicated at the bottom of figure (small red line should be the cut), and soldering the wire as indicated on top of the figure, will make the Flash memory write protected.  The receiver doesn't know the chip will not accept programming, so it will accept schedule for upgrade and will also start to receive upgrade packets, but when it would try to program the flash, nothing will be programmed, once the receiver will read back the flash to make sure the data was recorded, it will find it failed, so it will stop the programming and will try to schedule another programming later.  It was already confirmed. Receiver said programming failure, re-scheduling for later time. H card still being used without any problem.




The Zoomed section for the Circuit Board Track Cut

 
The zoomed section for the Jumper very close to the Green LED.

 

IF YOU WANT TO FOLLOW STEP BY STEP.

For those without much soldering practice here it goes all the procedure:

Remove completely the power cable from power outlet. Make sure of this. Twice.

Remove the 3 screws that hold the top cover. Screws are located at the back on top. Save the screws.  Screws need a special hex key, not a regular philips screw drive, not even a regular knife screw driver.  It is called "bristol" key.  There is one stripe on each one of the 6 sides of this little key.  If you are desperate, just use a pliers to grab and turn the screws, they will come out, but it is a barbarian act, you are advised. :)

Now pull the cover to the rear. Some covers can't come out easily, you can use a small screw driver at the cover vent to pull it to the rear, so it will come out from 1/8 to 1/4 of an inch. Then lift the cover and remove it.

The above picture was taken looking to the internal circuit board by the rear. The picture shows the upper left side of the board as you see it.

Using the picture to helps you, locate both points, the "CUT HERE" and the "ADD THIS JUMPER" points at your receiver board.

YOU DON'T HAVE A SOLDER IRON.

Go to your local Radio Shack or hardware store, and buy a small soldering iron, from 15 to 25 Watts will be ok. It needs to have a very small soldering tip, imagine a halfway used pencil tip size, that's a good one.  Buy also a small quantity of solder, they use to sell in rolls or a yard or two coiled into plastic tubes. Solder is cheap, buy it anyway.  Tell the sales person you want to solder integrated circuits, so he will guide you to the right stuff.

You can practice cutting and soldering at any other electronic circuit, as old fax/modem cards from your computer, even that old broken computer mouse, or lots of broken toys have circuit boards inside. Consider also an old radio or broke telephone or calculator.  

The cutting process should be done with precision, short and easy strikes, repeat it as many times you want, until you can be sure the board trace was really cut.  You can visually see the separated copper borders at each side of the "valley" cut at the board.  Avoid to apply strong force to cut, the blade can slip and cut other traces around, just to easy and repeat it with patience.  5 to 6 easy passes of the blade in the same place would be more than enough to isolate it. Try to do a cut at certain angle, the next with opposite angle, so you will open a small valley, and not only a single deep cut.

The soldering process is quite simple.  Turn on your solder iron, wait it to heat during one or two minutes.  Lay the iron over some heat protected thing as for example a metallic surface or ceramic tile.  The heat generated by the iron can put fire in paper or even damage your nice desk or computer keyboard or cables, so consider it dangerous always.

Grab a piece of wire, two inches is more than enough, any wire, as for example a piece of telephone wire, or a wire removed from the old mouse or keyboard cable. Wire gauge number could be from #20 to #30, it doesn't matter really, any tinny wire will do.  Remove the insulation of each end of the wire, something like 1/8 to 1/16 in length, keep the rest of the wire with its insulation. .

Now you will need tree hands, but you can do it nicely with only two.  Apply the hot tip of the iron to one of the end of the wire, heat it for few seconds, then apply the solder right in the middle in between the iron and the wire.  The solder will melt and will be deposited at the exposed wire metal.  Make sure the solder just grabbed well around the wire metal.  Do it at the other side of the wire too.  If the wire insulation start to melt and retracts to much because the heat, just put it away and do it again in another piece of wire.  With few practice you will do it quite nicely.

Now with the iron tip heats point FP a the circuit board, you will see the existent solder melt, you can apply a little bit of the new solder, just to add a little bit more to the FP point.  Do the same for the Ground point.

Now, heat again the FP point, when the solder melts again, make the wire touch and melt its own solder to the FP point. The FP point in true is a hole, with the solder melted try to insert a little bit of the wire exposed wire into the hole. That is not necessary, but a good practice.  Remove the solder iron, and hold the wire in place while the solder cools down and fix the wire in place.  It will take 2 to 3 seconds, you can blow air to accelerate the process, mainly if the heat from the solder point reach your fingers trough the wire, remember, metal is a good heat conductor.  You can also hold the wire with a small pliers or any other instrument. It is not really necessary, a fast soldering like that will be easy and will not burn your fingers.

Repeat the other side of the iron for the Ground point.  When you finish, you will have a steady wire soldered from FP to Ground. Try to pull the wire gently and make sure it is firmly in place and will not get out easily.  If it does, redo the solder for the loosen side.

WANT TO BET? IT IS DONE!

Your Hardware Modification is complete.
Install the top cover in place, insert the 3 screws and you are ready to rumble.
Your receiver is write protected against Dr. Evil software upgrade.

PLakner/