DVR - Panasonic PWT550 Faults, cooling mod and HDD replacement

Crazy2287

Member
Good day all,

I've recently done some work on a PWT550 and this forum had some good info that helped me fix the issues. (Thanks guys)
original thread: Panasonic720-Installing a New Internal HDD- How to do it

HDD Replacment.

Attached is a file containing the DRM data from the start of the factory HDD in my PWT550 unit. As far as i know this should work for other similar units.
The most reliable way to do this is to copy the data from your own HDD. But if you've had a total failure, the data in the attached file should get you out of trouble.

You'll need the HxD hex editor to access the raw data on your HDD. So go ahead and download then install it form here:

You need to connect you new HDD (and your old one if making the backup yourself) to your computer. Do not format them. They do not need to (and won't) display under 'My computer' as a drive as the Panasonic DVR uses a format that is unknowen to windows.

Your new drive will need to be a fresh format without partitions. It may help to zeroise the disk if it has previously had data on it (Change all data to zeros). If using an SDD, this can be done quickly using the 'Secure Erase' function available in the HDD/SSD managment tool provided by your hard disk manufacturer. For example, Samsung's free 'Samsung Magician' software available on their website.
I could not do this as it appears my SATA controller is too old to support this function (Motherboard circa 2006) so i did a full format/erasure which is generally not recommended on SSD's as it can slightly shorten their life.

WRT SSD life, a quality server or NAS based HDD (such as these: Internal Storage Drives - HDDs & SSDs) would be more appropriate and have a greater life span for use in a DVR then an SSD or cheap HDD. But i had this SSD around doing nothing so in it goes.

Once you've got a fresh HDD ready to go, launch HxD in administrator mode (right click, run as administrator) and then go to the drop down the 'tools' menu and select 'Open disk'
Select the disk you want to open, and if you want to be able to edit the disk, ensure you untick 'open in read only'.

Accessing your DRM

Here you need to copy your DRM data from the start of your old HDD. If you're using the data i've attached, skip ahead.
Open your old disk in HxD. Then navigate to somewhere around sector 2900 (In the left column of HxD, Offset (H) line 00001757F0 in my case) and find the end of your DRM data. In my case for my PWT550, this data stopped at 1757F0. Sector 2,987.
Click after the last bit in the sector, then right click and select 'Select Block'. Then change the 'Start-offset' to Zero '0'
This will select all data from your selected point, all the way to the very first bit on the drive.
Right click, and select 'copy'

Placing the DRM on your new drive.

If you're using the attached DRM data: Go to 'file' and 'open', then navigate to and select the "PWM550 DRM Backup" file. Once open, use ctrl-a, to select all, then right click and select 'copy'

Load your new drive in HxD and ensure you untick 'open in read only' so that you can edit the drive.

Go to the very start of the data in that drive and ensure your cursor is at line zero, word zero. This is important, otherwise your data will be offset from it's proper location and the drive may not work.

Once you've selected line zero, word zero on the target drive. Right click and select 'paste insert' this will paste the data from your original drive (or the attached file) into the start of your new drive.

The data will show in red, to show it's not yet written to the drive. Scroll to the start of the drive (sector 0, line zero, word zero) and ensure its pasted correctly.

Now select save, to save the data, and close HxD. Shutdown the PC and remove the new drive from your computer.


Install your new HDD and setup the device.

Install your new drive.

The following will need to be carried out quickly to avoid the HDD error message.

Plug the panisonic DVR into power. After the please 'wait message' on the front screen, press the power button and wait until you get a display on the monitor. The front display of the unit will show 'D' and a number for the channel, showing the TV tuner working. Immeadiatly press 'Setup' on the remote, and navigate through the menu to carry out a HDD format.
If you're quick enough, you'll be able to carry out a format before the device goes into an error mode.
If you're not quick enough, Remove the power cord, reinsert the power cord, and try again.

Congrats, Hopefully the unit is working with a new drive.


Mods you say?

Yes, mods.
So the cooling on this device is freeking horrible. The CPU is cooled though the chassis, via a thermal pad, that is over 4mm thick. and the contact is marginal. It seems the CPU is kept cool through faith rather than atcually trying to properly cool it.

We are going to use a pice of ally, to increase the pressure against the CPU when installed, and create a larger mass to improve the ability of the CPU to transfer heat to the chassis. At the same time improving the contact of the thermal pad.
Putting pressure against the CPU solves an issue I'm worried out. With heat cycles, and no support on the cpu, especially when it's cooled poorly, there is a possiblity to induce failures in the solder pads that the CPU relies on. Knowen as the 'lack of complience' downside associated with Ball Grid Array (BGA) devices Ball grid array - Wikipedia

Remove the mainboard. (it's the middle one)

While you've already got the HDD out, you'll have the top cover off, along with the faceplate, Additionally remove the back panel, ensuring you remove all the screws in the back panel as this ties the mainboard to the chassis via the IO connectors.
Gently disconnect the relevant connectors off the mainboard (Power supply ribbon, fan, WIFI if fitted, and disk drive. Remove the screws securing the mainboard.

Lift the main board stright up.

Underneath you'll see the CPU and a pink pad, about 15x15mm that looks like a sticky sponge. It's the thermal pad.
Don't get it dirty.

Remove the thermal pad and clean the CPU die (the shiny bit), and the chassis using alcohol and a lint free cloth/tissue/rag.
In preparation for reinstalling the mainboard, stick the thermal pad to the CPU die. Ensure its square on and evenly covers the die.

Make a heat spreader.

Get a small piece of 3mm thick alloy. Make sure its FLAT. Whatever method you use to cut the ally, cannot distort the metal. Good axampels would be a hacksaw/jigsaw with appropriate blade, 1mm cutting disc, or tungsten tipped metal cutting blade on a 4-5" grinder.
Cut somewhere in the size of 40-50mm square, shape is not critical as long as it is flat,

Using some fine sand paper, 1000-2000p, smooth both faces of the ally to ensure it's flat. Clean both faces.
Apply a generious ammount of thermal paste to one side, smear it evenly over the ally, then press it onto the chassis of the PWT550, directly beneath where the CPU will be when installed. Press firmly onto the chassis while supporting from underneath, and move the piece of ally against the surface left to right, up and down about 1mm each direction. This will aid the thermal paste to find all the low points and squishes out of the high points. Giving best thermal transfer. Don't be alarmed if a lot of the paste squished out from under the ally, The more that coems out the better as the best thermal transfer will occur when the metal is directly touching metal, with no thermal paste. The paste is just there to fill voids and aberrations between the two surfaces.

Reassemble.

Then reinsall the mainboard. The thermal pad will deform and you'll get a very slight flex on the main board as you screw it down. But the thermal pad is very malleable, so any distortion will be minimal. We atcually want a small amount as it's a sign that there is pressure on the new 'heatsink' as it will hold it in place and provide us the above mentioned advantages.

Now with the unit operating, you'll notice a much larger hot spot under the unit where your new heat spreader is.


A fault...

So i forgot the hook up the fan. The fan is a 3 wire, so it reports it's speed to the unit. So the unit knows when it's not spinning.
When it detects the fan not operating, the unit will, without warning, shut itself down about 20-30 seconds after powering on. It offers no explination. Just goes black and the font panel says "Bye".
So if you've got yourself stuck in a power cycle loop. Where the unit only turns on for <1 min then shuts down without explination, ensure the fan is operating.

Before replacing the HDD. It's hard to say, i'm not familiar with the factory operation of the unit as i only got it after it was broken, it was kinda just been dodgy. Not recording properly. Skipping while attempting to record and loosing data. Not sure if it was the HDD at fault, or something else i've disturbed while screwing around it . It was very slow to respond and now it works, and responds much faster to controller inputs (Faster due to SSD?)


Thats it for now. Sorry i didnt take any pics during my teardown. If people REALLY need pics, I can pull it apart again and take some. But it's really a pretty simple unit to teardown. I can tell it was designed to be easy for the service centres to troubleshoot and repair these units.

Thanks a lot to Jonoro, The information they shared was absolutly critical to allow me to produce this fix for the PWT550

Bye bye.
 

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