Question DMR-BWT735 HDD replacement HDD error

rayc24

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Hi, I’m new to this forum.
Hoping that someone can advise me on a problem with HDD replacement.

I recently acquired a DMR-BWT735EB on Freecycle.
The owner informed me that the unit had become unreliable and sometimes failed to make scheduled recordings. I formatted the HDD, without issue and the unit was functional. I decided to check the integrity of the HDD, so, I removed it from the unit and connected it to my desktop PC. The SMART data revealed reallocated sectors (0448), uncorrectable sectors (0658) and a recommendation of “Caution”.

I decided to replace the HDD with a good tested Seagate ST1000DM003, I had lying around. A few minutes on Google led me to this forum and I followed a procedure posted by jonoro:

Using HxD I copied the data (Offset 0000000 to 0170200) from the original HDD to the new HDD. I then hooked up the new HDD to the 735, powered-up and formatted successfully.
Within 20 seconds of returning to the normal display (BBC1) I get this message:

“Error has occurred. The operation stopped because USB HDD may have been removed without procedure of “USB HDD Disconnection” or there may be a problem with the disc. Press OK. Then this unit will be turned off and start self check and recovery after restart” (See post #15 Alla87 Dec 16 2019).

I press OK, screen goes blank and PLEASE WAIT scrolls across display. This is followed by U61 on the display. The screen then returns to normal display (BBC1) which is obscured by the message:

“Self check and recovery has finished. This unit is turned to off automatically. Please wait. After this unit is turned off press Power to restart”.
After about 1 minute PLEASE WAIT scrolls across the display and the unit turns off.
I then press the Power button. The screen then returns to normal display (BBC1) which is obscured by the message:

“Part of the last recording or copy may be lost due to removal of USB HDD or problem with the disc caused by scratches, dirt or quality of disc. Please use another disc if the disc has a problem. Press OK.”

I press OK and after about 2 minutes the unit suddenly switches off without any warning.

I have made the following observations:

No USB HDD is registered with this unit.
When I return the original HDD to the unit, it formats and I get no error messages.

When I examine the original HDD data, using HxD, starting at offsets 41020, 42020, 43020 and 2042020 I see the following data:

1S1GAA3N…...AM12 TS0100MV00-2C11T26

I think this data is related to the HDD serial no. (S1G1AAN3), firmware (MA21), and part no. (ST1000VM002-1CT162-125). The characters having been transposed/ abbreviated.

When I examine the new HDD (after formatting in 735), at the same offsets, I see exactly the same data. Should it not have changed, after formatting, to something related to the new HDD? (The new HDD is a Seagate Desktop HDD serial no. (Z9A67GEP), firmware (CC43), and part no. (ST1000DM003-1SB102-300)).

Any info or help would be much appreciated.
 
Hummh, not seen that problem, but I have never had a 735.
First I suggest that you try a factory/shipping condition reset.
If that does not work try making an image of the first x170200 of the original HDD using ddrescue, then copy this image to the new HDD. Thinking is that there could be some issues with that part of the old HDD.

As to your observations re model and serial numbers, it doesn't make any sense to me why would Panasonic want to read the data about the HDD ( from the private reserved sectors) and then write it back to the same HDD?
 
Hi Jonoro,
Thank you for your suggestions.
I have already tried the factory/shipping reset.
I cloned the entire original HDD using dd(conv=sync,noerror).
I have also tried the file, posted by yourself, for the 720.
In each case the unit failed as before.

Regarding the data from the private reserved sectors, do you think I am right in thinking that, after formatting, I should expect to see the serial no.,part no. etc. data change to that of the new HDD? Maybe the formatting process is not completing? If that was the case I might be tempted to acquire another HDD identical to the original.

Regards,
Ray
 
Ray
You are in new territory for me. I have read a few reports of others having non-existent usb reporting but I have not had that myself or read of any solutions.
As you have tried the 720 file with the exact same result it serms unlikely that it is a corruption of your old HHD further more the 735 with the old HDD does not give the problem.
I have used different makes of HDD with no problems. I should add that I have never used a USB HDD apart from a couple of test runs to investigate issues that others were having.
I still can not follow why data about a HDD would be written back to the HDD itself.
Did uou look at those locations on the 720 file to see if the data looked l8ke HDD id data?
I am now clutching at straws! Maybe register a usb drive if it will let you then delete all usb registrations. From the messages you get it seems like the 735 thinks it has been using a usb HDD but now can not find it.
 
Hi Jonero,
Please find attached .txt files. In each case the data clearly relates to the relevant HDD. As mentioned previously, I believe the data may be transposed/abbreviated. I have already tried registering/unregistering the would-be new drive as a USB drive successfully but when I reattempt to install it as the main drive, the errors return.

Regards,
Ray
 

Attachments

  • DMR BS850 working drive.txt
    530 bytes · Views: 84
  • Panny720HDD.txt
    533 bytes · Views: 98
  • Pipeline S1GAA3N Selection.txt
    533 bytes · Views: 117
Hi Ray
That is indeed interesting that HDD data shows up there, I have never looked for that, thank you.
There are a few posts on the site from others who have has usb disconnection problems.

This post for example:
https://www.avforums.com/threads/panasonic-bwt720-usb-hdd-disconnection-error.2237192/

I don't know if the OP managed to resolve the problem - you could ask.

You could try a clone of the whole HDD and see if that makes a difference.
I did look into USB registrations and found some HDD id data is stored on the I2C EEPROM which is mounted on the power supply PCB, see here:
https://www.avforums.com/threads/panasonic-bwt-pwt-bs-series-recorders-hdd-int-usb-registering.2271479/

If you get really desperate you could try clearing the areas on the EEPROM that are concerned with USB registrations.
 
Hi Jonero,

I enquired of the OP re. the usb-hdd disconnection error.....that has not been resolved. I have already cloned the entire HDD.....error remains.
I may try clearing EEPROM as you suggest but I'm still bugged by the HDD id data not changing after formatting.
I will let you know as things progress (or not).

Ray
 
Ray
I agree, it is very strange that the id data is there and that it does not change.
Have you tried changng the data to match the real id data from the drive itself?
 
Yes, I have changed the data. As I mentioned the data is transposed/abbreviated when it appears on the HDD. On the original HDD SN: S1G1AAN3 became 1S1GAA3N
PN: 1CT162-125 became 2C11T26

There are a number of ways this transposition could have been achieved.

I have been working through the permutations for the new HDD
SN: Z9A67GEP -----4 permutations
PN: 1SB102-300----4 permutations
That makes a total of 16. I have tried 4 so far.

Will let you know result if I don't go mad in the meantime!
 
I have now tried all 16 permutations, with no success.
Will post if there are any further developments.
 
Thanks Ray
I wish there was something more I could suggest.
 
Hi all,

I'm going to have another go and repairing my unit, see how I get on.

The EEPROM, is that stored on the power board or the main board?

Another question, the DMR BWT700, other than the hard drive size, were there any other hardware changes? I remember selling these Panasonic products but it's been a while since they was on the market.

I was just curious if boards were interchangeable eg Power Board.

Hope all is well with everyone
 
The EEPROM is on the power supply pcb, on the reverse side. Panasonic call this the "main" pcb!
I know some of this family of bluray machines have a different sequence of pins on this power board but can't recall which machines. The EEPROM is an orphan on the board, i.e. it is not connected to anything apart from the connector.
 
I have finally suceeded in repairing this unit.

The HDD was the problem. I obtained a WD 10EURX HDD from a Sky Q box I got on Freecycle. I copied data from offset 0 to 2042290 from the original Seagate Pipeline HDD to the WD 10EURX. The WD 10EURX was fitted to the Panny and formatted. Unit is now fully functional.

I removed the formatted WD 10EURX from the Panny and checked the data. The data has not been modified so I would conclude that formatting does not write data to the HDD.

I cannot explain why some HDD's cause a problem but it does seem to be the case.

Finally, I'd like to thank Jonero for providing detailed notes on programming the HDD using HxD.
 
Thanks rayc24, very interesting and so good of you to post updating the knowledge of all of us.
It seems then that when you found data on the HDD about the HDD model and serial number albeit in something akin to Big Endian format, it had nothing to do with the problem.
But still what in the first replacement HDD could cause the problem??
 
Hi Jonero,
I'd like to get to the bottom of that mystery.
If we had a list of HDD's that had been successfully installed it might shine a light on what the significant factor might be.

I wonder if this might offer a solution for Aleister's 720?
 
Yes.
I am trying to remember which ones I have used, certaimly the WD AV drive and a Seagate Pipeline.
But the actual models?
 

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