Question Panasonic DMR- BWT 720 Blu-Ray recorder Front Display stopped working.

mal2771

Novice Member
Hello hoping someone can help me here. I have a DMR-BWT 720 Blu-ray recorder which I have had since 2013 from new. Never had any problems with it and been very happy with my purchase. Went away for few days last week and when returned noticed we had had a power cut while away. On turning on the Blu-ray recorder it’s switched on like normal and had recorded the programmes it had been set for however the front digital display was completely blank, no counter, no clock on standby nothing. It plays ok all the menus on screen on the tv work, it still records and plays like normal. The red rec 1 and rec 2 show on the front display like normal just nothing else. Have tried unplugging for 2 mins and reconnecting but no luck. Just wondering if anybody can advise me on what the problem could be. Did the power cut blow something, had power cuts before and has been ok. Any advice would be appreciate. Thanks Mal
 

Gavtech

Administrator
Welcome to the forum.

The power supplies for this type of display are a little complex - and some element of it may have failed during blackout.

But micros can exhibit all kinds of very weird states when their supplies are interrupted and it could be blanking the display or suppressing some supply to it.
So to eliminate that small possibility, reset the micro and clear all buffers by disconnecting the unit from the supply for a period - say at least an hour then reconnect and try again.

If that makes no difference it will probably require proper bench analysis to determine the problem.
 

mal2771

Novice Member
Hi thanks for your reply. Tried what you suggested but no luck. Very strange I guess will have to get it looked at by someone to see what’s going on.
 

jonoro

Active Member
If you take the cover off, having switched it off and removed the mains plug and then checked again that the power lead is removed, you will see there is an orange colour flat plastic ribbon cable around the centre and right at the front. This is the FP display connector. It has a short blue strengthening piece attached where it plugs into the main circuit board. Grip both the blue piece and orange cable together and pull them up to unlug the cable, then reinsert it and unlug it again a couple of times, to clean the contacts.
It is important to not just pull on the orange cable alone, you can break it.
 

mal2771

Novice Member
Tried what you said and think I’ve now broke the connector as was very tight to get in there and ribbon has come out of the connector. Never mind did manage to clean some dust away while case was open. Still works just no front display. Will have to get it looked at at some point in future
 

jonoro

Active Member
No you grasp the orange ribbon and the blue strenghthener together between thumb and finger and then pull up, same but push for plugging back in, if you try and plug backin without holding the blue bit as well as ribnon cable you will just bend the ribbon cable.
 

mal2771

Novice Member
Ah so the beige connector doesn’t come out, just the blue end on the ribbon. Maybe I haven’t broke it then.
 

jonoro

Active Member
yes
The only bits to come out are the orange ribbon with the blue attached to one side.
The beige part is the socket.
You will see the orange part is very thin, soft and flexible, without the blue part you would not be able to push the orange part in, it would just fold.
You will see a black line on the blue part, that is to show it it is all pushed into the socket far enough, black line just visible above the brige socket.
 

mal2771

Novice Member
Ok sorry I haven’t broke the connector then. I only tried the once to take it out and just thought I’d broken it. I will have to take the cover off again tomorrow and try what you said removing and inserting it a few times. I held both parts like you said so not damaged it. Just out of curiosity if that has no affect on fixing it any ideas as to what else could have failed. And thanks for all your help today it very much appreciated.
 

jonoro

Active Member
There is a power supply section dedicated to the FP display, could be that.
But to double check, have you looked at the settings for the front panel display, they could have become corrupted?
I think the sequence from memory is
Function menu
Setup
Others
Unit's display
Then set for automatic.

You could also try a shipping condition reset - loose all tuning and timed recording settings.
 

mal2771

Novice Member
Tried removing and inserting the blue connector as you suggested back in up to the black line but made no difference. Also done a shipping reset but alas still no front display. Can’t work out why the counter/ clock isn’t working but the red rec 1 and rec 2 are showing on the front display. Are they using different power supply’s? Must be something else that has gone and failed which has knocked out the front display. Would it be expensive to fix? Thanks Mal
 

jonoro

Active Member
It was worth a try, easy free thing to do.
The FP display is a vacuum flourescent display, apart from the LEDs for rec1,2.
This FP has its own power supply, a bit higher voltage than the rest of the unit. This could have failed, there is also circuitary to blank the display, in stanby, this could be faulty, Then the VFD itself could be faulty.
Parts could be impossible to find, the VFD is bespoke to the recorders.
 

mal2771

Novice Member
Thanks for all your help anyway. Just annoying not having the front display working anymore, guess I will learn to live with it. No point buying a new one as everything else is working fine with it.
 

jonoro

Active Member
If you have a voltmeter I can look up which pins the supply is on and what the voltage should be, but of course that would not fix it.
The vacuum display vould have lost its vacuum, in that case they usually would show all or just part of it somewhat milky white, but I suspect replacements may be unobtainable.
 

jonoro

Active Member
Sorry about the delay- got sidetracked.
Attached are pages from the service manual which should cover all you need.
Unfortunately the 720 manual does not have voltage lists but the 700 manual does and the FP display part is the same
The 2 tables of voltages the columns are:
Item (IC or connector numbers) Pin number then 3 columns of voltages: Record- Playback - E-E
You will see that the power supply (confusingly called the "main board" houses the FPD power supply and the supply is then just connected via the Digital PCB.
I will try and attach all the files, if a problem with size I will post again.
The connectors you want are P6703 and P7201. The FPD driver IC is IC7201
Good luck.
 

Attachments

  • BWT720-Interconnect.pdf
    163.4 KB · Views: 32
  • BWT700-PSConnector.pdf
    46.5 KB · Views: 36
  • BWT720FPD-Driver-Voltages.pdf
    103.3 KB · Views: 37
  • BWT720-FPD-PS.pdf
    179 KB · Views: 27
  • BWT720Block2.pdf
    200.7 KB · Views: 35
  • BWT720-FPD-Block.pdf
    93.6 KB · Views: 35

The latest video from AVForums

Movies Podcast: Star Trek in 4K. Is the new boxset worth it?
Subscribe to our YouTube channel

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom