DMR-EX77

micchese

Novice Member
Hi everyone. I subscribed to this forum after reading many interesting threads about Panasonic DMR-EX series.
Some months ago my old beloved Panny (0) DMR-EX77-EC-S (bought in 2009) started doing strange sounds during a mastering session, after which it was completely unable read dvd discs anymore (Disc Icon appears even when dvd is not present). After reading these threads it became evident my laser diode died.
So I started buying several used/broken DMR-EX77, in the hope to find a working DVD Drive+PCB board (because laser calibrations are on Digital PCB Board). I bought in the order:

1) DMR-EX77 (no other codes present).
Had blown capacitors on Power Supply PCB. Once fixed, it worked again, and the dvd drive was good. However this model comes from England and thus interface is english only (I cannot change language beside English or its regions like Welsh and so on). The main disadvantage is that, even if I can tune digital channels to my country (Italy), when doing a programmed recording, it automatically selects english as main language (most channels in Italy now support dual-audio). I was not able to select the desired language for recording, or set italian as main language. Is this possible at all?

2) DMR-EX77-EC-K (k = blank, EC = ??? )
Blown capacitors on Power Supply PCB. Didn't have them, so I took out the repaired Power board from the previous recorder, and the VCR powered on. However, it remains in permanent Please Wait state, and DVD Drive start forcing eject 1cm per second, and keep forcing it out even after reaching end of rail. I suspect the Digital PCB is blown or unrecoverable.
I took out the laser assembly and put it in my old Panny (0). It reads DVDs without problem. However recordings are not readable (if you look at dvd surface, there seem to be some regions where the reflection of the recorded track changes, while previous readble recordings seem to have uniform coloring). It's like something has changed during disc rotation speed adjustment. I tested TDK and Verbatim DVD-R and all failed, so I assume something is wrong with laser calibration. It is strange that it reads DVD from start to end without hiccups, but maybe playing and recording are two different parts of the medal.

3) DMR-EX77-EG-S (s = silver, EG = ??? )
Blown capacitors on Power Supply PCB. Once fixed, it started with usual Please Wait message, and usual :( DVD Drive clunking sound with DVD icon when nothing is in the drive (G*dmnt). However I can access user interface (which supports multilanguage). The problem arises when doing channel setup. It seems to completely miss all the digital setup. It supports only analog tuning, which is useless since the switchoff. According to the repair service manual, DMR-EX77-EG-S supports Digital Tuning. So what am I missing? May be the firmware so old that it doesn't have the digital tuning part in it? My first Panny has the same code of this but the user interface has more options.
EDIT: another thing about this model is that although the SDCARD slot is present, it cannot be selected with the remote. I can switch only between HDD and DVD.

Yesterday I attempted to put Power Board PCB of (3) in (2), and put the DVD-Drive (broken) of (3) in (2) as well. The VCR started, but a U81 error appeared. User interface can be set in English or German (which makes me think that firmware is stored in digital PCB), recordings language can be selected, including italian as main language. However it doesn't start Digital Tuning (white screen until power off, and the Firmware version reports 0.00 - maybe because of missing communication with ST microprocessor, as U81 error seems to indicate). I see C1557 is blown, C1558 seems good though. I do not have a replacement for now.

Swapping hard disk between (3) in (2) proposes me to format it (I didn't format it). When put back in (3) hard disk is still recognized, without forcing a format or requiring DVD Firmware. It's serial code is probably stored in Main PCB (or in Backend PCB which I was unable to remove from any of my VCRs, it's pretty tied in and I have fear to break it. Manual says to pull it up, but when trying I do not see any perceptable evidence of detaching). Since I don't have a DVD firmware, and Panasonic support has been completely deprecable ("we don't have it" was their reply), I did a binary dump of the disks (at the least of the first 360MB) just in case.

Swapping DVD-Drive+PCB board of (1) in (0) allowed me to record my videos at hispeed without errors or strange dvd coloring in tracks. But, in this case, user interface turned english Only. Which gave me more evidence that firmware is really stored in the Digital PCB.

So, for now I have 4 VCR, none of which is completely functional. The reason why I'm telling you all this is to have some suggestions to obtain a completely working unit. So, to summarize:

a) Find a Firmware DVD for DMR-EX77, which may be different for English only (DMR-EX77), german market (DMR-EX77-EG), italy+spain (DMR-EX77-EC). Would a holy soul of you help me to find it?

b) Find a way to select Italian as main language in (1) model. This is the mostly working unit I have, but this limitation is currently too much penalizing for normal use.

c) Once made clear if (3) is effectively limited to Analog only tuning, maybe because of very old firmware (because my Panny 0 has the same machine code and it seems to me so strange that the firmware is so different), I may sacrifice it to desolder components to make of (2) a possibly working unit.

Sorry if I have been so pedantic, but I tried to be as much specific as possible.
I'm looking forward to read your suggestions and opinions.

Thank you all in advance.

Have a nice day
 
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Gavtech

Administrator
I cannot offer any immediately helpful solutions but here are some initial comments.

Firmware if it was available would be available on the Panasonic Global site:


(It may be easier for you to navigate to the Italian Portal on that site )
Note that you have to select 'Back Number' at the bottom of the page to go back to earlier years.
It only goes back as far as 1977.

Original firmwares have never been available on this site as far as I am aware.
It is only update firmwares that are available there.
Such updates are (usually) only ever released to address reception problems that have arisen as a result of broadcast changes.

It is essential that the firmware matches the hardware model and territory it was designed for.
As far as I'm aware if these do not match, it is not possible to install the firmware.

I have already looked and unfortunately I cannot see any EX77 updates - even though I know there was an Update for the English model back in 2008.

Service agents may have a firmware copy of the firmware and it may be your only hope.
I know of someone who paid a token fee plus begging and grovelling to borrow an update disc.


PCB's

The Power PCB is the same in all three machine territorial variants.

There are three different main PCB's :
EB version
EG Version
EC /EC1 Version

The circuitry differs significantly from each other. Some have IC's not present on others.
They have different value crystal oscillators and they each have different tuners to cope with the different territories.

The backend board is also different for each territory - so should not be cross mixed from machine to machine. (But FYI the way to release those boards under control is by using a lever under one end of the vertical board against the main PCB. A large wide bladed flat screwdriver will usually do it.)

The Digital module is also different for each variant and again should not be intermixed.

I have no definite information but I think the DVD RAM drive is probably the same in all cases.
 
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micchese

Novice Member
Thank you Gavtech for your kind reply.
Given the fact I cannot swap the boards because they are all different, I can only try to fix the U81 Error in the (2) unit which have many capacitors blown, cannibalizing (3) which seems the most unusable unit due to lack of DVB section. I'm going to posts some screenshost to evidence the fact that something is missing in (3). There is no firmware update option, and in service mode, after pressing 02 it should show 6 information steps, but this unit is missing the 6th (the ST microcontroller version, which incidentally is the DVB version and could possibly justify why DVB channel settings are missing).
Do you know if DVB firmware is held on Backend pcb?
 

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micchese

Novice Member
These screenshots are taken instead from the (2) unit.
This unit seems to be severely damaged by the previous owner who probably attempted reparing it without having the technique nor the right replacements: there are capacitors with different value and very high voltage difference like 35v instead of 6.3v, or 1000uf instead of 820uf, or 470uf instead of 330uf. I'm not surprised to see the two 1800uf cap on the power pcb exploded.
This unit reports DVB version 0.00 but this could be due to U81 error. DVB channel settings are present, but hang the unit when pressed (need to hard shutdown keeping pressed the power button). Service mode 02 reports ST 000 in the 6th step (which reflects the possible missing communication with the ST microprocessor, which is located on backend pcb, that's why I was asking before).
This unit has blown capacitors (330uf and 680uf surely seem gone, not sure about C1558). On the contrary, the (3) unit has flat head capacitors and indeed it doesn't show any U81 error (last two pictures).
I may try transplanting them (easy route), or take the long way road and order the right replacements (but this takes more time and money).
 

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Gavtech

Administrator
Additional - Re: 2) the DMR-EX77-EC-K machine.

If a machine cannot detect the operating system at boot up - perhaps because the HDD has failed or is corrupted then the machine assumes it does not yet have software and automatically opens the DVD drive to receive a CD Software disc. - That is why the drawer is opening.
 

Gavtech

Administrator
Re your reply posts 3 and 4 . I will try to get some time tomorrow to look at these in detail.
 

micchese

Novice Member
Additional - Re: 2) the DMR-EX77-EC-K machine.

If a machine cannot detect the operating system at boot up - perhaps because the HDD has failed or is corrupted then the machine assumes it does not yet have software and automatically opens the DVD drive to receive a CD Software disc. - That is why the drawer is opening.

I think this is not the case. It doesn't open normally, I mean with a fluent movement, and it cannot be closed with open/close button, so it cannot receive any firmware updates. This same unit works when I switched DVD-Drive+Digital PCB from the (3) unit, hard disk was good and holds part of the firmware and previous recordings too. The defective DVD-Drive+Digital PCB from (2) when put in another unit behave in the very same way. So I think it's damaged. I have taken out the laser assembly from this broken unit and put in my (0) unit, and I can read DVD flawlessy, but cannot record them without errors.
 

Gavtech

Administrator
Thank you Gavtech for your kind reply.
Given the fact I cannot swap the boards because they are all different, I can only try to fix the U81 Error in the (2) unit which have many capacitors blown, cannibalizing (3) which seems the most unusable unit due to lack of DVB section. I'm going to posts some screenshost to evidence the fact that something is missing in (3). There is no firmware update option, and in service mode, after pressing 02 it should show 6 information steps, but this unit is missing the 6th (the ST microcontroller version, which incidentally is the DVB version and could possibly justify why DVB channel settings are missing).
Do you know if DVB firmware is held on Backend pcb?

When it comes to replacing capacitors I would recommend getting new rather than cannabalising from another machine.
They are not unduly expensive and it is nearly always worth the speculative investment to try to get a machine going again.

It has to be said that capacitors account for virtually ALL problems with these machines.
The only other problem in the laser and very occasionally hard drives - but that is true for all such HDD included devices.
Secondary problems and further damage can arise for neglecting capacitor problems and running a machine with compromised power lines.

Regarding capacitor values that you mentioned earlier, being a value over is probably not too critical. Going to a higher voltage is probably OK too but that parameter should not be overdone.
Too high and capacitors cannot 'self-repair' which is in the nature of their function.



I understand the desire to analyse the problem so that an educated guess at how to fix it can be evolved - but that approach nearly always comes up against a point of insurmountable ignorance because there are areas of these machines which have ways of working that are kept from us mere mortals.
Deep technical information has just never been available.


As I understand it the eeprom is on the main board. It stores information such as channel tuning data.
My understanding is that on machines of this vintage the firmware was always stored on the hard drive.
How that firmware is handled and interchanged between moving and hard memory I do not know.


Rather than chasing and trying to speculate what may account for the missing reported functions and seeming missing reception firmware, I think it is better to concentrate on getting all the main power lines, and sub-power lines right by tackling all the capacitors that may be at fault.


For one thing, it is likely that there are missing or inadequate supplies in critical areas of the machine such that some sub-circuits cannot function.
It almost certainly accounts for the U81 code - which is a communication failure between processors... and if they cannot communicate, then presumably they cannot accurately report what functions and firmwares are present.

Getting all problem capacitors sorted out first is your best way forward.
You may still come up against a brick wall eventually but you have no chance of progress unless you tackle it first.
 

micchese

Novice Member
When it comes to replacing capacitors I would recommend getting new rather than cannabalising from another machine.
They are not unduly expensive and it is nearly always worth the speculative investment to try to get a machine going again.

It has to be said that capacitors account for virtually ALL problems with these machines.
The only other problem in the laser and very occasionally hard drives - but that is true for all such HDD included devices.
Secondary problems and further damage can arise for neglecting capacitor problems and running a machine with compromised power lines.

Regarding capacitor values that you mentioned earlier, being a value over is probably not too critical. Going to a higher voltage is probably OK too but that parameter should not be overdone.
Too high and capacitors cannot 'self-repair' which is in the nature of their function.



I understand the desire to analyse the problem so that an educated guess at how to fix it can be evolved - but that approach nearly always comes up against a point of insurmountable ignorance because there are areas of these machines which have ways of working that are kept from us mere mortals.
Deep technical information has just never been available.


As I understand it the eeprom is on the main board. It stores information such as channel tuning data.
My understanding is that on machines of this vintage the firmware was always stored on the hard drive.
How that firmware is handled and interchanged between moving and hard memory I do not know.


Rather than chasing and trying to speculate what may account for the missing reported functions and seeming missing reception firmware, I think it is better to concentrate on getting all the main power lines, and sub-power lines right by tackling all the capacitors that may be at fault.


For one thing, it is likely that there are missing or inadequate supplies in critical areas of the machine such that some sub-circuits cannot function.
It almost certainly accounts for the U81 code - which is a communication failure between processors... and if they cannot communicate, then presumably they cannot accurately report what functions and firmwares are present.

Getting all problem capacitors sorted out first is your best way forward.
You may still come up against a brick wall eventually but you have no chance of progress unless you tackle it first.
Thank you. I'll follow your advice and will start replacing capacitors with the right value and new parts, instead of getting them from the other unit. I seem to recall reading another thread where were detailed the voltage lines on a connector (1.8v, 3.3v, ...), but I can't find it atm. I'll try to search for it again tomorrow, as it was much clearer than going thru the service manual.
 

micchese

Novice Member
So Gavtech, I'm updating my recent progress in repairing the units. I started with (2), the german unit.
Following your advice to change all capacitors in the 3/4 part of the main board (as references in the service manual), and after changing a suspect capacitor in the power board with the head lightly blown, this fixed the U81 error. However after initial setup, the DVB version was still reporting 0.00 and no DVB channels could be setup.
So I tried to exchange the backend PCBs (yes, I know you said they weren't interchangeable). Following your advice to use a flat screwdriver, I could easily remove the backends. Exchanging them didn't produce any appreciable change, so I removed them again and cleaned the two connectors with Trichloroethylene and put back the german pcb backend into its unit. I also kept the unit disconnected for at least half an hour. I don't know if any of these two events was resolutive, however, after initial setup, in the System Update information, the DVB version was reporting a valid number (1.06). So I tried to set up DVB channels, and this time it worked. So I successfully brought back to life the (2) unit. Initially, I got DVB channels in black and white, though the user interface was instead in colour mode, and the HDMI signal wasn't detected. I exchanged the (3) and (2) HDMI pcbs, and fixed all the grounds to the external case, and the HDMI signal was finally detected, and RCA video is now in colour mode too.

About the (3) unit, the silver one, after changing a few capacitors here too, the unit booted once, but immediately got a U99 error (timeout during communication between ICTimer and Main board).
Having the Digital PCB not fully working I cannot test it more than this. If I put the german unit Digital PCB, I can initally enter in setup, but after a while, U99 error appears and unit is no more operable.

So, first let me thank you for the useful advices with which I could at least fix one unit.
If you have anything to comment about the U99 error, I'll read it with interest :cool:

Ciao
 

micchese

Novice Member
If you have anything to comment about the U99 error, I'll read it with interest
About the U99 error, once again it was due to Power PCB. There may be some component which needs replacing, though at first sight there are no evidences of capacitors blown out. However, switching Power PCB with another perfectly working cures the U99 error.

Yesterday I tried to mirror Hard Disk from my working (0) unit. I placed it in (3). The idea was that if firmware was on hard disk, I could have seen changes in user interface. Fact is: firmware is not on hard disk indeed. When put in, it asks to reformat it, which I did. However no change in user interface took place. This confirms me that firmware is indeed stored in RAM Digital Board: the IC55004 (S29JL03H70TFI01) is a 32Mbit flash memory. On the back of that board IC53201 and IC53202 are 512Mbit DDR2 SDRAM. IC53001 (BU2365FV) is a clock generator that has the built-in high-precision VCXO function and allows for high-precision synchronization with DVD Video clocks.

Pairing a RAM Digital Board (german, taken rom EG-S unit) + VEP77112B Backend (B is for 77EG models) gets a working german unit with DVB backend correctly communicating, even though HDD was coming from a 77EC model.

So, when Firmware DVD is inserted, what happens should be: update RAM Digital Board with new firmware if required, update Backend DVB firmware if required, initialize the first sectors of HDD with a signature that makes it recognizable by the unit, and finally format HDD. I'm pretty sure there is no firmware on HDD. You can copy the first sectors and it will be recognized as valid and asked to be formatted.

Rereading my first post, I realized I may have done some confusion:

2) DMR-EX77-EC-K (black)

This was an italian model, with broken digital ram pcb, and a working 77112C backend pcb. When I later acquired the german model, I put the Digital Ram pcb in it, and the unit worked but without DVB tuning, as backend was mismatching version, but I was not aware of this fact.

3) DMR-EX77-EG-S (silver)

This was indeed a german model. When I swapped backends, the 77112B backend that I put in (2) started to communicate with the digital board where firmware resides, and that's when I saw the correct DVB firmware version (1.06)

I think I'll stop here. I don't have any spare unit to test, and I have now 2 mostly working units (italian and german) and 1 fully working unit (the english one), along with a lot of knowledge more on these dvd/hdd recorders.
 

micchese

Novice Member
On a final note, I may add I recovered all my recordings from (0) unit, without having to copy them on DVD. After I made a mirror image of the hard disk, I used the excellent extract_meihdfs tool


to extract the original .VRO recordings. I slightly modified the program to allow me to process the HDD image without having to restart from scratch the extraction, but continue where it was stopped.
 

Gavtech

Administrator
@micchese - Apologies, my time has been short.
I will get back to address the above as soon as time permits.
 
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Gavtech

Administrator
About the (3) unit, the silver one, after changing a few capacitors here too, the unit booted once, but immediately got a U99 error (timeout during communication between ICTimer and Main board).
Having the Digital PCB not fully working I cannot test it more than this. If I put the german unit Digital PCB, I can initally enter in setup, but after a while, U99 error appears and unit is no more operable.

So, first let me thank you for the useful advices with which I could at least fix one unit.
If you have anything to comment about the U99 error, I'll read it with interest :cool:

Ciao

About the U99 error, once again it was due to Power PCB. There may be some component which needs replacing, though at first sight there are no evidences of capacitors blown out. However, switching Power PCB with another perfectly working cures the U99 error.

It is good news that you have made some very positive progress.

I think the U99 problem will almost certainly be due to one of the secondary lines in the PSU being compromised - either completely unsmoothed, missing altogether, or challenged when under load... thus causing problems with some sub-circuit function further down the line.

Again this will almost certainly be due to one or more of the capacitors in the secondary lines of the PSU being compromised.
A blown capacitor is most obviously compromised but I have seen many capacitor failures where there is no external indication at all.
An ESR meter is ideal for testing such capacitors in-circuit... but in a case like this blanket replacement of the secondary lines capacitors is an optional strategy.

It might be possible to get some clue as to which line is compromised by testing the voltages at the powers supply connector.

This is a 15 pin connector but many of the pins are commoned together so there are actually only a few output lines.

Pins 1,2,3, all common - 5.8V output - Associated capacitor C1607

Pins 4,5,6,7,8 all common are Ground

Pins 9, 10, 11 all common are 12V. Associated capacitors C1270, C1271, C1272

Pins 12, 13 all common are 3V. Associated capacitors C1401, C1402

Pin 14 is a signalling line that goes high when power is on

Pin 15 is 3.8V. Associated capacitors C1737
 

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