JVC DR-M10 Loading and Repair Question

[emlsnws]

Mig-45,

It looks like you've demostrated that extra heatsink on the digital can (your extra copper plate) makes an difference. If you can't add even more heatsink, maybe now is the time to lower the supply voltage too.
The principle is the same as CPUs .... heat is related to voltage. People undervolt their CPUs to permit no-fan heatsinks etc.

Or in the JVC case, bringing it down from 1.99V to something around the right voltage (I set mine to 1.77V if you remember).

Undervolting is not always bad, most digital devices work ok with mild undervolt, and you will know when you've gone too far .... there will be operational or video problems. Then just increase it a little.

In my MV1S there is no space for this, but perhaps you could go further and solder on lots of thin copper fins to the digital can? I think I wrote earlier in the thread how I used a VGA heatsink fixed by thermal tape, which was enough for me, but don't forget I also have also reduced the D1.8V to 1.77V.

Perhaps even solder on a small Zalmann heatsink, but you'll need a plumber's blowtorch to do that.
That would be cool in more ways than one!
Make sure also you have airflow going past the fins or it won't cool effectively... I put extra holes in the front right hand side to pull air past the digital can then out through the fan.

It sounds like you're getting closer to a solution.

[trhouse]

Mig-45 and emlsnws,

Looks increasingly that you both have the same problem or at least the same solution. +1.77V is not really undervoltage, the DMN8652 is quaranteed to work properly with +1.62 to +1.89V with +1.8V typical. It has twice as much margin going lower (0.18V) as going higher (0.09V).

[MiG-45]

As I wrote - I add copper plate to DMN`s cover to add more heatsinking. Not sure about lowering voltage. One thing looking odd - if the problem is realy in DMN`s heatsinking, why then only DR-m10 model suffering from it ?Why M30 doesnt` ? Would be interesting if owner of M30 tell us if heatsink contruction is same as in M10

[trhouse]

The M10 was introduced in March, 2004, the MV1 in April, 2004, the MH30 was not available until June, 2004. That may have provided enough time for the M10 problems to have surfaced and solved in the MH30 before it went to production.

[MiG-45]

Would be intersting to see M30 service manual to find out if there are schematic differencies (excluding HDD interface part)

And also to see in there are any visual differencies inside - somebody with M30 could post photos.....sigh

[MiG-45]

Damn! Green lines lots of them are back! But....only when drive activates - tray opne/close, disk spining etc - something isn`t right - need to find out how drive operating affects power supply - checked 1.8 - its in normal condition in all circumstancies.
Check +5V on drive connector - when drive activates - especialy tray - voltage seriously flows from 5.24V to 4.79 ! On +12V - same drive connector - it flows from +13.2 to +11.5. Is it normal ?

[trhouse]

I went back over the power supply schematic for those voltages. DV12V is an unregulated +12V that only supplies the drive and nothing else. It can be switched off by Q5316 in power save mode.

DV5V is an unregulated +5V that can be switched off by Q5315 in power save mode. It also supplies IC5308 which creates the regulated +3.3V labelled DV3.3V which supplies IC5307 which creates the regulated +1.8V labelled DC1.8V. Both DV3.3V and DC1.8V supply the DVD-RAM DRIVE for "except Europe". In your unit they should not be used.

So yes, that type of variation is pretty normal for unregulated supplies and these voltages seem not used for anything else in your unit.

P.S. there are two large, 2 watt resistors, R5307 and R5308. They are at the output of the +12V to the drive. These resistors consume power even in power save mode. They actually consume more power in power save mode. It might be worth checking if they are ok. Power save mode does not really turn off the DV5V or DV12V, they are on but disconnected from the drive.

[MiG-45]

Something is wrong here. I also see that +12 & +5V comes from separate lines only for drive`s supply, but how, then, it affect DMN`s behaviour ? And if heating is the only reason of disfunction, why then if I use additional coolers to cool down chips it doesn`t help ? Only switching off (any kind of way) solve problem ?
I monitored 1.8 on DMN pin whole day - all the time it was in range and can`t say it flows much

[trhouse]

Your tests and images are pretty convincing in that only the DMN can be producing the faults. Temperature and voltage are among the few external factors influencing the DMN. I would concentrate your efforts in those areas.

Why the reluctance to lower the D1.8V a bit?

[MiG-45]

Yeah , sure its DMN, but what cause its faults ?
D1.8 is fine - whatever happens around. Temperature - well at firs sight it seems so, but why then lowing temp with external methods - hardcooling, adding heatsinking surfaces etc didn`t help ? I specialy kept its temp around +40C and green lines appers exactly when they should be. And in the same time unplugging unit for even 3 mins - doesn`t cool too much have such a long effect - about a day of good work ?

[trhouse]

There is a difference. Turning off the power removes the source of the heat. Heatsinking removes heat to the surroundings. It is a little like heating water on a gas stove. The flame heats the cold water. The water absorbs heat until it boils. When it boils the water temperature remains the same as the steam carries the heat to the surroundings but the flame is just as hot as before.

[MiG-45]

So you mean DMN generates heat itself so much that it cause faults and heatsinking noway could help ? Or you mean something burned out inside chip ? But till doesn`t explane how drive behaviour makes chip behaves so... I`m start thinking ATAPI interface need to be checked - maybe drive (LG-Hitachi) become faulty. (Honestly, I`m not sure in LG components at all)

[trhouse]

"And in the same time unplugging unit for even 3 mins - doesn`t cool too much have such a long effect - about a day of good work ?"

The power in the silicon die is determined by the voltage and current you supply to it like via D1.8V. Below is a description of die temperatures for a reasonable life for the chip.



As you can see, the die may be at 175 degrees C when the heatsink is at 45 degrees C. The die is very small so when you turn off the power its temperature drops to that of the heatsink very quickly very much like if you turn off the gas, the temperature of the water does not change much in three minutes even though the flame is instantly cold.

If you want to prove anything about the drive, disconnect it for awhile. If you still have problems, it cannot be the drive.

[MiG-45]

Searching for solvation I found a guy who finaly got his unit repared and here is repairing history:
First repair on 8/16/04 and replaced:
PMD0100 AMECHA ASSY

Second repair on 9/8/04 and replace:
LPA10236-01C DIGI. PWD ASSY

Third repair on 2/25/05 and replaced:
LPA10236-01B DIGI. PWD ASSY
QECS1AM-158 E. CAPACITOR
QECS0JM-478 E. CAPACITOR

Im not sure - LPA10236 - is it complete digi board ???!

Note, that only after the last effort unit working fine till present time.

trhouse,
Will be interesting to hear your comments! I`m still not disconected drive because not sure unit will initiliazed fine without it.

[trhouse]

That is not very good news. The LPA10236 is the entire digital board. BIX reported on Jan. 17, 2005 on this thread

Under Parts:
Part Number: LPA10236-01E
Description: DIGI.PWB ASSY

the same kind of repair but it did not solve the problem like the second repair you showed. JVC must believe the digital board is the the culprit to swap it so many times. You do not have the option of swapping digital boards until one works like JVC. I would lower D1.8V. It is one of the few options you have left without buying a digital board.

Those capacitor part numbers do not exist in the parts list in the manual. They are 1,500 ufd ( QECS1AM-158 ) and 4,700 ufd ( QECS0JM-478 ) parts. They may be a replacement part which is more robust than what was there before but it is hard to tell which parts they replace. Either that or the manual is old and they are using those parts in newer units.

[MiG-45]

I`m analzyed facts and it seems that digiboard if it realy becomes damaged is an result, but not the reason. While capasitors are more like is the reason - all sympthoms looks that kind. Maybe I`m wrong - but need to find and check this parts... If they aren`t in PS part, they are works as filter.

[trhouse]

Do you have access to this other M10? The easiest way would be to look at the capacitors on the boards. These are not small capacitors so they should be not too difficult to find.

Remember that JVC found it necessary to replace the digital board not just the capacitors. That could prove costly if you need to do both.

[Pridepaqrk]

Hi, I could really do with some concise help on this issue. I have seen so many posts on this that I hope someone can clarify quickly and easily for me what I (may) need to do to repair my unit to get around the 'Loading' problem. Apologies if I am asking you guys to repeat yourself.
My unit details are: JVC DR-MV1 SEK (made in Germany)
S/n 109B 1658
I am in England and purchased the unit here for the UK market. The unit, as per everyone else's, was working very well for about 6 months and then I started getting green interference and snow which I could get rid of by powering off the unit for a few moments. That is until the other week when all I get is 'Loading'. The video unit still works fine but the DVD unit is totally unresponsive.
If anyone can point me in direction of which resistors need replacing etc then I would be extremely grateful.
Thanks
Richard

[trhouse]

A few questions first. How comfortable do you feel about getting inside the unit? Do you have access to some test equipment like a digital or analog voltmeter, ohmmeter? Do you have the schematics? Does the unit show a manufacture date?

About the problem. When you say the video unit works, do you mean the VCR, the TV tuner? Did the green interference resemble that reported by MiG-45 shown here?

[Pridepaqrk]

Hi trhouse, many thanks for speedy reply on this. My brother is a qualified telecoms engineer so he's got electrical testing gear and is more than happy to delve inside and do anything necessary - as long as I tell him what! Sadly I just have the std operating manual, no schematics, I did do a net search but either I wasn't serching for the right thing or there are none out there (freely available).
Yes, the interference was exactly as shown, in varying degrees of bad to terrible.
Yes, I mean VCR unit plays tapes ok and I can use as any other normal VCR unit: ie program, record, playback etc. This part of the whole unit seems totally unaffected by the 'loading' problems with DVD section.
Manufacture date: Hands up, I didn't check for one but will do when I get home from work.
If it helps at all, I did purchase this unit from QVC as they had a large 'managers special' on these units so my best guess is they knew of the problem in the states and quickly offloaded the UK stock before it become publicised over here.
Also, if it helps, my unit is identical to that as advertised in UK ebay auction 5803787523.
Any further info needed then just boot me up the rear and I'll get it. Thanks again
Richard

[trhouse]

Pridepaqrk,

or do you prefer Richard? I would suggest a private email to emlsnws who has posted above. He is also in the UK and has a service manual for the MV1. I received a copy from emlsnws for helping analyze his MV1 but I would feel a bit guilty giving it out again as I am sure he paid for his copy.

The first step would be to measure all the voltages from the power supply to make sure they are within acceptable limits. I believe emlsnws found one to be out of specification in his MV1 and also that a thermally conductive pad for removing heat from the encoder chip was not quite adequate for the job.

If he is not too far away, he may be able to share what he has done by showing you.

[edit] last I heard, he is no longer having any problems with the MV1.

[Pridepaqrk]

Hi, yes prefer Richard, especially since I can't splel and my username should be 'pridepark' without the 'q'.
That'll be a great idea thanks and will follow that through. If story has a happy ending I'll let you know.
Cheers again

[merkin]

I recently purchased a whole load of refurbished DR-M10S from Ebuyer here in the UK, 1 for me and 4 others for family members (they were selling at £74.99 which I thought was a great price). I'm in my second day of use and am now experiencing green lines all over the place and the system hanging requiring a restart. I hadn't known about any issues and, needless to say, I'm very gutted.

I haven't read through all 12 pages of this thread, but can someone just tell me if there's anything I can do to try and fix this? I'd have no idea what I'm doing in terms of opening the thing up, so that's out of the question. Should I just send the whole lot back and get a refund?! Anyone had any experiences with JVC UK?

[trhouse]

This is the problem MiG-45 is experiencing. You might want to look at his posts. The problem was never entirely resolved, except that JVC replaces some parts and the entire digital board as a solution. We found in this thread that a voltage to the digital board may be excessive and that a thermal pad to conduct heat away was not working adequately. What remains unknown is if these conditions do permanent damage to the digital board.

If only one unit behaves like this, the deal might not be too bad, but if more are this way, the cost of having JVC repair them out of warranty is probably prohibitive. If you do not feel comfortable opening them, I would suggest returning them if possible.

Regarding JVC UK, you might private email enlsnws who is also in the UK about his experience.

[emlsnws]

Hi trhouse & all,

I've privately emailed Richard about what he has ahead of him to see if his problem can be fixed.

My machine never showed green lines (like Mig-45 and others) so I don't know if my modifications detailed above in this thread will help them.

There is a listing of the factors that seemed to contribute to the 'loading' problem I saw, in my posting in this thread (page 11) back on 15th August 2005. Then in postings from then back to May 2005 there should be full details of the electrical changes I made. (The 'search' facility should be able to list all posts made by me, in this thread). I don't have a detailed listing I can post, and right now no time to prepare one. Maybe in the future. But by reading all my posts, someone could compile a list of what I did (and I could verify it).

It *could* be that the green lines are a symptom of a heat-damaged DMN chip, the one that I've heatsinked, and once damaged it might not be possible to recover the situation. (Or it may be, just exceeding a certain temperature and with more heatsinking it will not reach the green line level).
Richard is the one in position to answer that one (once his brother has got to work on the machine), and Mig-45 also.

Choosing a refund is a decision made when bearing in mind the alternative, possibly a month or two of waiting to see if someone solves it, and then having the ability to make the same changes to 5 machines. If you don't want to open the machines, following the refund path is best - I guess.

[MiG-45]

One thing is seems strange to me - I talked with sellers in many shops about this model. They says - nobody return units and there are no reclamations on this model. Same things people keep saying in service centers. I suspect that problem appers only when one day people activate powersave mode. At least in my case I have no problems unitll that.

[emlsnws]

Ah, I forgot to point out that I have DR-MV1S which is the combo model, not the DR-M10S.

I usually point it out in my other postings relating to modifications etc, but of course all detail relates to that model.

[trhouse]

We now have Richard, Merkin, and MiG-45 with the green line problem. I agree that Richard's brother and MiG-45 have the best chance of resolving two important questions. What is the primary cause and is the damage reversible.

Merkin with five units offers the best opportunity to see what temperatures and voltages are present in a correctly operating unit vs one with a problem but I would not suggest doing that if it is uncomfortable.

enlsnws,

I hope you do not mind my referring others to you. Even though you did not have green lines most of your work involved voltage and temperature issues with the digital board which seems to be the source of green lines as well.

[emlsnws]

No, I don't mind. Although in a few weeks I'm getting married so basically the next month is going to be v.busy with all the preparation and honeymoon. I'll keep an eye on the thread but can't promise to get involved much over the coming weeks...

Virtually all of my knowledge is here on the thread, albeit spread over quiet a few posts, so (as I suggested in a pm) someone could 'distil' it into a list of modifications. I could then check this for accuracy.

Having said that, it was only a good set of mods for (what appeared to be) heat-related restarts (with "loading" displayed) after 1-2 hours of dubbing or recording. Getting good media also made a big difference. The first -R's I tried did not record successfully and I thought I'd bought a lemon machine.
Also as I keep stressing, it's unknown if these changes might not be useful for the greenline problem, but they might - assuming no permanent damage has been done.

[trhouse]

Congratulations!!!