Sony MDS JB980 stuck on standby mode

[kgallen]

Don't necessarily agree. That chip supports a directly connected crystal across the XIN/XOUT pins. The crystal is excited by a lower amplitude sine wave than the usual digital levels. In this application they haven't used a directly-connected crystal, they are sourcing the clock from elsewhere. The clock they have sourced is probably a full-swing digital signal, and they don't want this for XIN so they've ac coupled it with capacitor C899.

-> I suspect this is as intended.

Hmmm. There are a few different datasheets about but none of them are particularly comprehensive.

From the CLKSEL and FS[1:0] settings looks like the input clock should be 11.2896MHz and the output 90.3168MHz.

It's not stated but it would seem reasonable that the CLKA output swings to the rails of the chip supply, which is stated as 3.3V typical. However there are some voltages annotated around that chip and it doesn't look like 3.3V on CLKA, more like 1.5V. Can you clarify on your document? OK just found the SM, it says 1.7V at IC803 pin5, even though the chip supply is 3.3V. From your top oscilloscope trace, it looks ok-ish to me (at 1V/div) - it's maybe 1.5V pk-pk on your scope but you are approaching the limits of that scope - 90.3168MHz on a 100MHz BW scope. Also the probe cap is probably 20pF on top of the input pin cap and that chip has a CLOAD(max) of 15pF.

Also I note the input the clock is driving, IC201 pin 20 OSCO. This chip also seems to support an external crystal on pins 19 and 20. It's likely it's ok with a low-swing clock signal on pin 20 as there will likely be a Schmitt-trigger stage internally to square-up and level shift the crystal resonance to the correct digital levels of 3.3V.

-> I would still conclude IC803 is ok.

But I do concede the SM seems a bit inconsistent between the schematic, the waveform page and possibly the chip datasheet.

[Petter Halonen]

18 minutes ago, kgallen said:

Don't necessarily agree. That chip supports a directly connected crystal across the XIN/XOUT pins. The crystal is excited by a lower amplitude sine wave than the usual digital levels. In this application they haven't used a directly-connected crystal, they are sourcing the clock from elsewhere. The clock they have sourced is probably a full-swing digital signal, and they don't want this for XIN so they've ac coupled it with capacitor C899.

-> I suspect this is as intended.

acording to service manual, the clock signal from ic803 shuld be 2.5Vp-p, mine is 1Vp-p.

[kgallen]

Edited my previous post a bit. In summary I'm not sure I see strong evidence that IC803 is faulty, sorry.

[Petter Halonen]

1.7V on pin 5 is DC, signal shuld be 2,5Vp-p as I undestand it... mabye I'm wrong again...  he he.

[kgallen]

From the data sheet for the chip I’d agree the amplitude should be somewhat nearer 3V. But at the level shown in your scope I’d be surprised if this is a fault given the way the circuit is configured. If you’re measuring at IC201 then the clock does have the series termination 100R and ferrite bead in the way. 

[Petter Halonen]

I mesured whit another probe on my scope and now the signal is correct, so you were right. My bad... again..

That is why I always have this mistrust to what I mesure and tripel or octcheck what I mesure if the signal look suspitious.

Back to start ( almost).

man this is frustrating...

[kgallen]

20 minutes ago, Petter Halonen said:

man this is frustrating...

It is I agree.

On the negative side it's annoying having a great machine out of service, particularly if it's your only one.

On the plus side, look how much you're learning about your machine!

Still keep looking for those 'obvious' / 'simple' explanations though. One rubber belt change can't kill a fully working machine!

If there's anything we've learned on this forum in recent times, these machines are well designed with quality components and rigorous manufacturing and test processes. It's tended to be something daft in the end...

[Petter Halonen]

Wondering if it is something caused by ESD. This is like a gohst kidding whit me.

The P down signal is 3,1 V... strange that it is only halfe in standby. mabye I'll have a look at it.

  I do have one md walkman, but this was my fawourite player of all time. 

I had just got it talking whit my win10 computer.

[kgallen]

6 minutes ago, Petter Halonen said:

Wondering if it is something caused by ESD. This is like a gohst kidding whit me.

With the components in-circuit you'd have to be very careless with e.g. bare ends of ribbon cables or deliberately rubbing your hands across the PCB after scrubbing your nylon clothes with a cotton duster. Out of circuit it's much easier to damage CMOS devices.

In the industry we use the ESD Human Body Model as one means to characterise the device in this respect.

[kgallen]

Explain to me again where we are with the Standby condition...

[Petter Halonen]

46 minutes ago, kgallen said:

Explain to me again where we are with the Standby condition...

The display is switched of and the standby LED is litt. but the power is not in standby. The Q911 is on so the rele is swithced on

.P. Down pin19 on IC1 is 3,3V.

I mesured whit osciloscope and then ther is a puls signal there, almost like it is trying to switch of or on but can't.

And that is how far I have got with it.

I mesured the P.Down signal whit the scope and sudenly the rele klikked and now it is dead. All I have is the 3.3V system power. 

Probebly easyer to find the fault now.. I hope.

[kgallen]

I think I'd be looking at the Standby issue for clues why it's not coming on. Some wire/cable disturbed when the drive was removed etc.

[M1JWR]

well this is an interesting link, only in the usa eh !

it appears you can still get new ones, others available if you explore the site

https://www.aliexpress.com/i/32994205071.html?spm=2114.12057483.0.0.5e4d3bdeOvK3Hy

[NGY]

I thought I'd share my experience regarding "stuck in STANDBY".
I saw this situation maybe 8...10 times. Some cases I could repair, some I could not. A few examples, that are worth to mention:

- an S38 came for repair, the OWH was broken off. After I replaced the OWH, the whole device stopped working. Popped the drive into a good 510, it worked well. Same when swapping the front panels (needed a little trick with the ribbon cable). Then with unit powered down, using my ESR meter, I checked the main CPU IC, and I found this: two pins were down to ground. Both were dead shorts, and were not supposed to be. Something burnt inside the silicon. Reason? Probably ESD related. End of the road.

- a JB930QS needed a new OP, as the old one run more than 3000 hours, and began skipping a lot. With the new OP in, the deck would not boot at all. It went into service mode, but was not able to spin the disc or move the sled back and forth. I swapped the switch board, the motors, yet another laser, no success. Then I swapped a BD board from a 530, and it all started to work again, with the original parts plus the new laser. Something on the BD board broke down. Reason? Again, probably ESD related, but might as well be some aged components on the BD board, like caps. I rescued the 930 by sacrificing a 530 for the BD board of it.

- I got a JE640, that would not turn on, but I could hear the eject motor whining. It seemed the mechanism was forced when someone tried to pry out the disc. I manually repositioned everything as they should have been, but the deck still would not accept a disc, not even pulling it in. After loading a disc "manually", when powering on the deck would just eject it and immediately go to STANDBY. I measured all laser emissions in static service mode, they were spot on, so virtually all OK. Then I replaced the OP by chance, and the device came alive. The OP was broken in a way, that the logic could not properly talk to it, and prohibited the whole unit from working.

- weirdest example: it was a 980 with C13 error. Turned out, that some plastic toy coins were stuffed into the drive slot, that the drive could not digest. I took the whole deck apart, cleaned, checked and tested all parts individually. After putting everything back on, the 980 did not come out of STANDBY. I went thru all parts, over again. No luck. Last I swapped the OP, when the device came alive. Then I put back the original laser, and the deck was still working. Never knew, what was the issue, and how it "cured itself".

Looking back on those, and after reading the whole thread, I would give a chance to swap the OP, a least for a quick sanity check, even without going deep into precise laser settings.

Quoting some of your thoughts above that would also suggest this:

"Is there any protection modes were the CPU shuts down if something is wrong?"
"I think we’re looking at a simple (ha ha ha) drive issue. USB is probably off track"
"are surely indicators that the CPU is alive. Just not talking to the BD"
"They look ok to me, only the disk does not spinn up"

 

[mikeyp]

Interesting that you comment on it being especially sensitive to ESD and possibly capacitor discharge.
I have an otherwise working 980 which needs its eject belt changing and am soon to attempt it.

Considering the warnings above I think it wise to do the following in advance of attempting the repair.

Ensure the unit is powered off and disconnected from mains for 24-48 hours before disassembling.

Press all buttons on the front in a further futile effort to make sure everything is discharged.

Ground yourself with an ESD wristband.

Ground the chassis with a croc clip to ensure it has no potential to discharge any static to you.

Normally I wouldn’t take quite such care but it seems these are really sensitive.

It might also be profitable to put a pen mark on each of the ribbon cables for orientation and alignment. I’m wondering if there is possibly an issue where people are getting the ribbon slightly out of line. If the pins get misaligned/shorted it could be causing it to not come on or worse, die altogether.

With enough caution, short of physically damaging something or extreme bad luck, it should be possible to repair with no issues.

Edited May 25, 2020 by mikeyp
Corrected some autocorrect corrections which were not correct.

[mikeyp]

Also, did you know that a JB980 with a failing eject belt will eject flawlessly if put on its side? I go for power button side but I’m not sure that it matters.

[mikeyp]

Sorry for the third post. Possibly a dumb question, but have you checked continuity of the ribbon cable and connectors. The conductors can break and lose continuity. Sounds like that’s possible. It might be worth trying fresh ribbon cables if you can find any.

[M1JWR]

there are posts on here about availability of ribbon cables somewhere, i think it was by kevin.

when you change your belt, be careful with that clip on the far end of drive unit, if you break it your stuffed.

[kgallen]

8 hours ago, M1JWR said:

there are posts on here about availability of ribbon cables somewhere, i think it was by kevin.

when you change your belt, be careful with that clip on the far end of drive unit, if you break it your stuffed.

Indeed. Here it is. I think 980 is the same PCB set as 480, referenced below. Check the dimensions on your own machine though. These ribbons seem quite robust, so unless they've been really abused I'd expect them to be ok. Oxidation of the exposed fingers is what we've generally found.

 

[NGY]

I am  curious to hear about Petter, whether or not he checked his OP (the laser head). I still give it a non-zero level of probability, that the OP is working erratic in some way. Unless it is proven being 100% OK (the quickest way would be testing it in another deck and vice cersa) thus out of question, further guessing might be misleading.

I also would recommend a quick check on the main cpu as I described above (check all pins against ground and Vcc rails, in a safe way, like with an ESR meter). Again, to exclude any silicon damage from possible causes.

Last, but not least, I am somehow missing some waveform checks on the power rails. I read the DC voltages were measured, but what about any AC component (noise) on the DC rails? Are we convinced, that all filter caps are in their good shape? (The 980 came to the market just in the middle of the bad caps disease of the industry.)

I understand this particular "stuck in standby" situation appeared somehow right after replacing the belt, and I certainly can understand if these "theories" considered weird or irrelevant. My point here is if you have no clue (I mean, "no more clues left"), then get back to the start line, and begin excluding all things that can be a cause anyhow, even those that cannot be not directly connected to such an easy disassembling/reassembling process.

[Petter Halonen]

I haven't checked the OP, but I have one brand new, so I can try to check that.

The situation now is that the player is stuck i standby. When I put in the main lead I can hear two clicks, so the rele is closed then released. There is 3,3V systempower. Today I borrowed a FLIR camera to see if anything get warm, but nothing was warmer than 24 C. 

I have a question. If the BD board is disconekted, will there be light in the display? 

[NGY]

On 5/26/2020 at 11:45 PM, Petter Halonen said:

I haven't checked the OP, but I have one brand new, so I can try to check that.

Before you pop in your brand new OP into your drive, you may want to check some parameters (I understood you can still enter Service Mode):

- in laser check, value for  0.93 mW laser power is "$11" plus/minus one step

- in laser check, value for  7,25 mW laser power is "$91" plus/minus one step

Besides these, on your new OP, there is a resistor and a pot on the side, the resistor must be 1k5 (not much to change there, just to make sure), and the pot should be somewhere around 1k2 plus/minus 100 Ohms or so.

Should any of those parameters deviate more than that, first take a note of the actual settings, then set these "default" values above in laser adjust and on the new laser head (the pot at very first, before powering up). If replacing the OP did not change the deck's behavior, you can enter the original values for the original laser. Then turn the pot back to its original value on your new head (we are not supposed to touch it at all).

 

On 5/26/2020 at 11:45 PM, Petter Halonen said:

 have a question. If the BD board is disconekted, will there be light in the display? 

I am normally hesitant to do this, as I am not sure whether or not the main cpu "likes" this. I did though a few times on earlier models. I recall some models with MDM3 drive variants showed a line of hyphens (or underscores, if you wish), others showed only the small numbers underneath the level bars. MDM5 drives don't show anything, if I remember correctly. And  I never did that on a 980, or any MDM7 type machines.

[NGY]

12 hours ago, Petter Halonen said:

When I put in the main lead I can hear two clicks, so the rele is closed then released. There is 3,3V systempower.

This definitely shows that the main cpu is "not happy" with something, and disables the PSU, via its pin 81. Somewhat dangerous, but you may want to try overriding this. Desolder and lift one leg of R911, and pull up the base of Q911 via a 2k2 resistor (or via the lifted leg of R911, if you chose the right one) to 5V (*). For a very short period only, to see if your main PSU comes alive, and "lights on" (funny they numbered these parts to ...911).

But first thing first, only after you are done with your OP test and no change.

(*) Emitter of Q411, regulated 5V for the ON relay

[NGY]

I went thru the whole thread again, and I am sorry, I overlooked this:

On 5/22/2020 at 3:29 PM, Petter Halonen said:

The Q911 is on so the rele is swithced on

But as I also read this:

12 hours ago, Petter Halonen said:

When I put in the main lead I can hear two clicks, so the rele is closed then released. There is 3,3V systempower.

What is the better describing?

If plugging the AC cord in, you get all power rails on and valid values, no reason to tinker with the "911" circuit. In that case, checking the "cleanness" of the DC rails might make sense, and peace of mind regarding the PSU.

If plugging the AC cord you get only the 5V for the relay (* as above) and the system 3.3 V (**), then my previous post may apply.

(** pin 3 of IC401)

Edited May 27, 2020 by NGY
corrected my last two posts for proper voltage references

[Petter Halonen]

58 minutes ago, NGY said:

I went thru the whole thread again, and I am sorry, I overlooked this:

But as I also read this:

What is the better describing?

If plugging the AC cord in, you get all power rails on and valid values, no reason to tinker with the "911" circuit. In that case, checking the "cleanness" of the DC rails might make sense, and peace of mind regarding the PSU.

If plugging the AC cord you get only the 5V for the relay (* as above) and the system 3.3 V (**), then my previous post may apply.

(** pin 3 of IC401)

During my search for the fault it changed from switching on, but no display, to switching on and and then off. So at the moment it switches of the rele and there is only system voltage (3,3V).

What happend was that I mesured PDOWN on pin 4 CN3 and sudenly it switched off. 

[NGY]

1 hour ago, Petter Halonen said:

During my search for the fault it changed from switching on, but no display, to switching on and and then off. So at the moment it switches of the rele and there is only system voltage (3,3V).

What happend was that I mesured PDOWN on pin 4 CN3 and sudenly it switched off. 

I got it.

The PDOWN signal is for the FL display to know when the unit is powered down (AC cord is pulled off). It does not control the main cpu I believe. I guess it is there to shut off the display before all other circuits go to full shutdown (all large filter caps drop their voltages).

But let's just put this aside for now, until you complete the OP check.

[mikeyp]

On 5/26/2020 at 12:47 AM, M1JWR said:

there are posts on here about availability of ribbon cables somewhere, i think it was by kevin.

when you change your belt, be careful with that clip on the far end of drive unit, if you break it your stuffed.

Thank you for the tip about the clip. I avoided the issue altogether.

I realise this doesn't help Petter at this point but thought I'd offer my 2 cents for anyone else reading this about to attempt the job themselves. I made sure everything including myself was earthed, I undid the 4 screws on the drive, removed the 2 grounding clips either side, left the ribbon cables connected and gently lifted the front of the drive. I then used some fine tweezers to remove the old belt and install the new one. Reinstalled the drive and everything working. Complete success.

I shall keep an eye on this thread as it's certainly interesting and wish you all the best with getting your unit working Petter.

[NGY]

I would love to hear back from Petter, whether or not he had time to move forward with his repair.

We all learn from these cases, and I am personally very interested, because I had a couple of very similar problems in the past, that I could never properly solve. And I also wish he was finally able to get his 980 back to life, as it is a valuable machine.

[Petter Halonen]

14 hours ago, NGY said:

I would love to hear back from Petter, whether or not he had time to move forward with his repair.

We all learn from these cases, and I am personally very interested, because I had a couple of very similar problems in the past, that I could never properly solve. And I also wish he was finally able to get his 980 back to life, as it is a valuable machine.

HI. I haven't had time to move forward, I tried to put the divice in service mode but it looked like on the picture below. I wil try to find time this week for repairing the player , as I love it very much, and was so proud to have it in my stereo. I have Tandberg amplifiers and cd-player, which maches well to the Sony MD-player.

[NGY]

Hi Petter, I am glad to hear about you again, although it is a bit worrying that you cannot enter Service mode now.

You may want to disconnect all cables inside the deck, so all individual panels stand on their own and not connected to each other by any way. Then, after removing the reset jumper, leave your deck with all cables and jumper removed for at least two-three days, before you will again have time to continue the repair.

There is another trick that I have been using back in the ancient times of first IBM XT/AT PC-s, but I just do not dare to recommend it for such a delicate machine. When we faced a computer being dead or irresponsive, had tried everything but nothing helped, we finally stripped it down to its individal cards, and put the cards into buckets full of clean water for 24 hours. In many cases, this "barbarian-like" treatment helped, the water discharged any hidden potentials in caps, IC-s, or between other components.

Now, I am not saying this is what you should do with your precious 980. But one of the main chips seems playing a game with you, that can also reasonably be some stubborn static charge (hopefully not yet an irreversible ESD damage) somewhere inside the silicon. A "lighter" version of the above trick we used on fine electronic measuring instruments for the same purpose was shorting the leads (talking about old through-hole components) of the ICs with thin copper wires, or, we simply covered the leads with aluminium foil, using a small brush (this also worked on SMD components later). If you decide go this way, it is important to re-emphasize the necessary, appropriate ESD protection measures.

[kgallen]

@NGY I feel like we're entering some world of voodoo electronics here. Have you been on the Unicum? :-P

[Petter Halonen]

9 minutes ago, NGY said:

Hi Petter, I am glad to hear about you again, although it is a bit worrying that you cannot enter Service mode now.

You may want to disconnect all cables inside the deck, so all individual panels stand on their own and not connected to each other by any way. Then, after removing the reset jumper, leave your deck with all cables and jumper removed for at least two-three days, before you will again have time to continue the repair.

There is another trick that I have been using back in the ancient times of first IBM XT/AT PC-s, but I just do not dare to recommend it for such a delicate machine. When we faced a computer being dead or irresponsive, had tried everything but nothing helped, we finally stripped it down to its individal cards, and put the cards into buckets full of clean water for 24 hours. In many cases, this "barbarian-like" treatment helped, the water discharged any hidden potentials in caps, IC-s, or between other components.

Now, I am not saying this is what you should do with your precious 980. But one of the main chips seems playing a game with you, that can also reasonably be some stubborn static charge (hopefully not yet an irreversible ESD damage) somewhere inside the silicon. A "lighter" version of the above trick we used on fine electronic measuring instruments for the same purpose was shorting the leads (talking about old through-hole components) of the ICS with thin copper wires, or, we simply covered the leads with aluminium foil, using a small brush (this also worked on SMD components later). If you decide go this way, it is important to re-emphasize the necessary appropriate ESD protection measures.

Thank you for helping me. I'll start with disconecting everything and wait a cuple of days. I don't think I will put it in wather yet.... 

[NGY]

3 minutes ago, kgallen said:

Have you been on the Unicum? :-P

Ha-ha, that's my younger brother's favourite :-) .

I can't count how many TV-sets, tape recorders etc. I also fixed when I was in the army and later at the university, by similar hocus-pocus ...

I have quite a few funny experiences, but this is not the right topic for them. Maybe one day I open a separate topic for these obscure stories ;-) .

[kgallen]

8 minutes ago, NGY said:

I have quite a few funny experiences, but this is not the right topic for them. Maybe one day I open a separate topic for these obscure stories ;-) .

We look forward to them! Maybe they will ease our pain with these troublesome machines!

[NGY]

For those who cannot sleep at night (or, like me, messing around with MD gear instead): today I got a 480 with the exact same symptoms that Petter had with his 980. I replaced the belt about six months ago, and the deck have been working fine since then. A few days ago it did not accept any discs, then finally today it just stayed in standby after powering up, so my friend brougth it again.

I went through my usual check list, mechanically all looked OK (incl. all BD board switches). If I "trick" a disc in manually, after powering on the deck spits the disc out and goes back to standby. In Service mode, the drive does not want to load the disc either (thus I could not check the laser so left it for later).

But here is the interesting part: after powering on, staying in Standby, the drive DOES do something! If I lean close and listen carefully I hear a very soft noise, like the laser was trying to focus. No light from the lens though. Also, I can see a faint movement of the sled motor, it tries to move the OP inwards (= towards the centre of the disc). Being already in parking position, it certainly cannot move further in. It keeps trying several times,  I actually shut the device down after a few, because obviously something was wrong there and I did not want to make the trouble bigger.

This much was for today, tbc.

Now, I wonder, if Petter can observe too the same on his drive. If he does, we are probably getting somewhere.

[DickyDread]

Hi,

Looks like I have the same problem, I recently replaced the eject belt on my JE440 following the many youtube guides.  However when I had it back together and plugged in the machine goes to standby and no further.  I can't get it to turn on with the facia button, remote, or by trying to load an MD.  I followed the on line instructions carefully and everything unplugged (two data cables) has been carefully reattached.  The only thing I noticed in my machine did not have an earth wire connecting the optical drive to the chassis that was present in all clips I watched?  Any advice on what I may have done wrong would be appreciated as I don't want to throw the unit away?  In the mean time I will have a go at removing the top of the drive and see if it resets.

[DickyDread]

Quick update, I followed the instructions about removing the top cover of the optical drive and allowing the unit to reset ... and it worked!  Everything now is working except the drive mechanism won't open the slider to reveal the disk (once again something new, and I assume related to how I restored the drive cover after resetting).  But I'm cutting my losses and just opening the disk before I insert it, something I have been doing for a few years now with the MD player in my car.

[sfbp]

Kevin, looking the manual, I am lost. Where is the gizmo that engages the sliding cover? I can't see it on the only picture of any of these BD models. Perhaps there's a clearer version on one of the earlier models so you can see just how the loading mechanism grabs the cover. I assume that's what DickyDread means.....?

[kgallen]

16 minutes ago, sfbp said:

Kevin, looking the manual, I am lost. Where is the gizmo that engages the sliding cover? I can't see it on the only picture of any of these BD models. Perhaps there's a clearer version on one of the earlier models so you can see just how the loading mechanism grabs the cover. I assume that's what DickyDread means.....?

I've only recently seen how this works and it was on a portable (my N510...). However it's so simple it's probably the same on the decks.

It's just a folded point of metal that engages the slot in the case and then it's effectively the case that slides and the cover "stays where it is". It's a relative velocity thing - the slider stays still and the rest of the case moves away from it - rather than the case staying still and the slider moving away. Cheeky and cunning at the same time?

[sfbp]

So, come up with a plausible explanation for how that mechanism might fail....?