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Sony MDS JB980 stuck on standby mode

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5 minutes ago, sfbp said:

Just a crazy thought. What about the timer/record switch (front left)?

That's not crazy, that's brilliant and inspired! (In one of the early photos it can be seen in the OFF (centre) position).

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All right. Another rewind. Was the belt you replaced actually broken, or were you simply seeing the **symptoms** that would lead to you wishing to replace the belt? Could it be that those symptoms actually arose from another cause (reason)? I finally made myself fresh coffee (it's only morning here).

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15 minutes ago, sfbp said:

All right. Another rewind. Was the belt you replaced actually broken, or were you simply seeing the **symptoms** that would lead to you wishing to replace the belt? Could it be that those symptoms actually arose from another cause (reason)? I finally made myself fresh coffee (it's only morning here).

The belt was not broken the rubber was old and did not grip corectly. I happen to have a video of the fault whitch I will atatch.( The disk finaly came out after I stoped filming.) I bought a new belt from Germany spesific for MDS-JB980.

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Thank you.

I'm not sure all those C13 errors after the failed ejection/reinsertion are normal. Kevin? I am wondering if some actual damage was done while it was grinding away in that video?

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I think the C13s are benign. The belt is too sloppy to eject or mount the disc properly. On a failed insert I've never seen the laser sled actually try to read the disc, I think the electrical and mechanical interlock mechanisms are too mature by this version of the MDM. So I don't believe any mechanical damage or stress will have occurred. I don't hear any mechanical torture going on in that video and I've had much worse (the "machine gun") with some of my machines and the drives have suffered no lasting damage.

The machine is pulling the disc back in because it has passed the threshold where the machine thinks the disc is out, then the disc sitting there creates a new insert detect so it pulls it back in. I had the same with pretty much all of those machines (440, 480, E10) I bought with "faulty loading" where it just needed a new belt.

I still feel at this point we're looking for a simple explanation - even if that is eluding us for now! Do no damage at this point looking for anything complex.

On which note, is that drive properly back together yet even if it's not mounted in the machine?

ETA - I have had the same as the video where you can't trigger an eject every time. Actually that was common on my 530 which ended up being oxidised ribbon cables in the end (remember those days Stephen, that's how you hooked me into this Forum! :-D )

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I had a similar issue with an MDS-JB980 when I replaced the load belt recently:

Are you hearing the relay click twice when you reconnect the power? I'm afraid I don't know what the issue was with mine but removing/reinstalling the drive mechanism and ribbon cables fixed it.

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6 minutes ago, Petter Halonen said:

I have trippel checked the drive. everything looks like it is suposed to. Also checked the riboncables.

This machine beats me, in my head everything seams to be ok and it shuld be behaving normaly.

Is there any protection modes were the CPU shuts down if something is wrong?

 

Your comment reminds me of the bad old days of microcomputers when 200MB was considered a large hard drive and which we shared over the network in our office. Following advice from the manufacturer (seriously!), whenever the drive wouldn't start up, the solution was to drop it onto a (carpeted) floor from loading dock height (just kidding, more like 25cm). This loosened the automatic brakes that stopped it from spinning up.

I am not for a single instant suggesting violence to such a lovely machine as the JB980, but maybe the **THREAT** of a short sharp shock might bring it back into line?!?!?

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If you're in "Standby", will it take a disc in? (Probably not, but I'm just wondering how the mechanics of the drive are "sitting" at the moment.).

If you're in service mode, can you go to the Check item that reads the Iop value? This requires the main PCB CPU to access the EEPROM on the drive.

From recent comments it seems the drive is "dead" (as in unresponsive rather than broken). We need to start narrowing down if it's getting any power (+5V and +3.3V rails) or whether the main PCB CPU is just not seeing the drive at all.

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The voltages you measured, where did you probe those? With the drive out and upside down I can see this is possible with care, probing on the underside of the drive PCB (I see you have schematics on your desk). Where are you probing the 0V when taking these measurements - on the drive too?

But I take the drive is getting the required supply rails and they are in spec.

For confirmation, if you disconnect the drive ribbons, does the Iop get reported in SM? (Trying to demonstrate the CPU is accessing the drive rather than pulling cached figures from RAM).

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3 minutes ago, kgallen said:

The voltages you measured, where did you probe those? With the drive out and upside down I can see this is possible with care, probing on the underside of the drive PCB (I see you have schematics on your desk). Where are you probing the 0V when taking these measurements - on the drive too?

But I take the drive is getting the required supply rails and they are in spec.

For confirmation, if you disconnect the drive ribbons, does the Iop get reported in SM? (Trying to demonstrate the CPU is accessing the drive rather than pulling cached figures from RAM).

I mesured them on pin3 of ic926(2.6V) and ic933(3.3V) 5V I mesured on pin1. GND on chassis.

I disconected the ribbons but the display was black, so I conected the long ribon and tryed again, then I got the message you can se on the picture.

MDS-JB980_testmode_whitout_powerribon.jpg

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Interesting! So that configuration generates an invitation to flash the EEPROM......

No, sorry, not about to open my unit up to see if that is normal. But I wonder if the Service Manual talks about it.

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According to the schematic, the long ribbon doesn't carry any power (there is one D-GND). It seems to have most of the "low activity" signals like switches and the EEPROM. All of the power comes in on the smaller ribbon plus many of the servo signals. Plenty of GNDs on the narrow ribbon with those fast signals which is what you need...

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5 minutes ago, sfbp said:

Interesting! So that configuration generates an invitation to flash the EEPROM......

No, sorry, not about to open my unit up to see if that is normal. But I wonder if the Service Manual talks about it.

Sort of, but it can't do it. Whilst the EEPROM SDA/SCL (I2C/IIC) signals are on the wide ribbon there is no power. So the CPU can't read the EEPROM, but similarly without the narrow ribbon inserted there is no power to write the EEPROM.

But please don't try it, input clamping diodes on chips can sometimes provide enough power via the input signals to operate the chip marginally (as an aside, that's apparently how the ARM CPU was accidentally discovered to be a "low power" design - they forgot to wire up the power pins, but the first chips still "operated" through the current available through the input diodes from sufficient input signals at "logic high".).

 

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Petter you mentioned the jumper - the one which resets the microprocessor. I presume that's back and making firm contact?

My other thought was maybe to press the NetMD button. There are endless warnings in these units about the chip (IC195 in this case) being one-of-a-kind because it serialises the machine for the purposes of copy protection. You literally CANNOT change that IC with a new part. Is that the EEP referred to?

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5 minutes ago, sfbp said:

Is that the EEP referred to?

I'm pretty sure that message refers to the EEPROM on the drive with the laser diode characteristics.

The part for DRM would be more like a fixed MAC address I suspect.

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3 minutes ago, sfbp said:

Petter you mentioned the jumper - the one which resets the microprocessor. I presume that's back and making firm contact?

My other thought was maybe to press the NetMD button. There are endless warnings in these units about the chip (IC195 in this case) being one-of-a-kind because it serialises the machine for the purposes of copy protection. You literally CANNOT change that IC with a new part. Is that the EEP referred to?

The jumper is back . The NetMD button does not do anything.

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15 minutes ago, sfbp said:

There are endless warnings in these units about the chip (IC195 in this case) being one-of-a-kind because it serialises the machine for the purposes of copy protection. You literally CANNOT change that IC with a new part. Is that the EEP referred to?

Stephen you're right:

image.png

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So that's evidence of a sort of the kind you were looking for that the mainboard is/is not recognising the drive (BD), in this case because the second cable is not connected? I wonder if that means the cables. It's almost as if the jumper never got replaced (yes, Petter, I know you did replace it - but not sure why you took it off!?). Or maybe some other initialization that has to be done after you've reset the CPU?

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7 minutes ago, sfbp said:

So that's evidence of a sort of the kind you were looking for that the mainboard is/is not recognising the drive (BD), in this case because the second cable is not connected? I wonder if that means the cables. It's almost as if the jumper never got replaced (yes, Petter, I know you did replace it - but not sure why you took it off!?).

I took it of because, I read someone had fixed a problem like mine that way. The took of teh jumper waited a few second and put it back, then when they put the main socket in the MD-player was ok.

I mesured the battery it is 2.8V, so maby litle low? It shuld be 3,2V?

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The CR2032? Don't know...

When you got that message "Init EEP?" what did you do? I hope you pressed MENU/NO. If you didn't but simply turned it off, I want to know what happens when you press MENU/NO.

 

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