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MDS-JE530 C13 intermittent

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Sorry for yet another thread on a C13 TOC read error... however having lurked on this Forum for a while I've signed up in the hope some of you knowledgable chaps can help me out with my MDS-JE530...

I think I've tried/performed most of the usual rectification steps advised for C13 but I've still not cracked it. I'll start with a little background which is that I use MD at my amateur theatre group. I'm at the point of moving back to using more MD because I'm sick of CD unreliability and the solid-state offerings I've looked at are either cheap junk or way out of my price range. And of course you never let any sort of PC near a live performance...

So, aside from other Sony and Tascam MD machines I have a MDS-JE530 sitting on the shelf with an annoying C13 issue and I've gotten it off the shelf with the aim of fixing it (I've been in a "fixing" mode recently with various pieces of kit!) and thus bringing it back into service.

What I've done: cleaned the laser lens with IPA (not the beer!). Cleaned and carefully regreased the rails and gears with Molykote EM-30L synthetic grease. Scanned the Service Manual and G**gle for any other bright ideas.

This machine will either read MDs (MO type) and play and record perfectly, or I get C13 when trying to read the TOC. If the TOC is read the machine will play (and when tried, record) perfectly, no subsequent C13s or any other error. I can eject and reinsert many times and I can get C13. An hour later I can try again and it will read the TOC and play perfectly many etc times. It's driving me mad because I just can't get it reliable. Just when I think I've cracked it, I'll get another C13 again.

This is what I've determined: it's had little use: reading the service info from the machine, play hours 80, record hours 77 - it's virtually brand new. Software code is 530 990797. IOP read gives me "56.4 / 54.4" and the laser label is marked H0564, so IOP looks in order (other label info: KMS260B 19X91). Retry errors are clean "r00 p00" but total errors as FF. Error history is EB6 (whatever that is) plus the rest are E04 like everyone gets. When I do continuous play, then AD=00 (maybe the odd 01 as allowed). Temp Check is OK. I can CPLAY MID, IN and OUT and it's error free and there is no noise and the sled tracks smoothly at all points.

The mechanism is quiet. I've inspected as much as I can and there are no broken gear or rack teeth that I can see. The machine is clean internally. It's well behaved otherwise. The disk detect and record protect tiny switches seem to be clean and moving freely, so I believe the disk insert is being detected. None of the MDs I'm using have bad label positions. The disk appears to nest correctly - trying different insertion speeds (the best I can with an autoloader) doesn't seem to throw the disk to a more reliable position. All springs appear to be in place and tensioning as required.

When the TOC can't be read, the machine is spinning the disc, slowing and retrying. But the sled doesn't move - then of course I get C13 because the OP is not searching/reading the TOC. When this happens there is no mechanism noise - I can't hear any motors straining and there are no vibrations - just the OP sled doesn't move. I can eject and try again, and often the OP sled will track and TOC can be read, other times the sled is stationary. I just can't work out why sometimes it will track and read, others not.

In Service Mode I did try the << and >> sled movement and usually this will work fine. I have however observed some occasions where the sled will slow and appear to struggle - in both directions. On a couple of occasions the sled, after slowing, did "stick" and wouldn't move more. Since recleaning and regreasing the rails this doesn't seem to have reoccurred but this could be coincidence.

So... what's the one thing I haven't done that will solve this? I reach out to the community to help me solve this one and keep this machine alive and back into service where this great format should be!

Thanks and regards,

Kevin

ps I don' t have a LPM or 'scope so a Fluke DVM is about my limit with test kit access. I do have the Service Manual and also own a fully-functioning MDS-JE520 if comparison is needed.

pps All of my discs are Sony or TDK. Tried both, same symptoms. All recordings are SP, nothing fancy going on here!

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This may sound absolutely nuts but try decreasing the laser read power by exactly one notch. The adjustment on Laser power is much more critical for read than for write (having said that, if you turn up the WRITE power you'll get to retire the laser much faster!).

Are you sure the insertion mechanism belt's not dead? That would account for it not registering sometimes but once it works, it stays working.

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Hi sfbp,

Adjusting the laser power was something I didn't try pending more informed input on what I should do rather than "hacking" blindly. I'll pluck up the courage to try your suggestion!

2 hours ago, sfbp said:

Are you sure the insertion mechanism belt's not dead?

On MDS-JE530 I don't believe there is a belt, I think it's all gears - certainly I can trace the gear train from loading motor to the crank arm that traces a slot on the loading cradle. Looking at the three servos in the unit, I don't see any belts in this particular drive: disk servo is direct drive, sled drive looks to be all gear train to the rack too.

Thanks,

Kevin

 

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Hahaha! The belt cannot wear out if there isn't one. I guess the 440/640/940 were the first "consumer" ones (MDM7) to use a belt. I wonder about something else in the drive train then. Sounds a bit like a missing tooth, doesn't it? 3D printer is the way to go on that one.

But C13 is usually the read power. Note that it's best to work with disks that were made on a perfectly adjusted unit, otherwise you're pushing the servo over its happiness (happyness - Will Smith) limit. It's fairly typical to see vibration of the head from side to side and when it vibrates too much you get C13, I think.

Sounds like you've done all the right things. All you need is the LPM. With the stable of machines you describe maybe it's time to try and find one.

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Hi sfbp,

9 hours ago, sfbp said:

Hahaha! The belt cannot wear out if there isn't one. I guess the 440/640/940 were the first "consumer" ones (MDM7) to use a belt.

According to the SM, this drive is MDM-5D.

9 hours ago, sfbp said:

Sounds a bit like a missing tooth, doesn't it? 3D printer is the way to go on that one.

Given the laser seems to be almost new from the play/rec hours, I'm really hoping it is a simple issue. I did inspect the mechanism quite closely and it looks brand new, no signs of stress or discolouration or dirt etc and no missing or stressed teeth that I could see - certainly no noise from the mechanism either good or unsuccessful TOC read. Quite bemusing as a result!

9 hours ago, sfbp said:

But C13 is usually the read power. Note that it's best to work with disks that were made on a perfectly adjusted unit, otherwise you're pushing the servo over its happiness (happyness - Will Smith) limit. It's fairly typical to see vibration of the head from side to side and when it vibrates too much you get C13, I think.

OK, that's helpful thank you. Actually other than during test procedures I don't think I've actually "recorded for real" with this deck so I can use a disk from my JE520 or one of my Tascams. When the unit is working the head is as smooth as anything. No jitter or wobble at all. When you AMS to a new track the head slides gracefully to the new point, there is a quick alignment seek then the track is running, looks perfect. I've been using a disk that is "full" and the servo and OP can track without issue to both the centre and very edge of the disk without noise or jitter so again, that looks perfect. As an aside it was interesting to see that the read buffer seems nice and large - I put the unit onto Repeat All, and played the last track. At a whopping 12secs to track end the OP moved back to track 1 ready for the repeat - I thought these units had a 6sec buffer (I think that's the minimum required by the MD spec), but this would imply 12 seconds or so :-)

9 hours ago, sfbp said:

Sounds like you've done all the right things. All you need is the LPM. With the stable of machines you describe maybe it's time to try and find one.

Do no harm first were my thoughts, so I had a good read around the subject from contributors (like on here) who appear to know genuinely what they were talking about, and then assess what I knew was ok and what could be suspect!

IOP adjust a click then...

Cheers,

Kevin

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Isn't the IOP just the "saved" copy after you (someone) measured it? I'm trying to recall. I think you have to look closely at what the SM says when telling you to adjust.

Yeah, Page 26. The one you want to change is the 0.9mW setting (LDPWR) not the 7mW one which is the write power.

Another thought. Did you check that this unit always plays CDs perfectly? (prerecorded MD which use a different technology). If the CD did the same I would be very tempted to think that the whole thing is mechanical or at least related to the loading motor. Maybe the loader switches off and relies on some capacitor discharging? I'm getting out of my depth as this is beyond anything I've ever tried to fix.

 

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As I understand it, it's supposed to contain the value on the label on the laser which I presume is some measurement made at the factory to set the drive current required for the laser to emit a specified intensity of light.

I then presume (!) that the IOP value is used by the controller to set the laser current used - how this is translated for reads and writes I don't know, as the two values will be quite different to achieve the low-power read and the high-power write (Curie temperature) requirements. I don't think the SM gives much background, but I'll have a read again tonight to see if it makes more sense now I'm considering "having a fiddle" with it!

I've not got any pre-recorded MDs; all of mine are MO type. I quite fancy getting Jeff Wayne's War of the Worlds on MD though! Thanks for the LDPWR info.

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49 minutes ago, sfbp said:

Yeah, Page 26. The one you want to change is the 0.9mW setting (LDPWR) not the 7mW one which is the write power.

When you say "one notch" is this "one notch" of the tenths value (viz change down from 56.4 to 56.3) or the units (56.4 to 55.4)? I will presume the tenths for now as a "small" change!

Thanks for the help.

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Yes one tenth! My understanding is that IOP is measured by the person with a voltmeter and a LPM and simply recorded. So that you can see if it changed the next time around. They also write the original value on the pickup usually in blue biro. I don't think any non-human agent actually uses the stored IOP. I never touched IOP - merely used (my) LPM to check and adjust values of the actual laser output power.

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Hi Stephen,

1 hour ago, sfbp said:

They also write the original value on the pickup usually in blue biro.

Well this had me completely foxed the other day when I was trying to find the IOP value. Everything I read online suggested I was looking for a pen-written number. On the top of the OP there was a printed number in blue, but this did not have the format I expected for the IOP.

However... when I was inspecting the mechanism for broken teeth etc I spotted the edge of a label on the underside of the OP sled. By winding the sled gears to move the sled to a mid-track position I was able to move the label into a small window/cutout in the transport metalwork. And this label was the ID information as shown on p27 of the SM: a computer printed 3-line label showing KMS260B/19X91/H0564. So in the end not a number scribbled on with a permanent marker, but a proper printed label! The testing regime must have come along a step or two!

So back to the machine, and of course by writing this I will doom things, but today I've not made the JE530 fail at all. I played with it this morning and it was fine, I left the machine on all day whilst I was at work, I came home this evening and had a play and it's behaving. Maybe the new grease has soaked in a bit! So I'm going to hold off on the IOP tweak just for now. I will however report back if the desk gets up to mischief again!

Thanks and regards, Kevin

 

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9 hours ago, sfbp said:

All you need is the LPM. With the stable of machines you describe maybe it's time to try and find one.

Hmmm, interesting. What sort of device would I be looking for (sorry it would be "on eBay"...), makes, models to look at and to avoid, and does it need any "attachments" such as a "remote" sensor that can be positioned close to the OP with the OWH in the way? What sort of money would I be looking at (any currency I can convert to GBP!).

Needs to be able to sense 780nm light, clearly!

So as an example does this look appropriate? Handles 780nm and power range to 20mW. The sensor looks a little on the large size for MD access but seems to be "the right sort of thing".

https://www.ebay.co.uk/itm/OPHIR-laser-power-Meter-Monitor-USED/253314347677?hash=item3afab6329d:g:xeIAAOSw-jFaM-V3

http://www.ophiropt.com/laser--measurement/laser-power-energy-meters/products/Laser-Photodiode-Sensors/Special-Photodiode-Sensors/BC20

Thanks!

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Look good to me. Just make sure they have a calibration chart for converting 780 to whatever the "reference" wavelength power is, ie a multiplier (fractional).

I see it even has a 780 button, you should be good to go

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So tonight, ye olde MDS-JE530 decided, from "cold" (room temperature) that it didn't want to read discs. Aha, here's my chance to have a tweak of the laser read power! (I don't have an LPM yet, so just nudging one step as per Stephen's suggestion).

Starting point: LDPWR 0.9mW$10 (for reference/comparison LDPWR 7.0mW$91)

Try one click down to 0F -> NG. Go back to 10 -> still NG. Go two clicks down to 0E -> NG. Try one back up to 0F -> NG. Try back at original value 10 -> NG. Let's go crazy and go one click up, try 11 -> TOC reads and is still doing so with a few more loading trials...

So is this real or just concidence, or maybe it's warmed up a bit - ok the whole sequence only took a couple of minutes, but who knows! Let's test again some more now, and try again "from cold" tomorrow!

Is it possible that this machine has so few running hours because the factory setup was just a touch too low for read making it unreliable for the original owner with the C13 Read Error problem? I can't see that the laser output power would have deteriorated with the recorded use it's had. Cosmetics don't suggest the machine has had heavy use and thus might have been "clocked". Maybe a little early to judge or draw conclusions, I guess only time will tell!

OK, so just for interest I adjust back to the original value of 10 -> surprise, surprise, TOC reads! I think I'll go back to the 11 setting and test again tomorrow. Who can tell!

I've just had a look at the settings on my fully-functioning MDS-JE520. I get: 0.9mW$11, 7.0mW$96, 0.7mW$0D, 6.2mW$85, IOP=55.8/55.4. I think this leaves me a little more comfortable trying the 11 setting on the 530, although I realise all of the lasers have the drive tuned to match their particular characteristics.

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The main reason I suggested down one click is that sometimes that's all it takes. Admittedly, one click up is more likely but also one click closer to overheating. You're probably done, I would guess :)

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Stephen - I don't mind either way, your help has been invaluable, thank you. When the LPM arrives I'll see if I can fathom that out and piece together more of the puzzle!

Thanks! Kevin

ETA: Nope we're not playing "read the TOC" any more on the 11 setting (or the 10 setting!). Disc reads fine in the '520, but the '530 he say C13 at the moment! Back to the drawing board...!

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Brief update... my 530 is still playing up. Fiddling with the LDPWR for read up and down by 3 clicks is not helping. The LPM I bought from eBay has a sensor head that is just too big to get anywhere near the OP what with the OWH in the way and all that. So I'm now looking at building an in-disc LPM like NGY did:

Unfortunately there is not much detailed circuit info I can glean from the otherwise excellent set of photos that NGY posted. However I have bread-boarded a design using a BPW34 photodiode and a LTC1050 op-amp configured as a transimpedance amplifier (TIA). This is working nicely on the bench with an LED torch, but this is of course not 780nm light and nor do I know how much the laser light will impact the PD surface. Thus I don't really know what gain to set the TIA at! On the bench with the torch, a 1M feedback resistor gives a nice voltage range with a 5V PSU but I've no idea how the MD's LD will compare! I guess I'll have to make a PCB with a number of options for selecting/paralleling resistors and "suck it and see". I've also been trying (in vain so far) to get the correct connector for the IOP socket on the MDM-5 drive. It looks like a JST connector but the 1.0mm SH series is too small, and the 1.5mm ZH series is too large. Having tried to measure the pin pitch, I've found a 1.25mm version, that the eBay sellers are suggesting is GH series - although when I look into this on the JST website, it looks completely the wrong style of connector! There's a similar Molex connector series, but no-one on eBay is selling any pre-made leads, and I'm not getting into buying crimping tools!

This is starting to feel like a "principal of" job now. I could have bought 3 machines at the current rate of spend.... :-(

More updates in due course... sigh...

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Now I feel like a twit. It didn't occur to me that your sensor wouldn't fit. I just got my LP1 out of the box, and yes it's smaller. Is the BC20's sensor the wrong size for a portable OP too? Is it the shaft or the rectangular bit that doesn't fit? I see they have a lot of different sensors available, but I dread to imagine what Ophir wants to charge.

Sad and puzzled

S

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28 minutes ago, sfbp said:

Now I feel like a twit. It didn't occur to me that your sensor wouldn't fit.

Hey fella, it's not your fault! I looked up the spec on the thing and thought it just might fit. "Nice" though it is, it just aint gonna go! The whole head is just too large to tuck in under the OWH and get close to the OP. It's got a bendy bit to the shaft but that doesn't help in this instance. That Sanwa LP1 looks quite cute - and annoyingly not that much more than I paid for the BC20... :-(

It's a shame I can't seem to raise NGY - I bet he's got some of those PCBs he made lying around...!

We'll get there in the end!!! Quite interesting if a little frustrating (and costly...!).

Kevin

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