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[HLD-X0] Technical: Won't Read Discs. Is it REALLY my laser?
https://forum.lddb.com/viewtopic.php?f=54&t=10011
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Author:  reelyinteresting [ 14 Sep 2021, 18:46 ]
Post subject:  [HLD-X0] Technical: Won't Read Discs. Is it REALLY my laser?

Hey folks,

I've seen others on here with this same issue... Looking for some technical help on this one (calling krbahr and/or similar with X0 repair experience)!

    PROBLEM SUMMARY
  • Pioneer HLD-X0 will not read any discs (NTSC or MUSE, any size).
  • No error code is displayed.
  • Disc does not spin up.
  • Player worked with zero issues; failure was sudden (final playback ended while I was in another room, turned the player off, failure was noticed when unit was turned on later that day)

    INITIAL DIAGNOSIS
  • Loading mechanism OK (All grease was removed and replaced; loads better than ever)
  • Spindle motor OK (Spins up if disc is spun backwards while attempting to read inside of disc, MTR RUN/STOP pin goes HIGH, Hall effect sensors OK; does not eject until disc is motionless)
  • Idle voltages OK at SRVD PCB (+7V is ~9V but is apparently unregulated, V+5M is GND but that appears to be switchable on the SYPS PCB so I'm assuming it's disabled unless a MUSE disc is recognized)
  • Laser sled moves, tilt actuates, laser sled locking mechanism OK (visible movement / attempts to read inside of disc when tray is closed)
  • Tilt sensor LED OK (visible via phone camera)
  • Laser focus coil OK (visible movement when tray is closed)
  • Laser power reads very low (0.05mV via laser power meter when laser is attempting to read inside of disc; internet says average LD player should be around 0.5-1mV?)

    ADDITIONAL NOTES
  • Laser sled struggles to move when player is on it's side
  • When a (thin) LD Single is inserted, laser is still strong enough to be seen through the other side of the disc (see attached picture)

I just can't believe the laser is dead since the laser is visible. and it happened suddenly. Looking at the service manual, it looks like the laser assembly uses a bunch of off the shelf parts.

    I thought I'd ask the following questions on here before I start spending money & hours chasing my own tail:
  • Has anyone resolved this issue before (whether on an HLD-X0 or on another model)?
  • Are there any places I should look first for more feedback? The RF TP? If so, what should I look for on a scope/DMM?
  • Should I look at the parts on the head assembly? Perhaps Q7 and/or the NJM2904M could be suspect?
  • I am conditioned to shotgun replace capacitors. Should I look into replacing the caps on the SRVD PCBA?
  • I have not been able to check PSU voltages when the laser is trying to read the disc, only when the player is idle. Could there be PSU issues at play here?
  • Any misc. tips or suggestions?

This player is very special to me for a number of reasons so any help would be appreciated!

Thanks!

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Author:  rein-o [ 15 Sep 2021, 17:43 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

Did the player ever work?? Or did you get it not working??

Author:  reelyinteresting [ 16 Sep 2021, 03:27 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

I've owned/used this unit periodically for about 6 years with no issues (except for the occasional loading mechanism issue from old lube which I've now resolved). This suddenly happened about 2 weeks ago.

Author:  cplusplus [ 16 Sep 2021, 05:41 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

reelyinteresting wrote:
Are there any places I should look first for more feedback? The RF TP? If so, what should I look for on a scope/DMM?

Look at focus error.

reelyinteresting wrote:
Should I look at the parts on the head assembly? Perhaps Q7 and/or the NJM2904M could be suspect?

Q122 feeds Q7 so start there.

reelyinteresting wrote:
I am conditioned to shotgun replace capacitors. Should I look into replacing the caps on the SRVD PCBA?

Need to figure out root cause first.

reelyinteresting wrote:
I have not been able to check PSU voltages when the laser is trying to read the disc, only when the player is idle. Could there be PSU issues at play here?

Not sure, but that would be the easy fix.

Author:  reelyinteresting [ 16 Sep 2021, 18:02 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

cplusplus wrote:
reelyinteresting wrote:
Are there any places I should look first for more feedback? The RF TP? If so, what should I look for on a scope/DMM?

Look at focus error.

reelyinteresting wrote:
Should I look at the parts on the head assembly? Perhaps Q7 and/or the NJM2904M could be suspect?

Q122 feeds Q7 so start there.

reelyinteresting wrote:
I am conditioned to shotgun replace capacitors. Should I look into replacing the caps on the SRVD PCBA?

Need to figure out root cause first.

reelyinteresting wrote:
I have not been able to check PSU voltages when the laser is trying to read the disc, only when the player is idle. Could there be PSU issues at play here?

Not sure, but that would be the easy fix.


Thanks for the tips! Probably this weekend I'll take a look at Q122 & follow the circuit forwards from there and post an update here. Need some parts from Mouser so maybe I'll buy a bunch of new caps for the SYPS PCB while I'm at it too.

Author:  edwin240170 [ 16 Sep 2021, 19:19 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

It might be interesting to get the player in test mode and see the what is displayed on tv screen, that might give you a hint

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Author:  reelyinteresting [ 17 Sep 2021, 18:26 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

edwin240170 wrote:
It might be interesting to get the player in test mode and see the what is displayed on tv screen, that might give you a hint


Since the disc isn't spinning up, I don't think that will give me too much information that I can't see with my eyes inside the chassis...but if someone has the hex codes for the TEST & ESC buttons on the GGF1067 then I can add them to my X0 remote profile and try it out!

Author:  cplusplus [ 18 Sep 2021, 01:49 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

reelyinteresting wrote:
Need some parts from Mouser so maybe I'll buy a bunch of new caps for the SYPS PCB while I'm at it too.

Recap of SYPS is fine, but I'd hold off on SRVD.

reelyinteresting wrote:
if someone has the hex codes for the TEST & ESC buttons on the GGF1067 then I can add them to my X0 remote profile and try it out!

See if ESC & TEST here works: http://www.remotecentral.com/cgi-bin/co ... cld-v2600/

Test mode will allow you to attempt forcing playback.

Author:  reelyinteresting [ 18 Sep 2021, 23:16 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

Update time!

I was able to get TEST mode going (Thanks C++...Fun fact: TEST is the same button as DISPLAY! ESC is the odd one) but...
First, the test mode that the remote pulls up is COMPLETELY different from what the service manual showed. It's a very simple, cryptic interface that seems to show main microprocessor information like playback status, activity, etc. Functionality of the unit is not changed. Please see "ManualTest.jpg" to see what this screen looks like.
Then, after poking around, I discovered that to get into the ACTUAL test menu as shown in the manual, both pins on CN714 on the CONT board need to be shorted for a couple seconds and then released. The player then reboots into the real test mode.

The great news about test mode is that I can turn the laser on indefinitely by hitting the play button on the remote.
The bad news about test mode is that I can't get the spindle motor to turn on. I tried poking all the buttons on the remote and I could do pretty much everything the S/M says, including switching between the three spindle "loops" (HD, FP, and FG), but I couldn't do anything to get the last digit to switch to anything but "1" (Brake). C++, is there a command combo or something I'm missing? I'm guessing that since it still doesn't recognize a disc it won't let me control the motor. Please see "PCBTest.jpg" to see what the test screen shows if I turn the unit on in test mode and press play on the remote.

I then moved on to taking a look at the circuitry around Q122. We might be onto something... According to the schematic, this circuit should be supplying -8V? It looks like I'm only getting -3.7V out of it! I wrote down most of the voltages in this circuit on the schematic (when the laser is on) and attached it as "LaserPowerVolt.jpg." Q124 and Q123 are hard to get to safely so I didn't document those voltages. I also noticed that Q125 gets hot very quickly (C200 seemed to get hot too after an extended period but I wonder if that's from proximity). It looks like this circuit works as a simple voltage regulator; the HZS9.1NB2 Zener (D110) has a breakdown voltage of 8.61V to 8.99V according to the data sheet. At this point, I'm wondering if Q125, HZS9.1NB2, or Q121 might be bad. The problem is that the Zener and the 2SA933 (Q125) are discontinued and no longer available...so I'll need to find a substitution! I also measured across the Zener and the 2SA933 in-circuit with my DMM's diode tester. The diode still tested like a diode (read about .7V in one direction...). The 2SA933, however, tested like a diode across all pins...??? The base and collector read 1.2V in one direction and .6V in the other.
I also found that there there is an undocumented extension to the circuit off of Q121. It appears to pull up the base to V+5S with like 56k of resistance? Without taking the board off, I can't really tell what's going on there. It just pulls the base of Q121 up to +5V when the laser is off.

Thanks to everyone for your help! I'm really starting to think that this might not be the laser after all! (+5 points to my intuition! :) )

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ManualTest.JPG
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PCBTest.JPG
PCBTest.JPG [ 75.02 KiB | Viewed 5698 times ]

Author:  cplusplus [ 19 Sep 2021, 01:40 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

reelyinteresting wrote:
Fun fact: TEST is the same button as DISPLAY! ESC is the odd one)

Interesting- I did not know that.

reelyinteresting wrote:
C++, is there a command combo or something I'm missing?

I've always just pressed play on front of player (twice).

reelyinteresting wrote:
According to the schematic, this circuit should be supplying -8V? It looks like I'm only getting -3.7V out of it!

Yeah I was thinking it was something about power going to it since it was still visible but faint.

reelyinteresting wrote:
Q124 and Q123 are hard to get to safely so I didn't document those voltages.

Good call. I have made a bunch of "oopsies" overextending myself.

reelyinteresting wrote:
At this point, I'm wondering if Q125, HZS9.1NB2, or Q121 might be bad. The problem is that the Zener and the 2SA933 (Q125) are discontinued and no longer available...so I'll need to find a substitution!

It is common for a lot of these active components to be NLA, so I have had to either find surplus stock or match the datasheet as close as possible. eBay has 2SA933. I'd order replacements for those three components (at least two of each).

reelyinteresting wrote:
I'm really starting to think that this might not be the laser after all!

It is a Pioneer, not a Sony!

Author:  rein-o [ 19 Sep 2021, 02:00 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

cplusplus wrote:
reelyinteresting wrote:
I'm really starting to think that this might not be the laser after all!

It is a Pioneer, not a Sony!


:lol: :lol: :lol:

Author:  reelyinteresting [ 19 Sep 2021, 02:19 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

cplusplus wrote:
Interesting- I did not know that.

Both are device 168, function 67! ESC is function 95. I have an IR device uploaded to hifi-remotes.com for the X0 that I'll be updating with the ESC code shortly...

cplusplus wrote:
I've always just pressed play on front of player (twice).

Just tried it and it made no difference. :( Just keeps hunting for focus.

cplusplus wrote:
It is common for a lot of these active components to be NLA, so I have had to either find surplus stock or match the datasheet as close as possible. eBay has 2SA933. I'd order replacements for those three components (at least two of each).

Will do! What's your opinion of the 1N4695 as a substitute for the HZS9.1NB2? It looks like the leads are a little wider in diameter but I'm not sure I have a choice here.

cplusplus wrote:
It is a Pioneer, not a Sony!

lmao Ain't that the truth!

Author:  cplusplus [ 19 Sep 2021, 03:57 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

reelyinteresting wrote:
What's your opinion of the 1N4695 as a substitute for the HZS9.1NB2? It looks like the leads are a little wider in diameter but I'm not sure I have a choice here.

Given that this is in such a sensitive path and this is the best player ever made, I would really try to buy the original. Due to MOQ the cheapest you could get (a ton for) is about $50 + shipping. :shock:
https://octopart.com/search?q=HZS9.1NB2 ... SD&specs=0

Listed at this site too- but this company always says they have parts that they don't: https://instrumentalparts.com/diode-hzs9-1nb2/

In regards to the 1N4695, I don't know enough to know if that is an appropriate replacement. Vz looks fine, but no idea on reverse current and resistance. You might could ask on an EE forum.

Author:  reelyinteresting [ 19 Sep 2021, 12:45 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

cplusplus wrote:
reelyinteresting wrote:
What's your opinion of the 1N4695 as a substitute for the HZS9.1NB2? It looks like the leads are a little wider in diameter but I'm not sure I have a choice here.

Given that this is in such a sensitive path and this is the best player ever made, I would really try to buy the original. Due to MOQ the cheapest you could get (a ton for) is about $50 + shipping. :shock:
https://octopart.com/search?q=HZS9.1NB2 ... SD&specs=0

Listed at this site too- but this company always says they have parts that they don't: https://instrumentalparts.com/diode-hzs9-1nb2/

In regards to the 1N4695, I don't know enough to know if that is an appropriate replacement. Vz looks fine, but no idea on reverse current and resistance. You might could ask on an EE forum.


Yeah, I've sloppily used Zeners in small projects before, but never a laser! I'm not sure what the engineers here were specifically looking at besides Vz.

I thought I looked on Octopart and nothing came up! I must have been half asleep apparently.

Looks like CoreStaff online has an MOQ of just 1 on the part! Never heard of them...but I'll give them a shot for a more reasonable qty! EDIT: Nvm, they have an MOV instead of an MOQ... I guess I can buy them all and sell them! EDIT 2: Damn, $60 USD to ship??? Brutal. This better fix the unit. lol.

Thanks for your help, C++. I'll get these parts on order and report back whenever they come in...hopefully not more than a couple of weeks.

Author:  cplusplus [ 20 Sep 2021, 15:12 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

reelyinteresting wrote:
This better fix the unit.

Hopefully. I'd just look at it as equivalent to one-way shipping cost if there was a place you could even ship it to. If replacing these with the exact replacements does not work, you can at least move to another area with confidence that these components are ok. Make sure to test them with DMM though before installing them.

Author:  reelyinteresting [ 29 Sep 2021, 03:55 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

Well, I got all the replacement 2SA933, UN2212, and HZS9.1NB2 (2,500 of them!) and installed them. In addition, I replaced all the capacitors in that area of the PCB. Finally, I also recapped the entire SYPS PCBA and replaced the primary line conditioning caps on the DACB board.

...and...

Now the laser power is reading even weaker on my laser power meter (.01mV)... The circuit's output is now up to -4.8V though!

My theory is that the laser is drawing a huge amount of current which is causing the circuit's voltage to sag.

Do you think it's even worth attempting to replace the NJM2904M op-amp on the head assembly or do you just think the laser is failed? The only thing that gives me hope is that when the laser first turns on it looks like the output is a tad brighter for a split second before dimming.

On a side note, the VFD is more evenly lit since the SYPS recap! Slightly surprising but no complaints!

Author:  cplusplus [ 29 Sep 2021, 06:16 ]
Post subject:  Re: [HLD-X0] Technical: Won't Read Discs. Is it REALLY my la

That is unfortunate.
reelyinteresting wrote:
Do you think it's even worth attempting to replace the NJM2904M op-amp on the head assembly or do you just think the laser is failed? The only thing that gives me hope is that when the laser first turns on it looks like the output is a tad brighter for a split second before dimming.

I do not know. NJM2904M is dirt cheap (and thankfully MOQ is 1), but I think the main issue would be testing/replacing it without causing any (further) damage to the pickup.

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