Electrical Adjustments for D-15?

I was lucky enough to buy a D-15 at a cheap price recently! I'd like to ask for help on the adjustments required by this machine.

The problem I encountered :
1) The player is sensitive to shock(I don't know if that's normal comparing to other D-15) and skips on it's own from time to time. It doesn't like CD-R either.
2) When I try to adjust the machine I noticed at the measure point of 6V I got a 7.4V, and it's basically same for all the other points that I got a value higher than it was rated. The adjustment for 3.4V was a pattern connection but even when I got to the lowest it's still more than 4V. I use it with a sony's discman adapter rated 9V 600mA, however I measured the device's jack on the inside while playing a CD, the input voltage was 13V... Way too high... Could this be the culprit?

For now I marked every pot in there and turned tracking balance a bit, which helped the skipping on its own - however it's still sensitive to shocks.

What could I do to solve these problems?
Thank you very much!!

 

Absolutely ALL first-gen Discmans are sensitive to bumps/shocks! But if you want to check if yours is ‘up to specs’ then play CD-R or a skip-test CD: if no play then you have a problem to fix... Not an easy fix, but doable

 

If the mains adaptor is heavy indicating it contains a iron cored transformer, it may be unregulated, which means that output voltage will vary significantly with the amount of current drawn. Many devices were designed to cope with this but maybe yours is struggling especially if it is the wrong adaptor.

Regarding CD players skipping with shock, in the early 90s we had a works night out having a Line Dancing lesson. The instructor was trying to use a no name CD portable that was so susceptible to shock that it ended up with someone having to stand there holding it, as, with it sat on a table, it skipped every time we started stamping our feet.
For the same reason, that is why cassettes stayed popular in cars and for jogging etc for so long.

 

Hey! thank you for your reply! It can play CD-Rs without skipping but with those scratched ones? No luck, it skips quite bad. Another symptom is that when it skips it skips really far, eg it could skip from the beginning of a song to its end then to another, I'm quite sure the FF button isn't broken so it's most likely not fast forwarding...

 

It IS heavy, and quite huge. I guess it's not regulated but the fact that when it's connected to the machine and be giving out 13V bothers me. I stopped using it yesterday because I thought this kind of usage - without knowing if the power supply is fine - could damage the machine...
Another symptom is that D-15 gets quite warm during its usage, not super hot but I've never seen this on a discman before... I've used D-245, D-11 and a lot more other machines, none of them are like this. All five electrolytic capacitors in D-15 are replaced with new ones that I bought so it can't be the capacitors' ESR causing the heat. My guess is that 1)The voltage is too high and it's dying(however this power supply was for D-11 and it had no heating issues with it) and 2)Its thin chassis and two boards stacked up against another without leaving space causes a lot of heat but doesn't dissipate them that fast.

To fix this, should I adjust the voltage pots? or I need a new power supply?
Thanks!

 

All original 9V transformer-based converters give 13-14V without load, this is normal. And if you compare them with modern 9V DC switch-mode wall-warts you may notice that D-150 sounds better with original Sony converter.
Also, take a look here at the battery pack designed for D-15: EBP-380. It accepts eight AA batteries, when fresh at 1.7V each total comes to over 13V. In short, Discmans were designed to accept 14V DC

D-15 plays CD-R, this is Very Good, your laser is strong and does not need any major adjustments!! That it cannot return to the same spot when bumped or when encountering a gap - it is fixable. This was discussed a few times, if I find a link will post here... in short, you should readjust pots for focus and tracking gain. Something you should NOT do unless you absolutely have no other options. Mark the position of pots before touching them! As a first step though, put a droplet of synthetic motor oil (5W-30 is as good as any) on the spindle motor, under the platter. I use long 22G and thinner needles with Hamilton 100uL syringe, but use whatever works for you. Just do not spill oil all over Discman, this is not as lethal as with Walkmans but CDs and laser they hate oil. Also, double-check that sled motor works without any glitches by FF and Rev laser mech a few times

Good Luck!

 

So glad to hear that it's normal. However is the voltage in the machine normal? The 6V becomes 7.4V thing and warm chassis ? Should I turn down the voltage?

I'll first try to turn all of them back to the original place. I marked them already just in case! I don't have a oscilloscope for the moment so I might not be able to do the most accurate adjustments. Also could you tell me what's the function of Tracking Gain and Focus Gain? I figured out the function of Tracking Balance and Focus Bias myself and the original setting seems fine. PLL is not something I can touch because I don't have a oscilloscope.

I guess this is not lethal if I don't lubricate it as for now. I can't go out to buy some because of the lock down... Will definitely do it later!
Do I need to open up the motor and lubricate it from the inside?

The sled motor can't be better, I lubricated it with Labelle's PTFE compatible lubricant after cleaning everything, including the infamous middle gear. Smooth like butter!

 

7.4V? Where? But looks exactly right for recharge voltage and myguess ‘6V to 7.4’ is a typo for 9-7.4? And YES, DC-DC converter gets seriously warm and in these slimline Discmans it dissipated thru metal case.
Focus and Tracking gain pots are there to fix exactly your problem but the problem itself is coming from an aging RF-410CH motor. Slim-line RF-410 is half the size of RF-300 used in most Discmans, and as you may guess half the height gives double stress on the copper bushings from the spindle. Getting a new motor (as we discussed a few days ago with @Recaptcha) would be your easiest 'fix'....... if they were still available. But they are NOT: what you see nowadays on sale as RF-410 have a shaft too short to re-set the spindle platter. That is why I suggested a drop of oil to make spindle motor run more smoothly. There is a hole in its butt, put a drop of oil there and let it seep inside overnight, then use a needle or forked toothpick to put a drop of oil onto the top bushing, let it play overnight on infinite repeat. If still no-go, only then start playing with Gain pots

 

Hello,
Thanks your your help again!
In the service manual there's a measure point of 6V and I got 7.4V, for other voltage measure points I got higher value too. Just want to make sure it's normal/it's not lethal. I'll go check if it's a typo later!

I'm almost sure that you're right about the motor thingy, just tried to play a copy of Carpenters Gold and on the first track(where the spindle turns the fastest) it skips periodically - in sync with the spin of the disc itself - which make me think the spindle is not fast&constant enough. Going to buy some decent lubricant online to fix that minor issue now!

 

https://imgur.com/a/f9JGYZ9 here's the part where on the manual saying 7.4V.
I hope I don't bother you too much with all these questions...
Also stay safe from COVID-19!

 

Yeah, It sounds like the classic motor problem to me. You could try placing the player on it's side and see if it still skips, not sure if that's been mentioned yet...

Also, is the spindle motor noisy or knocking?

Wow, 6V + or - 0.1V is a VERY slim window of adjustment to me, 7.4V seems WAY to high for that adjustment procedure. Still, electronics CAN change over the years, and this kinda thing has happened to me before, I can't say it's too much of a big deal.

General rule of thumb, before adjusting pots, I like to tackle everything I can replace or clean first, such as motors, cleaning lasers, capacitors, lubrication. and if fixing all of that doesn't work, THEN move on to adjusting pots.

As I mentioned with @Jorge on another thread, you 'Shouldn't' have to adjust ANY pots on the board if everything is still as Sony calibrated it at the factory... Just something to think about.

 

Thank you for your reply!

Nope I'd say there's a small hissing sound from the spindle motor... Will definitely lubricate it. Is opening the motor to clean the brushes recommended ?

Exactly! Still kinda worried about that. With this adapter a D-22 has high voltage measurements too... IDK who's the culprit, the adapter/player/multi-meter...

It actually skips worse and I don't know why...

Totally agree with you! I had thought of this a while ago and I put all the pots in their original position!

 

I would say your spindle motor is fine. Hissing is fine, It’s most likely the tracking circuit locking in the correct speed and regulation of laser which causes hissing.

I do not recommend taking the motor apart since in my experience it never goes together quite right. You should be able to lube the bearing without dismantle of the motor.

Typically, bad spindle motors make knocking sounds, and holding the unit at an angle causes the knocking to go away which in turn causes the skipping to go away too. So, I’d say your motor is fine.

with that said, check your center gear. If the teeth is worn down or damaged in any way, the laser can mistrack. This causes intermittent skipping. If the laser sounds abnormally noisy when changing tracks, this is a sign of a bad center gear.

This is because the center gear is moving very precisely during a song to keep the laser in exactly the right spot.


Also, 13v out of a 9v adapter is bad. Change the adapter.

 

Whew glad I asked !

Glad to hear that too.

Got it. I think it's fine but I'll go check it later anyway.

Oops I know there's something wrong with it. I doubt the abnormal high voltage readings are caused by this.
It's the original adapter. Would it be better to try to fix it or buy a new one? It's locked with special screws...
What are the specs? I know it's a reversed-polarity, 9V600mA AC/DC adapter, but I still want to make sure about the plug's size.
Thank you!

 

I'm not sure about the plug size, I have one, and it measures 11v right out of the plug, so it's not original spec either. I'd say replace it, you could either buy a generic 9v and terminate the old connector on it, or get one of those universal power adapters which come with a bunch of different plugs. I have one, and I love it.

Here's what I got. It's old, but it's the only one I could fine where you can reverse the polarity.

https://www.ebay.com/itm/Original-P...636745&hash=item2cfc28782e:g:Y5kAAOSw9gxdzd-J

If a new power adapter doesn't fix your issue, I'd say time to use a scope and look at the laser eye pattern. That usually speaks volumes about a laser's strength and ability. Strange enough, I've had bad lasers read CD-R's just fine, but skip on them, this is an probably an issue of focus, not power.

 

Hey! Thank you for helping again!
Actually mine measures 16V off load, 13V when D-15 is playing. Definitely weird to me but I didn't think too much as @Jorge said that it's something not to panic for (no blaming here). I actually just bought a universal plug similar to the one you posted this morning, will definitely update about it when I receive it!

 

WOW! 16v off load? Mine's 11v off load. That's insane to me. Great, just make sure the one you purchased has polarities that are reversible. Some do, and some don't. Some appear too, but don't.

I'm almost positive that your issue is AT LEAST partially caused by this adapter issue. Get that adapter and see what happens...

Maybe the laser is overpowered and can't focus properly. That's a pretty good hypothesis. Too bad you don't have any batteries to test.

Hey, There's a dude on Youtube that makes 3D printed custom lithium cells for the D-15. I've talked to him before, he might sell you one if you contact him.

Here's the guy's vid.

 

Ha! I think so too and I've stopped using it for a while cuz I don't want to cause some permanent damage...

That's a good one. I hope over driving the diode didn't damage it tho.

And yeah I'm following that guy, I watched his repair video lots of times!!
I'll try to contact him considering the fact that I don't have a 3D printer, even though I'd love to print one !

 

Yeah, I don't have a 3D printer either. Wish I did...

Na, I'd say you haven't damaged anything permanently.

This whole thing kinda reminds me of the JP/US voltage conundrum. Can you run a 100v appliance in America on 120v? Short answer is actually yes, but the real answer is yes, for a short while! Your voltage regulator is having to work double time to condition that extra power, which can't be good for it. I'd say you're getting a lot of heat on the D-15's chassis as well, aren't you?

 

I AM and I mentioned that before, @Jorge thought that was fine because this is a slimline discman(no blaming still).
And I just found out something interesting. My Roland adapter for my piano is rated 12V, I measured it and it's 13.5V! even lower than the one rated 9V from sony!
Gonna wait for the new adapter now...