YBA CD3 with Sanyo SF-P1 lens tracking problem : Please help.

Hi,

The player is unable to read TOC and play cd discs frequently.

The lens is cleaned.

Attached photos of the player showing tuning ports that can be adjusted to make the player track properly again. They are F OFFSET, F GAIN, E/F BAL, T OFFSET, T GAIN, K GAIN, PLL F.

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.


F GAIN, F OFFSET, E/F BAL was tuned ( rotated anti-clockwise ) years back by the authorised agent when the player had the same issue.

If you have knowledge with Sanyo SF-P1 lens / circuitry / tuning, give your advice.

I have ordered a New identical original SF-P1 lens to replace. Should i set all the tuning ports to original factory makings after changing the lens?

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.


Regards.
 
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You can't hope to do this correctly without an oscilloscope, a service manual and at least some understanding of what the adjustments are...

This is general info only and some of this may or may not be possible with your player.

PLL is adjusted with a frequency counter and reference to the service manual. Usually although it is critical to get right, in another sense it's non critical in that it's an all or nothing thing... the player works or it doesn't. It should never need to be adjusted.

If the pots have all been turned then a full alignment is needed... a good tech could probably do that without reference to a manual.

1. Focus gain can be surprisingly uncritical... you can turn the pot up until you "hear" noise from the pickup itself, then back off slightly.

2. Tracking gain can only really be set with a scope or "know how" using an audio amplifier to listen for a low frequency fundamental appear in the tracking error waveform. That said there is often a lot of latitude to the adjustment. In simple terms if the gain is low the player is sensitive to mechanical shock, if high the pick up is "noisy"

3. Focus offset or bias needs a scope to look at the RF. Again an experienced tech can do this by ear listening for a "null" in the white noise from the pickup itself.

4. E-F balance is very critical and needs a scope to examine the tracking error waveform during "track jumps" to adjust correctly.

Before doing anything all mechanical items have to be in order, spindle motor OK, sled free etc. I assume the laser power has never been altered... and it shouldn't be!

Is that a green LED stuck on the side of the pickup ? Why ?
 
The Sanyo SF-P1 is an incredibly reliable & stable laser. It's VERY UNLIKELY that you have anything wrong with the laser or the servo settings(assuming nobody has messed with them since original calibration).
It's a safe bet that either a)grease has dried up on the tracking sled guide rails or other interference with sled motion, b)the platter motor needs attention(often cured just by shooting up with a good silicone spray lub & excersizing), or there are electronic faults such as cold solder joints or failing electrolytic capacitors.
 
Is that a green LED stuck on the side of the pickup ? Why ?

It's blue and is there by design (back when blue LEDs where cool, expensive and yet not very stable)
As to why... it's the stochastic noise reduction mumbo-jumbo :p

Most likely the only 'benefit' (due to its own current thermal variations, power on transients + flex cable resistance) is fooling the constant power circuit into thinking that the voltage on the trimpot has changed.... Which means the servo loop has to re-adjust the laser current in order to keep the optical power constant.

My take on this: remove any variable load supplied through the same flex cable, be it red, green, blue... and the laser will last longer, with fewer errors...etc.:up:

A small TEC supplied by a CCS? well...that will be really cool.
 
You can't hope to do this correctly without an oscilloscope, a service manual and at least some understanding of what the adjustments are...

If the pots have all been turned then a full alignment is needed... a good tech could probably do that without reference to a manual.

1. Focus gain can be surprisingly uncritical... you can turn the pot up until you "hear" noise from the pickup itself, then back off slightly.

2. Tracking gain can only really be set with a scope or "know how" using an audio amplifier to listen for a low frequency fundamental appear in the tracking error waveform. That said there is often a lot of latitude to the adjustment. In simple terms if the gain is low the player is sensitive to mechanical shock, if high the pick up is "noisy"

3. Focus offset or bias needs a scope to look at the RF. Again an experienced tech can do this by ear listening for a "null" in the white noise from the pickup itself.

4. E-F balance is very critical and needs a scope to examine the tracking error waveform during "track jumps" to adjust correctly.

Before doing anything all mechanical items have to be in order, spindle motor OK, sled free etc. I assume the laser power has never been altered... and it shouldn't be!

Is the service manual available online?

Tell me more about Tracking Offset.

All mechanical parts are in good clean conditon, spindle motor ( Sanko 71820 ), lens motor ( Sanko 4A 0210 ) has been lubricated with high quality teflon lubricant, are working perfectly. Lens slides smoothly.

I am not sure if the laser power has been altered, & which pot is to adjust laser power?
 
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Tracking offset usually involves setting the output of the tracking servo to some predetermined DC voltage (often but not always zero).

Laser power is adjusted by a preset on the pickup itself... should never be altered unless you have an optical laser power meter. Normally viewing the RF (eye pattern) on a scope to check the amplitude is confirmation enough.

You'd have to search for manual...
 
Hello all,

The absolute first thing you have to do when you have reading problems with an Alpha or Delta series YBA CD player is clean the laser. When I say clean I mean using a Q-Tip soaked with glass cleaner. You would not believe how many times a dirty laser lens is what is the cause of the problem. I sometimes get an RF signal that is up to half a Volt higher after cleaning!!
As Mooly pointed out, there is no way to do a proper adjustment without an oscilloscope. You should have between 1.5V to 2V RF at TP16. Sometimes I have to crank that close to 2.5V as many customers want to read CD-R and CD-RW discs and the original setting was a little too low for that. I rarely have to replace laser pick-ups as they are extremely reliable.

As for real defects, the first thing to go bad on the Delta series of YBA CD players is the spindle motor. The second one is the YM7121B or C as the players are extremely sensitive to electrostatic discharges. The third one is the zener diode, D116, regulating the display "high voltage". The fourth one is the tray motor. I am beginning to see tray belts going loose since about a year now.

The easiest way to test the spindle motor is to connect an analog multimeter on the x1 Ohm scale to DM+ and DM- of CN102 and turn the platter very slowly to see if there are shorted spots. The needle should be steady around 15 Ohms.
The same goes for the tray motor on SM+ and SM- of CN102. A good indication that this motor is defective, IC104 gets burning hot.

Another problem I see from time to time is a jerking tray motor while reading the CD. It is more pronounced when using a CD that is not perfectly centered. When I first began to see this problem I thought it was because of off centered disc platters but after awhile I had to dismiss that conclusion as I saw more and more older players having this problem. Since I was not supplied with a schematic by YBA I had to "develop" a fix for that behavior problem. After a lot of experimentation I found that increasing the value of R164 from 2.2k to 15k I was able to eliminate the jerking. This can be done without removing the PCB by soldering the new resistor to the left side of R164 and right side of R166 and not forgetting to cut the right side of R164 AFTER the soldering is done. This new resistor value is not absolute and may differ from one machine to another. The best way is to install a resistor with full length leads in case you need to change that value.

I am at your disposal if you need more information or even parts if you can not find them and would be extremely grateful if someone had the schematic and could send me a copy.

Best regards,

Michel
 
CEC TL0 mistaking.

Hi, Michel, I have a similar mistaking problem with CEC TL0, that uses the same laser. I also noted that my main spindle (belt driven) that hosts CD has some wobbling that an indication of bearing gone. However, the problem showed up all of the sudden 2 weeks back but the bearing is worming itself out for 12 years I have been using the transport. So, I am not sure that I have to go for mechanical fix and perhaps the laser change would be required…

Alternatively, are you a technician who can actually fix the transport? I am in New England, US, not far from QC. Send me a message if it is the case as I do need to have this transport back to duty.
 
Can I save my beloved Caspian CD player?
Bought second hand 10 years ago and I know it's much older still.

Have posted before about dim display. Never did fix. Now almost totally gone. Found a lot more trouble shooting advice here just the other day so thought I might reach out again with additional issues.

I checked and now see diode at 116 had been removed completely and bridged with solder. So my display is probably a lost cause. I've lived without it so not the end of the world.

Tray was having difficulty opening and closing. Thorough cleaning and new belt fixed that a month ago. Cleaned and lightly greased rails. Drop of sewing machine oil onto motor spindles.

But the main issue is CD's would hang up during playback and eventually stopped reading altogether. I hoped the new belt was somehow related. No luck.

The table motor does not spin. I see red laser on for a few seconds but head doesn't go up and down. Maybe that's normal without cd inserted?

Tray motor has something loose on spindle that is hanging down from platter. Not sure if critical or just some extra glue or seal to hold platter onto spindle. Platter seems rigid enough.

I don't have a scope, only a DVM.

Getting about 12 ohms resistance when rotating by hand on either of the motors.

Complete Sanyo transport can't find anywhere.

Reluctant to take a chance on buying just the laser head.

Cost for taking in for service would probably get me half way to a new CXC transport.

I'm really tempted to try some adjustments listed in the posts but looks like not recommended without proper equipment.

But this is DIY forum. So is there anything I can try on my own? I can always mark existing positions and turn some pots.

Meantime using my laptop and USB out to my DAC. Nice and detailed but harsh. Very dissappointed. Not ready to go that route yet. Probably needs more research.

Any guidance for my Roksan appreciated.

Cheers!

Ed
 
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The lens should certainly go up and down when first closing the drawer. This is called the focus search routine and enables the pickup to focus on the disc. Typically the lens performs three such searches in succession each time the tray is closed.

The platter won't spin until focus is found.
 
Roksan Caspian Mk1 Lens Not Moving Up and Down

Well, I had the unit up on it's side and cleaned what I thought was a CD detector switch. I think it was just the green LED that's in there to bathe and improve the scattering of light. Anyways, low and behold the laser actually moved up and down after my tinkering. But when I hit play, back to nothing happening again. So I must have agitated something to make it work. I should shake it over my head like an old Etch A Sketch! Could be mechanical, electrical, loose wire, bad connection. Maybe I'll follow the path on the circuit board where the dozen wires come in/to the laser.
 
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I once had a Sony pickup (discman portable) where the lens failed to go up and down and the problem was actually the single spigot bearing on the lens carrier itself that was sticky. It might be worth you gently moving the actual lens with a matchstick and seeing if its basically free. I've a feeling the lens suspension on the Sanyo pickup would be totally different though and not give such a problem.
 
The lens assembly moves freely. Still not working. BUT as I was peering inside with the cover off, the CD started spinning when I tilted the unit at a slight angle. It then eventually stopped spinning.

So if I place a cd in the tray and hit play, it will shut and do nothing. Then if I tilt the player slightly it will start spinning. The play icon is visible in the display but no time counting. Only the track number and 0:00 time. The CD will slow down and stop. I cannot get it going again by tilting. But if I reject and repeat the process it will spin up again for a bit. Can replicate this many times.

Not sure if it is producing a signal. Likely not as the counter is not moving.

I suppose the problem could be the spindle motor.

More probing to do. Wish I was a tech. Or a millionaire!
 
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It sounds like there might be an intermittent connection somewhere in the focus coil circuitry. You've said all along the lens doesn't move up and down... and then it did when you tinkered. Now it spins up if you alter the physical position of the player.

So its possible it could be a break in the focus coil wiring.

You should be able to see a change in voltage on the focus amplifiers output during the focus search period. If you see that and the lens isn;t moving then that points to an open circuit.

Also try and check continuity of the focus coil by measuring its resistance where the pickup connects to the main board. It should read a few tens of ohms at a guess. Very low anyway and if you also used the diode check range on a meter then that should deliver enough voltage and current to visually move the lens a tiny bit.