Technics SL-PG400A CD Player repair attempt
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- เผยแพร่เมื่อ 26 มิ.ย. 2021
- When a CD Player won't read CDs anymore due to a bad laser, sometimes turning up the current through the laser diode helps. Will that trick work on this 1991 Technics SL-PG400A?
Follow-up video: • Finding the fault in t...
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Follow-up video: Finding the fault in the Technics SL-PG400A CD Player
th-cam.com/video/U7rxYJYoMFA/w-d-xo.html
many thanks, it was a bit advanced for me and fortunately for my needs, but did give me the confidence to open up my Technics CD player bought in the 1990s and clean the lens so that it now plays perfectly again.
I have the sl-222 model that started doing the same thing until it finally stop reading the CDs, i recently replaced it with the same model i found in ebay, thanks for the video now I know where to look for the problem.
Most people who deal with equipment like this know that Philips mechanical and digital systems were among the most used by many other brands that manufacture this type of equipment. The mechanical system use by this Technics (as you know) is the famous CDM-4/19 from Philips, used by dozens of models from a wide variety of brands (even by ROTEL in some models). Thanks for the video
A very interesting approach , thank you, keep your good work !
Dr Cassette I have been repair Cd players since they first came out in the 80s professionally and my shop was authorized service center for Panasonic and Technics and you are correct Phillips made the CD unit for them and I repaired a lot these when they were almost new .
The whole CD player transport and servo is Philips made and there will be at least one of those terrible blue axial cap ... I once fixed a PG520 which would randomly reject any disc just by replacing one such cap: It measured fine, but the player started working perfectly after fitting a new cap. Also note that in the CDM4 the laser output is adjusted based on what the Pickup PhotoDiode reads back and that means it fully compensates for any dirt in the optical path between the laser output, the disc the prism and the PD's array. I repaired many CD players with CD4/19 and none of those had a dead laser.
It's good to know that these problems may be caused by dead capacitors, I will make sure to check the next time I have problems with a CD player based on the CDM4 mechanism. I don't think I have ever had any problems with CDM4 mechanisms, except for the ones in the four Technics SL-PG series CD players I have had over the years...
@@DrCassette I saw a similar trend with the Philips CDM12.1 successor to the CDM4/19: CDM12.1 on Philips or Marantz CD players are mostly still fine, CDM12.1 on technics CD players are easily dead (e.g. PG370 and forward)
@@enricoself2256 , not necessarily. I have a 23yrs. old SL-PG 380A, bought used (but in good condition) 15 yrs. ago.. It works fine.
These Philips CDM 4/19 CD drives are very reliable and most of them can play CD-RW as well. But like some already mentioned the capacitors on the servo board (labeled 2501, 2502, 2503) fail very often. I only replaced the 2501 and my Technics SL-PG400A now works flawless. But I prefer the Sony KSS-xxx based CD players because they give you more options to tweak the laser, focus and tracking settings for faster performance and better error correction.
The next time I get in a CD player with CDM4 mechanism I will be sure to check the capacitors on the servo board.
Nice video.. Learned a lot as usual
Thank you :)
*Dr. Cassette:* If I turn it on, you can see the vacuum fluorescent display is very dim, very worn out...
*Me:* Hey, that VFD looks pretty good to me, Doc's eyes going bad or sump'n?
*Dr. Cassette:* It actually looks better on camera than it does in real life...
*Me:* Oh, my bad!!!
The camera indeed made the display look a lot better, in real life some segments were so dim they were almost invisible.
@@DrCassette Yeah, experienced that with my Sony ~CandyHam~ I mean HandyCam! Repairs were unsuccessful, but then again, I needed the entertainment, so, thanks for uploading!
I have a thirty year old 100A. Still in use, never failed in any way and even outlasted my NAD.
You gave it a valiant try Dr. Better luck next time. Yes the video was enjoyable. 😎👍
Thank you :)
ok thankls for the video...opened my exact same model up and cleaned the lens with spit on a cotton bud, dried it other end, reloaded cd and hey presto read perfectly, million thanks else i wouldnt have even known where it was!...guess i got lucky, its 1991 again now, thankyou
You are lucky that your CD player only needed its laser cleaned - these players tend to have problems with bad capacitors on the board below the mechanism as I later found out...
@@DrCassette ive had it since i think 1992, first problem, love this machine
walkthrough - two capacitors under the tray: th-cam.com/video/7dSgHbNxdSs/w-d-xo.html
I have a Phillips CD player with a similar mechanism that my parents bought in the late 80’s. We had many years of use out of it, nowadays it still kinda sorta works but it produces a kind of digital ticking sound, as if the laser can’t track the disc properly. It’s a fault my dad could never fix. I doubt if it is fixable, everything else seems fine. I still keep it around for nostalgic display purposes as it was our first CD player. Nowadays I use a DVD player to play my audio CD’s.
My 1987 DENON DCD-900 CD player, that still looks as good as new to this day, and was in use yesterday, simply required about 6 drops of oil, and all was well again. That oil had the optical sensor back to being able to be on the move across the CD once again, just as it should have been.
In addition to the focusing lens, you need to clean the optical assembly below, the prism. It's quite difficult to clean, I've already done it on an Aiwa set, and it works again. Congratulations from Brazil!
Looks to be a high-hours unit. And somewhat unusual to see such a dim VFD as the usual habit is to play a few CD's and then power down, so it's either seen a lot of use over the years or it's been left powered up for long periods. Either way, it's had a good innings!
I used to repair this kind of device adjusting two small screws that can be found right under the assemblage that holds the laser len. A small rotation of these screws could return the device to work in about 50 percent of the cases. I
This video was usefull and helpfull for me. If i find one of these cd players and if they don't read cd's.
Then i will try to what you did with these adjustments. And yes i'd enjoy this video
Thank you :)
Servo circuit, lyth capacitor c2521, 47 µF, 25 v, that horizontal one, this is a weak point of these CD transport's. Can change with any vertical lyth cap with same parameters of course. After that, adjust carefully laser power if needed. I personally recommend to change all lyth caps on servo circuit, clean all mechanical parts and lubricate spindle motor.
You are right, I checked C2521 and it is indeed bad. Measures 20 µF instead of 47 µF, and the ESR is 16 Ohms. The CD player has already been scrapped, but the next time I come across a non-functional CD player with CDM4 mechanism, I will make sure to test and replace that capacitor. I have made a follow-up video testing that capacitor which I will upload soon.
Thanks I've fixed mine.. I used 47 25v upright n a, dart to scratch off that seal stuff n it's perfect I got a spare from car amp n estended wires with a cheap blacksur soldering iron... The inset was hardest part two white wheel s mounted too back posts.. But it's fine n worth it
I know I'm late but I've been having the same issue, I had to use a 50v capacitor instead of 25, but after tweaking the laser a bit the disk inside stops spinning after 2 seconds but the display still shows zeroes everywhere and nothing works... Does it have to be exactly 25 volts in order to work?
EDIT: I tried to play again with the laser and focus a bit, it seemed it started working again at first, just a little skippy on some tracks but it was playing, then as soon as I started playing another normal CD the hard-knocking issue was back and it was struggling reading. I am considering to throw it away as well because I don't know what else to do and I've been reading that particular Philips mechanism has a very bad reputation (now I know why)
I have tried the same steps as you, up to before the oscilloscope on a VERY similar model of that family, also to no avail...
Pity because these were considered good quality cd-players once.
I will try again in the future, the player is safely packed and stored at my parents house and I very recently moved my old oscilloscope there, so when I have time I may take another crack at it.
However, from reading on the net, these had the rather early mechanisms and laser diodes that proved less reliable over the long run, so I am not holding too much hope.
As other people have pointed out in their comments, these problems can be caused by bad capacitors on the servo board. The next time I come across one of these CD players I will make sure to check those too.
I own two models from this era, no problem at all, fingers crossed!
In the follow-up video I found that the problem was caused by a bad capacitor on the board under the CD mechanism. So if your CD players ever develop a problem, check those capacitors. They are easy to replace.
@@DrCassette I've checked the second one but thanks!
Randomly adjusting the laser current is not a good idea. You need to look at the eye pattern. Good that you checked out the manual 😜 check caps on the servo panel.
I was hoping that just a small turn of the laser current adjustment would be enough. It only turned into random adjusting when a small turn didn't do anything... The CD player has been scrapped, but the mechanism with servo board has been put into storage for parts. I will make a note to check the capacitors before using that assembly.
Petfect
The MASH font is not an indication of Philips made components as it was also featured on the later Bosch made Technics and Panasonic players that had the Sony-type laser.
My first guess would be a dead laser. Service manual - parts number table - CD pickup model. The pickups for late 90s are still available from China
I have this same exact player I got in 1992. I havent used it in 20 years, I wonder if it still works? 🤔🤔
Wow it had a ac primary line fuse i see many with out a fuse
Win some lose some Dr.
I have a Sony CFD-5 boombox with builtin D50 CD player and it will read original cd's ok but has to warm up to read cd-r discs.
The drive belt is a common fault with most CD players with this mechanism. Technics are made by Panasonic, a while ago Panasonic, technics, Philips and Marantz were all connected.
It's funny. I seem to see the obvious issue with the unit that you and all that have watched so far have missed. The laser units with cd players are generally very reliable. But the motors that spin the disc and move the laser head are not. Not to mention the age of the lubricant on these parts. I can see the disc speeds up and slows down when you were adjusting the laser unit. The best thing to do would be to live the spin motor bearings and clean and re lube the laser head motor track. I bet this would make things unit work like new. The last 5 units I fixed had the same issue and it always overlooked. CD players need to spin at a very specific RPM to function. Also make sure the transport mech is also well lubed.
This, and also look for any failing electrolytic caps around the servo circuitry and on the power rails to the servo circuitry, voltage ripple there would play havoc. Generally, if a laser is failing, it’ll skip/mistrack until it can no longer maintain focus at all, at which point it won’t spin the disc up because it can’t detect a disc there. The spindle motor doesn’t turn when there isn’t a disc present, so if it does spin, the optical sensor is detecting a focussed laser beam. It really amazes me how many people automatically assume that all CD reading issues are down to a failing/failed laser, quite often, it isn’t the case, especially on these early Philips mechanisms, and mechanisms such as the Sony BU-1, KSS-151 etc, they were/are incredibly reliable.
I totally agree. I had skipping issues with my Technics cd player and i had checked everything but the motor with no luck. I finally sprayed some contact cleaner on the motor axle and problem solved!
I once found a Technics in the dump that had a linear voice coil laser pickup. Yes. Like the Philips, but linear. Never seen such a thing. That thing woulnd't read a disc. Or barely. Or maybe sometimes. However if you left it turned on long enough it would eventually start reading the disc and after a little more time also playing the disc. The PSU was working OK too. Couldn't find the fault, no one else wanted it so I put it back where it came from as well.
Over the years I have had two Technics CD players with the linear magnetic drive, one was an entry level model, the other was the fancy SL-P770. Both of them worked, I gave the entry level model to a friend who I think still has it. I sold the SL-P770 because I had paid quite a lot of money for it and I didn't want to wear out the laser and ruin the value of the device...
I once had a Harman kardon disk player that behaved the same way. I service said the laser was worn out. Probably those lasers work better when it's a bit hotter.
Yoiu should try to replace blue, axial philips capacitors on the transport board. They always fail.
My thoughts too a well known issue.
I second that suggestion: best case, it is half of the original capacitance; worst case, it is a dead short or has weird unpredictable behaviour
The CD player has now been scrapped, but the mechanism with servo board has been put into storage for parts. I will make a note to check the capacitors before using that assembly.
La unidad optica es la misma que en el modelo SL PG 440?
To be honest I've never really rated the CDM4 series, I've had a few dead ones. Changing the blue capacitor on the servo board can help but generally I've found that the digital output from them is very poor with a lot of noise and dropout. That says to me that the laser might be reliable but it is constantly mistracking, relying on oversampling and correction to sort the errors out.
The key advantage of the linear Japanese mechs was always that the laser was an easy and cheap swap out when it did fail. The Philips, much less so. Try getting a replacement for one of the less common variants like the CDM4/25 for example.
My Technics SL-PG520A had same problem. I noticed that the laser potentiometer had a bad soldering. Probably somebody has tried to adjust it by too rough manner.
My player has only one pot. After fixing the soldering, I was able to tweekie it by adjusting the potentiometer very very s l o w l y !
My player has two HOLES in the bottom where it was easy to adjust with PH00 screwdriver.
I also taped the dangerous fuse with thick clear tape. This sadly is Philips style whereas Japanese equipments usually have very well shielded mains components.
Did someone know where i can find a service manual or a part list for this SL PG400a CD -Player? Btw. great video!
Ich habe einen Grundig CDP 5100 SPCD und wenn ich eine CD einlege und Play drücke fängt das Gerät an die CD zu spielen aber nur bis 30 Sekunden. Habe die Linse schon gereinigt aber jetzt liegt das Gerät in meiner Ecke herum
Klingt für mich nach Mechanismus. Der Laser steckt wahrscheinlich in Spur 0 fest und mit dem Fokus kommt man nur ca. 20-30 Sekunden weit und springt dann. Vielleicht ist auch das Schmiermittel vom Laufwerk verharzt. Was passiert, wenn du den Laser Pickup manuell von der Mitte nach außen bugsierst? Findet er seinen Weg zurück nachm Einschalten?
@@senilyDeluxe werde ich demnächst Mal ausprobieren. Danke für den Tipp 😉
My friend , please i want like know what you use to clean the plastic and metal front panel , i have any pioneer and yamaha and i need clean frontal panel , i living here in Brazil ( Amazon)
For cleaning the case of HiFi components I usually use an alcohol based window cleaner.
@@DrCassette you can make a video clean a cassette deck player or receiver amplifier
No, I am not going to make a video just about cleaning. That is trivial.
@@DrCassette you are correct , what you think if I ship a defective Brazilian brand Cassette Deck player ? I have brands like GRADIENTE or POLYVOX. You not need pay or return the player ,. What do you think?
Thanks for your generous offer, but shipping from Brazil to Germany would be prohibitively expensive...
I have a Technics SL-P202A Recently didn't want to spin. If i give it a spin by hand it starts up. Motor seems weak i tried adjusting laser pots but no difference, needs a hand spin up. Wondering if motor os old or perhaps more likely power supply is weak. One guy fixed a similar issue by putting in a lower value resistor but this was on a slightly newer model.
The spindle motor gets lazy draws too much current and can't get up to speed.
@@glpilpi6209 This is not true. I found the solution. Look for the "metal can" capacitors on the board that is attached below the laser mechanism. Change any of these blue Phillips caps. Job done! Enjoy!
Tle laser light intensity potentiometer is on head itself, those remote ones shoud be for focus and tracking
The service manual makes no mention of any adjustments on the laser assembly itself. The laser power adjustment is on the servo board.
@@DrCassette There should be always one on the head itself, check it, the laser assembly head is showed as one whole module in Service manual, you won't see it described there, If not there then, another weak point is bearing on the spindle motor, you can replace it with any similar size motor with long enough shaft to fit the disk holder. The motor is tired and causing wobble, change it and adjust that pot again. I've repaired dozens of those Technics weak players. Also try to lubricate old shaft, if you have luck, it may not be that weared.
@@technixbul on that Philips CD transport, no. Laser power and focus adjusting pot's are only on servo board.
@@realsomething2981 yes i saw that, i have 3 of them, but this must be an older one, but the other part of my advices are still truth for that slide assembllies..
damn maybe I should use a dead moth too
It's a shame some models are so prone to failure. To me, it's often not worth the trouble of repairing it unless it's either valuable or no longer easy to come by online.
I have a Technics SA-CH455 with a dim VFD display. The CD player's display is perfect yet, but the tuner display and EQ display, not so much. I found a section of the PC board was burned, so I tested and subsequently replaced two of the resistors in that area, but still no joy. NO ONE has any ideas of where to go next with this thing. In fact, my local repair shop couldn't even identify the ohm rating of one of the resistors! Any thoughts?
BTW, your channel is my new "binge watch" channel! 😊
I would suggest testing all voltages the display needs to work. Heater voltage and the high voltage fed to the display driver circuit. If the voltages are fine, the display itself may be at fault. Starting in the 90s, the quality of these VFDs became more and more random. Some still look like new, others go dim. In later years, Technics' parent company Matsushita (Panasonic) was known to use bad VFDs.
Do reccaping and then try to adjust.
It helped me ;)
There is one specific capacitor in these CD players that needs to be replaced. There will be an extra video about that. However, replacing all capacitors is unnecessary.
@@DrCassette ;) OK!
@@DrCassette what do you do is this case buy a new laser or scrap the cd player?
@@brunomoyano8727 Scrap because the laser unit if you can even find one would be to costly
@@DrCassette so true but right now in my shop I have Sony portable radio from the 70s Sony used some really no name capacitor and found like 4 that were bad .
I have a cd player technics SL-PG590 and it has a problem: I press the open button to insert a cd but it closes by itself I give ooen it closes by itself and so on. If anyone can help me, thank you
Sounds like you have a problem with the limit switches detecting the position of the CD drawer.
The laser light does not appear to come on
The laser goes up and down trying to do its job
Can anyone help
Laser unable to find focus . Shuts everything down. Weak laser or photo diodes in the the laser block failing to provide signal for the focus servo loop.
No one has said It, so I will, The rubber band was standing In for the Missing Spring. You can't win them all.
As I have said in the video, there was no missing spring. There are provisions for installing a spring, but Philips did not use them. That space is supposed to be empty.
I you look closely, on the right side of the CD clamp there was a spring. It seems when they designed it they intended to use two springs, but probably found that a stronger spring on one side worked just fine and saved a few pennies and install time.
Perhaps an issue with one of the Ic's?
It later turned out the problem were some capacitors that are hidden on the servo board under the CD mechanism.
Maybe to change the laser unit. There are replacement parts which could be very expansive. But there is a chance to get this player running again.
I would have put tape over the top of that fuse. But to each their own.
Yes, I should have done that. But I originally expected only a small twist of the adjustment would fix the problem. In that case I would not have gotten anywhere near the fuse...
@@DrCassette I've found in the past that the half silvered mirrors under the lens can often be dirty and crazy hard to clean.
👍👍👍🇵🇱🇵🇱🤘🤘🤘
Many claim that the Philips type of mechanism is better than the Sony mechanism in CD players
I've never found a used not working CD player with a Philips mechanism that i could fix...
In the other hand i have fixed many CD players with the Sony mechanism inside ✌️
Some say the single laser beam was better at tracking scratched discs.
I repaired several CD players with either SONY or Philips Pick-up. I have a collection of dead Sony pick-up's (KSS240, KSS150, KSS213, ..) which needed a full replacement but I have yet to encounter a dead CDM4/19. In the ones where I checked laser output, they were all still perfectly within -50/-60 mV. So, yes, CDM4/19 are way more reliable than Sony transport. And if you need to find a spare CDM 4/19 they were used on a many CD players you can now get very cheaply.
I have Harman Kardon, laser was broken after 4 months. They give a new one. But 6 months later, same problem. The CD player 970 cost around 400 Euro, the original Chinese laser with the mechanics cost 8 Euro. Real rubbish.
Toca el fusible a ver si te pone los pelos de punta 😂😂😂
Not recommended...
Laser diode probably got burnt-out by someone maxing out the laser
That CD-R Verbatim is horrible (very light dye).
I use always original disc or "Almedio abex test disc" for the laser adjustment (to obtain the classic 0.9 volt peak to peak).
But yeah, the CDM 4/19 is pretty dead.
The good things is... these laser are not expensive like the Sony ones (KSS-151 for example).
I once had a batch of Ricoh CD-Rs. They wouldn't play in anything. I ended up having to adjust every CD player in the house and about every second CDROM drive. One wouldn't read normal CDs/CD-Rs after that.
@@senilyDeluxe I always use (during my childhood) Verbatim metal Azo, TDK reflex or Philips Silver premium
Hard to write, but excellent read stability!
The Verbatim CD-Rs are indeed horrible, the reflective layer is so thin you can almost see through it.
Remember those super cheap CD-Rs that had nothing written on it? I used to write "This side up" on them...
They weren't hard to read or write, but if you looked at them weird, the data layer would just flake off. And the data retention rate is maybe a few years.
I could see that metal hexagon key looked very close to that live mains voltage fuse,,,while trying to adjust the laser reader,,,would've been some fireworks if it made contact,,,,possibly blowing the machine to pieces and kill the video camera!!!
Nope, it wouldn’t do that… it might kill the person touching the Allen Key though… made me very nervous watching it, even though I knew he hadn’t come to harm because he’d uploaded the video. Too complacent for my liking. I insulate any metal tools like that with electrical tape or shrink sleeve to prevent any shorting, and I keep my fingers well clear of any high voltage bits… I’ve been shocked after accidentally coming into contact with 240v mains and not been harmed but it can kill you outright.
The hex key was not as close to the fuse as the camera angle makes it seem. Everything was safe.
@@DrCassette glad to hear it buddy, it had me wincing lol.
Seriously though, if you have a thin enough bit of shrink sleeve, just insulate the shafts of any allen keys or screwdrivers that you use for any trim pot adjustments, it saves any accidents from happening… I dropped a brick a few years ago when I dropped a screwdriver inside a Pioneer SX1250 receiver I’d spent rebuilding whilst it was setting the DC offset… I’ve insulted my tools ever since. It cost me many labour hours and quite a few parts to rectify that one. Luckily my customer was very understanding and grateful of my honesty… and he was delighted when he actually got his amp back.
Accidents like that are very unfortunate... I don't often come across adjustments that require a hex key, for most standard trimmer adjustments I have a set of ceramic screwdrivers with plastic handle, to keep everything well insulated.
@@DrCassette I learned from it, I do have some ceramic screwdrivers for trim pot adjustments, those are a great idea. I’ve got a few insulated allen keys too though. I insulate all but the tips of my probes too, I never want to make a mistake like that again. I went straight for the power switch but the damage to the output stage and power supply was instantaneous. Gorgeous amp once it was fixed though, gave my Linn amps more of a run for their money than I like to admit.
They were abused.Never had a problem with technics
Sounds like its the drive belt.
No, there was no problem with the drive belt. It was a problem in the electronics, caused by a bad capacitor. This has been discussed in another video I made.
@@DrCassette Hi yeah, I did watch the follow up video. I use a Technics SL-PG420A
Interesting you mention that all SL-PG players you had didn't work. Assuming you are in Germany, most of them (at least all up to the x60 models) will have had the CDM4 mechanism. That doesn't give a good impression of said mechanism, of which one can read a lot of positive opinions (except for the drawer gear issue).
None of the SL-PG series CD players I had over the years would properly play CDs, but I now have to assume this was not because of a problem with the mechanism or the laser, but because of some bad capacitors.
@@DrCassette Which would be an important information for me as well. Thanks for posting the update video! OTOH, isn't the servo board (where you found the bad capacitor) also part of the complete CDM4 drive assembly, made by Philips, and so should be found in other CDM4-equipped players, regardless of brand, as well?
The layout and choice of components used for the servo board looks very different from the other boards in the CD player, so I would assume that this board was indeed made by Philips. But I don't know if these boards were a universal part for all CDM4 mechanisms.
I had one of these back when they were new. An absolute piece of garbage! In the first year I owned it it spent more time in the shop then it did in my house. Technics actually gave me a replacement unit after a year and it wasn't much better. I finally solved the problem by buying a Sony, which ran trouble free for almost two decades before finally dying.
Can't win them all!
Thankfully this is not too much of a loss, as it was in very bad cosmetic condition...
@@DrCassette I know people love that Philips swinging laser assembly, but at least a KSS-210 )or similar) is easy and cheap to find and replace!