Vintage CD player repair : Pioneer PD-M40 6 disc changer, no read. - Page 1
Forum section: electronics / repair

author: Vince
author_rank: Super Contributor
timestamp: April 12, 2021, 06:32:52 pm
content: Hello people,This the very last player of my 20 CD player binge buying episode of late. I am not expecting any more now, received them all now.Got it this evening, already played with it of course.Sadly it arrived damaged during transport. Right side of the for panel got a really bad hit. There a re couple more of these players for sale here. One for 10 Euros the other for 15. Doesn't seem like either of them are planning to ship, but neither was the seller of mine, yet I managed to convince him to ship it anyway.So, it's a Pioneer PD-M40 6 disc changer. I like the 6 disc cassette changers, and this one looked cool. Seller said it was a high-end unit with good sound, and was the original owner of the unit. Looked like he actually loved his player. So, I gave it a try, bought it.Am not disappointed. It's indeed nothing like the 20 other players I have seen so far. This one is 3 times a heavy. Folded metal sheet chassis using very thick sheet. Very rigid and heavy. The bottom of the chassis is further straightened by a "honeycomb" looking grid of very deep stiffeners.Inside, neat layout with the changer mechanism on the left half of the cabinet, and on the right side a single large main board with everything easily accessible for probing around. There is no board that I can see that would be hidden under the changer. The transport is at the top, easily accessible. Just remove 4 screws and you can flip it with all the wires and cables attached to it no problem. This thing is a dream for servicing, it looks...Changer is very fancy, lots of thick metal sheet, not flimsy at all. Looks indestructible...The transport doesn't look anything familiar, and I can't see any markings on it to tell me what it is !There is some stuff printed on the pick-up flat flex, but I don't know if that's relevant.DAC ? don't know. Lots of big IC's on the board, all branded Pioneer of Sony... was there a joint venture between those two back then ??Small IC's around the analog / audio output section, not Pioneer or Sony. Not Philips / TDA either. Don't know what DAC that could be...Of course, it's an old player, late 1987, when they still bothered making well engineering and built players. Must have cost a pretty penny back the, but at least you got your money's worth.So I thought I would post about this repair, also because since it's different from every other player I have seen... I might need some help along the way...Found the service manual for it but.... only for SALE. Didn't find one I could download for free. So, for now, no service manual for Vince.Symptoms : seller said that the player was reading CD's erratically.Me: doesn't even detect the discs ! LOLHowever after a few minutes playing with the thing, I found a couple issues on the transport, which could explain why it can't detect a disc :1)I found " suspicious " looking tactile switch on the main board.. silk screen labels it as " TEST " hmmm.... could that be used to enter some kind of maintenance mode ? Pressed it... nothing happened. Power the unit off, held the switch down while at the same time powering the unit back on... hey presto, display goes weird, yeah, definitely in service mode, yeah !With no service manual to tell me how it works, I just pressed every button on the front panel, to see what I could get it to do. I found the the " NEXT " button, loads the current disc, tries to read the disc for 3 seconds or so, then unloads the disc.But much more interesting are the fast forward/rewind buttons ! They let you operate the sledge motor ! And... I noticed the motor made a horrible noise when I pressed these buttons ! Hmmm.... I removed the screws holding the transport, flipped it so I could see the pickup, then played with the switched again... yeah, I can see the pick-up moving back and forth at my command, cool !There is definitely a problem with the sledge motor. As you can see on the little video I made of it, the motor makes an agonizing noise, and the pickup does not even move.. then after a short while, pick-up eventually get moving, but does so very slowly, and still with that horrible noise. Can't be right....As you can see in the video, I moved the pick-up from end to end a few times, and at times, you can see that the pick-up, once t has managed to get off its stops, managed to move quite swiftly and with a much less horrifying noise ! so, it CAN do it ! It's not completely toast after all, great.The track looks very dry, and crusty at both stops. So I guess if I remove the old dry grease from the stops, and apply some fresh grease, and exercise the mechanism a bit... might be all it needs to come back to normal operation ? I don't have the proper grease for small mechanism like this...don't now how it's called, never mind where to get it from. Any advice appreciated...For now, all I have is fine machine oil. Should be good enough to at least confirm my diagnosis.2)As you can see on the video and pics of the underside of the transport.... it looks like there is a missing piece on the pickup. I remember seeing a video about something similar on a repair channel ( " 12voltvid " ) : the lens of the laser that comes off ! Apparently it's just glued... on my player I can see what looks like the remains of that glue..Guy on the 12voltvid simply glued the lens back on, and the player was back in business.So I definitely need to do that.... IF I can find that bloody lens ?! Hopefully the lens is wandering somewhere in the cabinet... hopefully. Let's cross fingers that the seller did not open the player and the lens fell outside the player and he didn't notice it. If I can't find it.. am I toast ? Can you buy replacement lenses ? Is it some kind of standard part ? ...Yeah, cheaper to just buy one of these other similar players, if I can persuade the sellers to ship.Anyway, here I am working on yet another old CD player ! Clearly I am hooked to these things. Addict I have quickly become

author: Gyro
author_rank: Super Contributor
timestamp: April 12, 2021, 06:37:37 pm
content: Nooo! I thought you were going to do the Philips CD371 next!

author: Vince
author_rank: Super Contributor
timestamp: April 12, 2021, 07:13:27 pm
content: I will !For now I was not going to do any CD player at all... I really need to get back to the construction work in my house.This one I only had a quick look at, because as I said I just received it ! So obviously I could not possibly NOT at least look at it...no way I would just let it sit there and not give it a test ride, I am just way too curious.I just so happened to find obvious things wrong with it, that should be quick and easy to do, so would be stupid not to tackle them.However if it turns out to be a lengthy or near impossible repair, then yes, won't spend weeks on it, will set it aside and switch to the " Radiola " / CD371, don't worry !I am intrigued by this serial interfaced LED displays, hope I can repair it. You said it could IIRC. I am impatient to see how it's put together.Might be sooner than you expect : gave the player a good shag, can't hear any part loose inside... so no lens. Unless it got stuck to some old grease while falling inside the changer mechanism, who knows. So, can replacement lenses be had ? Standard part ?... if not, player is toast so end of repair right here, unless I buy another one if the seller are willing to ship it, no guarantee...Had a closer look at the main board. Took note of each and every IC. Lots of them...As for the analog / audio section, found the DAC. It's a PCM56P, 16 pin, made by Texas Instrument.Then we have a triple 2 way analog switch (BU4053B) then a super low noise dual JFET op-amp, that's a 5238 made by Mitsubishi.Then to finish the chain, we have a couple dual opamps, super ultra low noise super wide bandwidth/high-speed, reference C4572C made by NEC.

author: Gyro
author_rank: Super Contributor
timestamp: April 12, 2021, 07:27:04 pm
content: I'll let you off then!The PCM56 is a decent DAC, it's multi-bit (like the TDA541) - as long as there are two of them, one per channel. It is a mono DAC and many cheaper players used a single DAC, decoding left and right channels alternately and then analogue de-muxing the signal to produce left and right audio. This requires additional circuitry to avoid glitches etc.

author: Vince
author_rank: Super Contributor
timestamp: April 12, 2021, 08:34:23 pm
content: Thanks for the info ! You don't just know Philips players then, you know even more ! Lucky me, glad to have you onboard !Well, looks like this PD-M40 is the bottom of the line one then, sadly : one one PCM56, and right after it, as I just said, there is that 4053 chip that's a triple analog switch !! However, right next to the PCM56, are a couple 16 pin (like the PCM) UNpopulated footprints !!! hmmm.... so me thinks there might be a higher-end version of the player, that used 2 DACs and no switching ?! Hold water anyway. And I do vaguely remember seeing indeed other versions of this player, same front panel but called M50 or M60 rather than M40. Given that i marketing "the higher the number the higher end it is"....So maybe I should investigate this route, and I should get, one day if one pops up, the big brother of this M40, and keep this bottom end M40 for parts, since 99% of them will be common with its bigger brother.I mean, this one looks on its last leg and maybe unrepairable :1) Missing lens2) cleaned and oiled the track. Pick-up now moves much faster and smoother, but is nosoiy when it moves INward... perfectly quiet when moving OUT ward, though. So maybe the chariot holding the pickup has some bearing inside that's worn out, or broken.. yet another impossible repair...3) Still having problems getting off the ground when the pick-up is at either stop... found out it's not the motor.. it's the rubber belt. Can't passe the torque at start-up, slips and makes this horrible screeching noise. So need a new belt.. but where to get one.So when you add up all the costs, several shipping to pay etc... this 15 Euro player will end up at 100 Euros... for a bottom of the line multiplexed mono DAC hmmm.... not clever is it ?So I think as I said it seems more clever to stop there, not spend a cent on it, nor even time, and just set aside and get it's bigger brother with a twin DAC instead.. hopefully featuring a lens and not so worn out pick-up chariot...So, see ? That was a quick one, now I can look at the CD371 !Video of the pick-up getting some exercise once I had cleaned and oiled the track. You can see how much smoother and faster and quieter it now moves, compared to the first video ! You can also hear the horrible noise when it moves inward....Video too of the belt. You can see it " ballooning" and screeching at startup.

author: Gyro
author_rank: Super Contributor
timestamp: April 12, 2021, 08:48:39 pm
content: That first video (in your last post) sounds just like an old dot matrix printer!The missing lens is a bit of an immediate showstopper, although a replacement assembly would fix it - if you deemed it worth the extra cost... Unless it's causing one of the rattles of course!P.S. This is the page that you need(ed!)...https://www.dutchaudioclassics.nl/the_complete_d_a_dac_converter_list/Just don't tell anyone!

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 12, 2021, 10:02:14 pm
content: Thanks Vince, you just did myself a favour...I've seen the lenses drop off Pioneer's before too.I have a PD-M435 6CD changer Pioneer player around, my last find in the E-waste. The cassette and remote are missing, I hadn't got round to having a peep inside until I read your topic.Now I have and found that here too the lens has gone.I suspect they come out through the front door in-between 2 CD's then vanish into the carpet / vacuum cleaner.I do have various dead or alive pickups around and may have been tempted to fool around with pulled lenses if I knew where to find them, however with the missing cassette and too many other things to do... Problem solved: Spare parts.According to ASWO on your player the pickup is a PWY1010 or PWY1003, the 1010 can be found for a lot of money.A pitty because the changer mechanism is well designed on these players.

author: Vince
author_rank: Super Contributor
timestamp: April 13, 2021, 05:20:16 pm
content: @Gyro : checked the interweb quickly.. there is indeed a M50 with the exact same front panel... but also a M44/450/460 or something, and also M500 and 501 and 502 and also blah blah blah... this style of Pioneer 6 dics changer spanned quite a few models it seems ! So my M40 is indeed nothing special and rahter low end from you said, DAC arrangement wise. So I think it's not wise to spend any more time or money on it. I will keep it though, for spares in case I can score a cheap bigger brother of my M40, in the future. Also, I just like it's engineering and build quality. It's just a way above average in its mechanical design and build. Complex, fancy, sturdy, not built down to a price at all. Way over-engineered compared to my old Philips CDC486 6 disc changer.Like the main board too. Good quality, noty cheap bakelite, lots of IC's to look at and prob around... I got a lot for my mere 15 Euros. Albeit no lens and a worn out pickup chariot it sounds like... So I think I will keep just for it is, I just enjoy looking at its internals, just like the linear motor player I got the other day.OK, so I buttoned it up, now set aside, stacked on top of my pile of unrepairable players...Now moving on to the little CD371, watch out for a new thread coming up soon, my dear Gyro !Maybe this evening or tomorrow. Real soon anyway.Quote from: shakalnokturn on April 12, 2021, 10:02:14 pmHello Sir Shakal !The forum/server did not deem appropriate to inform me of your message ! Luckily I checked the thread anyway... bloody annoying, I hope the data center will be fixed for good real soon, what a pain...QuoteHey, that's not a bad idea ! How imaginative...Interesting theory, would explain why it's not in the player anymore...QuoteLucky you ! I am not allowed to search the e-waste container in the dump yards where I live ! It is strictly forbidden, got myself in trouble once, when I got caught by the guy watching his security camerasHad to pay for mine, 15 Euros + 11 shipping... 26 Euros, and you got your for free ! GRRR !!!https://www.leboncoin.fr/image_son/1666900459.htmAs for the cassette the guy also sells 3 original pioneer cassettes in their original packaging. I bought one, so as to get two cassettes in all. Paied 5 Euros extra for the extra cassette. Guy sells them here :https://www.leboncoin.fr/image_son/1666898759.htmSays 3 for sale but since I bought one already, I guess that makes it only 2 left available, unless it was 4 originally and he adjusted the quantity after I bought one... can't remember.QuoteYeah not worth it... best to get a working one so that we are sure the lens is still on it and the pickup not yet 100% toast...QuoteYep, it is shocking how large, sturdy, complex this mechanism is compared to any other I have seen.Looks as large and complex as VCR ! That's what crossed my mind when I first opened the hood !It even has a nice piece of cast metal ?!Visible at the top left toward the front, on my pics.Anyway, off to start work on the CD371, before Gyro makes the trip down here to do it himself, what an impatient little bugger...

author: Vince
author_rank: Super Contributor
timestamp: April 13, 2021, 06:55:49 pm
content: Here you go Gyro, see you there :https://www.eevblog.com/forum/repair/vintage-cd-player-repair-philips-cd-371-aka-radiola-cd-1371/

author: shakalnokturn
author_rank: Super Contributor
timestamp: April 20, 2021, 02:04:50 pm
content: Just found another Pioneer PD-Z74T (dual tray). I haven't powered it up yet so can't say much more, it was making a rattling sound so I opened it, sure enough the lens was the free part.The pickup seems to be the same as on the now dismantled PD-M435 but there's no chance I'm going to knock that together again.With 2 pickups and other spare parts I'm very likely to repair the PD-Z74T but if it's not worth it or I can't be bothered I can post you the lens. I also have kept the faceplate from the PD-M435 if it can fit your PD-M40.

author: Vince
author_rank: Super Contributor
timestamp: April 20, 2021, 02:22:25 pm
content: Wow, yet another lens falling off ! It's a disease...Maybe the fact that the pickup is facing downward has to do wit hit... gravity does its thing once the old glue is perished...Lucky you, keep finding stuff god knows how... you definitely have connections that I don't have, I am jealous... thanks for your kiond offer, keep me informed... here is hoping your repair does not go well so I can benefit from that lens !Would still need to find a new belt for the radial motor, but I guess you can buy these things... somewhere.. somehow.