Philips DVD Player - Tray can't open

[ThunderZed]

A relative of mine gave me this cheap Philips dvp3850/12 DVD player as "present" but I've just seen its tray can't open... what a nice gift!
I used a flat screwdriver for first to manually unlock it from the bottom, then it worked a couple of times (open/close) so I guessed this player needed only a good lubrication and a new rubber pulley belt so I disassembled it, lubricated the plastic joints and gears involved in this motion and replaced the original and loose belt with a new 28mm diameter one but this issue remains.

I've taken this video that shows this issue. As you can see the problem is the lower cart group can't detach from the upper magnet, only if I manually rise up the upper magnet a little bit then the tray can open and close normally.

My bet is that its electric engine can't do its job anymore maybe because it's too old and/or stressed so it can't afford enough energy to the lower cart (the part with the reader lens) to get it down and detach from the upper magnet.

What's your opinion and how to solve this problem (if possible)?

[Hamelec]

I had a Philips and a Sony player with the same symptoms - in both cases it was the belt.
Don't forget to clean the pulley before you fit the new belt.

[audiotubes]

Agreed, I have seen this a few times also, and it was always the belt.

It's a cheap and fun way to amaze your pals. They bring you a beloved, hopelessly dead CD player. You smile knowingly and tell them everything's gonna be ok.

[ThunderZed]

I see, your opinion is the new belt is too large, isn't it?
After I had removed the original belt, I measured the right length using a very flexible string arranged as a belt linking the 2 pulleys (see my attachment) and the length defined by my ink marks was about 91mm so the diameter'd be 91mm/3.14=28.98mm so I bought a 28mm diameter belt, which is the one on my previous video.
Does this mean that I must buy new belts with different and shorter diameters until this mechanism works? It'd be great if we could know the right belt length from datasheet but I couldn't find any, can you help me with this?

[p.larner]

try dropping the old belt in a pan of boiling soapy water for 10 mins,refit and test.

[SeanB]

Quick test for the belt slipping is to boil it for a minute in a cup of water in a microwave, and the shrinking will get it to work better for a while. Belts need a little tension, so you might need anything from 24 to 26mm belt to provide a slip free transfer, but not damage the pulley and shafts.

[ThunderZed]

Let me see... I've just found this belt sold on ebay and the DVD player model matches exactly. Before any trial I think it could be interesting to ask that seller the diameter of that belt, I mean if 28mm is the right diameter then I know for sure the cause is other, else I'll buy a new belt with the right diameter. Maybe the right diameter is exactly 1 inch (25.4mm), who knows. Let's wait for his/her answer...
Meanwhile I'd want you to consider both the EAN and the manufacturer spare part numbers of that belt sold on ebay according to the seller: 4061285443162 and 15755.25. I've just tried to search the web for them but found nothing (but that ebay page). I wonder where the seller took those numbers from, I hope he/she didn't invent them!

[p.larner]

why not try what i have said before buying another belt,or are we wasting our time with you?.

[ThunderZed]

I had already washed-up the new 28mm belt before installing it but it didn't work so I posted my issue here, sorry if I didn't write it on my 1^ post. I always pay much attention to your suggestions.

Anyway I've just tried to use the original belt again and it works though it's stiffer than the new one and it's oval-shaped. I know this is not a solution but I think this means I just need a shorter new belt, imho.
By the way it's impossible to contact that ebay seller "due to the high volume of messages this seller has received" so until now it's impossible for me to know the exact diameter for a working belt.

[GLouie]

Yes, generally one needs to have a belt slightly smaller than the piece of string, so the rubber is stretched a bit and under tension. Just how much can be a bit of a guess. Sometimes, I will order 2-3 different sizes near what I think will work.

The ebay seller's prices seem very high at 12 euros + 15 shipping for one belt.

[CaptDon]

There is an easy cure for this. You have done the proper repairs already. Just keep a disk in the tray, even the blank one that is always included in a new caddy of CD's. It really is that easy!! Sometimes you may have to press the eject button 2 or three times, but it will open. This prevents the two metal parts of the clamp from magnetically sticking to each other and jamming!! When you are finished playing a DVD just leave it in when powering down or put in a CD that you hate, then power down.

[ThunderZed]

The ebay seller's prices seem very high at 12 euros + 15 shipping for one belt.

I'd like just to ask him the right size of the original spare part, I won't buy the belt from him, not for that price. The problem is that it's impossible to send him a message moreover I can't find the Philips service contact to ask them the right size.

I've just looked on Aliexpress what the eastern market offers as cheap spare parts in the 20-30mm range and I've found these ones:
https://www.aliexpress.com/item/1005002442007154.html - 25-170-1.5mm 20pcs - 10.77 euros
https://www.aliexpress.com/item/1005003464492885.html - 25-80mm/20Pcs - 5.46 euros
Anyway I'm sure it's impossible the right size would be under 25mm.
I'm more oriented to the last one just because it's cheaper but... what does "Folded Length: Approx.20-85mm" mean in this case? They're belts not folded sheets! I guess the seller refers to diameters range but I want to be sure not to make a mistake. Do you agree?

When you are finished playing a DVD just leave it in [...]

What an ALF-y trick! I prefer a definitive solution instead of a workaround

[Gyro]

There is an easy cure for this. You have done the proper repairs already. Just keep a disk in the tray, even the blank one that is always included in a new caddy of CD's. It really is that easy!! Sometimes you may have to press the eject button 2 or three times, but it will open. This prevents the two metal parts of the clamp from magnetically sticking to each other and jamming!! When you are finished playing a DVD just leave it in when powering down or put in a CD that you hate, then power down.

Seconded. This is a problem that can afflict earlier Philips swing arm CD mechanisms too. The top clamp on these is held by spring rather than magnetic attraction, but after a few days the alignment cone can start to stick to the inside of the aluminum hub. This normally frees when you hit eject but you can hear the motor labor and the 'clunk' as it frees, this puts avoidable strain on the belt. Preventing the additional strain in the first place seems like a good idea.

[CaptDon]

O.K., so with a new belt OF PROPER SIZE the tray motor would STALL and the tray not open any time the DVD player sat empty and unused for a couple of days. Diagnosis, the clamp was magnetically clamped and after all oiling, cleaning etc. the piece of shit would still jam if left empty and powered down for a couple of days or more. Cure, leave a disk in it when powered down. Not bogus at all if it f__king works!! Were the magnets too strong, did they not meet the original manufacturers spec? I don't know and don't care, I found a cure. How hard can it be to source the correct belt? I just replaced a belt on an 8-Track tape player and the model wasn't listed on any website of belt sellers. I cut and measured the old belt, it was about 13.5 inches so I ordered one that was 13.1 inches right off of a belt sellers website. $7.00 U.S.D. and it works like new again.

[ThunderZed]

Not bogus at all if it f__king works!!

Mmhh... honestly I think I'll sell this DVD player just because I've got no DVD to play I'd like this player worked at 100% so I won't get any complaint by my buyer though I know I don't have to give any guarantee because it's used stuff, it's just a matter of "fair play" for me, that's all

A new (kinky idea) has come to my mind: what about an o-ring to replace this rubber belt? I remember I used a couple of them many years ago for a hydraulic work in my bathroom; do you think it could work?

[GLouie]

O-rings can often work just fine. You still have to get the right size, and a suitable material and durometer.

[abhi1981]

You can make a new belt by using a 1.5 or 2mm urethane transmission belt. Its very strong and available in various diameters.
Its available on eBay.

[ThunderZed]

I've bought an o-ring and modified it and you can see a comparison between the original ovalized belt, the new but a bit too large 28mm belt I had tried and this new modified o-ring (see attchment) and you can see the modified o-ring installed as well (see attchment), moreover you can see it working in this video.
Now the tray works good and this o-ring spins firmly as opposed to the previous 28mm belt which "floated" a bit when spinning.

Now I'd want to show you my concern about this solution, I mean this modified o-ring. It's obvious these 2 objects (o-ring and belt) are made of 2 materials of quite different elasticity and the o-ring is stiffer, moreover an o-ring is not made to spin or to move anyhow. I'm afraid that after a quite long time (eg. 3 months) of inactivity inside this player this o-ring will get such a firm shape that it won't work properly anymore, eg. it will transmit the movement slower.
What do you think about that?

[Koray]

CD tray of Denon RCD-M40DAB was opening but very very slow. I first thought the belt was weak, so I replaced it with slightly tighter ones. It completely stopped working. Then it dawned on me that it could be a friction problem with the tray guides. I disassembled the unit and lubricated the plastic guides that tray moves on with special silicone grease. I lubricated the gear and the other mechanism that locks up the servo onto disc. Now the CD tray works perfectly with the original belt! See the photos below.

If a CD tray is acting up, first lubricate the guides! Makes a big difference.

Service manual for Denon RCD-M40DAB can be found at the following link:
https://www.manualslib.com/manual/3047142/Denon-Rcd-M40.html

K.