Ebay resto mds je440

[M1JWR]

Yet another spares or repair, a je440 for not a lot in exellent cosmetic condition, somebody has been inside, looks like nothing damaged, symptom is c13 when reading a disc and spits it out, i installed a belt first thing as there wasent one in there, i then checked with cover off, no activity whatsoever, no spin disc etc, i put another drive in out of one of the 470's i have here that i know works and it did, so that knocks the rest of the player out of the equasion, so ive just left it in there, (so now the thread is mistitled), i suspect the spindle motor, i do have another 7a drive unit that has a broken plastic part on it and i know various electronic parts work on it including motors etc, so i can use it for donor parts if needed, dont think things are as easily "got at" as with the 5 series drives, i have a proper bench psu theat can go to very low output voltage so the existing one can be tested in situe, so i think that will be a good starting point

[kgallen]

Why suspect the spindle motor? As we know lots of things need to happen and be good before the CPU will start operating the drive.

As you’ve got the drive out it is easy to put a resistance meter across the big blobs of solder on the motor connections and check for a few ohms of continuity. 

[M1JWR]

just a suspect kevin, if it dosent work ive got to find out why, i am aware it will probably lead elsewhere, got to start somewhere

[kgallen]

If you put the 440 drive back in, any different? (The ole tarnished ribbon cable trick!)

[M1JWR]

i actually put it into the 470 using its ribbons, they are different, one is much longer, same result

the 440 has the 470's drive inside with the 440's ribbons and works spot on

issue is with the drive unit itself, will investigate further later

could even be the connections for the ribbons on the drive itself

[M1JWR]

L141 on bd board has no contact and looked iffy on close inspection, soldering smc's is not my forte

[M1JWR]

have now swapped bd boards from the ex 940 broken drive to this one, it involves 1 screw, several solder points, mostly motors and a thin ribbon cable for laser to bd board, had 1 switch to align behind a plastic part and then re solder, if anybody wants to see the underside of mdm7 bd board here is a pic, i now have a working machine, not tested on record as yet

Edited September 19, 2020 by M1JWR
wrong word

[kgallen]

The EEPROM contents won't match the laser characteristics so some reprogramming will be required to avoid the laser getting damaged. I'd refer to the Service Manual which usually specifies what needs doing when certain parts are replaced. There is usually a section on what to do if the EEPROM is replaced, which is effectively your scenario with the BD board swap.

[M1JWR]

thats exellent kevin, i had to find out how to recognise number, its on a sticker on rear of drive unit, the ex 940 drive said 518 and sure enough in the menu it is 51.8, this drive has a sticker that says 505 so will change to that figure 50.5, followed procedure, had to swap drives back as ams on 470 needs cleaned as no contact when pressing it in with stop on service power up, cheers kevin, something else ive learned

[NGY]

Apologies for chipping in without being asked. I have a couple of thougths here, that might be useful for others who may read this topic later.

I have done this long time ago, therefore I might remember incorrectly: when I compared the EEPROM contents of the drives from a 440 and a 640 (not the 940 though), they looked identical. My conclusion was that the EEPROM content is probably related to the actual drive version, i.e., MDM-7A, etc., not the deck model. But this was just my calculation.

The EEPROM is not user writeable - except for the intialization process, where the content is taken from "somewhere" inside, maybe from another ROM chip or from the MCU ROM area, thus it must always be the same.

Laser parameters are stored in the NV-RAM, this is what we can access via Service Mode. Here I would be cautious when swapping OP-s between drives. Sure if you enter the IOP value handwritten on the OP and/or the one printed on the OP's sticker (those two are not necessarily the same!), you cannot go wrong and damage the laser diode (immediately). However, two important things to mention here:

- writing back this IOP value will not guarantee by itself, that the given OP will properly work in another drive. Laser power and IOP must always be measured together, and then values be recorded in Service Mode accordingly;

- besides these two parameters, there are several others that influence the laser's behavior. After an OP swap all of them must be appropriately measured and set.

Having said that, my experience is that these OP-s are fairly "robust",  and will just begin working with "wild" or raw settings. But the laser's lifetime can be badly shortened, not mentioning the excess load and wear on the mechanical parts too.

[M1JWR]

no problem with chipping in, its all good education, with us as amateurs lots of things are discovery and trial and error, i never even thought to check the iop originally, i thought as the drives as being 7a varient would be all the same and i couldent change that coil, and went ahh yes i have a replacement part, i wonder if that will work, and so far it looks to have done.

the problem with that old 940 drive was that the clip that holds the top part was broken off, and basically in that case i would imagine your screwed, ive seen people changing the belts on youtube and when they get to that part, i think is he gonna break it because i would imagine it would be easily done

[kgallen]

@NGY definitely not chipping in! No one ‘owns’ this thread! This is all good info and as @M1JWR says, we need it!

[M1JWR]

all good stuff, looks like some switch cleaner into the ams on that 470 now, looks like a front off job to get at it properly

[M1JWR]

on the 470 further investigation revieled a hairline through a track next to ams connection, soldered a bridge to start with, but wasent confidant so ended up with a wire link, all good,

working now

[M1JWR]

another deck on the way, a 470 with a disc stuck inside, i like it when they are like that, you get a free disc

[kgallen]

15 minutes ago, M1JWR said:

i like it when they are like that, you get a free disc

:-D

Love it!

I think the next purchase is going to have to be some more Ikea shelving to stack all these machines on!

A silver one eh? And with the remote? That's a rarity! What's that silver knob on the LHS of the front panel?

[M1JWR]

nah a black one, and remotes are rare and expensive, i bought a rm-d13m not long ago for a tenner inc post, bargain, it would be for a ja20es, its like a master remote as everything is on it.

the only player i got spares or repair with a remote was a 440, it came with a rm-d7m a while ago, remotes are sold seperately most of the time as they can be as much as the player. i saw a remote for a 930 not long ago and it made over 60 quid, crackers !!

[kgallen]

You're gonna have to give us a run down on what you've got now, you've been racking them up recently! You must have half a dozen at least from the 4xx series. You must have a few MDM-7-series drives in stock now.

[M1JWR]

no spare drives as such, just a 7 drive in many bits and a 5 drive with knackered owh

at the moment, 1 x 520, 1x 940, 2 x 930, 2 x 920, 1 x 480, 2 x 470, 2 x 440, and the 980 i have have had for a lot of years, 1 930 had nowt wrong with it when the guy thought it had, it was 35 quid, thats the price area i look at, might double that for a 940 faulty, a mate of mine does tape decks, he has about 20, then has a clear out every so often, he likes nak's, loadsa money for those, he has all the test kit for them, fixing them is his hobby, you could get a 470or similar , stuck on standby guarenteed it will have a disc stuck inside for around 30 quid or sometimes less, cheap enough to have a bit of fun and not loose any sleep over it, have a go, dont go for that 470 thats on there just now with 4.99 start with c13, that one is a dog, i sometimes vary out into marantz cd63/67 cd players, plenty of parts and easy to fix, even ones that are totally dead.

[NGY]

BTW " 470" - have you seen this one?

We, here on this forum do something totally wrong.

NO, just kidding :-) !

[M1JWR]

That other 470 arrived, usual issues, eject belt and as it seems with this model and the 480 no doubt, a slightly sticky ams function, switch cleaner only this time, chalk another up.              

the stuck disc was fubar though it went into the bin

[kgallen]

8 hours ago, M1JWR said:

the stuck disc was fubar though it went into the bin

Should’a saved that for when @NGY gives us the magic recipe to make his fantastic LPM project!

 

[M1JWR]

it had no sliding door on it kevin, i do have a sharp one somewhere that may qualify that came with a 440 a while ago that i have to blank sometimes as it can cause c13

[M1JWR]

anyway after all this, its my opinion that overall the 440 is better build quality than the 470/480 models despite the odd bell and whistle that the other two may have.

[kgallen]

Interesting. Aren’t they the same e-line flimsy case with the same display and an updated drive chipset but still cost reduced to hell and back?

[M1JWR]

the 440 admittedly has a smaller board inside, but with better quality proper components on it, the 470 has a larger main board with lots of jumper wires, the 470 board itself is more flimsy, diddent take much notice of chipsets themselves, i forget the psu section and the drive unit is the same obviously, outside the 440 cases are thicker material and the front panel is a more solid construction and overall the 440 feels a little heavier than the 470/480, display functions are similar though the display board is very different as controls are in different places, its a bit like the thread on the 980 vs 930/940 etc, in that case the 980 is the same as, say, the 940 on the outside, for example the 940 has a proper toroidal psu and the 980 has a nastier standard iron core jobbie, which looks like the 470/480 one, so yes as the years went by , cost reduced to hell and back.