denon dcd 485 no disc rotation and psu high

[jimbofz]

this dvd loads but wont spin discs ,
i used camera to confirm laser at least strikes ,
it does the usual shuffle.
so after cleaning lens and load belt replaced to ensure loading was complete
.i decided to check suppiles from psu. the + and- 5v are ok
but the 8v supply is 12v ?
ive checked all parts in psu esr and for s/c etc
im wondering if theres more than one version of this psu ?
and 12v is normal

the next mystery is that there are 2 leaf switches labelled 21 on exploded diagram to stop and start the tray
these are mounted on small pcb with the two motors
one of these(the second one in from the right) lives under the main loading cam 19 and it doesnt seem to do anything ive had the assembly apart and cant see how its activated ,theres nothing under the cam to switch it
any thaughts please i will upload pics

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

here are some pics

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

doesnt like my pics i will try again seems to have worked.
in the second pic the plug n skt on bottom right ,
next to it this leaf switch which works fine with the underside of the tray
but the one next to it does nothing?

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

can someone check +8 and -8v supplies ,icant fathom why its 12v i will post diagram

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

heres the cct

[R_J]

Re: denon dcd 485 no disc rotation and psu high

It's hard to say why the voltage is high, it is unregulated. It could be due to the caps C512 & C513 are bad, but it could also be a misprint, The similar dcd-920 calls it +/- 10v
I would find out why the tray switch is not being activated, something must be broken or out of alignment. That switch is the closed switch and needs to operate.
Also seeing the laser only means the laser is working, many times it is the laser detector that goes bad and will not output a signal

The switches are activated by the tray itself and not the cam gear, This Rotel manual might help

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

It's hard to say why the voltage is high, it is unregulated. It could be due to the caps C512 & C513 are bad, but it could also be a misprint, The similar dcd-920 calls it +/- 10v
I would find out why the tray switch is not being activated, something must be broken or out of alignment. That switch is the closed switch and needs to operate.
Also seeing the laser only means the laser is working, many times it is the laser detector that goes bad and will not output a signal

The switches are activated by the tray itself and not the cam gear, This Rotel manual might help

very useful manual thanks
,with regards to the switch , the top of it lives under the black main cam and therefore the tray (slides on top of the cam) so the only thing that can move the switch must be the cam?
,on one if the pics it shows a small hole in the cam which lies directly over the switch ,you can see through the hole the top of the switch
if i could see a pic of the underside of the cam maybee a small lug could have sheered off .

normally i would expect one switch to stop the tray trying to go too far out and one to stop it trying to continue loading once it has fully loaded,but my tray glides in and out and doesnt try to spit out the tray.
i will remove cam tomorrow and post pic of underside,for your thaughts ,thanks

[R_J]

Re: denon dcd 485 no disc rotation and psu high

Well then the cam must activate the switch, so it is either out of alignment and not activating the switch or the switch is broken.

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

heres the pics of the cam ive used a coctail stick to show where the hole is

just above the stick it looks like a small stud may have broken off ?,
ive cleaned and tested the switch and its fine,
the position from the centre of the cam( where the stick is shown)
lines up exactly where the top of the switch lives

[R_J]

Re: denon dcd 485 no disc rotation and psu high

That is very likely that the pin is broken, Is it still inside the unit? if not you may be able to drill a hole where the pin was and install a new pin.

[jimbofz]

Re: denon dcd 485 no disc rotation and psu high

a special thanks to RJ ,
its a good feeling when something eventually goes right
i drilled a 2mm hole where the stud had sheared off and fitted a screw ,
cut to the right length .
and re assembled ,i now had disc rotation ,but it was "hunting"
so i removed disc ,entered s mode and did as advised in manual ,
it was better but the servo wouldnt lock on.
so tried s mode again ,this time it locked perfect ,and when i started
cheering the wife brought me a cup of tea .so lifes good
you were right the unregulated supplies were just a red herring
we all live and learn

[R_J]

Re: denon dcd 485 no disc rotation and psu high

Good to here it's working, thanks for following up