denon udm3

[philberesford]

Another fixed UD-M3 here, thanks Fatz2000

Denon eat my shorts!

[newcoppiceman]

A Denon UD-M3 CD tray open/close failure fix with a twist!

Easily found the fix for the dead CD tray on this forum (500mA protection fuse PR003) but...

When I first checked out my friend's UD-M3 the radio worked ok but the CD mechanism didn't respond to the open/close control. Sure enough, PR003 had blown.

Then it got interesting; at some point during testing the unit died completely and I found a second protection fuse, PR004 (also 500mA) had blown. I found the cause of this was a nearby short-circuit zener diode, ZD004 (6.2V, 500mW). This is also used as a protective device, connected across the output of a 7806 6V regulator which is mounted, alongside two other regulators, on a heatsink screwed to the chassis. The idea is that if the regulator fails and lets through more than 6.2V (its input is at 23V) the zener will conduct (by 'zener action') and blow PR004; it probably failed from repeated application of power in testing after sitting for years with a steady voltage across it (which it has if the unit is plugged into the mains).

I did feel it important to return the unit to its original condition, rather than cobble-together some makeshift arrangement, so I ordered suitable replacement components from CPC (they're not expensive).

The regulators' PCB is connected to the main board via CN004:

pin 1 - 23V via PR004 to 7806 6V regulator input
pin 2 - 7806 common terminal/0V
pin 3 - regulated 6V output from 7806
pin 4 - 23V via PR003 to 7808 8V regulator input
pin 5 - 7808 common terminal/0V
pin 6 - regulated 8V output from 7808
pin 7 - on/off control to PQ12RA1 12V regulator
pin 8 - 23V to PQ12RA1 input
pin 9 - PQ12RA1 common terminal/0V
pin 10 - regulated 12V output from PQ12RA1

[echase]

Anyone know if this fuse repair works too on a Denon UD-M5 with triple CD changer? My symptoms are similar to what happens when fuse fails. But looking at the photo thumbnails mine seems a very different PCB layout. Any chance of gets the link to those photos fixed?

If the repair works will change the laser too as it’s failing. Only £12 or so from places like www.grandata.co.uk but not simple to reach the bits.

[echase]

There is a post relating to the UD-M5 here http://www.fogma.co.uk/electronics/353.html about various faults apart from the eject failure. It mentions a similar fuse setup to UD-M3.

Also there are posts in Japanese with lots of PCB pics that show the fuses if you search Google images for Denon UD-M3. The Goggle translator will change these to passable English.

I looked at my M5 and although the PCBs are different to the M3 I found similar fuse faults, as my PR004 750mA fuse that feeds a 12V regulator IC003 is blown. But sadly replacing the fuse makes no difference to the eject function, ERR message or anything else.

There are separate +12V and -12V supplies marked on PCB nearby and these were OK before I repaired the fuse.

The 6V supply is OK.

Any ideas folks?

[echase]

Is now OK. Found that I had left one of the trillions of connectors unplugged under the CD changer unit so none of my new found 12V was getting to the eject motor. If you follow the correct instructions here you don't need to do much dismantling on a M5 (just remove the top of case), unless all fails and you want to retrieve your stuck CDs.

This unit has got to be about the most complicated thing to dismantle. Digital cameras may be fiddlier as small, but for the sheer number of screws and PCBs the M5 tops them all.

Above post should have said search for Denon UD-M3. UB-M30 is a mistake.

[vtech]

Persistence and common troubleshooting at work...good job

Ps; fixed the typos above

[icardy]

Fatz2000

another mended Denon - many thanks - your photos really helped me
do the the business in about 30mins.

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[fatz2000]

Glad it helps - mines still working perfectly 4 years after the fix!

I drop back in here every few months to check the photos are still working.

Keep fixing!

[christianh]

Fatz2000,

thanks for your great work! Your howto just saved another UDM3.

[jnet76]

I have a Teac Dvd Micro System MC-dv639 and the cd wont eject.All functions work it just wont open.Any ideas???