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Denon DNS3500 screen fault

Printed From: Speakerplans.com
Category: General
Forum Name: Electro Frying Forum
Forum Description: Talk about drivers, processors and mixers
URL: https://forum.speakerplans.com/forum_posts.asp?TID=82399
Printed Date: 18 November 2019 at 7:15am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: Denon DNS3500 screen fault
Posted By: Majestic
Subject: Denon DNS3500 screen fault
Date Posted: 01 October 2013 at 1:36pm
Hi guys,
This puppy has a screen fault, nothing appears. I replaced the screen and the problem still remains. Any ideas?
Thanks



Replies:
Posted By: djeddie
Date Posted: 01 October 2013 at 9:22pm
PSU fault?

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Chas n Dave : it's like Drum and Bass but with beards.             E=mc² ±3dB


Posted By: kedwardsleisure
Date Posted: 01 October 2013 at 11:34pm
You'll have to elaborate greatly to get a meaningful answer from a distance.
What checks have you made that lead you to think the screen was faulty? Was it smashed? Does the rest of the machine work ok? The info on a VFD goes through a tortuous path before it makes the pixels light up.

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K. Edwards Electronics Engineers

North Staffordshire



Posted By: Majestic
Date Posted: 02 October 2013 at 12:41am
May be a PSU fault.
I tried changing boards from a spare, but not even switching on now.
Do you know which components could have failed?
Thanks


Posted By: Majestic
Date Posted: 02 October 2013 at 12:55am
Originally posted by kedwardsleisure kedwardsleisure wrote:

You'll have to elaborate greatly to get a meaningful answer from a distance.
What checks have you made that lead you to think the screen was faulty? Was it smashed? Does the rest of the machine work ok? The info on a VFD goes through a tortuous path before it makes the pixels light up.


Thanks for the reply.
No physical damage to the display, the denon logo flashed when was switched on. Everything else WAS functioning normal before I messed about.
I followed up on Eddies suggestion and changed the PSU from a spare 120v version, maybe that was a bad idea though as now it doesnt switch on at all. When i changed back to the original PSU, the denon logo had a pale flash but now there is no sign of life. All the fuses are ok and ribbon cables have been attached. What have I done?!


Posted By: Masai
Date Posted: 02 October 2013 at 11:59am
Originally posted by Majestic Majestic wrote:


Thanks for the reply. 
No physical damage to the display, the denon logo flashed when was switched on. Everything else WAS functioning normal before I messed about.
I followed up on Eddies suggestion and changed the PSU from a spare 120v version, maybe that was a bad idea though as now it doesnt switch on at all. When i changed back to the original PSU, the denon logo had a pale flash but now there is no sign of life. All the fuses are ok and ribbon cables have been attached. What have I done?!   

It does amaze me when I read on here how people go under the hood of a high voltage amplifier or a sophisticated bit of electronic kit which cost hundreds of pounds to have a poke around with no previous knowledge or experience of repairing such pieces of equipment and expect to some how fix it Confused Shocked 

You could have saved yourself a lot of bother (and now money) by just giving it out to a Denon authorised service who would have not only sorted out the problem but also give it service and software upgrade if needed. I'm not sure how old your unit is but is it still under warranty? Silly question maybe but I thought it best to ask...

I think you've learned a valuable lesson from your tinkering but I hope you get the unit sorted out. Good luck! Handshake


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Facebook: Masai Judah


Posted By: Majestic
Date Posted: 02 October 2013 at 12:58pm
Lesson learnt. Its not high voltage though, i wouldnt be sticking my screwdriver into an amplifier without discharging the capacitors first
Looks like i will be trying to get someone qualified to fix this one now. As it stands i now have 2 dead units and one fully working one to compare tests. Are there any links to free service manuals for these, all the one i can find are pay to download.
Thanks


Posted By: kedwardsleisure
Date Posted: 02 October 2013 at 8:52pm
PM sent

re high voltage - denon dns3500 uses a switchmode PSU at a very lethal 340VDC

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K. Edwards Electronics Engineers

North Staffordshire



Posted By: Masai
Date Posted: 03 October 2013 at 9:45am
So it's a case of 2 down and 1 to go yet you want a service manual??Confused

Doesn't sound like you've learnt your lesson to me..... Oh well......


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Facebook: Masai Judah


Posted By: Majestic
Date Posted: 03 October 2013 at 1:49pm
Thanks for your help and the warning Kev.
I will be getting someone else to fix it for me


Posted By: oscillo1
Date Posted: 21 December 2013 at 7:32pm
Hi guys,
Do you find solution for you problem?
Solution, replace ZD903 on power unit.
ZD903     00D 276 0831 902       0ZDZ2.4-Z

Regards


Posted By: Majestic
Date Posted: 22 December 2013 at 10:06pm
Originally posted by oscillo1 oscillo1 wrote:

Hi guys,
Do you find solution for you problem?
Solution, replace ZD903 on power unit.
ZD903     00D 276 0831 902       0ZDZ2.4-Z

Regards


Thanks for your help. Do you know where to order the parts?


Posted By: hmaudio
Date Posted: 24 December 2013 at 9:46pm
Abit off topic i know we had a problem with our's where we would get a massive belt when touched the platter or enything metal.

They come with a plug converter thing and use the neutral as a earth so make sure its the right way or replace with a proper plug, or enything thats earthed is now live.


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Nottingham based cab builder. https://www.facebook.com/HMAudio-154352667920145/?ref=bookmarks
This account is used by 2 people.


Posted By: ultrascan
Date Posted: 06 December 2015 at 12:36am
Hi all
No display is usually caused by ZD903, it is a surface mount diode on the underside of the power supply board, a tiny little thing, this is a 2.4 volt zener diode, care is required when removing it, but you can fit a real 2.4 volt zener diode on the underside of the board, the cathode is to the right with the diode position closest to you,  I used a 2.6 volt as that is what  I had to hand working no problems.good luck and don't forget to disconnect the unit from the mains supply before working on it, or you will have problems also make a note of the direction of the ribbon cables checking on what side the blue bit is before disconnecting them, it will save you a lot of time and trouble. good luck, kr Pete



Posted By: Nomakon
Date Posted: 05 October 2019 at 7:13pm
FIXED I PUT A DIODE Zenner 1n5221 1/4w non SMD adapt the DIODE. Works correctly.



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