simduv Posted October 16, 2007 Share Posted October 16, 2007 Just a quick question that I could do with some expert advice on.... I have a pair of Denon 1800 Twin cd decks in one room of the venue in which I work and recently the LCD display started to illuminate very brightly and slowly fade during the trading session, then tonight when powered up the LCD displays were not working at all. Could this be a power supply problem or an LCD problem...... Any ideas gratefully received...I have a soldering iron at the ready!! :-) Thanks in advance... Simon Link to comment Share on other sites More sharing options...
Sam Whitehead Posted October 16, 2007 Share Posted October 16, 2007 HiWas the player still chucking out audio or was it completely dead? Is it both the screens? LED back light units are known to go, the actually LCD is properly ok; it is the backlight that has gone. This is replaceable but unless you’re very competent I would not do it. Is it still under warranty? It may be something simple like a dry joint but I doubt it. Thanks Sam Link to comment Share on other sites More sharing options...
simduv Posted October 16, 2007 Author Share Posted October 16, 2007 The unit is still producing audio..... Would a failing backlight explain why the displays were lighting up 'super bright' for the initial 5 mins, then gradually fading...... When you say the replacement is a tough job, I am used to repairing moving heads and lighting fixtures to the extent of inidividual component replacement....is it on a par with that sort of task?? Thanks for the advice.... Link to comment Share on other sites More sharing options...
Stuart Basson Posted October 16, 2007 Share Posted October 16, 2007 You may know or have seen this already, since it was posted on this board a little while ago, but these people: http://www.chsinteractive.co.uk/ Are apparently the sole distributors for Denon spares, if you get that far. Answers to enquiries are prompt and informative and I was surprised how cheap the spare bit I needed was. Stu Link to comment Share on other sites More sharing options...
Sam Whitehead Posted October 16, 2007 Share Posted October 16, 2007 I would think you would be capably of the repair and if you contact the spares people talked about earlier then they should be able to give you good advise. Link to comment Share on other sites More sharing options...
simduv Posted October 16, 2007 Author Share Posted October 16, 2007 When I got to the venue this morning, the screens came back to life, lit brightly for five mins, then proceede to dim until nothing was visible, it does look like the lcd display dies completely, I.e not just the back light. Any more ideas on this one guys..... P.S - Both screens dim at identical rates.....would this indicate some sort of power supply problem?? Just a thought. Link to comment Share on other sites More sharing options...
greenalien Posted October 17, 2007 Share Posted October 17, 2007 some sort of power supply problem?This has all the hallmarks of a 'dry' solder joint, or a loose connector. The only way to find out is to open up the case (usual mains voltage safety precautions) and take a look. Sometimes just tapping a circuit board or waggling a suspect cable will pinpoint the problem. Link to comment Share on other sites More sharing options...
Brian Posted October 17, 2007 Share Posted October 17, 2007 Before we go any further, the DN-1800F does not have LCD displays. They are vacuum fluorescent. The fault you are seeing is fairly common with this display type but has a number of causes. As it's both displays it would point to a power supply problem but without a service manual, remote diagnostic is going to be difficult. Link to comment Share on other sites More sharing options...
KevinE Posted October 17, 2007 Share Posted October 17, 2007 Brian is right, the DN1800 is Vacuum-Fluorescent and doesnt have a backlight. Sounds like the fluoro inverter circuit, they are notorious for bad joints (as are the display glasses themselves) as certain wound components oscillate at a high frequency and I suppose they are loosened by the magnetostriction and filament heating/cooling. Link to comment Share on other sites More sharing options...
simduv Posted October 18, 2007 Author Share Posted October 18, 2007 Thanks for all the advice guys....would love to have a go at repairing this myself, just to gain experience really, so if anyone could spare the time to talk me through it at some point, I would be extremely grateful. Probably a slightly excessive request, but hey if we dont ask we dont get, and I do like to learn! Failing that I'm assuming the circuit is located in the Head Unit rather than the base, just need to know so that I can send the relevant parts off for repair if need be... Once again many thanks, although a reasonably new member I am already a massive fan of Blue Room and grateful of all the help and advice I'cve recieved to date. Simon. Link to comment Share on other sites More sharing options...
Brian Posted October 18, 2007 Share Posted October 18, 2007 ....would love to have a go at repairing this myself....Some photos of inside the head unit would be good, especially of the PCBs. I'm guessing there will be 1 or 2 boards behind the front metalwork and at least another on the bottom of the unit. We can then give you at least an idea of where to look. Link to comment Share on other sites More sharing options...
Shez Posted October 18, 2007 Share Posted October 18, 2007 I've got a Sony MD deck with a similar problem so will be reading on with interest. The display is very weak in some places, but fine in others - when text scrolls, some characters disappear as they pass certain points... I'm guessing this might be a similar cause? Link to comment Share on other sites More sharing options...
djmatthill Posted October 27, 2007 Share Posted October 27, 2007 Silly question , But have you tried another mini dini connecting cable ??? Link to comment Share on other sites More sharing options...
KevinE Posted October 27, 2007 Share Posted October 27, 2007 If you've got faded bits around the display on the minidisc, this is usually the display worn out, you can tell because the segments do not light evenly. In this case you'll need a new display glass. They go low-emission a bit like an old TV tube or valve. It's very common if the unit spends most of the day turned on. You dont need to dismantle the Denon much to gain access to the rear of the display boards, just drop the rear cover off the panel by removing the phillips screws and there you go. Dont be tempted to slacken the allen screws visible from the front. There's an upright board in there as well which can be carefully unplugged, (its stiff); take static precautions before you touch anything. It's certainly worth replacing the remote jacks and lead if you still have the problem especially if you use the connectors alot. Luckily the base unit boards are multi-layer and dry joints dont develop here quite as much. You can get a pack of 5 8-pin Minidins from RS or Farnell. Link to comment Share on other sites More sharing options...
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