mestkidd Posted February 1, 2011 Report Share Posted February 1, 2011 Hello I have an mz-r900 it works fine most of the time but every now and then whilst playing it will skip and I can hear the laser moving back and forth and I have to gently tap the machine to get it to work, so I'm not sure if the laser is out of alignment or so or starting to be faulty, but the main issue is also this happens every now and then too, all the buttons on the front panel seem to make the machine do random things and the buttons often do each others functions, ie u press vol+ and it will skip tracks, record mode will write a track mark, skip track will pause and so on, what could this be?, it's 9 years old who would have parts or could help me fix my mz-r900, thanks p.s finally is there any know cheats or hacks for it that will allow extra functions?? Thanks Aaron Quote Link to comment Share on other sites More sharing options...
sfbp Posted February 1, 2011 Report Share Posted February 1, 2011 I have not worked on an R900. However Jim (.Hoggarth) can fix these machines. I myself recently acquired the gear to fix and adjust most MD units, but it sounds like most of your problems may be to do with the contacts for the battery, especially if the button difficulties go away when running on external Alkaline (not internal NiMH rechargeable) battery or from the proper charger that the unit came with. You might try that first before contacting either of us. Is the LCD unreadable? That's one reason I ended up messing with all this stuff on my NH900 (HiMD), with a very successful outcome. And a sure sign that the supply voltages on the unit need adjusting as per the service manual. You might be able to do it yourself...... Stephen Quote Link to comment Share on other sites More sharing options...
mestkidd Posted February 2, 2011 Author Report Share Posted February 2, 2011 Hello Stephen, correct me if I'm wrong but I don't think the battery connections could cause the problems I'm having, ie how could that make the buttons on the front panel do each others functions and make the machine randomly jump, so I have to gently tap it to make it go again ( it almost sounds like it losses track or focus on the disc), these faults also have when on either internal battery, external AA or mains power, I'm written to Jim a few times about this and my 333es and thus far no reply, thanks Aaron Quote Link to comment Share on other sites More sharing options...
sfbp Posted February 2, 2011 Report Share Posted February 2, 2011 low voltages.... but if happening with every power source it's most likely a matter of re-adjustment of settings. Quote Link to comment Share on other sites More sharing options...
jim.hoggarth Posted February 2, 2011 Report Share Posted February 2, 2011 Hello I have an mz-r900 it works fine most of the time but every now and then whilst playing it will skip and I can hear the laser moving back and forth and I have to gently tap the machine to get it to work, so I'm not sure if the laser is out of alignment or so or starting to be faulty, but the main issue is also this happens every now and then too, all the buttons on the front panel seem to make the machine do random things and the buttons often do each others functions, ie u press vol+ and it will skip tracks, record mode will write a track mark, skip track will pause and so on, what could this be?, it's 9 years old who would have parts or could help me fix my mz-r900, thanks p.s finally is there any know cheats or hacks for it that will allow extra functions?? Thanks Aaron Hi Aaron. R900s can develop a number of unique problems, and you may have come across one of them. Generally, faults of this nature on this chassis are caused by the sled motor or the optical pickup. Both of these can produce similar faults, so it's not easy to say which may be at fault immediately without looking at the machine and running a few tests. But the R900, and to a lesser extent the R700, G750 etc, do have a specific problem that causes many weird faults, some just as you describe. The sled motor has a capstan mounted gear, which drives a secondary transmission gear. This is made of white plastic. Over time, it can distort like an umbrella turning inside-out, so that the gear teeth lift above the gear on the capstan, causing slippage. In extreme cases it is accompanied by a loud noise as the gear teeth clash. This may be all that is wrong, and is a part I change regularly on these models. As for the button problem. I am tempted to say it is just bad switch contacts, and indeed it probably is, although it is rare you find so many switches all misbehaving. The switches are configured to select different resistance values, depending on which key is pressed. Dirty (aka 'ohmic') contacts can present incorrect resistances to the microprocessor ADC inputs and be interpreted as a different key press. If the problem affects all buttons at the same time, it is more likely to be a logic/ADC fault on the main board, however. Jim Quote Link to comment Share on other sites More sharing options...
mestkidd Posted February 2, 2011 Author Report Share Posted February 2, 2011 Hello jim, thanks mate, where are you based? I'm thinkinung if you can have a look at my r900??, p.s did you get my pm to you about my 333es?? Thanks Aaron Quote Link to comment Share on other sites More sharing options...
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