Yamaha DTXpress/DTXplorer/DTXtreme

OK, thanks much Keith. Sounds like you've had some interesting 
challenges as have I! I will have at it Monday-weekend commitments take 
me over.  I use the pro contact cleaners, sparingly if at all. I've had 
unfortunate experiences cleaning carbon conductive parts with anything 
but water and an air duster. And this module will be a nice step up from 
the DTX 2.0 which has been as steady as a rock for at least 10 years I 
can remember. Have a good weekend.

             Joe
On 12/12/2015 11:39 AM, Keith Raper keith@... [DTXpress] wrote:
>
> My thoughts are a disturbed connection in transit.  It happened to me 
> with a spectrum analyser once. Also, an old CRT monitor I dug out 
> wouldn't work but started to do so when I was checking connections. I 
> was once sent to Dubai to fault find a brand new broadcast transmitter 
> which started working when I put my multimeter on one of the 
> connectors. Connections are a PITA.
>
> So pull off any connectors and re-connect them, using contact cleaner 
> if you have some. The same applies to any socketed parts although 
> pushing them firmly in their sockets often does the trick.
>
> Regards
>
> Keith
>
> On 12 Dec 2015 16:05, "JDBlackhawk jdblackhawk@... 
> <mailto:jdblackhawk@...> [DTXpress]" <DTXpress@yahoogroups.com 
> <mailto:DTXpress@yahoogroups.com>> wrote:
>
>     No signal generators/oscilloscopes but several multimeters one of
>     which has limited ability to measure frequencies but not like a
>     good scope. I see 2 eproms seated very firmly doesn't look like
>     anyone ever touched this inside. Main cpu and ram/rom is surface
>     mount not socketed. I've also tried my own coldboot
>     technique-connecting the internal battery + to ground without ac
>     power to see if this might clear any jumbled memory reading
>     writing. This worked on an ancient general music keyboard but not
>     here. There are 3 mainboards one of which I haven't checked. The
>     original owner maintained something happened during shipping but
>     I've seen no documentation that UPS, FedEx or post office uses any
>     scanning that might effect memory chips or cpus. This was sent
>     UPS.  It does look like something has messed the basic os, the
>     unit itself looks well taken care of not abused. I'm getting no
>     sounds at all as well. I'll implement your suggestions and thanks
>     for the trigger schematics, very nice!
>
>     On Dec 12, 2015 10:39 AM, "keith@...
>     <mailto:keith@...> [DTXpress]" <DTXpress@yahoogroups.com
>     <mailto:DTXpress@yahoogroups.com>> wrote:
>
>         I may have a service manual but won't be able to check until
>         Tuesday. A simple bad connection could give you the symptoms
>         you describe if it has a microprocessor with external program
>         memory - it depends on what is inside the box. If there is a
>         socketed EPROM, try removing and reinserting it. Check
>         voltages - I would guess it is 5V inside, the DTXpress is.
>
>         What diagnostic equipment do you have?
>
>         Regards
>
>         Keith
>
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