mrdelurk - 21 December 2018 05:24 AM

Well, this time we did get a nonstandard result for sure. To enter into test mode, I held the 3 buttons that the manual said.

Is “3” a typo? It should require just two buttons to enter Test Mode,
[REMOTE] and [ * ] (Record).

If that doesn’t work correctly, then there are apparently problems on the digital level. In that case I would suggest that using the S/PDIF connection until/unless you can find a “donor” XS might be the best approach.

In some rare cases, reloading the OS can resolve strange problems, but it also can lead to the Motif being “bricked” (http://www.google.com/search?q=brick+electronics). Since your XS8 currently functions with S/PDIF, I suggest that you don’t try that.

I counted the Power switch for the third button. (I didn’t hold the Power switch like Remote and Record, of course, just turned it on normally.)

One extra thing I tried yesterday was removing the 2Gig of third party RAM from the XS8 to see if Test Mode will load. It did not make any difference, so the culprit wasn’t those RAM chips.

I already upgraded the XS8 OS to 1.56 once, I think, it did not cause issues at the time. All in all, I agree, running the XS8 through SPDIF will be the best choice for now. As we don’t even know what is wrong with the XS8, I might need to find a whole broken XS8 and change all the parts one after the other. I think when this happens, the power supply might need to be changed first, that is my main suspect for irrational symptoms of this type.

mrdelurk - 21 December 2018 04:26 PM

I counted the Power switch for the third button. (I didn’t hold the Power switch like Remote and Record, of course, just turned it on normally.)

OK, thanks for clarifying that.

 

mrdelurk -

One extra thing I tried yesterday was removing the 2Gig of third party RAM from the XS8 to see if Test Mode will load. It did not make any difference, so the culprit wasn’t those RAM chips.

The mLAN board could also be removed, although not nearly as easily as with an XS6/XS7, where it’s much more readily accessible since it’s optional.

 

mrdelurk -

I already upgraded the XS8 OS to 1.56 once, I think, it did not cause issues at the time.

The last OS update for the XS was version 1.60. Properly completed updating in itself doesn’t cause problems - my own XS has been running 1.60 without difficulty. Rather, sometimes the OS memory gets corrupted, causing problems.

The concern is whether your XS8 would allow an attempt to reload the OS to succeed. Whatever is causing the current problems might also prevent a new OS installation, hence the “bricking” warning I gave.

 

mrdelurk -

All in all, I agree, running the XS8 through SPDIF will be the best choice for now. As we don’t even know what is wrong with the XS8, I might need to find a whole broken XS8 and change all the parts one after the other.

You shouldn’t need to limit your search to an XS8, other XS keyboard models could be donors. The various boards communicate with each other - for example, whether there are 61, 76, or 88 keys is automatically detected, and relevant changes are made to screen displays, etc.

 

mrdelurk -

I think when this happens, the power supply might need to be changed first, that is my main suspect for irrational symptoms of this type.

The power supply unit provides three basic outputs - +12V, -12V, and +5V. We’ve already tested for the 12 volt ones, and based on apparently normal operation of much of the XS, the 5 volt supply isn’t particularly suspect. There are numerous possible failure points, including several DC-to-DC regulators on the DM board. Taking voltage measurements can sometimes be helpful, but that won’t reveal if there’s excessive ripple on any of those supplies - an oscilloscope is what’s usually required to see that.

Good luck with your quest.

mrdelurk - 16 December 2018 02:52 AM

I see, user error, sorry about it. I repeated the measurement on IC9 with a 200V multimeter sensitivity setting. Now Pin 4 read 11V, Pin 8 read 12V, both together read 23V.

CN4: seemed like I need to unplug it to reach the pins with the probe, so I powered the XS8 off Find here sizegenetics unplugged CN4, powered the XS8 back on, and measured CN4 with the probes. Pins 3 and 6 on the footing read 0V at 200V sensitivity. Pins 3 and 6 on the incoming cable oscillated a lot before settling on 12V each at 200V sensitivity. Together they measured 24V.

Powered off XS8, replugged CN4 really well, powered XS8 back on, measured IC9 again: still only 23V for both pins. Those crafty ants inside must be stealing one Volt.

Thank you for the detail instructions, I learned a lot.