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The Stec Records Forum  |  Audio Gear  |  MPX G2  |  Post Battery Change Startup Problem « previous next »
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Author Topic: Post Battery Change Startup Problem  (Read 1780 times)
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« Reply #4 on: May 23, 2016, 12:31:07 PM »

Hello, everyone.  An update on my issue.  As referenced in my previous message, I gave Advanced Musical Electronics a go to see if they would be able to determine if I had done some damage to the unit that I didn't have the sophistication to divine.  I enclosed a note detailing my effort to replace the board batter and requested the inspection begin there to eliminate the possibility that I may have made a bad solder joint, damaged the board in that region, etc.  This is a request I reiterated each time I contacted AME and was assured it was being considered.  In the end, I was told that there was no way to repair the unit that would be cost effective.  I paid the return shipping.  When I got it back, I opened the case and saw no change to the battery I had installed.  Figuring I had nothing to lose, I removed the old (new) battery and checked it's voltage which came in at a bit less than 2.9v.  I had a spare battery that checked in at something like 3.28v.  In the battery storage area of the board, there appeared to be a secondary location for installing a replacement battery with closer pin spacing.  I carefully bent the pins of the new battery to match and installed it in the board.  It started up and allowed me to run all of the user diagnostic tests, re-initialize the system as laid out in the user's manual, and has since behaved as if it were a new unit.  The last test I will be performing today is ensuring I can store a user preset and have it retained after power-down.

The only negative in the deal is that, thinking I was not going to have a usable G2, I now own an eventide H9 Max, and EH Cathedral.  (SCORE - More is better!!)  I'm hoping they all play well, together.  More options than I'll be able to control well, probably, but I'll go down swinging.

Ed
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« Reply #3 on: February 14, 2016, 01:21:52 PM »

Bob,

Thanks for the reply.   As usual, fantastic that you take the time to show where the breadcrumb trail may be for us.  Sorry it has taken a while to get back to you, knee deep at work, and likely won't have much time to give to the effort till mid-spring.

No scope here, so I may be reaching the limit of what I should try.  I do wonder, though, if it may be possible to desolder the battery I installed and use what looks to be a secondary location for joining a battery with closer pin spacing  to the board. 

Failing that, Lexicon customer service recommended Advanced Musical Electronics in LA as a potential repair shop that would have expertise/access to necessary resources to make a repair, if feasible.  If they're familiar to you, any opinions on their work?

Thanks again,

Ed
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« Reply #2 on: January 26, 2016, 11:39:17 AM »

Hi Ed,
By "the MIDI position of the main screen" I suspect you are referring to the program number display but the fact that the word Lexicon appears on the display indicates that the device is at least partially booting up. Power up test 2 is a checksum test for the flash (ROM) chip but on my system the word "Lexicon" appears after 2 is displayed for a while so I'm thinking it's the next test that is failing and that is the SRAM test; the part that the battery is connected to.

While it's possible that something got damaged with static, it's pretty rare and much more likely that it is a physical problem. If the device was booting up before you changed the battery, it's most likely that some stray solder is shorting a couple of pins somewhere or that an etch on the board got damaged. The good news is that it's likely in the area you were working and visible with the naked eye. I'd start by doing a close inspection under a bright light.  The only other thing I can think of that might be causing trouble is if you put to much solder into the holes and they are shorting out on the bottom of the board.  I know it's a huge pain in the ass to get at the bottom of the board so start with the top first.

Another thing you could try before pulling the board out is to check for shorts between the address lines and data lines on the SRAM since that is the test that is failing. If you have a scope, you can just probe each of these lines and look for data. Sometimes the lack of activity on a particular pin can indicate a problem. The data should go cleanly from hi to low but if two address or data lines are shorted you'll see activity in the middle.

This page has additional information on the diagnostics: http://www.stecrecords.com/?RecordId=378

The service manual is here: http://www.stecrecords.com/gear/mpxg2/doc/mpxg2_service_manual.pdf
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« Reply #1 on: January 13, 2016, 09:09:29 PM »

Hi, Bob.  I've attempted to replace the board battery, which was simple enough. Didn't encounter any problems during the removal or installation, but have hit a snag on power up.  Hoping I can get oriented on a next step to try.

Following replacing the board battery, I attempted to restart the G2.  My results are the Load and Clip lights illuminate along with 888 on the main screen.  This is followed by 1 and 2 on the MIDI position of the main screen and lexicon in the preset title portion of the main screen.  It freezes in this position and does not progress.  I have attempted to start up in the forced diagnostics mode and there is no change in the result. 

Thanks,

Ed
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The Stec Records Forum  |  Audio Gear  |  MPX G2  |  Post Battery Change Startup Problem « previous next »
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