Xpantastic!

Hi Tony,

Don't Fret, we will try to get him happy again. I have been helping 
Phillip (member) off post with almost the same problems. If you  
want to keep these long threads off the group feel free to send 
direct emails. 

OK, First off, the power supply has several outputs: A set for the 
digital and display. And a analog set. So in theory the PS could be 
causing the problems. You can check these with a voltmeter easy 
enough. But a scope would be needeed to check ripple. BTW if you do
not have a 60 Hz-buzz on the audio output then the power supply is 
probobly not the issue.

Out of tune Points to the DAC, pray it's is not failed because it's 
even harder to find than the CEMs. 
Can you tell if the filter still sweeps well? Or - Turn off the VCO 
waves and turn the resonace all the way up,and the cutoff all the way 
down, Mod by keyboard to see if you can play the filter like a voice. 
Once we know if it's the DAC or 
not we can go from there.

Note: These guys are getting 20+ years old, this points to Bad Caps 
and old bad solder joints. It can probobly be fixed with more love 
than 
money.

Keep Me Posted

Karl  


 
--- In xpantastic@yahoogroups.com, "Tony Cappellini" <cappy2112@...> 
wrote:
>
> It looks like I won't need to do an A/B comparison with Jeremy's 
wave file,
> I can easily hear now that my Xpander is not working well.
> 
> Prior to this and the reason I had posted a message looking for 
someone
> local to the SF Bay Area was that only on 1 patch did my Xpander 
sound very
> bad.
> 
> I had found one voice which was flaky, so I turned it off.
> 
> Recently, I happen to hit several keys at once and could hear the 
vcos being
> grossly out of tune.
> 
> After trying to tune everything, I get FAIL across the board.
> 
> In the past, when I would see FAIL after running autotune, I would 
wait 30
> min, run it again and all tests would pass. This is not the case 
now.
> 
> 
> Fortunately, I've got a few spare CEMs which I hope are all 
working, that I
> can use to troubleshoot with.
> 
> I haven't looked at the service manual in years- I hope there are 
some
> measurements I can make with a voltmeter to give me some ideas.
> 
> I can probably borrow a scope to check for ripple on the output of 
the PS
> but don't really know how much ripple would be excessive for the XP 
PS.
> 
> All other front panel functions & midi appear to be working 
normally, so
> it's probably not likely to be a PS issue.
>