DigiTech XP100 Works Only Partially?

[Rocket Roll]

I've acquired a DigiTech XP100 Whammy Wah which works only partially: the tuner works, and the presets from 01-12 work as well, BUT NONE of the whammy / harmony presets (13-29) do not work as they should. I only hear a strong motorboating signal, a sort of digital oscillation.

Strange. Why would wah and autowah / filter settings work, but whammy and harmony settings wouldn't? Could it be the memory?

It's the model with "72-3144-21 v1.01" written on the EPROM at U9 and DV41464P-10 memory at U19, so I'm guessing its older than september 1997, judging by this schematic: http://www.experimentalistsanonymous.com/diy/Schematics/Vibrato%20and%20Pitch%20Shift/Digitech%20XP100.pdf

Any thoughts on this would be greatly appreciated!

[Rocket Roll]

I was able to find a Korean made HY53C464S-10 D-RAM chip and all the presets now work as they should.

Thanks once again to Dirk Hendrik - his hypothesis was that "the pitch shifter patches use more memory than the wah's. If an adress line fails that would explain what you hear exactly since samples would be written to and read from an incorrect address." Seems like it's verified now.

[Taylor]

I don't have one of these units, but thanks for posting the resolution - it will be helpful for future searchers I'm sure.

[Rocket Roll]

It's essential to post the resolution - I cannot remember how many times have I googled up a thread that describes the problem I'm interested in and just ends there, without a solution of any kind. So, you're welcome 

[MOfoSlayer]

My friend has the same version XP-100 with the EPROM as Rocket Roll and it's having the same problem. Wah's are good, whammy's make a clicking noise but some of them you can kinda hear the guitar and a resemblance of the effect through. He's probably gonna try to get some RAM chips soon and see if that'll fix it. Thanks for making the thread Rocket Roll.

[digi2t]

Have you tried doing a hard reset? When doing XP-ALL conversions, there are sometimes glitches that occur in some patches. A hard reset usually set everything right. From the XP-100 user manual;

Factory Reset/Pedal Calibrate - To reset the User programs to their factory settings and calibrate the
expression pedal, press and hold the <BYPASS/(Hold)TUNER> foot switch and apply power to the unit.
Wait until the letters rS appear in the display and release the foot switch. The display will now show: Pd
and  CA , indicating that you are in pedal calibrate mode  Once  Pb appears, rock the pedal back and
press the <BYPASS> foot switch. When PF appears, rock the pedal forward and press the <BYPASS> foot
switch.
SA will next appear in the display to confirm the pedal is now calibrated.

Try that, and let us know what happens.

[MOfoSlayer]

Oh it hasn't been modded yet. I meant it was a model that had an EPROM stock. Resetting it didn't help but my friend got his order of chips yesterday and I'm told replacing the old RAM chip fixed it.

[vitaobass]

Rocket Roll!!! Thank u soooooooooo much!!
I almost throw away my xp-100, but when i found this this topic my hope for fixing my pedal just comeback!
I only founded the HY53C464S-10 on AliExpress and USA stores, but i live in Brazil, then i discovered in this forum  that we can use a HM50464P-12 from Hitachi as well.
I founded one... and now its working beautifully!!!!

thanks for this forum and you, again!!!