thoughts on Digitech Space Station eprom copying?

[digi2t]

I just got the new chip in the mail, and it is with great regret for myself that I have to say, no change. 1 is stil XP100, 2 is nothing, 3 is XP200 and 4 is XP400.
But then again at least we can cross that out now and I can try to find something else as the culprit.

Well.... that's good.... in a way. I guess. Maybe.

It's as if it's a wiring problem, related to the switching logic. Bizarre.

[Mojsisije]

Exactly where my thoughts went, seeing as the program code for the XP200 and XP300 are inverted, and one requires 1 1 0 to the pins and the other 0 0 1, there might be something to it. I'll look into it when I get the time. Also I think I've scored an XP100 locally so I'll see what I can do with that one, as I now have extra chips.

[marmaliser]

Good news in a way, at least I know my chips / programming and adapter board are good.

Agree it is somewhere in the switching / logic.   

Look forward to your findings  Moj...   and digi2t thanks for the continued input 

[mongo]

  Hello everybody,

At last, I finished reading the whole thread, I'm starting to gear up to perform the mod, I have some questions (and I'm sure I'll have more when all the pars arrive)

Could I replace the tantalums with electros?

Are these just "preset" machines? could there be a way to manipulate parameters or to create some more "presets", say for the XP300?

Incredible work everybody, thank you!

Mongo

[digi2t]

Could I replace the tantalums with electros?

This question has come up before, and I believe that you should stick with Tantalums. They're stability, and longevity, are desirable traits where your precious RAM is concerned.

Are these just "preset" machines? could there be a way to manipulate parameters or to create some more "presets", say for the XP300?

Way above my pay grade. Sorry, no idea.

[Mojsisije]

Are these just "preset" machines? could there be a way to manipulate parameters or to create some more "presets", say for the XP300?

Absolutely. But, to do so, you'd have to look at the .bin file for the desired model, figure out where the individual programs start, how they affect the signal, what parameters do they use, and much more. However, all we have from the factory compiled .bin files is a bunch of hex data, which to a third party, is literally gibberish. Should we somehow get some specification as to what does what, for example, the value "FF" on the address line "&AAEEDD00" states the volume, then we could go somewhere. However, since I don't see it happening anytime soon, we could safely say that we'll just stick to the presets at hand.

[Govmnt_Lacky]

Absolutely. But, to do so, you'd have to look at the .bin file for the desired model, figure out where the individual programs start, how they affect the signal, what parameters do they use, and much more. However, all we have from the factory compiled .bin files is a bunch of hex data, which to a third party, is literally gibberish. Should we somehow get some specification as to what does what, for example, the value "FF" on the address line "&AAEEDD00" states the volume, then we could go somewhere. However, since I don't see it happening anytime soon, we could safely say that we'll just stick to the presets at hand.

In other words..... We would need the source code. That... you are most likely NOT going to be getting from Digitech/Harman.

Or... you could find yourself a software and coding guru who can nerd out and spend countless hours trying to reverse engineer the coding.

Either way.... I think you are stuck with what we have for presets 

As for the Tantalums... I second what digi2t says.... why fix something that isn't broke? 

[mongo]

Thanks for your replies guys!

I undersand the difficulty of what I asked, I just thought it would be cool to come up with our own contraptions!

[drm0120]

Hi all,

I could modify my XP200 to XP300 with this thread!!
Thanks a lot !

from japan

[digi2t]

Hi all,

I could modify my XP200 to XP300 with this thread!!
Thanks a lot !

from japan

Hi, welcome to the forum.

Glad we could help.

From Canada.

[mwynwood]

Hi guys,
Help! I'm having some trouble.
It doesn't matter what the switch is doing, it's always an XP-100!
Have I missed something?

In addition to missing the SMD chip that digi2t stated, you also have a wiring problem. It will be addressed in the build documents but I will explain.

It has to do with there your RED wire is going. I know that digi2t wired his conversion this way however, it leads to problems once you want to use the stereo output jack.

To fix the problem, you will need to desolder your red wire from where it is on the PCB and solder it DIRECTLY TO THE SLEEVE TAB ON J2 (right output jack)

Trust me 

I have done several of these conversions and it will not work correctly the way you currently have it wired.

I'm sure digi2t will back me up on this one 

Hmmm... I just soldered in a 74HC574, and moved the red wire to the sleeve of the "dry out" jack (which is ground) and it is still not working
It's driving me mad haha 

[mwynwood]

Here's where I'm at:

[Govmnt_Lacky]

Here's where I'm at:

Look next to the BLUE wire on the PCB..... did we forget to remove the SMD 10 ohm resistor (R38)?? 

This resistor HAS TO be removed in order to allow the CPU chip to go LO when in XP300 mode. Otherwise, even when you switch the DPDT toggle, the CPU chip will be held in a HI state.

I cannot tell 100% from the picture but, it looks to me like R38 is still installed. That needs to go 

Since you forgot to remove that SMD resistor, you might want to check if you remembered to remove R30 as well. It is located directly behind the Input jack (WA1) on the PCB. If this is not removed, you will not get the stereo output in XP300 mode (you also lose the Dry Out when in XP100 mode.... its a sacrifice you make when modding to another pedal)

Also..... If I were you, I would NOT use the audio jack for the DPDT toggle ground. I have recently made changes to my own builds as I found this to be an unrelaible place to solder (the solder joint can become weak as the contact flexes when jacks are inserted/removed)

I would advise that you solder your RED wire to the GND side of C59 (the green chicklet cap next to the power in jack) MAKE SURE YOU SOLDER IT TO THE LEG CLOSEST TO THE POWER JACK!!!

[mwynwood]

Thanks so much for your help - this project has been driving me crazy for ages haha *feeling stupid* 
I haven't removed R30 yet, as I don't really care about the stereo-out or the dry-out.

Anyway, I removed R38.
Now, it loads up fine as an XP100, but when I power down, switch the switch and power up again, I get nothing at all.

[digi2t]

Bad U8 (74HC574)? 

[Govmnt_Lacky]

I agree with Dino.

Do you have the XP100 schematic? It can be found easily online. The U8 chip pins connect "mostly" to the XP300 EPROM. You should check your SMD soldering. It is easy to have them look like they are connected. 

[mwynwood]

You should check your SMD soldering. It is easy to have them look like they are connected. 

IT WORKS!

One of the legs of the 74HC574 wasn't connected!!
Thanks so much for all your help guys!

[Govmnt_Lacky]

Awesome!!!

I always check that chip to make sure ALL legs are making contact. Its habit now 

Enjoy.... and we will see you back here when you want to do the Output Volume mod. YES... you WILL want it... just wait! 

[digi2t]

+1 on the output volume mod. Realy helps it play better in an effects chain.

[mwynwood]

we will see you back here when you want to do the Output Volume mod. YES... you WILL want it... just wait! 

haha one step ahead! Already done:


I think that's the mod you guys are talking about?
It's a dual-gang pot to turn the output down.
(PS: This photo is old, before I got it fully working)

Thanks so much for your help Govmnt_Lacky and digi2t!