thoughts on Digitech Space Station eprom copying?

[digi2t]

FWIW, I've done a comparison of the XP-ALL bin file you emailed me, and the one I have used / published, and they match.

Problem is elsewhere. 

[Mojsisije]

It would seem then that the previous owner installed the last one. I bought it used with a missing bypass switch PCB and main EPROM, but I was going to replace that anyway. And a few missing components that were since populated.
But the XP400 doesn't even work now, it only passes dry signal, whereas the other modes don't even do that. Unfortunately my phone's in the shop so I can't take any pictures right now, but nothing seems out of the ordinary so far. I'm more concerned with the EPROM chip than the RAMs, I can get them locally, albeit for a bigger price, but why NOTHING works now is baffling me.

The one I emailed is not the one marmaliser flashed onto the chip, I've only sent him this one when I discovered the same problem he had. Since the only components we shared in our builds are the EPROM and a single 0,39uF cap, I strongly believe it's the EPROM's fault. I'd like to at least try a different chip, but I don't want to spend $100+ on equipment that I'd only use for one or two builds. I might make my own EPROM programmer if I get the time, but right now I'm trying to get it to do at least something.

Thank you all for your continued support and help!

**EDIT**

Ok, so a factory reset made everything back to how it was before, so, position 1 is XP100, pos 2 nothing, pos 3 XP300, and pos 4 XP400, and I forgot to mention, patch 48 on the XP400 mode resets the device and makes it boot to patch 44 on occasion. So I'm thinking it IS in fact the EPROM's fault. So I'm still looking for a proved working version of it.

[Govmnt_Lacky]

OK... lets think about this logically and dangerously!  

- Is there any way that you can put the XP back to its original configuration? Can you install an original EPROM chip with the XP400 coding on it for testing?

- If you are indeed missing the Bypass/Effect PCB, then something you could try is to QUICKLY short the pads where the switch connects to the PCB. Does the pedal say "BP" on the display? I am thinking that since the switch is missing that your pedal is stuck in bypass mode. If you QUICKLY short the two pads while the unit is powered then you might be able to switch it into effect mode and that might solve your dry out issue. But again, this is ONLY if the display is reading "BP"

- If the pedal does NOT say BP and it shows a program number in the display then your problem(s) are elsewhere.

EDIT: I would HIGHLY suggest posting up some pics when you can of the entire PCB.

EDIT2: OK... look like you should focus on getting the Bypass switch replaced. I recommend that you do that before proceeding 

[Mojsisije]

It's something the fake RAMs did to the pedal, a factory reset got it back to original specs. I've wired a momentary pushbutton to the footswitch button's original place so that's of no concern to me, and I've crafted a replacement footswitch board that wors just fine as well.
Like I said, it worked fine before, I can distinguish the bypass mode from when it's on, and that's the first thing I tried. This isn't my first pedal modification 

But thanks for the swift and detailed replies. Now all that's left for me is to get a working EPROM, or buy/make a programmer.

[Govmnt_Lacky]

PM'd Moj...

[digi2t]

Ok, so a factory reset made everything back to how it was before, so, position 1 is XP100, pos 2 nothing, pos 3 XP300, and pos 4 XP400, and I forgot to mention, patch 48 on the XP400 mode resets the device and makes it boot to patch 44 on occasion. So I'm thinking it IS in fact the EPROM's fault. So I'm still looking for a proved working version of it.

WT...!! 

Calling up a patch number, sends it into reboot?

Something is rotten in the state of Denmark.

Seeing as how (to date) I'm the only one with a working + version, burning and testing a chip here, and sending it to you is a tempting proposition. Just so we can put all this EPROM squawk behind us. 

[Mojsisije]

If it can be done for around $20, you may just have yourself a deal

[marmaliser]

Hey guys,  I really hope that this is something I am doing wrong with the Eprom because we can at least sort it and I can give Mos a new Chip no probs

I have the TOP853 and using Version 6.13 on Windows XP (have to fire up an old pc everytime)(have tried on two diff PC's)
I choose the Eprom in my case TI27C010  then do a read to check it is all blank.  Screen shows all FF
Then load the bin file with odefault options so - BIN,  Normal ,  Fill by FF , Buffer start 00000
All i do then is do a burn and verify. 

Is there anything else I should change / check

I have also tried with an STI27C001 with same results

Just made a new ALL bin with the files in reverse and I get XP100, XP200, XP100 and XP100 as I turn the switch

[Govmnt_Lacky]

@marmaliser

Does your GUI program for the burner have a comparative function? If it does, you should install one of your freshly loaded chips into the burner. Then, download digi2t's program from the gallery (.BIN) and set it as the loader file in the GUI. Then, do a comparison of the loaded gallery .BIN file to the file that is on your chip.

If there are any errors in the comparison then that is your issue.

This.. OR... you could just download the VERIFIED file from the gallery and use it. If you are still having problems then it might have something to do with your programmer's setup in the GUI

[marmaliser]

Done loads of verify's and file comparisons...As an IT Professional this is the only part that I truly understand.  The rest is just paint by numbers with a little learning thrown in.

[Mojsisije]

Well so far I've hardwired it to the XP100 mode and just made the true bypass part so I have a usable replacement for my whammy, I'll continue with the arduino-controlled switching once I get the rest of the modes working.

Thanks for this awesome project! I'll post some pics once I get my phone back from the shop.

[Michael Allen]

Having some issues maybe you can help with.

I am converting my second XP100 to an XP100/300. The first worked well, using memory from Jameco, 100nS and EPROM flashed by digit.

The second I have working in XP100 mode and technically working in 300 mode but it sounds disfunctional. The effect sound is very digitally distorted/degraded and does not clear when it should. For example, playing a note will play whatever program is loaded and will mostly decay but some trail and about a half second of sound will loop indefinitely and never clear.

I have swapped out the memory from my other working unit as well as the XP300 EPROM, and the unit still doesn't function. Worth noting that on volume pedal program the unit does work fine. To me this probably means a memory issue since the volume unit doesn't use the extra RAM. Any suggestions apart from the obvious resoldering all sockets and added parts? I did at the second hc574, but have resoldered it as well.

Out of ideas here since I don't know how the memory stuff works.

thanks,

[digi2t]

Having some issues maybe you can help with.

I am converting my second XP100 to an XP100/300. The first worked well, using memory from Jameco, 100nS and EPROM flashed by digit.

The second I have working in XP100 mode and technically working in 300 mode but it sounds disfunctional. The effect sound is very digitally distorted/degraded and does not clear when it should. For example, playing a note will play whatever program is loaded and will mostly decay but some trail and about a half second of sound will loop indefinitely and never clear.

I have swapped out the memory from my other working unit as well as the XP300 EPROM, and the unit still doesn't function. Worth noting that on volume pedal program the unit does work fine. To me this probably means a memory issue since the volume unit doesn't use the extra RAM. Any suggestions apart from the obvious resoldering all sockets and added parts? I did at the second hc574, but have resoldered it as well.

Out of ideas here since I don't know how the memory stuff works.

thanks,

OK, just so I'm on track here,

1) Have you have tested the second EPROM in the first working unit, rather than vice versa? Just to be sure that the second EPROM is OK.

2) Might it be that the 74HC574 you soldered in has been damaged (too much heat on a leg(s), for instance)?

[Michael Allen]

Yes, the two EPROMS both work in the first unit. They are good. I have more 74hc574 so I may just try to swap that out and see.

I emailed digitech support and they replied

"Michael,

Check DRAMS(u16-u19), and/or TMS chip(u15).

Regards,

Digitech Support"

Pretty helpful..... I asked if they had service document or ways I could test for issues. They didn't give me much more than I already knew. All RAM are getting 5v, I don't know what else to look for voltage wise.

[digi2t]

OK. It's a good thing that you have a working unit to A/B with.

Start with double checking that all your RAM is good (U16 - U19), swapping, and testing, all between the two units. Do a pin conductivity test on each pin, of all RAMS.

Change out the HC574 if the RAM test checks out. Once it's replaced, do a pin conductivity test on all pins.

Do the above, and then we'll maybe consider U15. I find that one a bit of a stretch.

[Govmnt_Lacky]

If it works in XP100 mode just fine and you are getting distortion and/or missing patches in XP300 mode then my bet is that the problem is with your RAM chips. Specifically, U16-U18. 

[Michael Allen]

Got it, there was some bridging between the pins of the TMS chip where the second RAM is connected. Must have been there all along but never caused a problem with only one RAM chip.

[marmaliser]

That's great news and something for future modders to look out for.  And what the hell is the chance of two people with the same name posting on this thread.  For one minute i thought i had created another account or been hacked

All the best
Mick A

[digi2t]

Got it, there was some bridging between the pins of the TMS chip where the second RAM is connected. Must have been there all along but never caused a problem with only one RAM chip.

HOLY SHIT BATMAN!!

And the TMS was last on my list of things to check. Goes to show... the more you learn, the more you realize how little you know.

OK... that's a new one. Good catch.... no, check that.... GREAT catch! I guess you got a "Friday afternoon" production unit. The QC dept. must have gone home for the long weekend.

[Mojsisije]

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.