thoughts on Digitech Space Station eprom copying?

[mitchschaft]

I'm having problems deciphering the Alpha switch. And I think it's because the numbering on mine doesn't match your switch. I don't see a pic of the numbering on the bottom of your switch to compare it to.



For instance, the switch schematic says to hook the orange stereo relay wire to lug 7, deck 2.



But, your picture in the build doc shows the orange stereo relay wire connecting to lug 1 of deck 1. Atleast compared to how my switch is numbered on the back. Another example, the schematic says to hook the LED's up to 13, 14, 16 and 17. But, what you have your LED's hooked up to in the pic match my switch's 7, 8, 10, 11 lugs.



If I'm not mistaken, did you switch deck 1 and deck 2 in this pic compared to the schematic?



Or maybe I'm just confused  .

[digi2t]

Hi all,

Just bought an xp100, and I'm considering to mod it to XP300. I don't have a Programmer... Could someone of you sell me a programmed eprom? I live in Europe but I will pay for the chip, time consumed and shipping costs. Thanks!

PM me. I'll set you up.

[digi2t]

I'm having problems deciphering the Alpha switch. And I think it's because the numbering on mine doesn't match your switch. I don't see a pic of the numbering on the bottom of your switch to compare it to.



For instance, the switch schematic says to hook the orange stereo relay wire to lug 7, deck 2.



But, your picture in the build doc shows the orange stereo relay wire connecting to lug 1 of deck 1. Atleast compared to how my switch is numbered on the back. Another example, the schematic says to hook the LED's up to 13, 14, 16 and 17. But, what you have your LED's hooked up to in the pic match my switch's 7, 8, 10, 11 lugs.



If I'm not mistaken, did you switch deck 1 and deck 2 in this pic compared to the schematic?



Or maybe I'm just confused  .

Firstly, the diagram you're using is not the correct one. You are using and older version of the build document. Please download the correct version from here; http://www.aronnelson.com/gallery/main.php/v/digi2t/Information/XP-ALL/

As for the switch poles, the diagram is simply a guide. If you look closely, what you have is two 3P4T switches, sandwiched together. Looking at ONE DECK, poles 6, 12, and 18, are the commons for three groups of contact poles. At the end of the day, it really doesn't matter which GROUP of contacts you use to do the switching. For example;  in the diagram, I show the LED's using contacts 13, 14, 16, 17, and 18 as the COMMON. You can just as easily use 7, 8, 10, 11, and COMMON 12 for the LED's, and use the other group for the relay.

At the end of the day, look at it as a group of rotary switches, with the common poles moving all together when you twist the knob. As long as you commons, and poles, are wired correctly, it shouldn't matter which group you us for what purpose.

[mitchschaft]

Ok, I'll check that out. Just an FYI, I've been using the latest version of the build doc. That's the pic that is in it.

[digi2t]

Ok, I'll check that out. Just an FYI, I've been using the latest version of the build doc. That's the pic that is in it.

That picture is not from the correct version. Please follow this link, and scroll to page 56 of the build doc; http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=51931

Note that A15 and A16 order are reversed, contrary to the picture you posted.

Here is the link for the first half of the build doc;
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=51928

The latest doc was published on 10 September, 2015, and is dated as such.

[mitchschaft]

I see. I just took that pic out of your photo album. But the one I use is from the latest doc. Oops.

[digi2t]

I see. I just took that pic out of your photo album. But the one I use is from the latest doc. Oops.

OK, thanks for the info. I'll have to delete that picture.

[mitchschaft]

Alright, I'm back  . I sorted out the 6P4T Alps switch issue. It was easier than I was thinking...

I completed the XPALL+ project a couple hours ago. Everything except the LED's since I'm waiting for them to arrive.

I ran into a problem when I powered it up. The display was a garbled mess and nothing worked. Turned out to be a leg on the U8 chip wasn't connected. After I fixed that, everything powered up and looked great.

I did a factory reset, ran through all the programs without plugging into an amp. Everything displayed and switched properly through all of the presets on all 4 programs.

I plugged in and started in XP100 mode. Bypass works. Checked out the volume mod and that works fine. All of the wah presets work like normal. But, as soon as I hit the whammy settings the sound is just a mess. Loud, jumbled noise. It's almost the same with the  200, 300 and 400 programs. Some of them are silent, some are clean with no effect coming through and some of them are a loud racket.

I tried a factory reset a few more times. I tried removing the 3 newly installed ram chips leaving only the original. I hope it's bad ram, but the original ram in XP100 mode is there and none of the whammy presets work so I'm not sure.

I ordered a 5 piece set of ram some months back and he still has them for sale: http://www.ebay.com/itm/5-pcs-UPD41464C-10-DRAM-65536-4-Bit-100ns-Memory-D41464-41464C-10-NMOS-NEC-NEW-/130891206445

I tried swapping all 5 around in the 3 slots, but left the original alone in the 1st slot.  If you think it's bad ram, I'll try to order some more from somebody else.  I reflowed solder on the newly installed ram slots and checked continuity. Maybe I have the ground coming off of the adapter board going to the wrong place. Do I have the R30 leads in the right place? Yellow on the left most pad to the adapter board.

The only thing I haven't tried is reprogramming the 27C1001 chip.





















I scratched the hell out of it during this build and accidentally rubbed some alcohol below the switch lol.

[caleb.oaks]

I just tried to do a straight XP100 to XP300 mod, including a switch to go back and forth between the two. I also added the output mod. The parts I used were a programmed eprom, 3 extra ram chips, the 3 tantalum caps, a 100r resistor on the switch after taking out r38, and the smd chip for U8.

Once I finished rigging all that up, I went to test it, and while the whammy side still worked, when I unplugged and switched to the Space Station side, as soon as I hit the strings I got horrible white noise over top of my signal. I could definitely hear some signal coming through underneath the noise, and as far as i could tell, it had the correct effect on it. The output control seemed to work fine. That's when the really stupid decisions began...

Not knowing much about how this thing worked, I tried to take off the SMD chip to try a different one in its place--big mistake. In the process of taking it off, I totally destroyed 3 or 4 of the solder pads on the board. I could clearly see a couple of the pads going to little through hole points, so I tried to jumper those points to their respective chip legs, but not all of them have obvious through hole pads that I can use. Now, the whammy side still works fine, but when I switch to the Space Station it won't even power up!

I suppose the help that I need would be to direct me to alternative points on the board that I can jumper the SMD legs to. I looked at the schematic, but I don't trust my schematic reading skills.

I believe that the problem legs are 14, 15, and 17.

[Govmnt_Lacky]

@caleb

First of all, if you are still getting some sort of "proper program" signal under the white noise, then this tells me that your EEPROM is programmed correctly AND the U8 chip was soldered correctly.

My #1 suspect in this situation would be the RAM chips. Specifically, U16, U17, or U18. Try swapping these 3 RAM chips (one at a time) into U19 while in Whammy/Wah mode. See if one of them will cause your Whammy/Wah to act the same way. Even if they don't, they could still be causing the issue though.

As for the busted traces on the U8 chip, you might be in luck. From U8, those three traces each go to the EEPROM chip U9.

U8 Pin 14 ---> U9 Pin 5
U8 Pin 15 ---> U9 Pin 6
U8 Pin 16 ---> U9 Pin 7
U8 Pin 17 ---> U9 Pin 8

Good Luck with the fixes.

[MüThing]

Just snagged that XP400 off eBay, I dunno if I wanna burn the chips myself or see if one of you guys might be willing to send me a couple.

If anyone from the UK wants to send me some xp1/2/300 chips I'm willing to give you a good deal.

[mitchschaft]

Well, the problem with mine isn't ram since I just got more in from Jameco. I guess it's a solder/trace issue or a bad SMD chip.

[mitchschaft]

I fixed mine and it's working 100%. I found a solder bridge on ram slot 3 and also reprogrammed the 27C1001 just incase.

Well, it's not 100%. Sometimes I have to power it on/off after switching between the 100 and any other ones on the occasion when there is no sound after making the switch. I wonder if the relay is bad.

[MüThing]

Is it normal for all the RAM sockets to be populated even when not all four are being used.

[Govmnt_Lacky]

Is it normal for all the RAM sockets to be populated even when not all four are being used.

XP100s and 200s only use 1 RAM chip (U19)
XP400s used three of them (U17, U18, and U19)
XP300s used all four

I have never seen any 100s or 200s with more than 1 chip. Never seen a 400 with more than 3 chips.

[MüThing]

Sorry, I didn't really articulate that too well. What I mean is is it normal for the pedals to have sockets installed even if the pedal isn't using them? My XP400 has 4 ram sockets soldered in but as you said it only uses three of them.

[Govmnt_Lacky]

Sorry, I didn't really articulate that too well. What I mean is is it normal for the pedals to have sockets installed even if the pedal isn't using them? My XP400 has 4 ram sockets soldered in but as you said it only uses three of them.

Never seen that  Although, its not out of the realm of possibility.

Might want to take a good look at it to make sure it wasn't a resale of a mod gone wrong 

[MüThing]

I don't think I can get the board out to take a proper look without desoldering the LED board which I don't feel like doing right now.

From what I can see though the extra slot is put in pretty cleanly, it has all the pins sticking out on the back of the board like the rest of them. It's missing the third tant capacitor but I'm not sure how important that is to make everything work.

I also took a look at the EPROM and jotted down the text on the label in case it might be important:

XP400   V1.00
72-3144-19V1.00
CS:7588

[Govmnt_Lacky]

Probably just a mistake at the factory when they assembled the PCB. As long as the pedal functions as an XP400... nothing to worry about then. 

[MüThing]

Marmaliser hooked me up with a set of each chip and an extra ram chip just recently, if anyone else needs one or a 27C1001 he's your best bet if you're in europe. Thanks again, man! My 400's a 300 for now.