Question about XP-100 to XP-ALL Conversion/Mod

[shoegazecity]

Hello all,

I'm new to this forum, just registered for the purpose of asking this. I am going to attempt the Digitech XP-All conversion. I have received the unit, all of the required components, and am waiting for a pointy soldering tip to come in the mail (for SMD purposes).

I'm using the guide by  Govmnt_Lacky and digi2t. – 27/09/12 that was updated on 28/01/14

I have read the guide for this conversion many times, and on Page 7, it shows a gut-shot of the XP-100. I opened my xp-100 up, and there is a 75DH0FK-HC574 IC already installed on U8 on the board. The gut-shot shows nothing in place of U8 (this is where I'm supposed to install the 74HC574D IC). My question is: is this supposed to be here? do I have to unsolder the 75DH0FK-HC574 IC and solder the 74HC574D IC? or is it possible that I have to leave the existing IC in here?

Also, the gut-shot shows nothing in place of where the eprom's go (U9 on board), and my XP-100 has the XP100 eprom installed in a socket, in U9. I'm assuming this is normal, but figured I'd ask.

So to recap; shouldn't the guide instruct me to desolder the existing IC before soldering in the new one?

Any help would be greatly appreciated. Thanks

[Govmnt_Lacky]

All good news my friend!!!

You managed to get one of the few early releases of the XP-100. The early runs of this pedal utilized an external EEPROM chip for the Whammy code. To do this, they had to install the second 74HC chip. So, the good news is that the only SMD work you have to do is to remove the R30 resistor. 

- No need to install the 74HC chip
- No need to remove the 10 ohm SMD resistor (R38) and move it to R47. R47 should already be populated with the resistor and R38 should be empty.

On top of all of this.... you have a pre-loaded EEPROM chip with the XP100 code on it. On the newer models, that code resides within the CPU chip.

The rest of the build document applies. Do you have the other 3 XP pedals EEPROMs written and ready?

Happy modding!! 

[shoegazecity]

Holy hell! You just made my night! That is seriously amazing news. I'm fairly good at soldering, but this would be my first SMD project, and I'm glad I don't have to risk screwing this up! hooray for eBay!

Thanks so much for the specific answers, really glad I made an account haha.

I do have the other 3 EEPROMS, all written and labeled neatly from hobbyroms (didn't feel like spending money on the eraser/programmer, probably won't need one for a while).

Like I said, I've read this guide soooo many times, and am always impressed by the professionalism. Nick Reinhart from Tera Melos has an XP-200 converted to an XP-300 on his board, and he seems to love it, so I figured I'd give this a shot. Very excited to get started.

Again, thanks so much for the fantastic guide and the answers I needed. I'll post again if I have any trouble! 

Max

[shoegazecity]

Oh quick follow up question;

Will the stacked EEPROM's be too high to fit in the enclosure with 4 sockets/IC's instead of 3?

Other than that concern, this is a win-win-win situation.

Cheers,
Max

[Govmnt_Lacky]

Like I said, I've read this guide soooo many times, and am always impressed by the professionalism.

All of the credit for that guide goes to Digi2t. HE wrote it... I was just lucky enough to help him with pictures and being the guinea pig... 

Will the stacked EEPROM's be too high to fit in the enclosure with 4 sockets/IC's instead of 3?

They will NOT fit with all 4 chips socketed.

You will need to solder all 4 chips together WITHOUT sockets. I do it all the time. Just take your time and don't spend too much time with the hot iron on the legs of the EEPROMs. Get in... melt the solder... get out.

Don't forget the resistors between pins 20 and 28 on ALL 4 of the EEPROMs. 

[digi2t]

You managed to get one of the few early releases of the XP-100. The early runs of this pedal utilized an external EEPROM chip for the Whammy code. To do this, they had to install the second 74HC chip. So, the good news is that the only SMD work you have to do is to remove the R30 resistor. 

Would it be possible to get some good pictures of this version? It would be nice to add this to the build doc, just to cover those models.

[shoegazecity]

All of the credit for that guide goes to Digi2t. HE wrote it... I was just lucky enough to help him with pictures and being the guinea pig... 

All hail Digi2t!

They will NOT fit with all 4 chips socketed.

You will need to solder all 4 chips together WITHOUT sockets. I do it all the time. Just take your time and don't spend too much time with the hot iron on the legs of the EEPROMs. Get in... melt the solder... get out.

Don't forget the resistors between pins 20 and 28 on ALL 4 of the EEPROMs. 

Gotcha, sounds easy enough! Thanks!

Would it be possible to get some good pictures of this version? It would be nice to add this to the build doc, just to cover those models.

No problem! I'll post some now, just let me know if you need any more, or any specific photos. Also, it's my first time posting photos here so I apologize if the images come out super large.. 

Max

[shoegazecity]

Again, sorry if the sizes are huge, just download them for a better view 

[Cozybuilder]

Shoe-
You can reduce the size by doing the following:

Where the first "{img}" appears, type in a space, width= and some number, say 500, so it looks like this:

"{img width=500][/img}"

Then copy the image info between the brackets as before. Try the preview and adjust the number until its a suitable size.

[shoegazecity]

Shoe-
You can reduce the size by doing the following:

Where the first "{img}" appears, type in a space, width= and some number, say 500, so it looks like this:

"{img width=500][/img}"

Then copy the image info between the brackets as before. Try the preview and adjust the number until its a suitable size.

Thanks so much! I'm clearly new to forums, but I'll remember that for future reference. Thanks again

[shoegazecity]

Oh and last question I promise 

On page 20 of the build guide, it says to desolder holes for C61, C64, C65 (10uF), and Q63 (0.39uF).

Is it supposed to say C63 instead of Q63? My circuit board reads C63, just wanna make sure I'm reading everything accurately.

Thanks

[Govmnt_Lacky]

Is it supposed to say C63 instead of Q63? My circuit board reads C63, just wanna make sure I'm reading everything accurately.

Yep! You got it.

[shoegazecity]

Yep! You got it.

Thanks Gov'ner! I have dedicated tomorrow to attempting this mod, and have yet another couple of questions regarding the EEPROM's.

Once the sockets are soldered to the EPROM's, solder a 10K resistor between leg 20, and leg 28, on each EPROM. Use heatshrink to ensure that the resistor lead doesn't touch the other pins on the EPROM. Now solder a length of wire to leg 20 of each EPROM. Assemble the EPROM's, but do not install the EPROM stack, or socket, on the board just yet.

So since I'm soldering the EEPROM's together without sockets, should I first solder the 10K resistors to each individual EEPROM, then solder the length of wire to leg 20 of each EEPROM, and then solder all EEPROM's together? Or would it be easier to solder all EEPROM's together (stacked on top of the existing EEPROM on the PCB), and then apply the resistors/wire?

Take the socket that will be soldered to the board, and cut off pin 20. Make sure you cut this pin as flush as you can. Now, solder a length of wire into the hole on the PCB where pin 20 of the socket would normally go.

Do I still need to cut off pin 20 of the socket that's already installed? (keep in mind, there's already a socket with the XP100 EEPROM soldered to the board), and then solder the wire into the hole of the PCB?

So in a nutshell, I'm confused about the order of the EEPROM installation, because I'm not using sockets, and because of the already installed socket/XP100 EEPROM. Sorry to be a pain in the ass, but this is kind of a big deal for me! 

Thanks again!

Max

[Govmnt_Lacky]

So since I'm soldering the EEPROM's together without sockets, should I first solder the 10K resistors to each individual EEPROM, then solder the length of wire to leg 20 of each EEPROM, and then solder all EEPROM's together? Or would it be easier to solder all EEPROM's together (stacked on top of the existing EEPROM on the PCB), and then apply the resistors/wire?

Take each EEPROM and bend out leg 20. Stack the EEPROMs and solder all of the pins together EXCEPT pins 20 and 28. Attach the resistors (I use 22K) to each of the EEPROMs from leg 20 to 28 (this is also when you solder all of the pin 28s) according to the build document. Finally, attach a wire to each of the pin 20s.

Do I still need to cut off pin 20 of the socket that's already installed? (keep in mind, there's already a socket with the XP100 EEPROM soldered to the board), and then solder the wire into the hole of the PCB?

What you can do is de-solder pin 20 of the existing socket and remove it. it is a leaf-type socket so it takes a bit of work but, it can be done. Then, slip a wire into the hole and solder it to the PCB.  I recommend cutting a tiny bit of the socket edge away next to pin 20. This will give the wire room to "lay down" when you insert the EEPROM stack.

So in a nutshell, I'm confused about the order of the EEPROM installation, because I'm not using sockets, and because of the already installed socket/XP100 EEPROM. Sorry to be a pain in the ass, but this is kind of a big deal for me! 
[/quote]

No worries... that's what the community is here for! 

[shoegazecity]

Ok, so I'm at the point where the guide says to take a well deserved break (before moving onto the wiring). I think everything is going pretty well, 2 more (and hopefully final) questions about the EEPROMs.

1. Am I supposed to add a resistor to pin 20 & 28 of the XP100 EEPROM that came with the circuit? I ended up desoldering the entire U9 socket and taking it out (this made detaching pin 20 of the socket and wiring the PCB much easier). I have the other 3 EEPROMs all set with resistors in pins 20 & 28, but should I also do this with the XP100 on the bottom, or not?

2. You mentioned

Stack the EEPROMs and solder all of the pins together EXCEPT pins 20 and 28. Attach the resistors (I use 22K) to each of the EEPROMs from leg 20 to 28 (this is also when you solder all of the pin 28s)

. Does this mean that pins 28 on all EEPROMs will be soldered to each pin 28 below it? (with the resistor there also). Was the point of not soldering pin 28 at first just to make it easier to solder with the resistor in?

Thanks again

[Govmnt_Lacky]

1. Am I supposed to add a resistor to pin 20 & 28 of the XP100 EEPROM that came with the circuit? I ended up desoldering the entire U9 socket and taking it out (this made detaching pin 20 of the socket and wiring the PCB much easier). I have the other 3 EEPROMs all set with resistors in pins 20 & 28, but should I also do this with the XP100 on the bottom, or not?

You need to put a resistor between pins 20 and 28 on EVERY EEPROM! Even the chip that came with it.

2. You mentioned Stack the EEPROMs and solder all of the pins together EXCEPT pins 20 and 28. Attach the resistors (I use 22K) to each of the EEPROMs from leg 20 to 28 (this is also when you solder all of the pin 28s). Does this mean that pins 28 on all EEPROMs will be soldered to each pin 28 below it? (with the resistor there also). Was the point of not soldering pin 28 at first just to make it easier to solder with the resistor in?

Yes, eventually ALL of the pin 28s will be soldered together AND they will have 4 resistor ends soldered to them as well..... one resistor for every EEPROM with the other ends of each resistor going to each of the 4 EEPROM's pin 20s.

Basically, it should look just like the picture in the build doc EXCEPT you will only have the very bottom IC socket installed.

[shoegazecity]

You need to put a resistor between pins 20 and 28 on EVERY EEPROM! Even the chip that came with it.

Awesome, glad I asked!

Yes, eventually ALL of the pin 28s will be soldered together AND they will have 4 resistor ends soldered to them as well

That's what I thought, always good to double check. Gracias

That well deserved break is over, back to it!

[shoegazecity]

So unfortunately, the mod did not work 

Before I post photos of my work, here are a few things that I think I may have done wrong, please let me know:

1.

Before we proceed any further, we need to solder four more wires to the board.

This is the first sentence of the wiring section, and I only counted three wires (one to the left of U8, one above the 33 marking, and the ground). So am I missing a wire?

2.

You will need to desolder these holes to insert your wires. The holes are quite tiny as well, and I don't think that anything bigger than 28AWG will fit;

These holes did not need to be desoldered, they were already empty. Normal? And also, I used a chisel-tip on my soldering iron for this entire project (Hakko Iron did not come with pointed tip), so it is possible that the 33 and U8 holes are not soldered well, however, when testing the pedal, I made sure that there was continuity between the connections, and still no luck.

3. The rotary switch in the guide has numbered lugs. The rotary switch I have, (which was fairly inexpensive) has no numbers. I oriented it to match the layout of the one in the guide, but is it possible that I need to buy a higher-end rotary switch, with numbered lugs?

4. The wiring diagram in the guide says to connect the wires from pin 20 on each EEPROM to lugs 10, 11, and 12 of the rotary switch (which I did correctly, assuming I have the right rotary switch). I also soldered a length of wire from pin 20 of the XP100 EEPROM to lug 9 on the rotary switch (which in the guide is left blank), I figured I would need to do that. Right? Wrong? 

5. I did not use any heat shrink. I put electrical tape in the spots that I felt absolutely needed it, but I made sure that there were no unwanted connections. I triple checked this, so I don't think it's the issue.

6. You mentioned that you use 22K resistors for connecting EEPROM pins. I used 10K like it said to in the guide. Should I use 22K instead?

That's about all I can think of, other than screwing up soldering the EEPROM pins together. I went back and checked to make sure that all EEPROM pins were touching the correct pins, and it turned out that some were not soldered properly, so I soldered them properly, and still no luck.

Note: I am getting the clip and signal lights when i strum my guitar. When I finished this mod the first time (before I went back and checked the EEPROM pins), the display would read glitchy numbers, which were different every time I powered the unit. Sometimes it would say 7.7., other times it would just be 2  horizontal lines towards the top of the display (had no dry or wet signal). Now when I power the unit, there is no display at all, and still no dry or wet signal.

Please let me know if you can diagnose this from what I've said, otherwise, I'll post photos of my work. Thanks so much

[shoegazecity]

Correction:

I just plugged it in, and the display reads 9.9.  , still doesn't work, but just thought I'd mention it.

[shoegazecity]

And lastly, is it normal for the THM7128 Transformer (at least I think it's a transformer) to get hot? because with it plugged in for 2 minutes, it's pretty warm.