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DIY Stompboxes => Digital & DSP => Topic started by: MüThing on March 29, 2017, 07:42:36 PM

Title: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 29, 2017, 07:42:36 PM
Hey there everyone,

I purchased a used Whammy mk.1 (Rev J board) from eBay, the seller was selling it for a crazy low price because they cannibalised it for the EPROM chips; namely U10, U11 and U22 or 23 (I can't find the actual chip number until I actually receive the whammy, it is the large labelled EPROM just below the rotary switch).

I was hoping someone may know what types of chips I would need to replace them as the chips are covered with labels in every photo I can find, as well as possibly knowing where I can find a copy of the ROMs for each of them (similar to how the old XP300 ROM was made available). I have a feeling those may not be around for people to download however, I hope it doesn't come down to it but maybe some intrepid user has a WH-1 of their own they're willing to take a look at.

If anyone has any info they can spare about any of this I'll greatly appreciate it, I'm not sure what I'll do with the pedal once I get it in working order but I'll be sure to keep anyone interested up to speed!
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 29, 2017, 08:06:10 PM
Seems like I've found an example for U11, and more than likely for U10. A peeling label shows the letters "N825147AN" but looking that string up on Google only brings up datasheet websites that lead to 404s, and two single Alibaba listings for what seem to be the wrong chip. It might be worth finding whatever I can and seeing whether some kind of equivalent can be found.

Thanks to Govmnt_Lacky for finding the photo, now to find out what U22 is:

Could it be that the connections from the encoder to the PCB are wrong? Do you have any pre and post pictures of the encoder in the circuit?

Couple pictures I found of the encoder.

(http://i771.photobucket.com/albums/xx358/mixervw/whammy1verg.jpg)

It looks like part of the encoder on one of the versions was "wired" and the wires were twisted.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 29, 2017, 08:12:55 PM
Derp! That 5 was actually an S (making it N82S147AN), I was sort of close though.


Looks like it's some kind of TTL PROM, the old kind that would be programmed by blowing out nichrome fuses to represent binary data. Doesn't look like the kind of thing I can do myself with one of those cheap TL866 units.

http://pdf1.alldatasheet.com/datasheet-pdf/view/115308/PHILIPS/N82S147AN.html
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: EBK on March 30, 2017, 09:23:50 AM
they cannibalised it for the EPROM chips
What an incredibly odd thing to do!
Did they take the EPROMs out to reverse engineer the pedal for Chinese knockoffs?
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 30, 2017, 12:07:47 PM
What an incredibly odd thing to do!
Did they take the EPROMs out to reverse engineer the pedal for Chinese knockoffs?

Doesn't seem like it, they said they picked it up to raid it for the chips but for what purpose I have no idea. Plus if they were going to reverse engineer anything you would imagine they'd take the L4A0256 from it (I personally wouldn't mind a knockoff of that thing).
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: digi2t on March 30, 2017, 12:47:14 PM
Send a request to Digitech service, and ask for the schematic. That's how I got all the XP schematics, so they might be kind enough to send you that one. The chip numbers will be on the schematic.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 30, 2017, 06:46:36 PM
Send a request to Digitech service, and ask for the schematic. That's how I got all the XP schematics, so they might be kind enough to send you that one. The chip numbers will be on the schematic.

I sent them one this morning, checked my emails just a while ago and they came through for me.

According to the schematic, U10 and 11 are 82S147 chips (the name seems to differ by brand. And U22 is a regular 27C64, which is good news for ROM backup/flashing.

My only concern right now is how expensive the 82s chips are and how the flashing process isn't the same for them, I'm wondering whether someone else has figured out a more compatible alternative that can be flashed in the same way as the 27C would be. Only issue with that would be how quick they would need to be in order to work like the 82S chips do, they have a latency around 45ns iirc.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: EBK on March 30, 2017, 07:19:31 PM
My only concern right now is how expensive the 82s chips are and how the flashing process isn't the same for them
You are facing a mountain of other unknowns, my friend.  You have no idea whether this pedal worked before the mysterious chip harvesting, and you haven't yet sourced the ROM code....

My advice?  Buy an identical but working version of this pedal.  Swap the ROMs from that into your original to test.  Then, if things go well, proceed to fix your original and sell one of the working units when you are done.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 30, 2017, 07:31:22 PM
You are facing a mountain of other unknowns, my friend.  You have no idea whether this pedal worked before the mysterious chip harvesting, and you haven't yet sourced the ROM code....

My advice?  Buy an identical but working version of this pedal.  Swap the ROMs from that into your original to test.  Then, if things go well, proceed to fix your original and sell one of the working units when you are done.

Sound advice, my only issue is how expensive/rare they are these days. It could take months before I find someone else with a working WH-1, more if I'm hoping they'll let me experiment like that.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: digi2t on March 31, 2017, 06:24:03 AM
(http://images2.static-bluray.com/reviews/13883_1.jpg)
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on May 16, 2017, 08:48:13 AM
You're right about this one Digi, but I'm determined to get an end result from it.

I've done some digging online and found some people in the retro arcade communities who needed replacements for older 82S bipolar proms. A couple years ago someone was selling adapter PCBs for 82S123s, 147s and the like, I managed to find their account on eBay where they were still selling the boards and they told me they only made a couple of the 147 adapter boards and didn't have any left, but they were fine with sharing a diagram of the adapter with me.

(http://i.imgur.com/2a57p6V.png)

This means that I can both read from the 82S147 proms as though they were a typical 27C type eeprom AND use 27Cs as replacements for the prom. Their choice of EEPROM replacements are the W27C512-45 by Winbond; the -45 suffix standing for their 45ns access time (the same as the 82s147 proms). Meanwhile the 27C64 for the main instructions can be read as is in a universal programmer.

I have a second WH-1 arriving soon that I hope to use for reading the ROMs from, I'll be sure to swap the chips into the other WH-1 before doing anything else to make sure that the lack of the ROMs is the only thing wrong with the unit.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on May 22, 2017, 10:24:34 AM
Some excellent news!

The "donor" Whammy arrived this morning (from Slovenia), I swapped over the U10, 11 and 22 from that one into the other unit and it worked perfectly! The only issue was the rotary encoder didn't seem to match up with what it was supposed to be but that appears to be because of the shoddy rewiring job the previous owner did.

(http://i.imgur.com/Yhd3Ytg.jpg)

It seems as if they had some issues with the encoder and tried to rewire it by running the 4 pins from the encoder down underneath the board and connecting them to pins P1.1 through 1.4 on U20, that's something I'll have to get sorted out as well.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on May 22, 2017, 01:15:12 PM
More progress:

(http://i.imgur.com/GGVYNgP.png)

(http://i.imgur.com/saarOHc.png)

Connected the PROMs up to my programmer based on the pinout of the adapter board; it read it perfectly fine. I don't have the replacement 2716 EPROMs just yet, nor do I have the 27C64 to replace U22. Once I have both of those however I'll get to work on making a prototype adapter board out of vero and then maybe make a proper board via OSHpark or do it myself if possible.

I've also uploaded the .bin files to MEGA in the minute case that anyone wanted or needed them, I guess if Digitech doesn't have them or wants to give them out it's up to us to have these kinds of things available.

https://mega.nz/#F!wIlgDK6R!SpVNXL4LhpAtmIz9BtFPHg
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: EBK on May 22, 2017, 01:53:28 PM
I'm amazed and extremely happy for you at the same time.  I had previously expressed some doubts about your project, but I admire your ambition and perseverance.  Consider me a hybrid cheerleader-mime, silently hoping for your victory to come.  :icon_wink:

I'm especially glad that there appear to be no (serious) mysterious side effects from the still-perplexing chip harvesting that took place.  My current theories are:
1) generic chips with a certain number of pins may be worth something to counterfeiters, but STILL, that doesn't explain why they bothered to keep/sell the thing afterward.   :icon_confused:
2) chips easily removed because they were socketed were useful as an arts and crafts supply.  (Yay, good guys!  :icon_razz:)
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on May 24, 2017, 09:56:12 AM
(http://i.imgur.com/Z3AemNP.png)

The easy part's done, the 2764 EPROMS arrived this afternoon (TMS2764JL-30 to be exact). I burned the ROM I made and stuck it in and found that it worked perfectly. I was worried the added access time of these chips would cause some problems (the original is 200ns according to the schematic while the TMS ones are 300).
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on June 13, 2017, 05:21:54 PM
(http://i.imgur.com/hidFekl.jpg)

Another update, this one took longer than I was hoping because the 2716 eeproms I receive weren't erased or blank checked and for some reason no amount of UV exposure would make them completely blank. I stumbled upon the pin-compatible 2816 eeprom a while later and gave that one a try.

Unfortunately the Whammy doesn't seem too happy to work with them; my guess is the access time of the 2816s are way too slow for what the rest of the system is expecting (the 2816s have 250ns access time, the original 82s147s have 45ns) causing the while thing to hiccup and start outputting random glitchy noise.

I'll see if I can get in contact with some small business that can burn proper bipolar proms (I have my eye on eprompro.com but if anyone knows anyone else please let me know), it seems this is about as far as I can go by myself but I'm still rather happy with the progress I've made so far.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on January 21, 2018, 11:13:49 AM
A very small update, I've been putting off doing anything new for this project but I'm certain that the ROM I extracted from the bipolar PROMs myself wouldn't work even if I got it burnt onto the proper medium. I'll be looking into getting them properly duplicated from the working WH-1 PROMs very soon.

As well as this, I've recently found a store page in Russia that is supposedly selling suitable replacements for the rotary encoder (they specifically say they're for the WH-1). I attempted to place and order but the sysadmin sent me an email saying they'd get new stock in about 2 weeks. Finding replacement encoders seems to have been a big problem over the years with loads of old topics for it, so I'm leaving a link to their store here: https://pedal-parts.com/en/home/potentiometers/encoders/whammy-wh-1-encoder
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: Prehistoricman on January 21, 2018, 10:00:57 PM
I'm certain that the ROM I extracted from the bipolar PROMs myself wouldn't work even if I got it burnt onto the proper medium.

Why's that?
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on January 22, 2018, 01:53:57 AM
Because I extracted the contents via a dubious looking 2716 to 82S147 adapter used in reverse, and looking at the contents of the .BIN files I extracted the code seems to loop several times rather than looking like a single block of code like the WH-1 27C64 ROM I dumped.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: mitchschaft on January 22, 2018, 02:13:26 AM
Thanks for sharing. I'm pretty sure the rotary on mine is shot.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: mitchschaft on April 03, 2018, 03:51:32 AM
I ordered that rotary after you posted this in January. It still hasn't arrived. He keeps saying wait two weeks. Lol
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on November 10, 2018, 04:25:38 PM
It's been just a little while, things have come and gone that have made doing any more on this project not any easier, but I'm back on top of it now and I hope I'm on the home straight.

Mitch, I'm awfully sorry to hear the encoder didn't arrive in such a timely fashion, I hope you either got a refund from them without much trouble or they eventually got it to you and reimbursed you in some way or another.

As for dumping the PROMs, I've taken the time to build a proper 82S147 -> 2716 adapter board (as proper as my skills will allow) and take some new dumps of both 82S147 chips.

(https://i.imgur.com/O866wxd.png)
(https://i.imgur.com/4mvfDxj.png)

They show up just fine in my programmers software and are different from the dumps that I took back in 2017. I have all of the resources to build another pair of 2716 -> 82s147 boards, and am waiting to receive some more 2716 EPROMs as the ones that I tried months back seemed to be corrupted and wouldn't erase (their contents would change with every read I took, even when done seconds apart).
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: mitchschaft on November 10, 2018, 11:57:04 PM
I ended up reordering abd it showed up. Apparently the first order didn't go through and I wasn't even charged.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: Prehistoricman on November 14, 2018, 04:05:16 PM
Would you upload your new ROM dumps? Thanks
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on November 16, 2018, 06:08:34 PM
Would you upload your new ROM dumps? Thanks

Sure, I'd honestly forgotten to do this sooner: HERE! (https://mega.nz/#!scMnXK4J!i9KFFta7h2q1R9PMtyw8tkV9Y3cR1vaFogR4BN6_9N4)

Bear in mind they're still in the raw 2kb dump format due to being read as a 2716, but I imagine it'd be easy to trim the excess.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: AdrianM55 on July 05, 2020, 04:23:07 AM
Hi,
Any updates on your project? I'm having slight problems with my Whammy in terms of Bypass signal being mixed with original signal on Whammy mode. I don't know how to address it hence I found this thread being very informative.

Adrian
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: mitchschaft on July 05, 2020, 05:04:32 PM
I think the point was to dump the roms. Which he already did. That's as far as the project was supposed to go.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: swellsoundelectronics on September 08, 2020, 03:24:25 PM
Do you know the firmware version of the eprom  for the .bin files you uploaded? I'm assuming it's V2, but I think I need V3.

Thanks,
Sam

Would you upload your new ROM dumps? Thanks

Sure, I'd honestly forgotten to do this sooner: HERE! (https://mega.nz/#!scMnXK4J!i9KFFta7h2q1R9PMtyw8tkV9Y3cR1vaFogR4BN6_9N4)

Bear in mind they're still in the raw 2kb dump format due to being read as a 2716, but I imagine it'd be easy to trim the excess.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: AdrianM55 on February 08, 2021, 03:06:20 PM
It's been just a little while, things have come and gone that have made doing any more on this project not any easier, but I'm back on top of it now and I hope I'm on the home straight.

Mitch, I'm awfully sorry to hear the encoder didn't arrive in such a timely fashion, I hope you either got a refund from them without much trouble or they eventually got it to you and reimbursed you in some way or another.

As for dumping the PROMs, I've taken the time to build a proper 82S147 -> 2716 adapter board (as proper as my skills will allow) and take some new dumps of both 82S147 chips.

(https://i.imgur.com/O866wxd.png)
(https://i.imgur.com/4mvfDxj.png)

They show up just fine in my programmers software and are different from the dumps that I took back in 2017. I have all of the resources to build another pair of 2716 -> 82s147 boards, and am waiting to receive some more 2716 EPROMs as the ones that I tried months back seemed to be corrupted and wouldn't erase (their contents would change with every read I took, even when done seconds apart).

Hey mate you've got any progress on these??
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on February 13, 2021, 04:14:12 PM
Hey mate you've got any progress on these??

Funny you should ask..

I've gotten back into this project as of late and have a set of adapter PCBs designed and on my way here. One being a revised version of the TL866 adapter monstrosity you've already seen, and the other a (hopefully) fitted dual adapter to go to a pair of W27C512s. I also went and checked the continuity between my good and bad whammy rotary encoders and wrote up a pseudo truth table for them.

(https://files.catbox.moe/v3r7s3.png)
(https://files.catbox.moe/ulayoe.png)
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: MüThing on March 03, 2021, 09:59:59 AM
I don't want to disappoint anyone but... it didnt work  :-[


(https://i.postimg.cc/xNJhK8FD/IMG-20210303-140657.jpg) (https://postimg.cc/xNJhK8FD)

(https://i.postimg.cc/MXNhz0vW/IMG-20210303-145036.jpg) (https://postimg.cc/MXNhz0vW)

(https://i.postimg.cc/NL53hCGJ/IMG-20210303-145110.jpg) (https://postimg.cc/NL53hCGJ)

There's probably something else I'm missing but I'm not certain what it could be at this point. Just need some more time and patience and I'll get there. At least I'm confident these new roms are complete and functional, and I'm sure a pair of burnt 82S147 chips would be a fine solution in the end.
Title: Re: Digitech WH-1 - Anyone know the eprom chip models? + ROMs?
Post by: AdrianM55 on February 01, 2022, 04:18:22 PM
I would say don’t give up as you’re closer than anyone so far :) holy grail is waiting.