SR-JV Wi-Fi Expansion Board

Buy this product: https://www.ddzheng.cc/?page_id=666#buy-now

Table of Contents

• Disclaimer & F.A.Q.
• About This Project
  • Compatible Hosts
  • Parts and Function
  • Board Info
  • Comparison with Sector101’s Romulator
  • Releases, Changelog and Known Issues
    • HW Rev 1.2
    • HW Rev 1.0
    • FW 1.10 Release
• User Guide
  • Installation
  • Connecting to the Card
  • ROM Content Management
  • Configuration
    • Wi-Fi Credentials Configuration
    • Wi-Fi Power Off Configuration
      • Waking Up the Card/Activate Wi-Fi
    • [FW 1.10+] Wi-Fi Channel Setting
    • [FW 1.10+] Wi-Fi Hidden SSID Setting
  • OTA Firmware Upgrade
  • Resetting Config
• Open-source Hardware
• Buy Now
• Resources
• Production Record & Schedule

Disclaimer & F.A.Q.

• Experimental product. May not work for you. May not work at all.
• Special care required when using multiple. See Wi-Fi Power Off
• Shipping may be slow. Price may go up or down without prior notifications
• California P65
• I have no control over how page-ID is generated in WordPress

• Can I get a refund if the product does not work?
  • If it’s due to a quality issue, you can have a refund. You can also ask for an exchange to get another unit for free.
  • If it’s due to incompatibility with a host device not previously tested, you can have a refund.
  • If you simply don’t like/want the product, you cannot have a refund.
• What’s the procedure for a refund?
  • You should first contact us via email, See Contact
  • You do not need to return the card. You need to destroy the card and send the evidence of destruction (image or video). We’ll then refund you.
• There are audio noise after I installed the card
  • You need to disable the wireless. See Wi-Fi Power Off. You may need to recap your synthesizer if it’s old. If problem still persist, please contact us via email
• There are pops and clicks in the audio
  • The data read from the card is corrupted. Ensure the upload completed successfully. Use Wireless off if not already done so. Try to clean the expansion connector with contact cleaner. You may need to recap your synthesizer if it’s old. If problem still persists, it’s likely an issue with the card itself.
• How does the firmware handle the image file?
  • The firmware writes the image file to the flash chip as-is without any modification.
• The card is a little bit shifted compared to original card
  • This is a known issue and should not interfere with installation. However, installing an original Roland card side-by-side with this product may be a little bit stiff.
• The standoffs are hard to align/rotate into place
  • Roland devices from different eras use different quality standoffs. Some of those will be hard and brittle by now, do not force them.
• Is this card compatible with Sector101 SR-JV Romulator Extension?
  • No, due to flash speed is slow, you cannot add extension cable.

About This Project

This board is a re-writable ROM card with a Wi-Fi based user interface. It can store a ROM image up to 8MB/64Mbit, usually custom authored, and be used in compatible Roland synthesizers in place of an original SR-JV80 series expansion card to research the sound generation and synthesizing.

Compatible Hosts

This card is designed to be compatible with all Roland synthesizer which have slot for SR-JV80 series expansion cards. However, not all hosts are tested. See Known Issues for details and workarounds, modifications. Now in stock are HW Rev 1.2, older revisions listed for reference in case someone run into these. Green means the combination of hardware revision and host is tested to work, while orange means partial or complete incompatibility. Blank means it’s not tested but should work.

Synthesizer	SR-JV80 Slots	Lot No. 1 (HW Rev 1.0) Compatibility	Compatibility for All New Cards After Lot No.1 (HW Rev 1.2)
JV-80	1	YES Workaround or Modification Needed	YES
JV-880	1	YES Workaround or Modification Needed	YES
JV-90	1	User reported not working	YES
JV-1000	1	User reported not working	YES Some user reported problem
JV-1010	1	YES	YES
JD-990	1	YES Wireless off is required to remove interference	YES Wireless off is required to remove interference
FA-76	1		YES Won’t work when using waveform from this card and internal/SRX in a patch at same time
XP-30	2		YES
XV-88	2
XP-50	4	YES Won’t work in slot C & D	YES Won’t work in slot C & D
XP-60/80	4	YES Won’t work in slot C & D	YES Won’t work in slot C & D
JV-1080	4	YES	YES
XV-3080	4	YES	YES
XV-5080	4	YES	YES
JV-2080	8	YES	YES

Parts and Function

1. Button – for activating Wi-Fi and resetting configuration
2. Remote Button Header – user can solder a remotely mounted normally open button to this footprint. A button wired here has exactly same function as the onboard button
3. Power Indicator – on when power is supplied to the board
4. Status Indicator – blink slowly when Wi-Fi is on and no operation; on solid when operation in progress; blink rapidly when error; off when Wi-Fi is off
5. USB connector – for powering the board when out of a synthesizer
6. Expansion connector – for connecting to host synthesizer, the connector has been filed on some location to reduce stress
7. Production header – for developer only, provides access to ESP32 UART, BOOT0 and RST. Can be used to program ESP32 in case the firmware is corrupted, or to develop own firmware

Board Info

Designed by me, Connor Zheng, in Beijing, China. Assembled in Beijing, China with components sourced globally. PCB by JLCPCB. 4-layer FR4, Lead-less HASL, RoHS 1, UL 94V-0. All components RoHS. SAC solder.

Comparison with Sector101’s Romulator

This is not a clone of Sector101’s product. The Romulator is a more faithful reproduction of the original Roland cards, using nothing but 4x 2MB Flash on the card. The programmer is standalone and not included on the card. This means electrically the Romulator card is exactly same as original card, which won’t have power consumption issues, wireless interference or signal integrity and delay issue, and is guaranteed to work in all hosts. You will have to take out a Romulator card from the synth to re-program it.

This product use 1x 8MB Flash and incorporates a ESP32 wireless microcontroller as on-board programmer. It is easier to use, can be programmed while inside synth, however have higher power consumption. Due to the address encoding, compatibility is not guaranteed on all slots of all hosts (need testing, see compatibility matrix).

If you need a programmable card in any of the following situation, you mustn’t purchase this product and instead you will need to use the Romulator:

• Usage in slot C or D in XP50, XP60, XP80
• Need to combine waveform from SR-JV and internal/SRX at the same time in one patch when using FA-76
• Usage in a incompatible synthesizer
• Require minimum stress on synthesizer
• Require maximum reliability for critical application (e.g. on-stage performance)

Releases, Changelog and Known Issues

HW Rev 1.2

• Changed address encoding chip to 74AHC86/74LV86 to reduce propagation delay
• Changed CE line control circuit to 4x 74LVC1G125 to reduce propagation delay

HW Rev 1.1 – No production

• Changed reset circuit, flash reset is now isolated, should be fully compatible with JV-80 and JV-880.

HW Rev 1.0

• Initial Release. Modification or workaround is needed to work on JV-80 and JV-880. Does not work on XP-50/60/80 slot C and D due to delay
• Affected Lot Numbers: 1
• Affected Datecodes: 2506
• Workaround for Lot No. 1 board on JV-80:
  • Press and hold NUMBER 1 button while powering on, or if this doesn’t work:
  • Boot synth in test mode and exit test mode (Reference service notes)
• Workaround for Lot No. 1 board on JV-880:
  • Press and hold EDIT and COMPARE button while powering on, or if this doesn’t work:
  • Boot synth in test mode and exit test mode (Reference service notes)
• Modification for Lot No. 1 on JV-80/880: https://www.ddzheng.cc/?page_id=805

FW 1.10 Release

• Added AP channel selection function, changed default channel to 11
• Added AP hide SSID function
• Added show current value function for configuration dropdowns in HTML

Download FW 1.10: https://drive.google.com/drive/folders/1DnFtr_di28IOTllp2gWrjLeQtrrozbTT?usp=sharing (Upgrading to this version will erase all your current configuration and reset the ROM status. ROM content will not be affected.)

FW 1.00 Release

• Fixed an issue where Apple devices are not supported in Bluetooth LE wakeup.
• Fixed an issue in HTML
• Fixed an issue where Bluetooth LE advertisement is sent once on boot, even if wireless mode is set to All Off

FW 0.99 Release

• Bluetooth wakeup only supports Android phone.
• Affected Lot Numbers: 1
• Affected Datecodes: 2506

User Guide

Installation

Please follow the original Roland SR-JV80 series expansion card operator’s manual to install. Before installing make sure to unplug the mains power from the synthesizer. If you want to program/configure the card before installing, you can power the card by using a regular USB type-C cable and connect the other end to either a power supply or a computer.

Note: It’s highly recommended to use anti-static wrist-band connected to a solid ground connection to avoid static discharge damage to either the card or your synthesizer.

Note: If the board holder is too tight to rotate into place, do not force it. Leave it as is.

Note: If using multiple expansion cards it’s strongly recommended to configure Wi-Fi off in the configuration page.

Connecting to the Card

When the card is powered up and not in Wi-Fi off state, you can connect to the card’s Wi-Fi hotspot. Default name is “SR-JV-XXXXXX” where XXXXXX is the last 3 octets of the Wi-Fi interface’s MAC address and no password:

Once connected, open a new browser tab and navigate to “http://192.168.4.1“:

Click on any one of the link to go to their corresponding section.

ROM Content Management

Note: Change the synthesizer’s current selected patch/perform/rhythm to not include anything from the card before manipulating flash ROM. Otherwise the synth may crash and/or the synth patch data may get corrupted.

The status indicate whether the flash ROM is erased or programmed. Possible states are: ERASED, ERASING, PROGRAMMED, PROGRAMMING and UNKNOWN.

Before programming, the flash need to first be erased. Click “Erase Flash” to erase flash, this will take about 1 minute:

After the erase is finished, the page will automatically refresh.

Then you can program the flash with a image file. Browse for a BIN file and hit upload to write the flash, a full 8MB image will take 6 minutes to write:

Do not close the browser tab or disconnect Wi-Fi when writing. If “Upload failed” is displayed, it’s due to Wi-Fi interruptions or browser issues and is not related to the card’s hardware. Please plug in power if using laptop, disable screensaver and auto screen off, disable power saving function of browser, and stay in the tab while the upload is in progress.

Note: After writing is finished you need to power cycle your synthesizer to use the new ROM.

If the erasing or programming operation has been interrupted or failed before finish, a power cycle will recover the status to UNKNOWN and you can try program the same file again without erasing. In the state UNKNOWN you can either erase or write the flash. But if the flash is partially programmed and you try to program another file, the content will become corrupted and need to be erased.

Configuration

Wi-Fi Credentials Configuration

You can change the Wi-Fi hotspot name (SSID) and optionally set a password.

Note: SSID cannot include space (” “) and cannot be longer than 32 characters; Password cannot be shorter than 8 characters or longer than 32 characters.

Once you have decided on the SSID name or password, click submit to confirm it. A restart is needed for configuration to take effect.

Note: You’ll have to wake the card again after using “Restart” if Wi-Fi power off is configured. If you experience difficulty connecting with password changed, after you hit “submit”, instead of using the restart button, try do a power cycle. Depending on the operating system and wireless network card used, you may also have to “forget network” before connecting to it again, especially if the SSID name is not changed.

Wi-Fi Power Off Configuration

Installing more than one card without using one of the low power modes may cause your synthesizer’s 5V power supply to overheat, go into overcurrent protection, and/or be damaged. If you don’t need to change the content or if you have access to the button switch, just use Wireless Off mode. There’s no guarantee that these low power modes will solve all issues. I’ll not be held responsible if your synth burns up.

Normally this card would consume about 150mA with Wi-Fi on, and when actively writing the current will be 200mA or more. When multiple cards are installed this will likely cause the synthesizer’s power supply to go into overcurrent protection. In such case, you can configure Wi-Fi off to minimize current consumption. If you experience RF interference, you can also use this function to eliminate it.

There are 3 options: Always on, Wi-Fi off with BLE wakeup, Wireless all off.

• Always on: Highest power consumption. The Wi-Fi interface is always on, suitable when no interference and only 1 card is installed
• Wi-Fi off with BLE wakeup: Medium power consumption. Wi-Fi will be off upon boot. Wi-Fi can be activated by button or Bluetooth. This is suitable for a closed chassis situation without a remote mounted button. Current consumption is about 80 mA when Bluetooth is advertising with an average of 30 mA.
• Wireless all off: Lowest power consumption. Wi-Fi and BLE are off. Wi-Fi can be activated by button only. RF systems are shut down.

Once you have selected an option, click submit to confirm it. A restart is needed for configuration to take effect.

Also, after manipulating the flash ROM on one card, remember to return to low power mode by using the link in the webpage or power cycle, before moving on to wake next card.

Waking Up the Card/Activate Wi-Fi

In both Wi-Fi off modes, you can press the button to activate Wi-Fi, either the onboard one or a user-soldered remote mounted button switch. Press the button for about half a second until the status LED starts to blink slowly. When waking up from sleep, holding the button down won’t clear the config.

If using BLE wakeup, you can use a smartphone, tablet or computer to wake the card’s Wi-Fi by initiate a pairing attempt with the card. Navigate to the Bluetooth settings of your phone, and select the option for pairing a new device. The device name is same as the Wi-Fi SSID configured. Click on the device name to initiate a pairing. You may need to click more than once for it to work. The pairing attempt will fail, and Wi-Fi will be activated.

Note: It’s by design that the Bluetooth pairing attempt will fail. This eliminates the need for an app, and you won’t need to un-pair the device before next Bluetooth wakeup.

Apple device users: Please update to FW Ver 1.00 or later to use Bluetooth wakeup on iOS devices.

[FW 1.10+] Wi-Fi Channel Setting

It’s now possible to select a channel for the Wi-Fi AP. Recommended channel is either 1, 6 or 11. Default channel is 1 in FW versions before 1.10 and 11 in FW version 1.10 and later.

[FW 1.10+] Wi-Fi Hidden SSID Setting

It’s now possible to hide the Wi-Fi AP. You can still connect to it if the SSID and password (if any) is known, but it won’t show up on Wi-Fi scans if it’s not been previously connected. Please make note of SSID if you are changing that at the same time.

OTA Firmware Upgrade

If you are updating using a pre-compiled BIN file, skip this step. If you are compiling from source, select “Export Compiled Binaries” in Arduino IDE:

If you got a firmware ZIP file, decompress it.

Select sketch BIN file and update:

After the progress reach 100%, the card will reboot to the new firmware and the page will redirect to homepage after 5 seconds. If Wi-Fi power off is configured, the redirect will fail. You need to wake the card again. Please disconnect Wi-Fi and reconnect to the card in such case. If you cannot connect to Wi-Fi after an OTA update, a power cycle will restore things to normal.

Note: Updating to certain versions will cause the configurations to be erased. This will not affect ROM content.

Note: If the BIN file is corrupted or wrong, the update will be rejected and error (fast blinking) will be shown on STATUS indicator. If the ESP32 cannot boot the new firmware, it will revert back to the working firmware. In rare case that the board cannot boot, it can be flashed normally by using the production headers and USB to TTL adapter. The ESP32 has an internal bootrom so it is not possible to actually brick it. Follow guides on developing ESP32 to know more.

Resetting Config

If you forget the password or otherwise need to reset the configuration, please follow these procedure:

1. Power off the synthesizer or unplug USB power, wait at least 10 seconds
2. Press and hold the button down
3. While holding the button down, turn on the synthesizer or plug in USB, the STATUS LED will blink rapidly
4. Continue to hold button down, after about 3 seconds STATUS will light up solid
5. Release button, card will automatically reboot, config is cleared

If you let go of the button too early, the card will return to normal working mode and configurations will not be cleared. Resetting the configuration will not erase the flash ROM, but the ROM status will become UNKNOWN.

Open-source Hardware

Hardware Repo:

https://github.com/connorzheng97/srjv

Firmware Repo:

https://github.com/connorzheng97/srjv-fw

Buy Now

Last update: Sep. 24, 2025

5th batch is sold out, thank you!

No further production is planned. If you want this product, you can join the wish list here. If demand is high enough, it’ll be possible to make another batch run.

Stock availability notification subscribe – SRJV

Resources

• Image library, can be used to study the SR-JV sample / patch data format: https://drive.google.com/drive/folders/1de3TqrR-FJ5FtymICBgGj5p4qxhLRtZC?usp=sharing

• SRJV Authoring Tool by PythonBlue: https://github.com/PythonBlue/SRJV
• Chab’s fork of SRJV Authoring Tool: https://github.com/chab/SRJV
• The ultimate Roland JV, JD, XV F.A.Q. https://www.donsolaris.com/?p=404
• Roland Wave Expansion Cards https://www.dtech.lv/techarticles_roland_exp.html
• All SR-JV80 Card Patches SysEx for Auditing (on JD990) https://gearspace.com/board/electronic-music-instruments-and-electronic-music-production/1156668-cult-roland-jd-990-a-24.html#post16521659
• A product that has similar function, Sector101’s ROMulator: https://sector101.co.uk/sr-jv-romulator.html
• Gearspace thread: https://gearspace.com/board/electronic-music-instruments-and-electronic-music-production/1442130-diy-re-writable-roland-sr-jv80-card-wifi.html

Production Record & Schedule

To identify your board, scan the QR code printed on the board. Under “Unit Identification Number” you can find a 3-section code (example: “SRJV-2506-0001”). The middle section is the datecode in YYWW format. If a board have a large white block instead of a QR code, this info will be written on the board or on a sticker.

Lot No.	Date Code (YYWW)	HW Rev.	Factory FW	Batch Size (pcs)	Date Available / Date Expected	Status
1	2506	1.0	0.99	40	Feb. 13, 2025	Sold out
2	2509	1.2	1.10	100	Mar. 13, 2025	Sold out
3	2511	1.2	1.10	100	Apr. 6, 2025	Sold out
4	2514	1.2	1.11	100	May. 7, 2025	Sold out
5	2519	1.2	1.11	100	Jun. 13, 2025	In stock

This document should not to be re-distributed as archive since it is subject to frequent change. This document is Licensed under CC-BY-NC-SA.