Hello,
I have (what looks like) a voltage regulator for a Boss DD-500 guitar pedal that needs replacement. It only has the markings J04 and also some code of dots, which would probably help if I knew how to decode it.
It’s surface mount with pads that stick out the sides at the bottom, but the chip itself has about a 2.3x3mm footprint, pictured.
Can anyone identify this, and/or know the code?
Thanks!
Zack
Hello, Zack.
Do you have any idea of the specifications for this device? Voltage input or output, current levels, anything? I’m not able to find any useful information on the “J04” mark alone, sorry.
If I were to hazard a guess, I’d say it’s more likely an op-amp than a regulator, but I could find nothing with such markings to help. A schematic is probably going to be required to figure it out.
All I could locate is below. It might be a good start.
https://www.boss.info/us/products/dd-500/
But is for Model Boss OD-1 OverDrive
• IC: RC3403ADB, uPC4741C, NJM4558D, uPC4558C, uPC4558C, TL4558P, JRC4558D, JRC4558DD, JRC4558DC or C4558C (depending on your model)
https://www.digikey.com/short/zh892z What we have for op amps
• Q1: 2SK30ATM-Y (N-channel JFET transistor)
• Q2: 2SK30ATM-GR (N-channel JFET transistor)
• Q3, Q4, Q5: 2SC945-P 2SC1815-Y (NPN silicon transistors)
• Q6, Q7: 2SC732TM-GR (NPN silicon transistors)
• D1: RD11EB-3 (500mW 11V Zener diode)
• D2: RD5.1EB-3 (500mW 5.1V Zener diode)
• D3-D10: 1S2473 or 1S1588 (switching diodes)
• D11: SLP135B (LED)
Thanks, everyone.
I’m not certain it’s a voltage regulator, but it comes very early in the power stage, and the symptom this has is no response to power. I don’t think it’s an op amp.
This is a digital pedal and pretty different than an OD-1. Thanks for trying/looking for that and a schematic; I could’t find one either.
These tend to have a few DC voltages in them after the power stage, 3.3, 9, often 5v. It’s 9VDC input.
I doubt I’ll get info from Boss but will try with them. Too bad that code of dots didn’t mean something to you all.
Thanks!
Zack
Hey Zack,
Did you ever get a replacement for your J04 I.C. for your Boss delay?
I could use one for my Roland UA-1010.
Thanks
Jim
Hi Jim,
No, I hit a dead end on it. Please let me know if you crack the code or get info back from Roland.
Thanks.
Zack
Zack,
Did you try to get a schematic from BOSS? I can not get one from Roland. I’m certain my Roland UA-1010 uses the same J04 part. It appears to be a power supply switch or regulator with an in on 2 pins and an out on 2 pins. I’ve been a tech for decades. A solution to this will NOT elude me.
Boss is a division of Roland… I think all the contact info was the same when I tried?
I appreciate your commitment to solving this and hope I can ride along when you do! Please keep me posted, thanks.
Zack
Ok. Can I have your contact information and the model of your delay?
Grab a ticket and hold on!
What do you think Zack?
Sounds, good, thanks. The pedal is a DD-500. Let’s keep any results in the forum here in case you solve it and someone else can find it in the future.
Ok. I need your contacts with anybody you corresponded with for parts and I don’t have anything to share with the group yet.
Sure, I sent you a message at the same time I posted that. I don’t have any contacts to share. Thanks again for looking into the part/solution.
Hey Zack,
It’s been a while but I think the part that we are looking for is a Rohm QS8J4 dual P channel MOSFET.
2920291.pdf (1.7 MB)
QS8J4CT-ND Click here
How about a sample of a $1 I.C.?
Samples you have to contact sales by email or phone
Hey, great. Thanks for reporting back in. How did you come up with this, did you make contact with Roland?
No, just kept at it on the internet until I got what looked like it made the most sense. I’m still not 100% but if you look at the 1010 circuit you can see traces between pins 5, 6 and 7 and 8 and pins 1 and 3. 5, 6 and 7, 8 would be the redundant connections to the Drains according to the Inner Circuit on the Datasheet for the QS8J4 and pins 1 and 3 would be the Gates. I am going to get my hands on a few and see if it works and let you know.
If you like I could send you a spare. The shipping will cost more than the parts.
Jim
