FIX YOUR SIX (Bus Pirate 5XL/6 resistor fix)

This applies to the first batch of Bus Pirate 5XL/6 that shipped around August 10th, 2024. All other boards are okay

The new RP2350-based Bus Pirates need an extra external pull-down resistor to fix silicon bug E9. We’re going to replace all the shipped boards, no need to do anything. However, here are some instructions if you’d like to try a fix.

Confirm the E9 bug

First, let’s confirm the E9 bug on your board. Download the latest firmware, disconnect anything from the Bus Pirate 10P header and then:

  • m 8 - Enter DIO mode (or any mode where IO0 is not in use)
  • W 5 - Enable a power supply between 3.3 and 5 volts.
  • bug e9 - Run the bug command E9 test

The Bus Pirate will perform four tests. Test 1 and 2 confirm if E9 is found.

Resistor type and value

  • 4.7K resistor array (4.7K-8K should all work)
  • 4x0402 package (also called 0804 or 2010M)
  • Convex type (pads on the end of the leads, not between the leads)
  • These are usually 5%
  • Generally 1/16th Watts, but not important in this application

Resistor array location

We need to replace the pull-down resistors on the RP2350 pins that control the Bus Pirate IO pins: RN302, RN307. Circled here on the 5XL and 6.

5XL resistor location.

bp5xl

6 resistor location

bp6

The fix

There’s at least three ways to apply the fix. Easy, Pro and Goblin mode.

Easy Fix

Instead of trying to remove the existing 100K pull-downs, we can leave them in place and solder the new resistor array on top. Arrays are usually 5% tolerance, so the 4.7K resistor value may vary by 235 Ohms. The extra 100K is almost nothing compared to the tolerance of the 4.7K resistors.

image

Look closely and find the side of the resistor array where all four leads connect together and to the ground plane. Start soldering on this side because it’s okay to be messy, and the thermal mass of the ground pad will keep everything in place while soldering the more sensitive side.

Start with the ground side. Hit it with flux and add a solder blob until everything is connected together. The pins all go to ground, so it’s fine if there are shorts between pads.

Now, hit the other side with some flux. Add a little solder at a time while heating the pads of both arrays. “The force” (surface tension) should keep the solder in the right place. If pads are shorted with too much solder, hit it with some more flux and gently remove the excess a little at a time with a copper wick. It’s easier than it looks, and all four pads can be soldered at once - the surface tension keeps the solder where it should be.

Pro Fix

Use a hot air rework tool to remove RM302 and RN307. Solder the new resistors on place.

I would argue this is the easier fix, but the LCD will burn easily so you need to know your stuff. I melt the LCD and need to replace it about 50% of the time I rework a Bus Pirate board.

You might be able to use a knife to gently cut away the 3M tape holding the display in place and then flip it away from the PCB. Be careful, that stuff is meant to last and often the LCD cracks in the process.

Goblin Mode Fix

Not suggesting anyone try, but Matt at Blinkinlabs soldered four tiny 0201 resistors on top of the 4x0402 arrays to help us test this fix ASAP.

Test the fix

It’s probably a good idea to run the self test in HiZ mode using the ~ command. This will check for any shorts in the soldering.

Finally, run bug e9 -a to confirm that the fix is working. Disconnect anything from the Bus Pirate 10P header and then:

  • m 8 - Enter DIO mode (or any mode where IO0 is not in use)
  • W 5 - Enable a power supply between 3.3 and 5 volts.
  • bug e9 -a - Run the bug command E9 test. -a runs the E9 test on all 8 IO pins

The fix worked if the GPIO pin is 0 after the test.

I Fixed My Six!

Post a pic of your Six Fix (or attempt) and I’ll send you this sticker!

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Ordering parts today for sure! Thats has to be part of my sticker bomb project!

But seriously, on this note, can you recommend a decent price/ quality set of solder tweezers? I am used to high end aircraft electronics equipment, but dont have access to that currently.

@ian @Jin or anyone with info? All input is much appreciated as ive looked for years for a precision pair and have only found bulky useless products.

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Rhino brand, even the good knock-offs, are great. I use style XH-11 (straight and thin).

When I bought my first pair Tool Brother stabbed them repeatedly into his glass counter top to prove how tough they are. They’re tough, but he still damaged them a bit :roll_eyes:

Jin says these are in the DirtyPCBs shop somewhere, but I’m sure you can get them closer/faster.

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I got myself one full set of Rhinos and they are amazing nothing like those cheap <1$ ones. Acid resistant esd temp resistant and simply good quality metal. They do not bend at all. I didnt do any crashtest tho

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Thanks for the feedback! @ian @AreYouLoco

Ill check the dirtypcb shop. If I’d come across them before, I definitely would have picked up a set. Ill look around and see what I can find.

What I used in the past that I miss:
https://www.tequipment.net/WellerWX2021.html?Source=googleshopping&gad_source=1&gclid=CjwKCAjwufq2BhAmEiwAnZqw8hmAYaJiKO_Xd_BOhZcF4A_Uxw6eUNA_CtaGhfAy8Ig5AJ0I2E4szBoCiRIQAvD_BwE

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Oh man, I’ve never actually used a soldering tweezers. It seems populating 0402 passives on a board that’s been paste stenciled might be super fast, but a lot of my nightmare parts are the sot-523 (sc70) stuff which has more than two leads. Do they work for that stuff too?

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I had no idea the tweezers had come this far. Im intrigued by the solder pins as well but i have yet to pull the trigger. Coming from a full solder station, no one hss convinced me that the usb pens work well enough to maje the transition.

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Yes, they have interchangeable heads and have different size tweezers for different size chips. You just want both sides to heat up to the same temp when using to install parts. Otherwise the part tends to drag towards the colder side when you go to release the part.

Once you use a set of tweezers, you will will rarely go back to the iron!

https://www.tequipment.net/Weller0054465499.html?Source=googleshopping&gad_source=1&gclid=CjwKCAjwufq2BhAmEiwAnZqw8p2hWUIDmj-Y3eTGv5IDGE2IwhtkBVkl8Uu-zbul8BHch_Ba-Onz7hoCXCMQAvD_BwE

I had a very early version of those that used an msp430. I don’t think it was the same company. I guess they’re great for reverse engineering, but I never really needed it. If a part flings across the room I just get another, it’s not worth digging in the rug to find out which unmarked resistor is the one I lost :slight_smile:

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Also, i do have a set of the tweezers from dirty pcbs shop abd i plan to buy several pairs next order. I recommend them to EVERYONE. I have tweezers that are techitool i think. They cost up to $180 USD/ pair. Its insane what etching “made in italy” can do for profit margins. :laughing:

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I wonder if there is IronOS for it already. Not yet it seems:

I am using old good TS100

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Wish they covered my iron, it’s so cheap and amazing. Some clone of the instant heat irons. Probably the best tool upgrade i’ve ever purchased that I didn’t know I actually needed.

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Until you’ve had that luxury of a good iron, you don’t understand how much it can expedite your workflow and create less scrap. IMHO

I keep hearing about the ts100 and i rabbit hole some nights on whats better, yet still haven’t been able to pull the trigger on one. Wish we could poll to see what everyone recommends. Maybe then my OCD would allow me to pull the trigger. Right now mine just works, but i want to start looking for an upgrade. I have some amazon all in one station.

Downside to the TS100 / Pinecil, last time I looked, was that the USB-PD power supplies were expensive. Maybe it’s time to look again? I’m currently using a Hakko FX-888D…

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Here some links for lazy people :wink:

https://www.digikey.com/en/products/detail/cts-resistor-products/S41X083472JP/9558022

https://www.mouser.es/ProductDetail/Bourns/CAY10A-472J4LF?qs=IS%252B4QmGtzzrtEkVHNsjlzg%3D%3D

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Similar link for the lazy, this one is Automotive qualified (AEC-Q200), rated for twice the power (62.5mW), is from Panasonic, and costs the same:
https://www.digikey.com/en/products/detail/panasonic-electronic-components/EXB-28V472JX/256295

It appears I was successful in removal of both resistor networks:


I used copper tape around the part, hot air gun to warm things up, flux, and application of low-temp solder with soldering iron (to mix with the existing solder). Came off pretty clean, but I followed with flux & copper braid for the final shots shown.

Half-way there, right? :slight_smile:

Now I just need to acquire the replacements and solder them on. How does one solder such tiny surface mount components, anyways?

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Ah, I didn’t think about chip quick. To solder, put a tiny dot of solder on one pad. While keeping it liquid, nudge the chip into place with tweezers. After one pad is soldered and the chip aligned, slobber solder over all the pins. Finally, hit it with flux and wick up the excess with copper wick.

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I found the Weller controller board for the iron and tweezers on dirtypcbs.com

https://dirtypcbs.com/store/designer/details/7775/6182/weller-driver-v1-1

And the project article:
http://kair.us/projects/weller/index.html

Added to my cart to ship with the next order I place.

They are beyond dirt cheap. Just picked up an Anker 100w single-port for $23 on amazon to become my new Daily, and put my 60w for portable. The whole point of the Pinecil vs the ts80/100, is that it can run off the barrel jack OR usb-c. And run the same IronOS open source firmware. Not sure about it now but I have a v1 Pinecil and it has the spot to put a Hall on the pcb, so it can detect when you put it in a holder, but it comes with accel to determine when you put it down, and cool the tip down. I enjoy mine greatly, I use my ISDT 60w usb-c pretty much just for the pinecil, c4air, and 608pd. Also around $20. The 608pd is an r/c 6s any chemistry balancing charger that runs off xt60 input or usb-c input to 100w. But it has a neat secondary use, if you hook up a power source to the charge port first, it becomes a 100w powerbank instead, letting you run off your batteries. I’ll be honest i use that feature more than as a lithium charger.

Forgot to add, my main is a hakko 888d as well. I use either interchangeably, my hakko’s cord is shorter than the usb-c cable I use, so if it’s a big project or on the ground, it’s 100% pinecil for sure. I had to repair like 8 of these big PA speaker assys, and trying to use the hakko for that repair would need the box shoved into the housing and trying to balance the tip holder etc. Or the pinecil with usbc made it… nothing in comparison. just fwiw

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I don’t have the quad parts, but I do have plain 0402s, I replaced mine by removing the existing parts with hot air then put the 2 middle 0402s on edge and the 2 outside one the normal way.

It’s fiddly, probably not for a beginner :slight_smile:

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