Disclaimer
Only attempt this if you are confident in your soldering skills/electronics ability. If you don't know what you are doing this can end in magic smoke or injury. If you choose to proceed this may still end in magic smoke if you do something incorrectly. If you do everything correctly this may still end in magic smoke.

Basically I take no responsibility for any damage sustained from using this tutorial it is intended as guide on how I have hacked these ESCs hopefully it will work for everyone else but as we all know this may not be the case.

Ok so now to something more interesting.

1. Required Equipment

Parts
Tz85a ESC $36.59 + 1.99 p/h - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10331
2x3 ISP connector - $3.33 + ?? p/h - http://littlebirdelectronics.com/products/6-conductor-ribbon-cable-with-idc-connectors-12
2 x EC3 Plugs (optional) - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9625

Tools
2mm (I think) - Allen Key
Pololu AVR ISP programmer - http://www.pololu.com/catalog/product/1300
Sidecutters
Soldering Iron + solder

Information
(It is useful to print this before hand)

high res
http://dl.dropbox.com/u/815267/Plush30/repo/docs/TZ85A/TZ85A_wiring.png
(if these links become broken again they are in the repository on launchpad)



Software
This assumes you are using windows.
Have the drivers for pololu programmer installed
Have AVR studio installed
The pololu avr development bundle has all these tools

2. Soldering on programming pins
Video - http://www.youtube.com/watch?v=EAKYSyOx75Q
- Unscrew the four bolts on top of the ESC
- Carefully peel off the thermal contact material. Try as much as possible not to tear or rip it.
- Cut the IDC connector in half
- Separate 6 wires
- Strip and tin wires
- Cut down so that only 2mm of wire is left exposed
- Poke through case of ESC so you can reassemble it latter
- Solder to respective pins on ESC
- Cut off port C (optional)
- Solder on EC3 plugs (optional)
- Bridge power switch (optional)
- Reassemble ESC


3. Programming the ESC
Video - http://www.youtube.com/watch?v=i1-bWNeuAqA

- Connect Pololu Programmer
- Power and Turn on ESC
- goto http://launchpad.net/brushed and download Tz85a_rXX.hex (XX is highest number)
- Open AVR studio.
- In avr studio goto "Tools" -> "Program AVR" -> "Connect"
- Select AVRISP and Auto then click connect
- Select the Main TAB
- Under Device and signature bytes select ATmega8
- Click read signature
- Underneath it should say signature matches. If you get an error here check your wiring
- Select the Programming TAB.
- Under Flash, browse ( [...] button) and select the tz85a.hex file
- Then click program.
- If this is the first time you have programmed the chip you may get a warning saying the chip is locked and programming it will erase all data. It will, so you will never be able to revert back to brushless mode. If you still want to continue click yes.

You should now have a brushed controller.

Enjoy and please post test results in development thread. Only posts relating to tutorial should be made here.
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Thanks for putting this together and all the work you've done making inexpensive ESCs available. For someone who hadn't done something like this before, the video was very helpful.

I created a printer friendly version of solder connections:


I was also able to successfully use this programmer from Hobbyking:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=21321

It's $20 cheaper than the Pololu one+IDC Cable, and can be ordered from HK with the ESCs, However, it was fairly difficult (for me) to get it installed and working properly. I can provide instructions if anyone is interested though.

I have a question though:
Does the ESC need to be powered on if the programming card can supply the voltage?

No, but it is dependant on the programmer. Pololu one it did need to be (to get it to work reliably) , STK500 dev board I use mostly it doesn't.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

"It's $20 cheaper than the Pololu one+IDC Cable, and can be ordered from HK with the ESCs, However, it was fairly difficult (for me) to get it installed and working properly. I can provide instructions if anyone is interested though." [i]


I'd be interested in that. Still plucking up the courage to try reprogramming myself. I Have the HK programmer.

Pete

www.kitbots.com

I read with much interest this thread that is a few years old. But I'm disappointed to not being able to use the cheap Talon SR for our tank models. The Talon SRX are much more expensive (66% price increase!)

So I got some Turnigy Brushless ESC 85A w/ 5A SBEC, and I was looking forward to make this flashing to turn them into Brush ESC (they are running MY1018 450W or 250W motors in those tanks)

But I want to make sure I align that "red dot" properly on the chip. Also, if I look straight up at my flashing tool, I have those connection and I'd like to confirm they are accurate
https://scontent-lax3-1.xx.fbcdn.net/hphotos-xat1/v/t1.0-9/12241398_722609627869334_9132102862880124914_n.jpg?oh=dc77b993dcc7a01551648a29e9a1ba3d&oe=56F8C839

https://www.facebook.com/Field-of-Armor-6th-Scale-Icons-165372040259765/

That pin-out diagram looks wrong; here is the pin-out straight from the Atmel data sheet:



And this is the HK connector diagram (which is upside down compared to the above):



As long as you align the dots, everything will be fine.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

The 250Ws should be fine.

The 450W perm magnet ones might be problematic. They are usually much more than 450W peak/stall at the rated voltage and the BEMF spikes are big. I did some testing on the 1hp winch motors (750W) I measured at > 500V and they have comparable inductance to Eteks (glen) so watch out.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

I believe even the 250W ones have the cobalt magnets and low inductance too
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

The MY1016Z's (250/350w versions) will be fine.



The MY1018Z's (250/450w) have the different magnets/low inductance and can throw some nasty spikes.

_________________
https://www.halfdonethings.com/

Thank you gentlemen. This is much helpful. I'm obviously NOT an electronics or robotic genius, since my education is in Chemical Engineering.

But I will test the flashing tool, and then the workings of the ESC with my motors. I will report to let you know what happened.

Usually with other ESC, we had a button on the ESC to calibrate the range on the transmitter stick. I don't see a button, so I will have to read on the ESC manual and see how this is setup

This feature is included in the retail version with the programming box @ BotBitz.com.

Otherwise you need to edit code.
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com