Rep1 voltage regulator replacement/upgrade: Is there a howto?

[Eric Pavey]

I've had my Rep1 since they first shipped, and it's been running like a champ.  The voltage regulator issue always gives me fear though:  I've read lots of forms/blogs about them going south, but what I haven't found is one that actually explains how to replace\upgrade it:  Usually they're just links to people asking for help.  I know there's a guy who has what looks like a breakout board on thingiverse that was supposed to solve it, but it looks like he's been AFK for quite a while now (I pinged him, never heard back).

Is it as simple as removing the old voltage regulator and soldering in a new one, or is more involved?  And if it is that easy, anyone know what the recommended replacement is?

Many thanks

[Joseph Chiu]

Yes. The main thing is to be careful when you do it.  Work carefully.  Mark the pins with a dab of paint to make sure you have the input, ground, and output right.  Otherwise, pffft.

[Darrell jan]

I was going to do it myself, when I read about others with lots more soldering experience that me, having problems. So I keep putting it off.

[Jetguy]

Don't worry, when it's time- it will let you know.

[Jetguy]

https://www.flickr.com/photos/90025904@N04/sets/72157639842879535/

[tramalot]

I use these, I just remove the old one which is easy with hot air, then solder it direct to the board shifted 1 pin to one side with a small jumper wire on the end pin.

try and find someone with a rework station is my advice, if the traces pull up things get fun

http://www.recom-power.com/pdf/Innoline/R-78Exx-0.5.pdf

[Jetguy]

+1

[Eric Pavey]

Thanks for the info guys, appreciated.

[Eric Pavey]

Jetguy, if you wouldn't mind elaborating on the photoset you posted (I'm guessing it's yours?), it looks like the voltage regulator was wired up two different ways:

One with a diode and cap:

https://www.flickr.com/photos/90025904@N04/11986676973/in/set-72157639842879535

And the other with the red and blue wire:

https://www.flickr.com/photos/90025904@N04/13425170183/in/set-72157639842879535

Was one way preferable to the other?

thanks

[Jetguy]

Sorry if this post is brief and doesn't completely answer. I'll try to get back to this.

Over time, I used various regulator modules- some were too large to attach to the board.

The round disk is not a capacitor, it is a resetable thermal fuse device- fully explained in a post on the subject in the MakerBot operators group

The diode was yet another layer of protection. The one by the USB port is actually a 5.1 volt Zener diode to safety buck the circuit so that it cannot exceed 5 volts.

Not all of that is required, but just extra steps.

[Jetguy]

The quick answer is this:

The OEM regulator is a simple 3 pin regulator

You are replacing with a different 3 pin regulator

The problem is, the stock regulator pinout is 

GND, Output, Input

Most every regulator we are going to replace is

Input, GND, Output

The solution is to slide the replacement regulator over nearer the USB port, solder a short wire to the input pin, and the  GND and output pins line up with the board.

That's it.

[Eric Pavey]

Your knowledge is much appreciated, thanks.

Time to order some parts...

[Eric Pavey]

Wanted to that you all again for the feedback:  I successfully did the replacement this weekend, went off without a hitch.  Blogged about the process as well, to maybe help others that run into the same issue:

http://www.akeric.com/blog/?p=2836

Go team Makerbot Users! :)

[Jetguy]

Hint, no cooling required.

That was never a heat issue. The boards simply failed because of the regulator failing and it was never heat related. In fact, we tell people to run without a fan at all.

[Eric Pavey]

It makes sense that it's just a bad component failing unrelated to heat, but you're saying the mightyboard needs no cooling fan at all?

[Dan Newman]

On 25/01/2015 9:36 PM, Eric Pavey wrote:
> It makes sense that it's just a bad component failing unrelated to heat,
> but you're saying the mightyboard needs no cooling fan at all?

Doesn't need it.

It's a remnant from early MakerBot MightyBoard designs. The boards were
failing in house before the Rep 1 was released. One or both of the linear
regulators were failing. They thought it was heat related. So they added
the fan. It may even have been heat related for the 3.3V linear regulator
which they were feeding the full 24V into its input. That's pushing the limit
for that regulator as about 20.7V goes into heat the chip must dissipate. To
heat sink the 5 and 3v3 regulators, they just used some copper on the PCB --
about the size of each regulator's tabs.

After they finalized the rev E board and produced them en masse, they then
realized that they should have fed the 5V regulator's Vout into the 3.3V
regulator's Vin. They manually cut the 24V input trace for the 3.3V regulator
on each and every board and hand soldered a wire from the 5V regulator's Vout
to the 3.3V regulator's Vin. Lucky for them they had also done the dumb
thing of putting the 3.3V regulator on the main board. It really should
have been on the other board with the SD card -- the consumer of the 3.3V
rail. Shipping the 3.3V over the ribbon cable along with the 5V was
not ideal, especially since they didn't put any reserve capacitance on
the LCD/SD/keypad board. (And no terminating resistors for the ribbon
cable either.)

At any rate, that fan wasn't needed. And it's my understanding that
most people at MBI disconnected their fans owing to the noise. The
internally-used Rep 1's which MBI gave to Jetty and myself in order
to port Sailfish had those fans disconnected as well.

And, as many folks know, the 5V regulators like to blow on MBI's rev E
mightyboards. Has nothing to do with that fan being there or not.

Dan

[tramalot]

the fan is just to stabilize the thermo chips.... half of 12 6 of the udder

[Eric Pavey]

Good history, thanks for the info guys :)

[Ryan Carlyle]

As long as the thermocouple amp chips stay below, say, maybe 80C or so, they don't need to be cooled or stabilized. They have a built-in thermistor that is used to compensate for cold-junction temp.

The main thing on any 3D printer mainboard that needs cooling is the stepper drivers, and stock Mightyboard BotSteps use low enough motor current that they don't need any supplemental cooling.