Replicator Loud Pop, Spark, and Magic Smoke :(

[Chuck Joga]

Just venting and maybe someone knows how to fix this.  It looks like the voltage regulator blew.  I opened a support ticket, but maybe this is something that I can just replace myself and save some time.  I've been using this machine for about 5 months, but not heavily.  I read that there may be a short in the endstop that causes this problem.  So if there is a quick fix where I may be able to source some parts locally, that would be great.  My question is is there is specific "value" or part number of the voltage regulator that I might be able to find at Radio Shack or an electronics parts store?  I attached a pic below.

For those of you who received new motherboards, does Makerbot charge for replacements?  If so, how much?

Thanks,

-Chuck

[Martin Galese]

The bad news is that you probably won't be be able to replace just the voltage regulator.  When they blow, they tend to take a number of component with them and require replacement of the board.  The good news is that Makerbot hasn't been charging for replacements, at least for the 3(!) I've had now.

I find it frustrating that this is an issue apparently solved in the Rep 2 with better components and fuses, but that Makerbot just keeps shipping the same (flawed IMHO) design in the replacement boards for the Rep 1.  Basically, that voltage regulator is under considerable strain to step the 24V down to 5V and it is vulnerable to almost anything going south, be it a short or just ESD.  

-Chuck

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[Chuck Joga]

Free replacement sounds good.  Your assessment doesn't sound good as a long term prospect.  If they stop making the mobo, we're all in trouble.

The worst part is not having the machine available.  I'm already getting withdrawal symptoms. ;)  I'm hoping I can get this turned around quickly.

-Chuck 

On Monday, December 3, 2012 9:53:10 AM UTC-7, Martin Galese wrote:

The bad news is that you probably won't be be able to replace just the voltage regulator.  When they blow, they tend to take a number of component with them and require replacement of the board.  The good news is that Makerbot hasn't been charging for replacements, at least for the 3(!) I've had now.

I find it frustrating that this is an issue apparently solved in the Rep 2 with better components and fuses, but that Makerbot just keeps shipping the same (flawed IMHO) design in the replacement boards for the Rep 1.  Basically, that voltage regulator is under considerable strain to step the 24V down to 5V and it is vulnerable to almost anything going south, be it a short or just ESD.  

--
Martin Galese

[drando...@gmail.com]

I wonder if there's a component replacement? Maybe there's a way for use Rep1 people to be proactive and fix it before it blows?

[drando...@gmail.com]

Or maybe its thermal? I know those voltage regulators get hot. Maybe just putting a heat sink would help.

[Gary Crowell]

I don't know about the short in the endstop cables, but the basic problem is that the MightyBoard uses a linear regulator to get 5V from the 24V input voltage.  This is a simple and inexpensive way to do things, but it suffers from a basic problem.  If the board draws 100ma of 5V current, that's 0.5 Watts.  But to get that, the regulator must dissipate (24-5)*0.1 Watts, 1.9 Watts, as wasted heat.   I don't know what 5V current the MightyBoard actually draws, but if it's more than 100ma, then the wasted heat is proportionally higher.  Whatever, that's a lot of heat to get rid of in the regulator's non-heatsinked surface mount package.

I can imagine the design review where this decision was made; I've been there before:  Designer: "Here's the 5V regulator, a simple switching design that will cost about $2 in parts."  Manager: "Can't we just use this 30 cent linear regulator?"  Designer: "Sure, but it'll get hot..."  Manager: "Fine.  Linear it is."

...And they wind up spending 10x+ dollars more on replacement boards than it would have cost to just use the switching regulator.  (A switching regulator dissipates a fraction of the heat that a linear regulator does.)

The simplest and most immediate prevention you can do is to improve the cooling on the MightyBoard: Replicator MightyBoard Airflow Rework

If you wanted to get into the board, it would be possible to replace the existing regulator with a packaged switcher, something like: PT78HT205V   But that's not a simple replacement; it would require 'deadbug' mounting above the board somehow.  Not impossible, just not a drop-in.

And, as someone just mentioned, it would be possible to stick a heat sink onto the regulator.

The Replicator 2 board uses a switching regulator.

Gary

----------------------------------------------
Gary A. Crowell Sr., P.E., CID+

Linkedin  Elance  KE7FIZ

[Gary Crowell]

Oh, and BTW, as the inexpensive fans in the Replicator age and fail, more boards are going to pop.  Even a heatsink won't protect against that.

[Hammerhead]

Probably a good business decision on their part.

Put your business hat on for a second.

Would you go to the expense of redesigning an entirely new board, incur the cost of better (?) components, tie up your cash for a minimum order of 'x' many boards for a machine that's slated to go end-of-life shortly for the occasional 1 out of 500 boards that go bad?

It's faster and less expensive to just give you a new board, thus smarter.

[drando...@gmail.com]

I've been ecstatic with the airflow rework using Gary's side port idea and my divider fan mount idea combined. It's moving a lot of air over the board and even the exhaust air is fairly cool. I think as a precaution I might add a heat sink on the regulator just because. I've been lucky up to this point with not blowing any boards and my machine has been under heavy use since day one.

[Chuck Joga]

They are sending me a new board and X axis endstop cable also.  Gotta hand it to these guys for handling these problems quickly.  I'll probably do some kind of airflow mod also and maybe find a heatsink too.

-Chuck

On Monday, December 3, 2012 12:31:48 PM UTC-7, Mark Cohen wrote:

Makerbot is sending me a new board. I have also asked for a new fan as mine was getting loud. They said the issue is the x endstop cable and they are sending me that also. If people are having this problem more than once it is probably because they did not change the cable, they said. I don't lnow if all that is true but we will see.

[Chuck Joga]

What is the divider fan mount?  Is it on Thingiverse?

-Chuck

[Gary Crowell]

The divider fan mount is in Dave's thing:

Replicator Circuit Cooling Re-Designed

And I re-used it here:

Replicator MightyBoard Airflow Rework

Gary

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[Clinton Hoines]

All these posts about the Regulator failure scared me a bit when I first got my Replicator. I put a heatsink on it and mounted dual fans to cool the board. So far so good, hope it keeps on keeping on. :)

 

Clinton

 

 

[Dan Newman]

On 4 Dec 2012 , at 10:27 AM, Clinton Hoines wrote:

> All these posts about the Regulator failure scared me a bit when I first
> got my Replicator. I put a heatsink on it and mounted dual fans to cool the
> board. So far so good, hope it keeps on keeping on. :)

Pouring gasoline on the fire, I'll observe that my Rep 1 came with the fan
for the motherboard disconnected [1]. At some point I connected it, disliked
the noise, and disconnected it again. However, I did a while back replace the
regulator with a vertically mounted (TO-220 package) LM1084-5.0 with its own air
cooled heatsink.

By the way if you switch to one of those DC-DC switching regulators which Gary
cited, note that the pinout is different from a LM1084. And the cited unit
requires a 100 uF cap across the output and ground. Should not be a surprise
to anyone, but though I'd mention it.

Dan

[1] I suspect that my Rep 1 was being used briefly within MBI for some
purpose before it was sent to me as a loaner. So, it may have been someone
within MBI who intentionally disconnected the fan to limit the noise level
at their desk.

[Ethan Dicks]

On Tue, Dec 4, 2012 at 2:39 PM, Mark Cohen <markc...@gmail.com> wrote:
> So since i will have an extra motherboard soon, is it easy to change that
> part?

If you are used to surface-mount soldering, it should be easy - if
that's the only thing that blew.

I would heat and lift the leads from the PCB one by one, then heat the
body. That will take a bit of heat. A Chipquik kit (indium solder
alloy) would lower the heat requirements and minimize potential PCB
pad damage.

-ethan

[Dan Newman]

On 4 Dec 2012 , at 11:39 AM, Mark Cohen wrote:

> So since i will have an extra motherboard soon, is it easy to change that
> part?

The original LM1084 is in a surface mount package and not the easiest to
remove as its tab is soldered to the board and is of large area. If you're
used to doing rework and have a reasonable iron, then it's removable. Me, I'm
lazy and just cut the leads at its base (of the original regulator), desoldered
the leads, and then soldered in the new LM1084 and soldered the green wire from
the 3.3V regulator back in place. It's not the sturdiest vertical mounting, but
works.

Dan

[Dan Newman]

On 4 Dec 2012 , at 3:28 PM, Mark Cohen wrote:

> Exactly what i was thinking. Most of the thing is blown off anyway. How is
> the heatsink attached if it is standing up?

Clip on or Clip on & Screw TO-220 heatsink.

Dan

[Chuck Joga]

Finally got my replacement board and X-axis endstop cable.  I decided to make a cold air intake that doesn't require cutting the cabinet.  It seems to work great so I published it on Thingiverse.  I have a heat sink on order and will install that soon.  Hopefully this prevents the voltage regulator from failing due to heat.

http://www.thingiverse.com/thing:37387

Just a quick not on motherboard replacement.  Since, I have the single extruder, it was giving a message about not being able to read the temperature.  So had to set it to single extruder.  It also would not preheat the the preheat settings.  Re-flashing the firmware to 6.2 solved that problem.  Things seem to be back to normal for now.

-Chuck

[Dan Newman]

Mark Cohen wrote:
> I received and installed mine on Friday. Everything works fine. But I
> don't think a heat sink will do anything.
Personally, I think there are two issues: one is an overheating issue
associated with extended run times, and
second a short circuiting problem. And a nice short of Vin to Vout on
those regulators will blow them really
fast and really loudly. In theory they have Vin to ground and Vout to
ground protection, but that only buys
you so much. At any rate, I've been curious if there's actually a
condition under which the +5 and +24V
rails might short to one another. And keep in mind the tab on those
LM1084's is Vout and not ground and
it's the tab that those regulators dissipate heat through. So, if I
ever have my board out I want to look closely
at where the tab is soldered to the board and see if there's any 24V
traces too close nearby. Of course, such
a short could be anywhere if there's one at all.

Dan

[Gary Crowell]

I opened up the .brd file in Eagle, and there are two places where the 24V is in proximity to the +5V.  The first is on the backside, where the wide 24V trace from the power connector to the switch passes close to the corner of the filled area for the regulator's board heatsink.  The second is where the 5 and 24V LED's and resistors are next to each other just to the right of the regulator (R79, R80).  But I believe this is eliminated by the trace cut that moves the 3.3V regulators input from 24 to 5V.  I guess there is one other place; there are a pair of vias that take the 5V to a trace passing under the 24V to R108, just below the 5V regulator.  The vias aren't too far from the 24V trace.  Those vias *are* near where the 3V3 volt mod is made.  The rest of the 24V, looping across the bottom of the board, up the right side, and back across the drivers, seems pretty clear.

.pdf attached.

Gary

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[Jetguy]

Guys, going over the design and maybe this has been mentioned, we DO
NOT NEED the 5Volts at the endstops. All Makerbot electronics since
Gen3 have always used the internal pullups of the microcontroller and
sense when the endstop pin is shorted to ground pulling it low. The 5
Volts is only used to light the LED on the machincal switches. Back in
the day with the Cupcake used optical endstops, we needed 5 volts to
them, but never with the mechanical ones.

So, one thoery is that the endstop cables are shorting out and thus
blowing out the 5 volt regulator. All you need to do to prevent this
is remove the white wire from each endstop connector down at the
Mightyboard. I have personally tested this on a Dualhead Replicator.
Again, eliminate one possible cause of the blowouts.

On Dec 3, 11:26 am, Chuck Joga <chuckj...@yahoo.com> wrote:
> Just venting and maybe someone knows how to fix this.  It looks like the
> voltage regulator blew.  I opened a support ticket, but maybe this is
> something that I can just replace myself and save some time.  I've been
> using this machine for about 5 months, but not heavily.  I read that there
> may be a short in the endstop that causes this problem.  So if there is a
> quick fix where I may be able to source some parts locally, that would be
> great.  My question is is there is specific "value" or part number of the
> voltage regulator that I might be able to find at Radio Shack or an
> electronics parts store?  I attached a pic below.
>
> For those of you who received new motherboards, does Makerbot charge for
> replacements?  If so, how much?
>
> Thanks,
>

> <https://lh6.googleusercontent.com/-8AZnhplOhcI/ULzSVjU_f-I/AAAAAAAAGv...>
> -Chuck

[Jetguy]

Um, yeah, I kinda implied that, but you also won't let out the magic
smoke. Which is worse, an LED does't light up at the switch for luxury
function we could care less about or a board that doesn't blow up? The
LED is not required for function or even testing. Hell Sailfish
firmwares have and LCD function that shows the endstops function (at
least on Gen4 it does).

Again, while nice, also not worth the problem if that's causing boards
to go pop.

On Dec 15, 9:17 am, Mark Cohen <markcoh...@gmail.com> wrote:
> But then the LEDs will not light.

> > --- Hide quoted text -
>
> - Show quoted text -

[Jetguy]

Go get a paper clip and bend it so you have a leg straight. Then use
that to push on the tiny little bent metal tab in the side of the
black body of the connector that keeps the socket from sliding out.
The wire and socket slides out. When you sell it, put the wire and
socket back in. Nobody would EVER know. Take a piece of tape and
insulate it.

I just don't agree with your reason which is very weak to not do it.
An ounce of prevention or likelyhood of a major problem later. I mean
what good is a bot with a blown board? The instructions above are so a
novice can do it (for others on the forum). Please, don't take this
the wrong way. It's your machine and do what you feel is right for
you. You personally helped me out the other day.

Other people read this post and the instructions are really for them
as an alternative to your stance that it ruins the bot for later. In
other words, I'm trying to argue your stance on not doing it, not
directly with you.

On Dec 15, 10:15 am, Mark Cohen <markcoh...@gmail.com> wrote:
> True. But I hate modifying a machine that I might sell until I know for sure.

[Joseph Chiu]

It *is* their design and offering, so yeah, I'd have to agree with you.    

On Sat, Dec 15, 2012 at 8:39 AM, Mark Cohen <markc...@gmail.com> wrote:

Good idea.
I also dont mind asking makerbot for more motherboards if it blows. I figure its their fault anyway.

--

--
 
 

[Gary Crowell]

Did you get a discharge at the SD card, or the platform, or both, or someplace else?

Gary

On Tue, Jan 22, 2013 at 8:26 AM, Steve Lugovsky <st...@thelyonessgroup.com> wrote:

For the love of God... mine JUST blew like this exact same way 5 minutes ago :((((( Did they not ground out the case?!?!? I submitted a support ticket, hopefully they get back to me soon. Man, this is really too bad....

Did it take them a long time to get out the new board, etc?

Secondarily: Is the replicator 2 construction any better/less prone to these sorts of issues? (not sure I even want to go there, as I love ABS, and am not sure about PLA)

:(

Steve

On Sunday, December 16, 2012 4:50:55 PM UTC-6, Justin M wrote:

My 3rd MakerBot blew today.  As I was removing a print there was a small static discharge on the build platform.  I then placed my hand on the side of the Replicator near the SD card (as I always do when I navigate using the controls).  There was another small zap.  This time the screen flickered.  The system seemed like it was off, then it would click on, then instantly off again in a loop.  Like it knew there was a short somewhere (computers do this when they detect a short).  I turned it off asap.  When I turned it on, POP!  Smoke.  The voltage regulator literally exploded.  A big chunk was missing (right / top corner).

My first makerbot voltage regulator also blew when the power lines for the extruder fan bridged.  They are squeezed with a screw on the dual extruder models and they became frayed.  I observed smoke from these wires and turned off the machine.  When I turned it back on, POP!

So, lesson one, relocate the wires that power the cooling fans for the extruders.

Lesson two, discharge before operation.  Winter is prone to dry air.

When I got the replacement board for my first replicator, they sent a replacement cable for the X-Max port on the board (end stop).  It looked identical to the one already in place (numbers, and all).  Since I knew it was the fan power cables, I didn't risk replacing it since it was difficult to remove.

I've also had 2 makerbots fry the connector to the heated platform.  They sent me a better cable at request.  I recommend everyone check those.  If it starts to darken, you have an issue.  Mine started to show sparks and fried on pin 1.

--
 
 

[Steve Lugovsky]

Hi Gary, this discharge actually happened on the case frame, believe it or not. I was no where near the SD Card or platform. 

Thank you for the reply . I appreciate it.
THis is a sad day

[Gary Crowell]

Sorry to bug you in your time of grief.  Can you be specific as to where on the frame?  I'd like to get an idea of what the discharge path was, and how it got back to where it could do damage.

Gary

[Steve Lugovsky]

Hi Gary! You're not bugging me AT ALL. Thanks for the reply.

To answer your question: Specifically I had placed my left hand on the front top left corner of the unit, and my right hand onto the interface toggle button (was about to preheat the build platform).

I placed both hands approx the same time. I believe that my left hand was wrapped around touching the metal guides for the nozzle mechanism. This is where i "felt" the static discharge.

This is ironically, as I think about it, the position I take EVERY time I kneel down to fiddle with the thing. Funny, but true.

[Jetguy]

Steve sorry to hear about another failure.
I know it doesn't help but do not even try to re-use any of the
current system. Have Makerbot replace it all (Mightyboard, Botsteps,
and the LCD).
I know this because I had the exact failure the week before Christmas
and paid Makerbot for the extra shipping to get the replacements
Friday overnight delivery.

In the other thread of failure and prevention, I spent the Holidays
doing a lot of analysis of the system. When this happens, it kills the
8u2 which is the USB interface, it kills the Z botstep which is likely
what carried over the 24 volts into the 5 volts bus and blows the
regulator. Bascially, 24 volts has likely gone through all of the
logic chips on the board. There are 2 buffers on the LCD control panel
that may have been damaged, the 1280 may have survived but likely has
some inputs and outputs damaged and the 8u2 prevents any look inside
the 1280 anyway. Because the 8u2 is so tiny, most home soldering
repair work for SMT makes that impossible to replace. In other words,
don't bother with your time to replace the failed regulator, your only
going to the find the board unuseable and for most cases unrepairable.

If you want to prove for yourself, power the board with a controlled 5
volt source via the endstop connectors (I used some jumpers and stole
power from a FTDI cable) (an easy place with known 5 volt and ground
pins that will power the board)
Mine gave me the startup beeps, but even after removing the failed 8u2
and connecting a Sparkfun 8u2 in it's place, I foudn the serial lines
were destroyed in the 1280. So while it seemed maybe I could salvage
something and do minimal repairs, the truth is, 24 volts killed every
chip in some way. Just not worth the time or effort.

On Jan 22, 11:58 am, Steve Lugovsky <st...@thelyonessgroup.com> wrote:
> Hi Gary, this discharge actually happened on the case frame, believe it or
> not. I was no where near the SD Card or platform.
>
> Thank you for the reply . I appreciate it.
> THis is a sad day
>
>
>
> On Tuesday, January 22, 2013 10:54:45 AM UTC-6, Gary wrote:
>
> > Did you get a discharge at the SD card, or the platform, or both, or
> > someplace else?
>
> > Gary
>

> > On Tue, Jan 22, 2013 at 8:26 AM, Steve Lugovsky <st...@thelyonessgroup.com<javascript:>

> >>>>>> > >> >> <https://lh6.**googleusercontent.com/-**
> >>>>>> 8AZnhplOhcI/ULzSVjU_f-I/**AAAAAAAAGv..<https://lh6.googleusercontent.com/-8AZnhplOhcI/ULzSVjU_f-I/AAAAAAAAGv..>

> >>>>>> .>
> >>>>>> > >> >> -Chuck
>
> >>>>>> > >> > --- Hide quoted text -
>
> >>>>>> > >> - Show quoted text -
>
> >>>>>> > > --- Hide quoted text -
>
> >>>>>> > - Show quoted text -
>
> >>>>>> --
>
> >>>>>>  --
>
> >>>>  --
>
> > --
> > ----------------------------------------------
> > Gary A. Crowell Sr., P.E., CID+

> > Linkedin <http://www.linkedin.com/in/garyacrowellsr>  Elance<http://www.linkedin.com/redirect?url=http%3A%2F%2Fgaryacrowellsr%2Eel...>
> >   KE7FIZ <http://www.arrl.org>- Hide quoted text -

[Gary Crowell]

Dang.  I had been planning to put a grounded 'touch-plate' near the SD card.  Looks like it needs to extend elsewhere as well.  I've been putting it off 'cause I've got printing to do - probably should get at it.

I hope MBI will make it right for you.  Wondering when they're going to run out of replacements.

Gary

[Steve Lugovsky]

JetGuy,

Thanks SO much for the reply and the information here. They haven't gotten back to me yet, but when they do I'll let you know what they say.
I'ts a good thing I have some experience in soldering, etc. but what if you didn't? What if you were a designer that just wanted to make prints for quotes?

Gosh... it seems like that it a high expectation for your customer base.

Are you saying I need to pull the nozzle mechanisms for both stepstruders as well?

thanks a bunch

Steve

[Jetguy]

No, sorry if somehow I didn't say it clearly. The Mightyboard has the
5 botstep stepper drivers in sockets, and then the entire front LCD
control panel. Also ask for an M button and they might charge you 5
buck but that way, you have all shiny new and known to work parts,
rather than replacing just the mightyboard, and finding that the LCD
pannel buffer chips lock it up when it's plugged in.

The motors and stuff all should be fine. No reason to take any of the
mechanics apart.

> ...
>
> read more »- Hide quoted text -

[SteveO]

Jetguy, thank you for clarifying that! Im sure you were very clear. You are just dealing with someone who has a very basic understanding of this kind of thing, so thank you for your patience as well!

I have my fingers crossed....

[SteveO]

Quick question: No response for Makerbot support yet for my incident.

How long did they take to get back to you?

Steve

[Jetguy]

I called them, after opened a ticket. The number is on the card they
give with the bot.
I

[Shawn]

They are a little behind due to the sudden influx of new Rep2 owners
over the christmas break. At least this is what I was told with regards
to my support issue. If you sent a request and received a ticket #,
reply to the automated email that gave you the ticket #. I did this as
a follow up 3 business days after my initial request. I had a response
in a few hours after that. I *think* they are starting to catch up.

> --
>
>

[SteveO]

Thank you Shawn.  I haven't gotten a reply to my original ticket request yet. Thanks for the info.

Ive bee on the phone with them on hold for an HOUR so far (still holding as I type this). Unreal!

SO glad they are getting lots of business, but I hope it enables them to hire more people and serve their customers a bit better.

>          > read more �- Hide quoted text -

[SteveO]

The minute I hit "post" here, they answered! HAH! I take it back. :)

[SteveO]

They are sending me a new mighty board! Woohoo! The tech that answered the phone was AWESOME . Great guy. Super helpful.

I'l let you know how it goes!!

FYI Im in CHicago...it is -1 here, and very dry. Static electricity is extremely prevalent right now. I'll make sure to ground myself out before I touch this thing in the future.

[Jamesarm97]

What is the current on the 5V side? We use these at work and are usually a drop in replacement. 7-36V in, 5V 1.5amps out (switching). http://www.digikey.com/product-detail/en/OKI-78SR-5%2F1.5-W36-C/811-2196-5-ND/2259781

On Monday, December 3, 2012 1:11:28 PM UTC-5, Gary wrote:

I don't know about the short in the endstop cables, but the basic problem is that the MightyBoard uses a linear regulator to get 5V from the 24V input voltage.  This is a simple and inexpensive way to do things, but it suffers from a basic problem.  If the board draws 100ma of 5V current, that's 0.5 Watts.  But to get that, the regulator must dissipate (24-5)*0.1 Watts, 1.9 Watts, as wasted heat.   I don't know what 5V current the MightyBoard actually draws, but if it's more than 100ma, then the wasted heat is proportionally higher.  Whatever, that's a lot of heat to get rid of in the regulator's non-heatsinked surface mount package.

I can imagine the design review where this decision was made; I've been there before:  Designer: "Here's the 5V regulator, a simple switching design that will cost about $2 in parts."  Manager: "Can't we just use this 30 cent linear regulator?"  Designer: "Sure, but it'll get hot..."  Manager: "Fine.  Linear it is."

...And they wind up spending 10x+ dollars more on replacement boards than it would have cost to just use the switching regulator.  (A switching regulator dissipates a fraction of the heat that a linear regulator does.)

The simplest and most immediate prevention you can do is to improve the cooling on the MightyBoard: Replicator MightyBoard Airflow Rework

If you wanted to get into the board, it would be possible to replace the existing regulator with a packaged switcher, something like: PT78HT205V   But that's not a simple replacement; it would require 'deadbug' mounting above the board somehow.  Not impossible, just not a drop-in.

And, as someone just mentioned, it would be possible to stick a heat sink onto the regulator.

The Replicator 2 board uses a switching regulator.

Gary

On Mon, Dec 3, 2012 at 9:53 AM, Martin Galese <mar...@galese.net> wrote:

The bad news is that you probably won't be be able to replace just the voltage regulator.  When they blow, they tend to take a number of component with them and require replacement of the board.  The good news is that Makerbot hasn't been charging for replacements, at least for the 3(!) I've had now.

I find it frustrating that this is an issue apparently solved in the Rep 2 with better components and fuses, but that Makerbot just keeps shipping the same (flawed IMHO) design in the replacement boards for the Rep 1.  Basically, that voltage regulator is under considerable strain to step the 24V down to 5V and it is vulnerable to almost anything going south, be it a short or just ESD.  

On Mon, Dec 3, 2012 at 11:26 AM, Chuck Joga <chuc...@yahoo.com> wrote:

Just venting and maybe someone knows how to fix this.  It looks like the voltage regulator blew.  I opened a support ticket, but maybe this is something that I can just replace myself and save some time.  I've been using this machine for about 5 months, but not heavily.  I read that there may be a short in the endstop that causes this problem.  So if there is a quick fix where I may be able to source some parts locally, that would be great.  My question is is there is specific "value" or part number of the voltage regulator that I might be able to find at Radio Shack or an electronics parts store?  I attached a pic below.

For those of you who received new motherboards, does Makerbot charge for replacements?  If so, how much?

Thanks,

-Chuck

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[Jetguy]

Current is not the problem. I did a post in the other thread, worst
case is less than 400mA. Typically under 250mA all the time.
The issue is not the regulator. I am getting failed boards from people
and it's pointing at the Z botstep failing. When that happens, the 24V
is backdeeding the 5 volt rail which then blows the regulator, but the
damage is already done. Anything over 5 volts kills the 8u2 dead, and
thus you have no USB to serial coms. I also found that tends to kill
the 1280 serial port too, even after the 8u2 (which is very hard to
remove and not damage the PCB traces) is removed. Sp basically, all
the chips are 5 volt and all get blown. There isn't much in the way of
repairs even if your good unless you have a reflow oven.
Again the regulator is not the fault, it's blowing because of another
fault. I also don't buy the BS idea the endstop cable shorting is the
cause. That stock regulator is 5 Amp rated and should at least begin
to smoke the wires long before the regulator dies or burn a trace on
the board.

On Jan 24, 3:41 pm, Jamesarm97 <armstrong.ja...@gmail.com> wrote:
> What is the current on the 5V side? We use these at work and are usually a
> drop in replacement. 7-36V in, 5V 1.5amps out

> (switching).http://www.digikey.com/product-detail/en/OKI-78SR-5%2F1.5-W36-C/811-2...
>
> <http://media.digikey.com/photos/Murata%20Photos/MFG_OKI-78SR.jpg>

>
>
>
> On Monday, December 3, 2012 1:11:28 PM UTC-5, Gary wrote:
>
> > I don't know about the short in the endstop cables, but the basic problem
> > is that the MightyBoard uses a linear regulator to get 5V from the 24V
> > input voltage.  This is a simple and inexpensive way to do things, but it
> > suffers from a basic problem.  If the board draws 100ma of 5V current,
> > that's 0.5 Watts.  But to get that, the regulator must dissipate (24-5)*0.1
> > Watts, 1.9 Watts, as wasted heat.   I don't know what 5V current the
> > MightyBoard actually draws, but if it's more than 100ma, then the wasted
> > heat is proportionally higher.  Whatever, that's a lot of heat to get rid
> > of in the regulator's non-heatsinked surface mount package.
>
> > I can imagine the design review where this decision was made; I've been
> > there before:  Designer: "Here's the 5V regulator, a simple switching
> > design that will cost about $2 in parts."  Manager: "Can't we just use this
> > 30 cent linear regulator?"  Designer: "Sure, but it'll get hot..."
> >  Manager: "Fine.  Linear it is."
>
> > ...And they wind up spending 10x+ dollars more on replacement boards than
> > it would have cost to just use the switching regulator.  (A switching
> > regulator dissipates a fraction of the heat that a linear regulator does.)
>
> > The simplest and most immediate prevention you can do is to improve the

> > cooling on the MightyBoard: Replicator MightyBoard Airflow Rework<http://www.thingiverse.com/thing:33779>

>
> > If you wanted to get into the board, it would be possible to replace the
> > existing regulator with a packaged switcher, something like: PT78HT205V

> > <http://www.digikey.com/product-detail/en/PT78HT205V/PT78HT205V-ND/307220>

> >   But that's not a simple replacement; it would require 'deadbug'
> > mounting above the board somehow.  Not impossible, just not a drop-in.
>
> > And, as someone just mentioned, it would be possible to stick a heat sink
> > onto the regulator.
>
> > The Replicator 2 board uses a switching regulator.
>
> > Gary
>

> > On Mon, Dec 3, 2012 at 9:53 AM, Martin Galese <mar...@galese.net<javascript:>

> > > wrote:
>
> >> The bad news is that you probably won't be be able to replace just the
> >> voltage regulator.  When they blow, they tend to take a number of component
> >> with them and require replacement of the board.  The good news is that
> >> Makerbot hasn't been charging for replacements, at least for the 3(!) I've
> >> had now.
>
> >> I find it frustrating that this is an issue apparently solved in the Rep
> >> 2 with better components and fuses, but that Makerbot just keeps shipping
> >> the same (flawed IMHO) design in the replacement boards for the Rep 1.
> >>  Basically, that voltage regulator is under considerable strain to step the
> >> 24V down to 5V and it is vulnerable to almost anything going south, be it a
> >> short or just ESD.
>

> >> On Mon, Dec 3, 2012 at 11:26 AM, Chuck Joga <chuc...@yahoo.com<javascript:>

> >> > wrote:
>
> >>> Just venting and maybe someone knows how to fix this.  It looks like the
> >>> voltage regulator blew.  I opened a support ticket, but maybe this is
> >>> something that I can just replace myself and save some time.  I've been
> >>> using this machine for about 5 months, but not heavily.  I read that there
> >>> may be a short in the endstop that causes this problem.  So if there is a
> >>> quick fix where I may be able to source some parts locally, that would be
> >>> great.  My question is is there is specific "value" or part number of the
> >>> voltage regulator that I might be able to find at Radio Shack or an
> >>> electronics parts store?  I attached a pic below.
>
> >>> For those of you who received new motherboards, does Makerbot charge for
> >>> replacements?  If so, how much?
>
> >>> Thanks,
>

> >>> <https://lh6.googleusercontent.com/-8AZnhplOhcI/ULzSVjU_f-I/AAAAAAAAGv...>

> >>> -Chuck
>
> >>> --
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>
> >> --
> >> Martin Galese
>
> >> --
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> > --
> > ----------------------------------------------
> > Gary A. Crowell Sr., P.E., CID+

> > Linkedin <http://www.linkedin.com/in/garyacrowellsr>  Elance<http://www.linkedin.com/redirect?url=http%3A%2F%2Fgaryacrowellsr%2Eel...>

> >   KE7FIZ <http://www.arrl.org>- Hide quoted text -

[Dan Newman]

> I also don't buy the BS idea the endstop cable shorting is the
> cause. That stock regulator is 5 Amp rated and should at least begin
> to smoke the wires long before the regulator dies or burn a trace on
> the board.

And the regulator has short circuit protection for both Vout <-> gnd
and Vin <-> gnd. But as anyone who has ever done destructive testing
on these linear regulator knows, you can blow them quite simply
by shorting Vout <-> Vin. It's not instantaneous that they explode --
rather it does some internal damage and then some seconds til a minute or
so later it explodes, presumably from internal heating. And looks just
like the pictures I've seen.

Thus my unsubstantiated, empirical theory that at least some of the
failures have been from 24V spilling onto the 5V rail as that's
a Vin <-> Vout short.

Dan

P.S. So playing around in physics lab counts as destructive testing, right?

[Andrew]

Hey guys.

Jetguy pointed me to this thread from another thread.  I didn't realize the problem & solution for board failures had actually been discovered.

Which replacement regulator would y'all recommend I buy?

Two replacements were mentioned:

http://www.digikey.com/product-detail/en/OKI-78SR-5%2F1.5-W36-C/811-2196-5-ND/2259781

http://www.digikey.com/product-detail/en/PT78HT205V/PT78HT205V-ND/307220

I don't mind paying $20 bucks over the $5 component if it will do the trick and extend the life of my Rep1 and prevent board failure.

BTW, I know almost nothing about circuits/wiring/voltage/amps etc.  I have done some soldering over the summer, so I at least know how to do that.

thanks

-Andy

[Clinton Hoines]

I bought the first one on Jetgguys recommendation, works perfect.