Mendel90 build: ATX power supply modifications

May 26th, 2015

Before even receiving my Mendel90 kit I knew that I’d need to prepare a power supply, since Nophead does not include one on kits shipped to the US. I’m pretty particular about power supply quality so I went ahead and got a Corsair CX430M, a very nice ATX supply which is probably overkill for this project. All the same, I’ve had too many experiences in which a bad power supply can mess up a project with difficult to diagnose problems.

Note that there is a very comprehensive guide to making these modifications on the RepRap wiki, as well as some specific steps in Nophead’s assembly instruction pdf.


Testing the 12V output by bridging green to ground with a small resistor



I used a 56 ohm resistor here, better than just shorting it

Hacked off the main ATX harness and ignored the additional harness modules

Hacked off the main ATX harness and ignored the additional harness modules

Tied off extra wires (3.3V, extra 5V, power good), so that they'll stay inside the bundle loom

Tied off extra wires (3.3V, extra 5V, power good), so that they’ll stay hidden inside the loom bundle

Used some large heatshrink to close off the main bundle with unneeded wires terminated  inside

Used some large heatshrink to close off the main bundle with unneeded wires terminated inside


Soldered the PWR ON to ground through a small resistor, then covered the whole thing in heatshrink. Will replace this later if I need some kind of soft power control.

Nophead recommends using all the ground leads, so I soldered them in a neat bundle. Hope it fits into the terminal on the controller board.

Nophead recommends using all the ground leads, so I soldered them in a neat bundle. Hope it fits into the terminal on the controller board. Like my 5-way braid?

Resulting output leads

Resulting output leads

Basically I ended up with the following outputs:

  • +12V (yellow bundle)
  • ground (black bundle)
  • Two extra ground wires, just in case (black)
  • Two +5V wires, for an Arduino etc (red)
  • Standby power wire, just in case (purple)
  • Soldered PWR ON to ground lead (green/black)
  • +3.3V bundle, capped off, again just in case (orange)

Controlling thumbnail generation on a Synology NAS

March 26th, 2011

Synology NASI’ve had a Synology NAS (an old DS107+, one of the earliest models) for several years now, and I love it for its simplicity of use and low energy/noise footprint as a home file/media server. I also like the fact that Synology does a pretty good job, for the most part, of keeping the software up to date and introducing nice new features.

However, when I upgraded my unit to version 3.1 of their Disk Station Manager (DSM) last week, I found that they had added a very undesirable “feature” which generates large thumbnail images for anything in your photo directory, apparently for use with the iPad app. Since I neither have an iPad nor have even enabled the PhotoStation component of the DSM software (which provides for a hosted web photo gallery–no thanks, I’m fine with Picasa web albums), I just wanted to turn this off. Furthermore, I found within a couple days of installing the update that the thumbnail generation process was constantly churning the disk and running the CPU at 100%, to the degree that normal file serving operations ran poorly. With the thumbnail process running, the unit could no longer even keep up with simple operations such as watching a video from the server over the normal Samba shares.

To my dismay, there is no option in the extensive DSM user interface to turn off this feature. I remember being slightly annoyed at this in previous versions, but it only made the system unusable once they added the XL thumbnails for the iPad app. (I have an nightly script that backs up my photo library to an offsite host via rsync every night, and I’d written it to ignore the @eaDir directories where the thumbnails are stored.) The synology forums seemed to be full of a lot of confused people trying to figure out how to turn off the thumbnail generation, but I was eventually able to identify the two key parts of the system that affect this.

If you want to simply disable XL thumbnail generation and leave everything else as-is, the file to edit is /usr/syno/etc.defaults/thumb.conf. You need to edit this file to remove the block starting with [thumb 1280]:

[thumb 1280]

Note that there’s also a /usr/syno/etc/thumb.conf, but on my system it didn’t have an XL thumbnail block so apparently the file in etc.defaults was overriding it. (BTW if you need help getting an ssh session into your box and editing files, there’s lots of help for that on the Synology site. I logged in as root and used vi.)

The thumb.conf file is read by a thumbnail generation daemon (service) that is started through /usr/syno/etc/rc.d/ So after editing the thumb.conf file you can either restart your system, or just restart this service:

/usr/syno/etc/rc.d/ stop
/usr/syno/etc/rc.d/ start

Once I did this, I no longer had “convert” processes at the top of my process list churning the hard drive and maxing out the CPU.

Alternatively, it sounds like you can also just prevent the thumbnail daemon from running at all on system startup. The rc scripts work a little differently from other *nix systems that I’ve used (although it’s been awhile); renaming the file didn’t appear to prevent it from starting when I tried that. The Synology wiki recommends adding a premature “exit” line right after the initial #!/bin/sh as a means of preventing a service from starting automatically (or ever, actually). I may go ahead and deactivate the process at some point but for now I was just satisfied that the XL thumbnails weren’t being generated.

In closing: Hey, Synology! Nice idea about the iPad gallery, but how about making it an option, once that’s not on by default, and with the warning that it will make older units practically unusable for their main purpose if activated?! I figured it out, but I’ve got some experience with *nix systems and the command line. I can see how a normal consumer user could be left completely helpless trying to address this problem and most likely end up blaming it on a (nonexistent) hardware fault.

Resetting a lost ViewSonic DVI connection

November 6th, 2006

I recently upgraded to a shiny new graphics card (NVIDIA 7900 GT) and was bummed when the DVI connection on my ViewSonic VA2012wb LCD monitor couldn’t detect a signal from it and just stayed in standby mode. At first I thought the card was just dead, until I tried using the DVI to D-Sub (analog VGA) adapter to send the monitor an analog signal, which worked fine. This mystified me, since the card and physical port were apparently working, but refusing to output a DVI signal. I’d just unplugged the monitor from my old DVI card, so I figured the monitor wasn’t the problem. Turns out the monitor was indeed (partially) the culprit.

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Two Words: Monkey Park

September 9th, 2006

This photo caught our monkey friend with his mouth open, since he was yelling something about expecting a really big banana for having to pose with these two idiots.

Now, anyone who knows me is certainly aware of my affinity for all things simian. Everything is better when you add monkeys, right? So imagine my surprise and delight when, upon exiting the train at Arashiyama station just outside Kyoto, I spot a large, colorful advertisement for the “Arashiyama Monkey Park”, adorned with cartoon drawings of various cherubic monkeys obviously enjoying themselves and beckoning me to join them. The ensuing conversation with my wife went something like this:

“Where should we go for lunch? How about that zaru-soba place?”

“Monkey park.”

“We’ll see that if we have time after the other stuff. Should we go to the shrine first?”

“Monkey park.”

[Various threats and admonishments in Japanese]


Hai, hai.

“Monkey park!”

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Two machiya in Kyoto

September 7th, 2006
Nunoya garden

Most machiya, including that housing the Nunoya ryokan, include a nice enclosed garden.

Finally managing to get out of Saijo for a few days of travel before returning stateside, we spent a few days in the old Japanese capital of Kyoto. We split our stay between a fairly expensive (for our budget) traditional ryokan, and a very inexpensive (by Japan standards) guest house. I’d expected a pretty wide gap in terms of quality of service and accommodations between the two, so I was very pleasantly surprised when the latter very nearly matched the former in terms of overall quality of experience.

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Noodles and beer

August 13th, 2006
I’m pretty sure I’ll be able to get this one up on

Yesterday was the beginning of the O-bon holiday in Japan, during which most people go home to the countryside to visit their families and pray to their ancestors. That being the case, the population of Saijo has now doubled or tripled, and I enjoy grumbling about all the “damn foreigners” with their fancy out-of-state license plates overrunning the highways.

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Willie Winkie

August 10th, 2006
Willie Winkie
In honor of the Willie Winkie bakery’s answering my “needs” with good combustible sandwiches, I have adopted their name as my new euphemism for the male genitalia.

There’s definitely been a change in the retail environment here in Saijo since my last visit two winters ago. Just like in the U.S., the big stores are moving in and pushing out the Main Street shops. So far I’ve counted at least three new supermarkets and four or five new giant drugstores, most of which are part of a chain called “Mac” (coincidence?). That basically increases the city’s allocation of each by more than double.

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Hoppy McBathtime

August 7th, 2006
Keitai Coke
This Coke machine takes payment via infrared transmission, cellular phone screen reader, or cellphone IC (prepaid?) card. This is in a city with no wi-fi access points.

Internet access has turned out to be another technical challenge out here in the countryside. I’d hoped to find a café or library with wireless access available, but even after inquiring at city hall we came up with nothing—the closest option is a MacDonald’s in a neighboring city, which is about a $10 train ride away. Actually, it turns out that I’m not even allowed to bring my laptop into the local library for some reason. The best we’ve been able to manage is an AOL Japan dialup account, which is free for the first month (which is as long as I need it anyway) but due to the high cost of landline phone calls here ends up costing a couple dollars an hour. Needless to say I will not be downloading American TV programs or playing any online games on this arrangement.

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Bathing via bicycle

August 5th, 2006
Japanese gardens are known for their fine stone sculptures, such as this stunning rendition of Ultraman taking a dump.

Despite my best efforts to take advantage of staying in downtown Osaka that first night, I wasn’t ultimately able to make it much past 9:00 before turning in. I was up early the next morning though, during which time I was able to take a quiet walk through the neighborhood before the oppressive heat and crowds set in. The bus ride from Osaka to Saijo City took about five and a half hours and would almost have been pleasant had it not been for two kindergarten-age sisters sharing a seat next to their entirely oblivious and/or incompetent mother, shrieking and singing and fighting and babbling for the whole trip.

Saijo is located in Ehime Prefecture, on the island of Shikoku, itself off the southern coast of the main island. There are a lot of rice fields and waterways here, owing to the plentiful natural springs that provide cool, clear water even in the heat of summer. The water is so good that Asahi Beer has a major plant here, and decorative fountains adorn the downtown sidewalks, from which people fill up jugs to use at home.

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Next time, I’ll take the bus

August 3rd, 2006
Mt. Fuji, I think
Mt. Fuji as seen from the plane. I think.

I’m pretty sure it was Mt. Fuji that I saw poking through the clouds shortly after our plane came within sight of land after our trans-Pacific crossing. Unfortunately I had nobody to point it out to at the time, since my wife had come to Japan about a month earlier due to a family health emergency, leaving me to make the trip on my own. As much as I enjoy traveling alone from time to time, there’s something sad about seeing something so majestic but not having anyone to share it with.

Rather than embarking on the 14-hour marathon of taking the all-night ferry to Nana’s home island directly from the airport, I opted to spend a night in Osaka. It’s been a few years since I’ve spent any amount of time in Japan by myself, and I was looking forward to poking around the downtown Umeda district that evening. Upon clearing customs and immigration at Kansai International (remarkably quickly compared to what I’m used to at Tokyo’s Narita airport) I headed for the airport’s JR train station.

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