Friday, August 28, 2009

Orion Surgery

My Ten-Tec Orion transceiver was 5 years old in February. It's getting to be an old timer -- in computer years, at least. It needed a few chores done.
  1. The LCD panel was flickering. Internet scuttlebutt says this may be because of impending failure of filter capacitors that were undersize (in terms of ripple current handling).
  2. With the current version 2.xx firmware, the LCD contrast is close to zero after a hardware reset. This can be a serious problem, depending on room temperature. Contrast is normally set via a menu adjustment -- that requires you to navigate through the LCD display. The display could be so faint that you couldn't make the adjustment. There is an internal bias control that should fix this.
  3. Finally, I have been seeing the "RIT freeze" problem that others have noted. At times, the RIT control loses the ability to make any adjustments. Many people have reported this problem, but the cause and cure have not been well understood. It seems that you can fix it temporarily by grabbing the RIT/XIT encoder control and twisting hard in odd directions -- as if there were a bad solder joint on the PC board. A recent report suggests the trouble is actually with one of the board-to-board connectors making unreliable contact.
All the above have been discussed on the helpful Ten-Tec reflector, which I recommend to other Orion users. I have been saving up these problems for some time now. Hopefully, I only have to disassemble the Orion once!

Making a long story short, I pulled the rig out of my operating position, unplugging many cables, unscrewed many screws, and finally spread out the works on my bench. The RIT fix requires disassembling the front panel and the LCD/computer board. That's a fairly big operation, particularly since a wrong move with a tool could lead to a very costly repair job.

I located and replaced 3 electrolytic capacitors on the A9 board with higher voltage, low ESR units, per the helpful analysis of N6IE. Soldering was tricky, to prevent inadvertent short circuits and to get enough heat into the ground connections, which were not thermally isolated from the big ground planes on either side of the board. (That could have been avoided by a better PCB layout!) OK. That's problem #1 done.

The email instructions say that to solve #3, you need to look for bent or misaligned connecting pins on the computer / LCD board. I looked very carefully, but saw no misalignment or other problem. Still, it's possible there was some oxidation or dirt. I cleaned the pins and the sockets as best I could. So problem #3 might be resolved.

The LCD bias issue (#2) turns out to be easy. There is a control on the LCD/computer board that sets the default bias for the display. You just adjust it for a good display with the LCD menu set at the default 50% level (and of course with the power on and the rig having a chance to warm up).

Accomplishing all this, I reassembled the Orion and put back all those screws, and put the rig back in the operating position. Everything appeared to work, except no transmit power. Oops! There are a lot of reasons why this could happen. Fortunately, I did not smell smoke, and that eliminated some of the more expensive possibilities. Still, I'm not sure how much bench testing and repair I would be able to do, if this turned out to be a non-trivial problem. Thinking of where that shipping box might be, and how much Ten-Tec charges...

So, what did I really do in that repair process? I changed out the capacitors, true, but the fact that everything works in receive mode indicates that the power board was probably working. The other thing I did was to unplug many internal cables, disassemble the LCD boards, and reassemble. There could be a loose connection or a misplaced cable.

The problem was "fixed" by opening up the box all the way again, and carefully reinstalling all the cables and screws. We have transmit power for now. I hope it stays that way!

The triple repair job is done. The LCD is behaving much better than before, and at least for now, the RIT/XIT controls work smoothly.

One thing I hadn't counted on was the trouble of reconnecting my ratsnest of cables to the Orion. I have a linear, a transverter, computer audio and controls, and other gadgets that need to be connected. All these just got hooked up over several years, and of course I had nothing documented on paper. Figuring out how to reconnect took a while, but it should be better next time. Now the cables have labels on them. Documentation is still pending...

Friday, August 21, 2009

Atomic Disintegration

My new, humble computer based on Intel's Atom CPU was a great little project at a low cost. It benchmarked at about half the performance of my older Athlon XP 2000+ on a per-thread basis, and it provided two hyperthread "processors" for Linux to use. All for about $64 for the board and CPU. (And it is 64-bit capable, but the value of a 64-bit OS is unclear in such a small system.)

Then, for larks, I set it up to run as a member of my World Community Grid effort. That had it running two threads for 24 hours a day. This was somewhat pointless, given that the new Intel Core i7 system is so much more powerful*, but it did manage to churn out some work-units for the Cause.

All was well for about 4 days. Then ping!, the Atom froze. I could reboot into BIOS sometimes, but couldn't load Linux or even memtest86+. An actual hardware failure -- I haven't seen many of these in recent years.

Over a period of days, I got more acquainted with my UPS driver, as I tried substituting various parts. Suspecting the hard drive or CD/DVD drive (old IDE technology). Tried a substitute 1 GB DDR2 RAM. No help.

So the fault was either in the Intel D945GCLF motherboard or the power supply. The motherboard has about 10 million times more transistors, so that seemed the likely culprit.

Using Amazon.com's amazingly efficient returns/exchange process, I had a new mobo in quick order, and all now seems well.

Do I dare run the WCG application any more?

As to ham radio, this system is my logging and digital modes computer for AA6E. We were dead in the water. I could have fallen back to my mic or key and used paper logging, but I wasn't quite that desperate!

--
* Both in absolute (45,232 MIPS vs 3,060 MIPS) and in power-specific terms (302 MIPS/W vs 64 MIPS/W).

Thursday, August 13, 2009

Comparative Blogging

I thought I'd try setting up a blog using the new WordPress facility at the famous Open Source Software facility - SourceForge.net. So far, the format is a little disappointing. What do you think?

Update 8/21/09: I see that the SourceForge.net blog (above) now sports a reasonable (if unimaginative) blueish skin. SF has now provided us with two (count them, two) themes!

Tuesday, August 11, 2009

Grid Progress

The big application for Gimli (Intel Core i7 system, described earlier) has been participation in the World Community Grid, which is an IBM-sponsored project for channeling volunteer computer systems into a "grid" that can apply supercomputer-level power to selected scientific problems, mostly in life sciences. WCG uses the BOINC framework from UC Berkeley. There are many other grid projects using BOINC, and that's where most of the physical sciences and math projects seem to be. (And where my sympathies really lie. I may have to jump off the WCG ship eventually.)

My desktop system is "competing" against zillions of computers (1,328,064 "devices" under control of 468,410 "members"). On the one hand, many members have tried the project but have not actively contributed. On the other, many of the members command fleets of computers in academic or industrial settings, and are able to direct much of their otherwise wasted CPU cycles to the WCG.

In my case, my one computer, running 8 parallel threads, delivers about 8 days of "computing" for every calendar day. My rank in the WCG project is improving on a daily basis. About 30,000 members have provided more processing power (over the lifetime of the project) than Gimli has in about 6 weeks. We'll never be #1, but we should be able to climb the ladder for some time to come.

Remarkably, Gimli is able to run 8 CPU-bound jobs around the clock (at low "niced" priority) without significantly affecting interactive work - - browsing, email, office applications, etc. Only in a few cases is there a noticeable slowdown, e.g., firing up a large VMware image to run Windows XP.

Readers of this blog may ask what all this has to do with Amateur Radio - our raison d'ĂȘtre. That's a good one. I am looking for ham applications that can profit from high-power desktop computing. You might think that Software Defined Radio would be one, but the SDR work I know of really works well in smaller-scale systems. Digital video would be a candidate. Do you have suggestions?

Friday, August 07, 2009

Gimli Perfected

If you read my earlier post, we left this new Gimli system (Intel Core i7 920) on the edge in terms of operating temperatures and cooling. We experimented with ducting and undervolting and got almost to the point of running at an acceptable temperature at full CPU load. Almost, but not quite.

The problem was Intel's default stock chip cooler system, which is marginal if you want to run full out for an extended period. Marginal, at least, if you don't implement their recommended side ducting system.

I wanted to get this problem solved so that I will not have to watch my operating temperatures so closely while running BOINC or other intensive applications. After some research, I ordered the Cooler Master V8, a large heat pipe / radiator / fan system that fills up my computer case very nicely. (Leaving a little room, but not much, for hooking up the wiring afterward. This kind of assembly is not for everyone.)

The following photo gives an idea of the scale and airflow. The flow from the cooler's embedded fan conveniently goes directly to the case's rear exhaust fan.
The bulk of the radiator system really does take up nearly all the volume above the CPU, but fortunately there were no mechanical interferences on my Gigabyte EX58-UD4P motherboard or RAM. The whole thing just fits in the Antec case without trouble. It does weigh almost 900 g (about 2 pounds). While the motherboard mounting seems fairly secure, I am sure that my computer will not fare too well if dropped on a concrete floor.

Results

The quick before and after comparison, with my undervolted i7 (Vcore=1.01250 V):

Temperatures are (Tgpu, Tcore, Tamb, Tchip in deg. C)
8 threads of BOINC code (Proteome Folding Project)

Before: 48, 80, 39, 75
After: 45, 52, 36, 45

The final (chip) number is the best one to focus on. An improvement of 30C is a lot more than I had expected, but I will accept it! This is all with the cooler fan running at 1767 rpm. It will run up to about 1970 rpm, but that noticeably adds to the noise level. The higher speed does not lower the operating temperature by much. We might need to speed up the case's exhaust fan if we care about cooling more than noise. (I don't!)

I should emphasize that "normal" interactive computer operations would be much less than the 100% load we are discussing here, so that even the stock Intel cooler would be fine. On the other hand, if you are spending the money for the i7 system, why wouldn't you want to run it full blast?

According to my (perplexed) intuition, having read much of the Intel literature, it should be fine to run at a chip temperature of 60 C, at least. So there is a lot of headroom to explore overclocking with higher core voltages.

Sunday, August 02, 2009

New Atom System

The latest computer system to come to life here at AA6E is based on the Intel Atom 230 processor. The Atom (out for a year now) uses the latest 45 nm fab technology for a chip that is optimized for low power consumption, but it supports either 32- or 64-bit operating systems and hyperthreading, giving the appearance of a dual-core system to the OS.

I bought the Intel D945GCLF board, which has the mini-ITX format -- it's really small compared to my other ATX and mini-ATX systems.

Intel D945GCLF Motherboard and Atom 230 Processor

The board mounts nicely in a spare Mini-ATX computer case, with all kinds of room to spare. I attached an older 20 GB hard drive and DVD to the legacy IDE port. Eventually, I may repackage the system into a smaller case, with more modern IO devices. But one of the nice features of the motherboard is its support for ancient interfaces -- Serial, Parallel, PS/2 Mouse, keyboard, and IDE, along with newer SATA, USB, etc.

The focus for me was low power consumption and low out-of-pocket cost. The CPU is supposed to require only 4 W and the basic board was $64 at Amazon, including CPU but no RAM. The major glitch building the system was that my numerous old PC power supplies did not supply the ATX12V connector (the 4 pin 12 V CPU power connector) or any SATA-style connectors. So, while I might have been able to wire up some connectors to use with an older supply, I sprang for a new unit. Selecting one was not as easy as it might have been. The power demand is minimal (under 100 W), but if you want "quality" (efficiency, power factor, noise filtering), those features are promoted for larger supplies. I ended up with a 500 W, $35 unit.

Performance

A thorough review of an Atom 230 system is available at Tom's Hardware. I did some testing that is more specific to my environment, comparing it with other systems here.

A favorite benchmark, which works with multi-threaded systems, is to "make" the hamlib system from source. (I am a Hamlib developer.) The make "-j" switch lets you specify how many parallel threads to divide the workload into. This is a useful test for some kinds of programming work, but it is hardly representative of all possible applications.

Pentium III 800 MHz
(This is the one that the new Atom system will replace.)
  • Idle power: 112 W (AC at wall plug)
  • Make (single thread) : 483 sec.

Athlon XP 2000+
  • Make (single): 239 sec

Core i7 920 (See prior article here and here.)
  • Idle power: 100 W
  • Full CPU load: 150 W
  • Make (-j 1): 41.8 sec
  • Make (-j 8): 17.3 sec
  • Make (-j inf.): 16.1 sec

Atom 230
  • Idle power: 40 W
  • Make (-j 1): 276 sec
  • Make (-j 2): 229 sec (showing improvement by hyperthreading)
  • Make (-j inf.): requires excessive virtual memory, never completes

Conclusion

The Atom-based system works very nicely for my application: running all my ham radio operations - digital modes (fldigi), logging (xlog), transceiver control, etc. The system has a responsive "feel" under Ubuntu that is equal to anything I was using before my Core i7 system came along. The low operating power and silent operation are pluses, and the small board size would be handy if I put it into a smaller case. Cheap is good, too.

Update:
BOINC benchmarks, Atom 230 (40 W)
612 floating point MIPS (Whetstone) per CPU
1530 integer MIPS (Dhrystone) per CPU

BOINC benchmarks, i7 920 (150 W)
2450 floating point MIPS (Whetstone) per CPU
5654 integer MIPS (Dhrystone) per CPU

Since the i7 920 has 8 "processors" (4 cores) and the Atom 230 has 2 "processors" (1 core), the i7 is much better in CPU MIPS per Watt.

KY Amateur Radio in the NY Times

In Kentucky, Officials See Ham Radio as a Backup


OWENSBORO, Ky. (AP) — Local officials are turning to older technology to solve some of the communication problems they encountered during January’s ice storm and the windstorm after Hurricane Ike in 2008.

Full article...

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