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TS-930 update

October 9th, 2008

TS-930S AVR board

Thanks to KA5IPF and WE0H, who answered my query on the TS-930S reflector! The oscillation was due to dried-out electrolytic capacitors on the AVR board and unhappy pass transistors on the heatsink in the back. I bought 105 C capacitors instead of the 85 C ones that Kenwood used, plus bumped the voltage rating up to 63 V instead of 50 and 35. Fortunately, I still had some leftover 2N5886’s, but I need to buy a replacement set of capacitors and pass transistors to have on hand in case the other radio fails. I haven’t tested it in contest conditions, but all signs are good that we should be ok. Maybe the NS tonight?

Have a Synton ARC (sorry about the ancient web site…we are going to fix it…sometime) meeting at 2:00 today. Everybody else in the Club is building SoftRocks. I’m bringing my IK4AUY preamp parts to start building. Need to order some PL-259’s, probably today. Yeah, and I need to finish writing my prelim exam document and presentation. So much to do. So little time.

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TS-930S power supply

September 28th, 2008

Benched TS-930S

Remember how I said that I thought the W9RE switchbox had terrible isolation? Well, although I didn’t measure it with a VNA, I was doing some testing the other day and noticed that it only seemed only bad when the left radio was transmitting. For example, I put the left radio on 40 meters and the right radio on 20 meters. There was terrible broadband hash whenever I closed the PTT line on the left radio. So, I put the right radio on 40 and the left radio on 20 and transmitted again on 40. No hash, just some faint trash that followed the keying.

I had noticed during the Sprint that the vacuum fluorescent display on the left radio was flickering following the keying. But, I didn’t give it much thought until now. I flicked the meter selection switch to Vc and sure enough, it was too high (>28 volts) on transmit. Plus, it would spike and pin the meter whenever I released the key.

Today, I built a band decoder cable (fortunately, I had stocked-up on the mini-DIN plugs and the PIEXX board uses Yaesu BCD format) for the Yaesu FT-840 and put it into the left radio position. It’s clean, too.
The left ‘930 is now on my workbench, which is barely large enough for it. It turns out that there is a substantial (4 volts peak-to-peak) ripple on the power supply when I close the PTT. I sent a note to the TS-930S reflector; but, unless KA5IPF answers it, I’m probably on my own. I suspect it’s just going to be a matter of disconnecting subsystems until I find the offender.

Until then, I’ll be using the FT-840 and the old TS-930 for SO2R. But, at least I’ll be able to hear! I’m also relieved that I probably won’t need to rewire W9RE’s switchbox. I just need to build some short jumpers and W3NQN filters for all bands.

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Station Automation, Part 1.5

August 18th, 2008

Over the weekend, I finished populating the KK1L controller board. Due to some boneheadedness, I managed to destroy two of the CMOS ICs. I have a large cache of 74xx and 74HCxx series parts, but no 4000 series. So, I ordered some more from Mouser. Turns out that NO9Z needed some more of them, too. At least the we had the foresight to socket the ICs. Half of the board works since the parts I destroyed were in the radio B circuit. Thank goodness for small favors.

The next problem was the PIEXX boards in the TS-930S’s. Chris at PIEXX had sent me the band data output information many moons ago. However, that’s the one e-mail account I apparently failed to archive over the past decade. Ooops. I filed a comment through the PIEXX website; but, I still haven’t heard anything. I also inquired on the TS-930S and SMC e-mail reflectors with no success. Armed with a volt-meter and a little knowledge, I was able to deduce the following on J19 (8P8C/RJ-45):

Pin	Function
1	Band Data D (MSB)
2	+5V
3	Band Data C
4	GND
5	Band Data B
6	?
7	Band Data A (LSB)
8	?

The band data are in the standard 4-bit Yaesu format enumerated beginning with 0001 on 160 meters.

Sarah was working on her Adirondack chair project on the front porch on Sunday afternoon; so, I elected to join her outside and build a 10/15-meter fan dipole. On 10/15 and 80/160, I’m adding a second relay box to select the correct W3NQN filter but share the antennas. Given the amount of activity on 10 and 15 right now and my preference toward domestic contests from home, this is an acceptable move. Ordinarily, I would like to have 80 and 160 separate; but, the geometry of our lot just won’t permit it without using a vertical on 80. Even when I stapled radials in the lawn, the man who cuts the grass managed to pull two of them up. Given that my primary foci are SS and the Sprints, the ability to be on both 80 and 160 is just not that important.

The fan dipole is coarsely tuned-up and ready to be installed. I have some ideas on where to put it; but, I haven’t made it up into the tree, yet.

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Bench Time: Airplane and a TS-930 repaired

April 23rd, 2008

As I lamented in the last post, I am surrounded by ailing gadgets in need of repair. Last weekend, I tackled two of them. The first was the airplane. A gust of wind had destabilized the plane sending it crashing to the ground. The front set of pegs where rubber bands attach the wing were sheared-off. A trip to a craft store with Sarah yielded an “1/8-inch” dowel and a sack of miniature thread spools. I reamed-out two of the spools and press-fit them to the dowel for a slick replacement (sorry, no photo). I have not flown the plane again, yet. However, the weather has changed favorably. So, that should happen any day now.

My older TS-930S developed a PLL unlock error over time. The error occurred when I changed bands or modes. Fortunately, several months ago, the topic had been discussed on the TS-930/TS-940 reflector, although I was just getting around to thinking about it. Clif Holland, KA5IPF, who has repaired Kenwood radios for many years, suggested that a common culprit is the 36.1-MHz heterodyne oscillator in the signal unit and prescribed a simple adjustment of L77. It took a little while to adjust it to my satisfaction. Indeed, I wasn’t even sure I’d made any improvement at all at first. However, once the radio warms up, band and mode changes are seamless again! This sure helped out for fast QSYs in the Michigan QSO Party.

On the topic of TS-930’s, I’m still having woes on SSB with the other radio. I swiped (and promptly returned) a microphone from the TS-850S at W9YH to ensure that the problem wasn’t my Pro-Set. It has to be something between the mic jack and the signal unit. But, the mic jack is a real pain to get to. Someday.

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Repairs and junk…

April 13th, 2008

One of the curses of attempting (I say ‘attempting’ because I’m mostly a failure) to be a “sustainable consumer” of electronics and appliances is the inevitable repairs. My venerable desktop PC of 8.5 years (known affectionately by it’s hostname “sakhalin”) is finally showing its age. It has trouble finding the boot drive from time to time. The “A radio” TS-930S doesn’t transmit on SSB anymore (this is a long-standing problem I have yet to diagnose), which is unfortunate because it has the roofing filter and Inrad SSB filters. The power nozzle for our Hoover canister vacuum cleaner needs an agitator belt. I need to find a local vacuum repair shop because none of the big stores carry the right size. I think Sarah would be just as happy to replace it with an upright. But, the canister still works! I wrecked the airplane a couple of weeks ago when the weather was not quite nice enough to be flying it. Fortunately, I have $3 worth of MacGuyver parts and epoxy that should be sufficient to make that repair. The wind broke one of the wires on my open-wire 80-meter dipole. (Finally, I reached the point of “if it stayed up last winter it’s not big enough.” The proof is in the performance, too.)

I’ll probably get the airplane and the antenna fixed yet this afternoon. The other problems are more long-standing. The desktop PC isn’t really necessary, especially since Sarah will be getting a laptop with her new job. So, I really probably could let it go. I still have the Pentium 166 that I bummed off of Dad for a contesting computer. It’s working great. But, do I unload the newer, superior computer that’s flaky? I have been tempted to dump the 166. I should try a new hard drive in sakhalin. Then there’s Sarah’s desktop…I can count on one hand the number of times it’s been turned on since we got married and I was the one using it! I’m holding onto Alan’s PowerBook because it’s the only place I have Adobe CS2. And, I have the ThinkPad “contesting laptop” that Ryan gave me when I got married… I guess if I weren’t such a tightwad and Mac-addict, I wouldn’t have this problem! No more junk!

We have five CRT’s in the house…two Dell 19″ Trinitrons on my desk, Sarah’s 17″ un-Trinitron Dell, my oscilloscope, and the TV. I’m not planning to replace the ‘scope or the TV anytime soon. So, I guess it’s the computers are the ones that will have to go…I just can’t let go of my junk… And, I went out and bought a new camera…sigh.