SB-301 Rebuild Progress - Part 4 -

 So, I spent some time making sure all the dial tracking issues were solved, and then put the front panel back on the radio, taking care to align the panel as specified in the manual, as if you don't do it correctly, the dial can bind up, and things can wear out. Then I cleaned the knobs and dial bezel, polished them a bit with some "NOVUS #1" cleaner/polish, and reinstalled them.

Then I flipped the chassis over, and began inspecting all the soldered connections, and checking for "Workmanship Issues" like unclipped wires hanging through terminals, like this one on the center terminal.

And this poorly terminated coaxial cable. The ground braid goes to the third terminal from the right, and you can see all the individual strands. The soldering on the capacitor on the right end of the terminal strip wasn't too neat, so I re-did those, too.

And you can see some excess lead length through the terminals on this wafer of the VHF Converter Select switch. This, too, was corrected.

In all cases, the solder was wicked off the connection using "Solder Wick", the excess lead was wrapped around the terminal like it should have been when first assembled, and then resoldered. This is more a reliability issue than a functional one, as the connections were soldered acceptable well, but "Accepted Practice" states you wrap the lead around the terminal to make a solid mechanical connection, and then solder it. Solder has very little strength; it's just there to enhance the conductivity of the mechanical connection, and to "seal" the joint a bit. Oh, sure, we've all just "tacked" connections together to bypass a bad part, but if the assembly that tack joint is in gets  subjected to vibration or rough handling, it might very well fail and pop loose. If the device just sits on a desk it's entire life it might work for 25 years, but it's not the right way to build things.

Tomorrow's activity will be to start the process of changing the 120VAC Input Connector from an old "Two Pin" style, to a modern three pin style that uses a three-wire line cord to ground the chassis of the radio.

This will require some metal work, as the mounting holes are further apart on the new connector, and the hole for it is wider and taller. The positioning of the new connector will be such that the lettering "120 VAC" will remain, but the "INPUT" label will be gone. Small price to pay to have an easily replaceable power cord, as the two-pin style cords are now considered "Vintage" or "Antique", and the prices have shot up.

I'm also going to change out the antenna connector, from an "RCA Phono" style to a BNC female. 

I did the "Initial Tests" in the manual tonight, confirming I didn't make any mistakes rewiring the power supply. After I change out the power connector, I'll be ready to begin the alignment procedure.

 

 

Heatkit SB-301 Rebuild Progress - Part 3 -

 As I was doing some clean-up work and just "spinning the knobs", I noticed that the main tuning knob seemed to be binding up over a segment of it's rotation, and was hard to turn at the upper end of the dial. Peeking/poking/peering into the innards as I rotated the knob, I noticed something appeared to be wobbly or misaligned, so I took a deep breath and began the disassembly of the front panel.

Off with the knobs!

Then remove the mounting hardware from the controls, and wiggly-jiggly slide the front panel assembly off the shafts.

The first thing I noticed was the clear plate with the fiducial marker on it was binding on something, so I pulled the dial assembly off the tuning shaft to get a closer look.

 I took off the retaining ring and inspected the parts.

Definitely binding on something from the circular scratch marks.

Turns out the shiny metal ring that was attached to the dial itself had popped loose. It was pressed on to the dial, and had little tabs that were bent over to hold it in place. Over the years, one of the tabs loosened up, and allowed the metal ring to pop loose and move away from the dial by a bit more than the available clearance between the parts, and causing the two parts to rub together. I pushed the metal ring back into the dial, and rebent all the tabs, and now it fits flush again on the dial.

The metal ring is part of the drive assembly, and uses a "Pinch Roller" on a shaft to turn the dial. The Main Tuning knob goes on the shaft, which rotates the pinch roller, turning the numbered dial, which is attached to the tuning shaft of the LMO, the "Linear Master Oscillator", and tunes the radio.

All back together and back on the radio. The original lubricant was all dried up, so I cleaned it off and put a bit of silicone grease on it, a very good lube to use in a plastic-on-metal situation.

And I cleaned and polished the various plastic bits.

Now for the fun part, and a main reason these radios have a love/hate following.

The dial itself is marked 0-99, corresponding to 100kHz of tuning range. The LMO has five turns of range, corresponding to the 500kHz total tuning range of the LMO. 

So, have I turned the dial twice? Four times? In order to keep track of the total turns of the dial, Heath molded-in a spiral pattern into the back of the dial, which you can see through the clear plastic center of the dial. The spiral is engaged by a little nylon pin on an arm with a slot in it. You can see the arm sticking out from behind the dial, between the "0" and "95" numbers on the dial. As the dial is turned, the nylon pin follows the spiral, and moves the arm from left to right. The slot in the arm engages a pin on the back of a sliding dial pointer, which moves from 0 to 5, indicated which 100kHz section you're tuned to.

Hard to explain without better pix or a drawing, but here's the "Hundreds" marker back in place.

The love/hate part comes with getting these parts to all play nice, so the marks all line up and track properly. It wouldn't look good if the dial was on "Zero", but the sliding hundreds marker indicated "250" instead of "200", so Heath built-in some adjustments. 

The metal arm is attached to the chassis with two 6-32 screws, nuts and lockwashers. The chassis holes are slotted horizontally, while the holes in the arm assembly has them slotted vertically, allowing a two-axis freedom of movement. Getting the arm screwed down to the chassis in the correct left/right, up/down position so that the hundreds pointer agrees with the dial takes a LOT of patience, but once you've done it (a few times.....) you get the hang of it, kinda like sighting in a new scope. A little to the left, a little bit up, oops, now the zero is off so reset that, spin the knob over it's whole rotation, and rats, now the "5" is off again, and on and on. Eventually you get it to track, where the "Zero" on the dial and the major divisions of the "Hundreds" slider all match up and follow each other over the entire range, like this:

 Yeah, it's a tiny bit off on the "5", but I'm going to live with it. Took me several hours to get it this good....

And there's some slop in the dial that I don't remember from the SB-310 Shortwave version of this I restored a few years ago, so I'll look into that, but short of replacing the plastic parts in the dial mechanism, I don't think there's much I can do about it. Perhaps if I slide the dial a bit further in on the shaft, which would engage the nylon follower pin a bit deeper in the spiral groove, it might help.

And the haze on the clear hundreds marker? Well, it's on the inside of the plastic piece, and if I tried to polish it off I'm afraid the numbers would disappear, too. I've already tried gently cleaning it with plain water, and then some highly diluted soapy water, and it won't budge. I'd try some Windex, or my "Special Sauce" cleaner, but some of the Heathkit lettering is extremely easy to damage, and replacement parts only come from "Parts Radios". Fortunately, I found one on ePay, so I can swap out the clear part when it gets here.

Heathkit SB-310 Rebuild Progress - Part 2 -

 After spending about 30 minutes reading the manual for the tube tester, it turns out I wasn't using it correctly. I didn't damage any tubes I've previously tested, but the measurements are meaningless. 

Anywhoo.....I found one tube that gave a "Merit" reading of 80%, which is the lower limit of the "Good" scale on the tester's meter. I pulled one of my new tubes from stock, and it read over 120%, as did several others from my stash. It's a 6AU6 "Sharp Cutoff Pentode", a very common tube, and there are three of them in the radio. One is used for the 100kHz crystal calibrator, a frequency reference used to calibrate the main tuning dial, and the other two are used as mixers, a type of frequency converting circuit.

With that out of the way, I pulled all the knobs off, as some of the panel bushings were loose, allowing the shaft the knob mounts on to be loose and wobbly in the panel. I also cleaned any old lubricant out, and added a drop of synthetic oil to smooth the action. I then cleaned the old lube from the detent mechanism of the rotary switches, and relubed them with some Mobil1 red synthetic grease. Then on to cleaning the potentiometers and rotary switch contacts with some DeoxIT cleaner. All the switches and controls now turn much smoother than they did before, and no more wobbly knobs!

And I tightened all the hardware on the chassis, some of which was a bit loose. Since some of these are used as tie-points to ground, retightening the hardware helps ensure I don't have any poor ground connections, which can cause noise, oscillations, and other gremlins.

Replacing the electrolytic capacitors on this radio is fairly easy. There are 4 lead-mounted capacitors under the chassis, and one large can-type mounted through the chassis.

Original parts. The three pinkish cylinders are capacitors, as it the smaller black cylinder.

Replacement parts installed.

The big can cap mounted from the topside has four terminals, and four locking tabs, and most are used as tie-points and component mounting.

It's a bit crowded in there!

The three black "bullets" with yellow lettering are the original silicon rectifiers that I'll be replacing with more reliable "modern" units. These are rated at 500V and 750mA, while the new ones are rated at 1000V and 1 Amp. They also have much better "surge" ratings, which means they're stressed less at a cold turn-on, when the capacitors draw maximum current.

Out with the old, and in with the new. You can see one of the new rectifiers installed just above the largest brown cylinder with the color stripes. It's the small, black cylinder with a silver stripe on the right end.

 I'll do some clean-up work tonight to get the solder flux bits and other loose trash out of there before I put the components back in. I'll also spend some time checking the soldering, as I found a couple of almost-cold (dull and grainy looking) connections. I also don't care for some of the workmanship by the original builder. He left some component leads longer than I would have, and a lot of them are just stuck through the lug and soldered. Proper technique should be to bend the lead around the lug before soldering, ensuring a solid mechanical connection. In some cases there was enough lead length left to do a partial wrap after I removed the solder, and in other cases there wasn't. Worst case was the lead had at least enough to make a 90* bend, which is better than just stuck-through-the-hole, but still not correct by the accepted standards in use.

At least they left a lot of length on the leads that were just stuck-though-the-hole, so once I remove the solder I can bend the excess length around the terminal or slot that it goes through, and then resolder.

This unit isn't as bad as some I've seen that made me wonder how it ever worked in the first place, but then it's not nearly as nice as others I have. It's a gamble you take whenever you buy a kit built by someone else. Sometimes the original kit builder did a beautiful job, and sometimes they didn't.

I'd give this one a B-.

What's On The Bench: SB-301 HF Receiver - Part 1 -

 Having gotten the downstairs Electronics Bench cleaned up, I decided to get cranked up again and get some things done after my usual mid-winter slump.

I was going to start on my Drake R4-B after spending several hours digging out my stash of Drake parts, but since I'm a bit rusty, I figured it would be better for all concerned if I started on the Heathkit SB-301 first.

Sorry for the crummy pix. Looks like my Indoor Photography skillz have tarnished a bit, too.

 Why this one? Well, a year or so before we moved here I rebuilt it's stablemate, the SB-310 Shortwave version of this, which is better than 90% identical to this one. Same tubes, same resistors and capacitors, same alignment procedure, etc. It differs only in the Heterodyne Crystals used to determine it's frequency coverage.

In other words, I've been here, and done this, so it should be easy-peasy.

And I've got out my trusty EICO 667 "Dynamic Conductance" tube tester:

 With both manuals:

Yes, I know how to "use" my tube tester, but it's way overdue that I sit down with the manuals and get to understand the tube tester. A quick check through the charts and a look at the sockets on it confirms that it will test any tube I currently use, or have in stock. I figured it would test the 6146 Power Amplifier tubes in the matching transmitter to this radio, but didn't really know until I looked at the tube listings. And a check of the front panel shows it will fit the Compactron tubes I use, and also Octal and Loctal tubes, which I don't.

And we have all the required replacement parts (less tubes) on hand:

If I need any tubes, I should have them, as I have two sets of "spares" for the SB-310. My criteria has been to reject tubes that read less than 85% on the tube tester. Is this valid? It's just something I've always done, but one of the reasons I want to RTFM for the tube tester. It has quite a good "How It Works" section, explaining how each measurement it's capable of making is made, and what the implications of the measurement are. 

So next up is to pull the tubes and read the tube tester manual while I go through them. After that I'll pull the chassis from the cabinet and clean it, and start doing things like cleaning the controls and switches, checking how well it's put together, tightening all the hardware, and doing some other basic checks to bring this back to life.

Cinnamon Rolls, V.1 Alpha Release

 Decided to try my hand at a batch of cinnamon rolls, something I've been threatening to do for a year or so. Found an easy recipe over at the King Arthur Flower site, and set about gathering the ingredients. Almost said "chemicals" there, but hey, baking is Applied Chemistry, isn't it?

Mixed everything up, and let the dough rise.

Mistake #1 - didn't turn out the dough and grease the bowl before letting it rise in said bowl. Wasn't a huge mistake, but made it "interesting" to get it all out so I could then roll it out and butter it up.

Then cover it with brown sugar and cinnamon powder.

Getting it rolled up, and sliced into approximately equal sections, was a Charlie Foxtrot, but Sweet Little Wife helped me out, and we eventually got to here after allowing the rolls to rise about 45 minutes.

While they were rising again, I mixed up the ingredients for the cream-cheese icing.

Mistake #2 - grabbed the wrong measuring spoon, and added twice the amount of vanilla that was called for. OOOPS!

After baking for what was deemed an appropriate amount of time, at an appropriate temperature as adjusted for the altitude, we we rewarded with these.

 

Mistake #3 - picked the wrong combination of time and temperature. I made adjustments to the time and temp based on published guidelines for adjusting your recipes to a 5000' altitude, and my bread baking, which confirmed the guidelines.

In short, you increase the temperature and decrease the time to avoid drying out your bread.

Guess what? This ain't bread. It's pastry dough, and bakes differently than just a straight yeast bread does. The extra butter and eggs change the chemicals enough to make the reaction go in an unexpected way. In this case, while the outside 2/3 of the roll is completely cooked, the inside 1/3 "core" of the roll isn't fully cooked. It never developed into the nice, light, almost flaky crust a Good Cinnamon Roll has through-and-through. They're not raw, just not fully cooked, and a bit doughy. They taste pretty good otherwise, although the icing has a bit too much vanilla for my taste.

Next time I'll make sure to use the recommended 400* oven, and let the time run the full 15 minutes. We took the pan out once to inspect the bottom, and it looked like the sugar was caramelizing nicely, but we just flat took it out too early, based on the rolls looking "Golden Brown". The higher temp got the outsides done just fine, but the shorter time didn't allow the heat to fully penetrate the denser dough and completely cook it.

Happy New Year, and Carving Almost Complete

 SOOOoooo....here we are, which is most likely not where we'd thought we'd be. A staged pandemic, an election with absolutely breathtaking amounts of fraud, and economy in shambles, and all the other stuff I can't be bothered mentioning, but we endured.

Yes, "endured".

No, it's not The Great Depression or a World War. Those may be Coming Soon To A Former Republic Near YOU!, but it's still not 100% decided. I don't know what's coming up this year, but I don't think it's going to be "pretty", for given definitions of "pretty".

So take care, keep your head on a swivel and your powder dry, and we'll see what comes.

On to more mundane matters....

Trevor The Tree Carver has been busy since the last update. He's just about finished, and has only some final detailing, sealing, and clean-up to do. It should look quite nice this summer.

Awwwww....RATS! Booger uploaded my pix in the reverse order I selected them in.

And I'm too lazy tonight to correct it.

A fitting end for 2020! Think I'll be down in The Bunker with a portable radio until 2020 is out of here.....

A Bit More Tree Carving....

 Took this today after Trevor left due to blowing snow!

He's been working on the trunk, turning it into a stack of boulders with roots growing down through them. The baby owl on the small limb was supposed to be a squirrel, but as he carved away the wood, a crack in the limb started to open up, and he was afraid it would break apart in a few months, so he cut the limb back, and carved the owl.

Should be pretty impressive when he's finished carving it, burning in more detail, and sealing it.

Tree Carving Resumes....

 At least for today and tomorrow.

Trevor is almost finished, and the next few days will be devoted to finishing it up, burning in some details, and then slathering the whole tree in boiled linseed oil to seal and preserve the wood.

The new figure is another owl. He started roughing in a squirrel, was a pretty far along on it, and the trunk split along a line he was worried about. So, we another owl instead of a squirrel.

Christmas Eve aftermath.....

Yes, the wrapping paper has been stuffed in a bag, or we'd be waist-deep in it!

Merry Christmas!

To you all. Christmas has always been special for me, like most people. The family gatherings, the food, the presents, and all the other things that go with the season.

But let us never forget the most important reason we celebrate this day.

Cold and Windy....

 Going down to the low teens tonight, and it's been pretty windy since about noon. Winds have been pretty steady at 25~28MPH with some gusts to 40+.

All the snow has melted, so no White Christmas, but the backyard is now dry enough I can gather up the one trunk of the crab apple tree the arborist removed and cut up for me. I'll drag it in to the garage to let it dry out and season until next winter. The sections I saved from the big branches that broke off last winter are really great firewood. Burns very cleanly, and throws off a lot of heat and light for the size pieces I wound up with.

TLG will be here Wednesday, and we're going to bake some bread for when he comes back with his Mommie and Daddy for Christmas Eve dinner.

Wishing you all the best for a Blessed Christmas and Joyous New Year, just in case I don't get off my duff and put something up for Christmas.

Farewell, Old Friend, Hope to See You On the Other Side....

 Rest in peace, Diamond, my big, lovable moose of a dog.

Diamond 2008~2020

Snow, Finally!

 Been very lightly snowing for a bit over an hour, and there's maybe 1/2" on my snow gauge.

NWS is forecasting 1~2" accumulation tonight, and possibly 1" on Friday. This is good, as we desperately need the soil moisture. Saturday is forecast at a 40% chance, and I'll watch that closely, as I have to go down to the airport to pick up SLW Saturday afternoon. I'll use the next two days to "test" the difference my 4WD system has between "4-HI Auto", which electronically controls when the front axle engages, and just "4-HI", which has the front under power all the time. The rear differential is an electronically-controlled locker, and it's been a while since I drove a vehicle with a locker-style rear end. 

Back In The Day, lockers could/would engage at inopportune times, causing the handling to change, sometimes radically. The people on the Chevrolet Colorado forum say you can tell when these lock-up, but the electronic controls make a world of difference compared to a mechanical locker. And they've said pretty much the same about 4-HI Auto and 4-HI, in that you can tell when the front axle engages, but it doesn't jerk the steering wheel or make the handling change dramatically.

My Jeep was true All Wheel Drive, and was very sure-footed in bad weather. If I flat-footed it on a slippery surface I could force all four tires to spin, but I don't drive like that. It'll be interesting to play with the Chevy in the snow to see how it feels. In dry weather it handles better than it has any right to, and the brakes are very good with outstanding pedal feel. GM's chassis group really has a handle on things in this department, and I'll see how it does in snow the next couple of days.

Unflipping Believable! WELL DONE SpaceX!!

 I watched the entire launch and "landing" of the SpaceX SN8 flight test today, and I'm pretty near speechless.

This is so close to the Big Silver Rockets of Bradbury and Heinlein that I grew up dreaming about that it's.......huh....not sure what to say other than some adjective I can't think of. It's one of those "American Exceptionalism" things that aren't supposed to exist, are hugely Politically Incorrect, make liberal heads go nova, and prompt questions like "How Many More Teflon Fry Pans Will We Get Out Of This?" (I actually heard that at a NASA presser) from the "press", and make me smile and feel a sense of pride.

I won't analyze the landing, other than when I saw the plume go bright green, I knew something was wrong, and remembered the line "All Hand Brace For Impact!" from the movie Destination Moon.

Here's the broadcast, courtesy of a link the Silicon Graybeard provided. The launch starts about an hour and 47 minutes from the beginning, so you can skip forward quite a bit.

Chuck Yeager Has Passed.....

 God Speed, General Yeager.

L.A. City and County Force Closure of Battleship Iowa.

 Gruesome Newsome and his Evil Minions strike again.

A partial quote from the management aboard the Iowa:

While we have operated safely outdoors since the end of May without a single Covid-19 case, we have been ordered to close. This resulting closure will undoubtedly set us back and without an immediate increase in donations, we will have to cut expenses and wages during the holiday season. Without your support, the decision on how much we cut and where we cut has to be made no later than December 13th.  

 

If you can afford to during these times, please consider donating to The Pacific Battleship Center.

More Tree Carving

 "Trevor the Tree Carver" came by this morning and got started on one of the big limbs coming up out of the trunk.

It's going to be a pine tree!

He's thinking of turning the third limb into a squirrel sitting on a stump.

Not like we need more squirrels here, but it should look cool.

Arecibo Drone and Camera Video of Collapse

 Just saw this on a random YouTube ramble.

These are separate videos; click to play.

Easy Round Trip To DIA

 Got SLW to the airport in plenty of time. It was very nice to see the mountains again, as last time we drove to DIA there was so much smoke from the fires that it was like Armageddon. 

BTW, all the fires I've been following have been declared 100% contained. "Trevor the Tree Carver" told me he took a drive up through there now that the roads are open, and some of the areas got singed, while other parts are just gone. He said in the hottest places the trees burned right down to the grass, and then the grass burned away. Nothing but dirt and rocks now. He also told me he's been trying to get some of the "Beetle Kill" wood from areas where the bugs got the trees, but it's quite difficult unless you know somebody. Some is on private land, and some is Forest Service land, and he's still trying to figure it all out. He said the wood is quite beautiful, with many different colors running through it.

And I finished up a work space in one of the unused basement rooms so the DIL could "work at home" from here. Her employer has had to severely cut back the number of people on-site due to Emperor Polis' latest Unlawful Edicts. So, most of the office staff is now telecommuting, and since she does some kind of customer service/liaison function, she can easily work from "home". It had previously been the desk with the weather station and mini-server, along with having all the gear I use to program radio gear with, so I had to pack up the PC I normally have sitting there, and rearrange the weather station and server, roll over a good chair from the workshop side of the basement. She brought over her laptop and docking station yesterday, and we set everything up and tested it. Worked fine, except that all these new fangled laptops ONLY have an HDMI video output, and one of the monitors I'm loaning here ONLY had regular video, and a DVI video port. She was supposed to bring another monitor and cable by tonight, but she hasn't shown up. Oh, well.....

So it's me and the dog for the next 10 days, and the "DIL-in-the-Basement" starting on Monday. She'll bring over TLG on Wednesday, so I've got to get cracking here to come up with some "Grandpa" stuff he and I can do.

And no, Beans, I still haven't bought a snowblower. We've got ZERO precip in the forecast for the next 10 days, and as soon as the model I wanted came in, it was gone. I may just have to order one on-line so I'm in the que for the next delivery.

And speaking of the weather, I just read where KFTG, the NWS Weather Radar in Denver, will be down hard for three weeks. The "Bull Gear" (like a giant-size ring gear) used to rotate the antenna in azimuth has failed. The parts are on-hand, and the specialists from the NWS Radar Operations Center in Norman, OK are either here, so since this is a well-known procedure, they should have it back up per the schedule.

I was about ready to spew some venom about this like geez, don't you guys inspect them at regular intervals, and then I read the story about how they did this to the weather radar in Binghamton, NY. The gear is buried inside the antenna pedestal, and doesn't appear to have any inspection ports you can use to look inside.

Le OUCH.....

Good thing the normal service life of this gear is 15~20 years, which is about how old most of the NEXRAD (rabbit hole alert!) sites are. The NWS is researching Phased Array Radars for the replacements, but I don't know the status of that program.