Sunday, January 19, 2020

Project Updates

Been keeping busy with all the little projects going on here.

Mounted a terminal strip in the Supro amp so I have some tie points for the new capacitors.

Next time you see the chassis I'll have it finished. I put the refurbished grill cloth back in the case, along with the new speaker and carrying handle, but didn't take any pix.....D'OH!

And I brought all the fiddly bits for my little "Senton" 4x4 truck down to the basement, put them all back where they belonged, and tested it for steering and throttle response while it was sitting on the test stand.

Next up for this little guy is to fit the GoPro mount, and wait for the geese to show up. Should be a real Hoot and a Holler!

I also gathered up the parts I had "in stock" for the "Limitless" Speed Run car. Here's the steering servo installed, and the radio being fitted-up.

And not wanting to spend $300 on a motor and Electronic Speed Controller ("ESC"), I found a new pull from another Arrma car on eBay, and picked it up for $100. I'm trying to keep the costs on this down, and this motor/ESC pair is plenty good enough for learning how to drive this thing. My fellow Arrm Forum members tell me this "beginner's setup" should be good for 80~85MPH with the stock gearing, and possibly good for ~100MPH with different gearing and some other tuning tweaks.

Electronics package mounted, along with the motor.

After I power the car up the first time and do the initial setup, I'll connect the servo arm, and do the final steering trim. 100MPH = 147 ft/sec, so you really have to have the steering dialed-in, and make some adjustments on the radio to calm it down some. At that speed, a slight twitch on the steering wheel can send you flying off course.

After I'm comfortable driving it in this configuration, I'll upgrade the ESC. The ESC I'm looking at is capable of passing much more current, while running cooler (less loss), and allows more adjustments, one of which is "Braking Strength". You should be able to lock up all four wheels at maximum braking effort (the little truck does this easily), and this ESC can't do that when the vehicle it's in is using the gearing required for high-speed running.

One of the things I have to learn more about are the speed controllers and motors. Way back when, in a different life, I used to design large "Variable Frequency" AC, three-phase motor controls, so I know three-phase power systems fairly well, but that was 40 years ago. One of the differences is that these little brushless DC motors use a permanent magnet rotor, whereas the big motors I used before are your typical three-phase "Squirrel Cage" motors that have aluminum or copper bars making up the rotor. The spinning magnetic field in the stator coils induces currents into the bars, and the rotor gets "dragged" around trying to follow the magnetic field. This causes the rotor to "slip", spinning at a lower speed than the magnetic field rotates at. The permanent magnet rotors don't do this, being pretty much locked into the same rotational speed as the magnetic field.

I've seen schematics of these ESC's on the web, so now I have to go round them up and study them. Time to brush-up on "4 Quadrant Control" again!

Wednesday, January 15, 2020

I Feel The Need....The Need For SPEED!

Oh, boy.....

The local Hobby Town is closing their store, and as a result, they're doing an "Everything Must GO!" sale, with prices cut by as much as 75% on some items, 50% on others, and 25% (for now) on everything else. I've wanted to get The Little Guy his own entry-level "Monster Truck", and had priced them before at $100~$150.

Got this little guy for half-price:

It's amazing that they can have a complete toy like this, including the radio and batteries, for $99.99 retail price.

For $50 I couldn't pass it up, so I bought it for his birthday in March.

And I also picked up some CA glue, paint, thinner, brass and copper sheet, small brushes, a bunch of other building supplies, a big bag of battery/power/balance leads stuff, and plastic model kit of a MKIV Toyota Supra. These list at about $30, and I got it for $12.

It's sad when a small "specialty business" like a hobby shop closes. They're more than just a store to buy things, as they had a full-service R/C shop for cars, boats, airplanes, drones, and helicopters, and you could hang out and talk about things with the store employees.

The family that owned the franchise for this store decided not to renew the lease, and retire instead. So I got a couple of gifts for TLG, and whole bunch of suppplies.

But what really caught my eye was this, an Arrma "Limitless" Speed Run (think Bonneville Salt Flats) rolling chassis.

"Rolling Chassis" means no powertrain, electronics, or battery; you have basically "limitless" options available to finish the car. Since I have most of the required parts needed to complete this, and it was 50% off, one followed me home.

Yeah, I's kind of a "Phil Type" thing, I guess.....just can't pass up a "good deal". I came home with the truck for TLG, and my Big Bag 'O Stuff, and told my Sweet Little Wife about the Limitless, and she promptly told me to go back and buy it or I'd be kicking myself later this year. Depending on the motor, batteries, speed controller, and gearing, these little cars are capable of doing over 140MPH, so finding a place to really let it rip might be a problem. I talked to the guys at the Hobbyplex where I run my little VTA car, and they told me that they "kinda" tried doing some speed run events, but didn't seem to get much interest from the local R/C racers. They have a couple of radar guns, so maybe once I get this built out I can take it up there to use the taxiways around the old FoCo airport.

Monday, January 13, 2020

Valco Supro Rebuild Progress

Besides bread making and playing Grandpa, I've actually been doing some other stuff, like continue the work on getting the little Supro amplifier back in working condition.

The input section has been completely rebuilt with all new parts. The resistors had all drifted high in value, well out of their loose 10% tolerance, and the tubular "paper" capacitors were all leaky. I also wicked all the old solder off the 1953-era connections, cleaned them, and resoldered them with a bit of rosin flux.

And the output section has been similarly rebuilt, adding (replacing, actually) a new fuse holder, new AC Line bypass capacitor, and a new three-wire grounded power cord, seen exiting the chassis out-of-focus.

Now I have to rebuild the power supply filter section. The big aluminum "Can" capacitor is leaky, and as usual, the resistors have drifted high and outside of their tolerance. I ordered a replacement filter capacitor for it, but, uh......I ordered the wrong one. I generally increase the capacitance a bit when I replace the filter since it gives better filtering, and the value I picked was based on a schematic for a slightly different amplifier. In short, this replacement is too big physically, and has too high a capacitance value to use. The original value(s) in the three sections of the can were 20 microfarads, 10 micofarads, and 10 microfarads. and I wanted to go to 40, 20, and 20.

The correct schematic (and the original can itself) shows all three sections being 10 microfarads, resulting in a smaller can.

The "too high a value" problem just appeared tonight when I was reading the "RCA Receiving Tube Manual", and found that for the 5Y3 rectifier tube used in this amp, the maximum recommended capacitance for a capacitor-input filter is 20 microfarads.


What I'm going to do is leave the old can capacitor on the chassis "for looks", disconnect it electrically, and use three new separate electrolytics under the chassis for the actual filters.

BTDT, and it works fine. So this is the next area of the chassis to be rebuilt.

I'll add a terminal strip under the chassis for the new tie-points I need.

And the new speaker grill material came in, and it's a joke. It looks like it was cut from a cheap suit, and would look totally out-of-place.

Hmmmmm.....this is what I had to start with. Very dirty, faded, and discolored. The "starburst" pattern around the dirty part was up against the inside of the amp, and you're seeing the imprint of where the amp's covering material was follded through the speaker opening, and glued to the inside of the amp.

But I have a plan.....I ran my shop vac over it with the bristle brush on it to get the crud off, and both sides got much cleaner. Then I realized if I just flipped it over, it would be reusable.

This is the side that was inside the amp, and had the speaker clamped down over it.

Looks presentable to me! And it fits in with "kinda keep it stock-appearing" theme, vs having a piece of cloth in there that looks like it came from a $20 suit.

I cleaned off the outside of the cabinet, and it's a mess. I don't want to recover this thing, so I'm just going to trim off any dangling pieces that are too far gone to reglue, and reglue any loose covering.

More to come.....

Sunday, January 12, 2020

Bread......Act IV

Got cranking again today on another batch. Last week's "Experiments in Bread" yielded decent results, but I made two glaring errors that came back and bit me.

Error #1 was mixing the dough too long. The flour company said 6 to 7 minutes, while the mixer company said 4 to 5 minutes. I watched the dough mix and the time, and right about 4 minutes in it started to look really good. Pulling away cleanly from the sides of the bowl, and balling up nicely. It still looked OK at 5 minutes, but I could sense it was changing (it didn't look as 'shiny' as it had), and by 6 minutes it was beginning to break up. Result? Dense bread, again.

BUT.....(Epiphany time) I now know and understand what the dough looks like, and how it changes as the mixing time progresses. This error won't happen again!

Error #2 was using the wrong stuff to dust the baking sheet with. I didn't have any corn meal or Semolina to dust the pan with (both items in stock now), so I bowed to my Sweet Little Wife's suggestion to use the package of Jiffy corn muffin mix that was sitting on the shelf.

WRONG! The mix has other stuff in it besides corn meal and flour, like lard, salt, sugar, and baking powder. This caused these "extra ingredients" to get added to the bottom layer of the bread, throwing the flavor and texture off. Not to mention the fact that when lard and flour get up to 450* or so, they SMOKE, then char, and that adds a "flavor" to the crust of the bread as it bakes.

Other than these two errors, I have the process and recipe tuned up to what should work pretty well.

So let's get this show on the road.....

Ingredients and equipment? READY!

Put 'em in the bowl.....

And after combining in the lukewarm water, the Happy Bubbly Joyous Yeast, and mixing for precisely 4 minutes and 30 seconds, we're rewarded with a nice ball of dough, not too dry, and not too moist.....

Pop it into the 100*F oven to raise, covered with a damp terrycloth, and go do something else for two hours.....

Yep....sure looks like it's doubled.....almost looks kind of "sourdoughy", with some big bubbles.....

Prepare the baking sheet with Semolina on the left side, and cornmeal on the right side.....

"Gently Deflate" the dough, divide it in half, do a bit of "shaping", and plop them on the baking sheet for the second raise.....

After 45 minutes, I removed the proto-bread from the oven, started the oven preheating, slashed each loaf three times across the top, and "generously" applied more lukewarm water with a brush, per the recipe.

Then we popped the sheet back in a 450*F oven for 25 minutes.....

Yeah, it deflated a bit when I cut the loaf tops. Still gotta work on figuring that out. I think next batch will get baked in the glass bread dishes we have.

22 minutes later, and we have BREAD!

And this time it came out really good. Like "High End Restaurant" good. The crust came out perfect again, with a nice hollow "Plonk" when you thumped it, but this time the insides are nice and light. And the flavor, devoid of the various adulterants I used for "cornmeal" last time, is superb.

I baked it using the regular "Bake Mode" on the oven, and I'm definitely going back to "Convection Mode", where a blower moves the air around inside the oven, as it bakes the top of the loaves in a much more uniform manner. It also bakes a bit faster, needing only 20~22 minutes vs the 25~27 minutes this mode took until it "Plonked" just right.

So, I'm calling this batch an inside-the-park home run. The only thing I can find "wrong" with this batch is the fact that it slumped a bit more than I expected, but wow, it sure tastes good.

Now if I can get it to come out looking like this......

Thursday, January 9, 2020

Been Busy.....

I'm chugging along on the little Valco amplifier, and I should have an update (with pix, or it didn't happen) later today.

Got the rest of the parts for it, along with some parts for the little race car. Turns out I have a steering linkage angularity problem that requires a more elegant solution than what I previously came up with, which was just a longer ball-stud on the servo to get things to line up better.

And since Grandma #2 (aka "Nana") is down with a really, really, really bad cold, we've had The Little Guy during the day while Nana recuperates.

He "helped" with the bread last Sunday, but decided right off the bat that he didn't like playing with squishy bread dough, so he mostly just watched. He got a real kick out of watching the dough hook rotate and orbit in the mixing bowl, though.

Be back later.....

This is the input stage and driver stage (dual triode tube)  of the little Supro amp:

I've replaced all the capacitors (they were leaky) and all of the resistors. The resistors, doing as 1/2 Watt carbon compositions resistors like to do, had all drifted high in value to outside their marked tolerance. I also changed the physical location and connections of several of the parts to eliminate ground loops, and give all the signal grounds a "Common Point Ground" connection. The new parts have higher ratings and tighter tolerances than the OEM parts, so once this is finished it should be good for another 50 years.

The new grill cloth arrived, and tomorrow I'll use the old one as a template to cut the new cloth. I'll scrub up the cabinet and replace the handle and hardware before I staple the new cloth into the cabinet. Then I'll mount the new speaker and the cabinet will be put aside for final assembly. Cleaning the cabinet will also involve some "rework" of the covering material. I can buy new, matching material to completely recover it with, but I'd like to preserve some of the originality of it. Think of this as being a "RestoMod" type of project and you're pretty close. New under the skin, but doesn't look a day over 60!

Sunday, January 5, 2020

Bread Experiment #3....The Third Time's the Charm!

Since my Sweet Little Wife gave me this really cool Six Hundred Watt  Christmas present, I've been itching to try it out.

And in order to get to understand it better, I went to what we'd call a "Reference Design" for a recipe. Just plain old white bread from a recipe that King Arthur Flour calls "Hearth Bread". It was printed on the back of the flour bags as "The Easiest Loaf of Bread You'll Ever Bake", and has flour, water, salt, sugar, and yeast. Period. Oh you use some butter to grease the bowl once it's mixed, but it's as simple a yeast-bread formula as you'll find.

I didn't take too many pix this time, as The Little Guy is over, and wanted to "help".

After mixing and raising once, I divided the dough, "shaped" the two pieces a bit, and put them on a cookie sheet. The "stuff" around the loaves is supposed to be corn meal, but lacking any corn meal, Sweet Little Wife said we had a box of Jiffy corn muffin mix, and I could use that. It has other stuff in it, like lard, and when you have lots of extra in the pan, it burns.

So here's ready to go in the oven.

And out on the rack to cool.....

Sweet Little Wife mauled the defenseless little loaf while I had my back turned to get the camera!

So how'd it turn out?

WELL.....I made two mistakes this time. The first concerns the mixing time. WOW.....does this thing CRANK! The mixer manufacturer suggest 4 minutes time, while the flour manufacturer said 7 minutes. I went from dry ingredients in the bowl to nicely mixed dough that was cleanly pulling away from the bowl in about 4-1/2 minutes. I should have stopped right there, as that's when it's properly mixed. Well, I kept mixing away, and stopped after about 6 minutes when I saw the dough was changing consistency. The good thing is I had an Ah-HAH! moment as I watched the mixer doing it's thing. I now grok when it's properly mixed, and that's a big thing to me. Ultimately, it appears to not have 'damaged' the bread, but the texture is a bit heavier. Not much, like that first (burp!) batch of rye bread I made, but the gas bubbles aren't what I'd call "nailed it", and since I got the yeast understood, the next thing is the mixing procedure so I can get consistent results.

The next mistake was using the Jiffy mix instead of straight corn meal. Besides the fact that the excess material on the tray charred, the other ingredients in the mix had an effect on the bottom of the loaf. You definitely get the corn meal taste and texture, but the (overcooked) "shortening" in the product flavored the bottom of the loaf. Not a bad flavor, but it's definitely "different" than what you'd expect.

Anyway.....these two mistakes are easily corrected, and I actually learned something useful about mixing the dough.

And the end result?

Half a loaf gone in 30 minutes. It tastes great, it's not heavy at all, and once again, the crust is superb. Without the two mistakes I made, I'm confident this would have been a hit out of the park for me.

Since I'm now out of yeast, I'm making up a list of stuff to get, like more flour, some straight corn meal, and some semolina to try in place of the corn meal. The recipe is "either/or", and I'd like to see the difference in taste. Since the recipe makes two loaves, I'll do one of each next week.

The next baking project will be cinnamon rolls, so I'll add those unique ingredients to the list. I really like cinnamon rolls.......

Friday, January 3, 2020

Drone Strikes and Squirrels.....

Well, looks like our military took out some more garbage. Others have commented on it, but one thing I found interesting were the pictures used of the vermin in various publications.

Fellow blogger Fredd used this picture in his story:

While the always PC and left-leaning Wikipedia used this one:

Quite a difference, isn't it? Who's to say which photo is more accurate representing the persona of this former person? I'm told even Satan can smile and be quite charming when it suits his purpose.....Guess this guy will get to find out, right before he gets handed his shovel to stoke the fires of Hell for all eternity.

But then we're not supposed to judge others.

On the home front, I never knew squirrels ate crab apples. These two are owners of the two nests up in a neighbors tree, and we see them almost daily. They also enjoy getting the 'spinner' seeds from the maple tree in the front yard, doing all manner of acrobatics to get at the large clumps of seeds out on some of the more flexible branches.

Rock on, squirrels, and thanks for getting those crab apples off the tree for us. At least they won't land on the ground, ferment, and give little Pebbles The Wonder Dog WMD-grade gas!

Enjoy your weekend!

Monday, December 30, 2019

What's On The Workbench?

I originally found this little guy stuffed under a workbench in my Sweet Little Wife's garage when I first moved in. The garage had been a "Man Cave" type place, with carpet and old couches, a little fridge for beer, big TV set, etc., etc, etc. Her first husband would hang out with his buddies after work and sometimes they'd get the guitars out and jam.

This is what he used, a Valco "Supro":

A very simple little "5 Watt" class amp with a single 6V6GT output tube, which is kinda the "little brother" to the ever popular 6L6GC. I showed it to her, and she almost cried, remembering the jam sessions, so I carefully put it away so I could see what it needed to sing again.

Fast forward about 10 years, and I decided to dig it out (she didn't remember me saving it) and give it a good going over. Over the years I collected all the information and schematics I could find for these small Valco amps, so I'm fortunate to have a schematic that matches the chassis 100%.

I flipped it around and pulled the chassis out:

And set it up on the bench:

Yeah, pretty crusty! I got out my EICO tube tester, and checked the three tubes. The rectifier tube appeared OK, but the 6V6 output tube had "shorts", as did the 6SL7GT dual triode input/driver tube.

And it's a "gimme" that the electrolytic capacitors are leaky, as are all the notorious molded paper capacitors, which are all those pink cylinders:

And to add a fourth 1/4" jack input, they removed the fuse holder, stuck in another jack, and scabbed a 4 Amp breaker in there:

Yeah, it's a mess:

Le Sigh.....

So I sent an order off a week or so ago to "Antique Electronic Supply", one of my go-to places for tube parts. Great service, fair prices, and wide variety of parts catering to old tube amps as well as "Luthier" supplies for old guitars, and things like correct replacement Fender knobs. Got three new tubes, some capacitors and odd resistors, fuseholders (I have fuses), and a new leather carrying handle and hardware for this little guy, as the original leather handle had disintegrated long before I first met him.

All I've done so far besides take the chassis out is to brush the dirt off it, and then wipe it down to get the nasty stuff off.  I pulled the "extra" instrument input jack and put a new fuse holder in there. I'm also going to install a proper 3-wire grounded cord on it a bit later. I cleaned the volume and tone controls, 1/4" jacks, and the tube socket pins with some Caig D5 DeoxIT. And I ordered a replacement 8" speaker tonight, as the old one is just too fragile after all these years.

It'll be interesting to see how it sounds after I finish it. Other than the new handle on top, I'm going to tray and leave the cabinet pretty much alone. I'll clean it and trim/reglue any loose covering, but I'm not going to recover it.

Saturday, December 28, 2019

Quiet Day, 2" of Snow, Not Much Going On.....

The snow had pretty much stopped by 0600 or so. The snow rake Well Seasoned Fool told me about worked just great on the car. It would have been nice to have after that big snow we had a few weeks ago, but now I have it for the next big snow:

Well worth the $40 I paid for it. The 48" hardwood handle makes getting all the snow off the glass a breeze, and it gets the snow off the roof above the doors so you don't get dumped on when you open the door.

And don't even bother to ask about that POS the auger motor won't turn on when you squeeze the switch on the handle. Got the sidewalk cleared, but then it took a dump doing the driveway. It's never acted right, and now it doesn't even click when you squeeze the handle.

And we now have this brute getting ready to be put in service:

The attachments and bowl are in the dishwasher (Dishwasher Safe!), and as soon as we finish the last loaf from the second Great Bread Experiment I'll be making some regular white bread to see how it works.

And from my son back in Kommiefornia, I present you the Best Mouse Pad EVER:

It's huge, and has a world map with time zones printed on it.

It's almost too big to fit on my operating desk here in the sun room, so I might have to rearrange the equipment on the desk to use it.