Category Archives: Mechanical

Cycle rectification

I had pulled all my test equipment out to align my radio again;

test bench

So, I started my bike up and checked the output of the generator with my oscilloscope.

scope on bike

The output was rather spikier than hoped for into the negative, so redoing the rectifier was in order. Possibly the vibration was too much.

circuit

I finished up the latest revision of the regulator board, with a new Zener to bleed off any excess input voltage, a resistance across the input capacitor to bleed off any stored charge, a mechanically better connection to the board and some adjustment pots.

More generator issues

Checked the output of the generator with nothing connected.

running

With no load it was causing the capacitor to saturate at about 46 Volts. Not so good!

fractured

Also, the main voltage regulator chip had vibrated loose and fractured off. I made a bracket to secure it to the board better.

secured

Bolted down securely, and relocated the capacitor; however with only the rectifier in place I’m reading a fairly significant AC component on my multimeter. I’m going to hook my oscilloscope up to it and see what the output looks like. I have a feeling possibly one (or more) of the diodes have failed.

Ergs

I had originally clamped the new exhaust pipe by cutting a couple slits in the end of the pipe, pushing it over the outlet of the muffler and clamping it down with a Jubilee clip. This proved unsatisfactory as the Jubilee clip could not be adequately tightened without slipping. They are ultimately not designed to be done up very very tight anyway, so I decided a U-clamp would be a better option. I went to the local hardware store and had a rummage around. I discovered a 3/4″ wire rope clamp, which had a decent clamping surface.

clamp

It’s a little oversized, but it has clamped the pipe very effectively. I also polished the pipe up, which came up really nicely.

diodes and coil

Next up was to pull the generator winding out and build up a bridge rectifier. I wanted to get the most out of the coil, so some modification was required. It was wound with one side to ground.

bridge rect

I de-soldered the end of the wire to ground and built a bridge rectifier so the device could use both sides of the wave output.

capacitor

Tucked in a capacitor.

generator fitted

Fitted everything back in and connected it up in a testing fashion.

led

Hooked up an LED on the low beam light, as it’s more efficient and will not drain the battery so much. The color temperature is also acceptable, at a moderately warm 2700K.

voltage regulator

Began work on building a voltage regulator. Built it up on breadboard first and tested with a 12V supply to check it regulated correctly down to the 6V required by the system.

breadboard regulator/charger

Translated the regulator and charger circuit to Veroboard, attempting to keep it as compact as possible.

warning light

I had wanted to have a no-charge warning light, so decided the best way to do that was to have a comparator circuit. Compare the voltage coming in to that of the battery (across a voltage drop, in this case a diode) and illuminate a light when the input was less than that of the output.

switch

The switches I had purchased were set up that the on/off rocker was green with a green LED and the on/off/on rocker was red with no illumination. The front panels were printed with I O II style lettering to show the positions. I took the on/off switch apart and fitted a red LED inside.

new faces

I reassembled the switches after having sanded the old labeling off and adding some new, more appropriate symbols.

lamp test

Testing showed the lamp illuminated adequately.

live test

Hooked the breadboard up to the bike and ran the engine to test operation. That proved successful.

comparator circuit

Completed build of the comparator circuit on the Veroboard.

bench test

Final bench test, under full load of the regulator and warning light circuits.

handlebars bare

Took a break from electronics at this point to clean up the handlebars, which were very rusty and flaking paint that was applied badly in the past (not by me!). Sanded the handlebars back to bare metal.

painted handlebars

Masked up and painted the handlebars gloss black to match the fenders.

handlebars reassembled

Reassembled, the finish is acceptable.

back to wiring up

Resumed wiring up the switches to the lights (with a set of diodes for the rear light so as not to back-feed the front lights.

first test

First test, on battery. Main beam at that point did not have a light bulb, the original was 12V.

wiring diagram

So now, it’s a bicycle, with a wiring diagram. The colors of the wires did not match as I had bought a trailer harness with a nice detachable plug for the back and the wires coming off the switch were all different colors.

leather bag

I fitted everything into the little leather satchel below the seat.

wired up

I need to finish up and cover this up with some looming tape or some other covering but for now it’s tidy.

neat

All set up, neat and tidy.

Reflecting upon red plastic

One thing missing from the back of my bike was a reflector. It likely had a rectangular one under the seat when it was new- that to me is not really very much in keeping with the ethos of the bike so I had a rummage and found this on Amazon:

Reflector

A 1 1/4″ round reflector, metal backed, made in New Jersey. I made up a small metal bracket, painted it black and attached it below the light on the rear fender.

lit

Ordered also a small module housing a couple switches to operate the lights and ignition- the push-button on the handlebar that currently kills the engine is going to be for a horn of some description, something a little louder than a bell.

switch

Annoyingly, it arrived broken. I glued it up and now it’s better. Next up, dismantle, rub down and paint up handlebars… then refit all the parts.

New paint; a stark contrast, illuminated.

Decided to rub down and repaint the fenders on the bike. I had never been very fond of the gray/white color scheme and with the addition of the gloss black fuel tank it started to look out of place. Plus, the white paint was beginning to look in poor condition from being stored out in the elements for years.

DA sander

Started with some 120-grit paper on the DA sander to take the old paint down to a good surface and provide a key.

rubbed back

Once rubbed back it was wiped clean. The paint is really very thick and has protected the metal well.

gloss

Gave the fenders each a couple coats of rust-protect gloss black paint and left them hanging to dry.

polish

Between times I decided to see how the exhaust pipe would react to a bit of polish. As it turns out, really very well.

reassembled

Moved the rear light to the back of the rear fender and reassembled everything. Just needs the handlebars rubbing back now and painting up (again, black).

as-was

It’s quite a difference from how the bike started out. This is a picture of it a few years back.

mag

Next, I turned my attention to the lights. The magneto stator was meant to come with two windings, but only arrived with one. I ordered a replacement but that arrived with one winding and two wires soldered to the output. Utter nonsense.

generator stator

Bought an extension piece to the stator that turned it from a horse-shoe shape into a full hoop with a second winding to generate power for lights.

illumination

At a fast idle it creates enough energy to light the 4.5W bulb in the headlight. I might end up doing what I did not want to and fitting an LED lamp to it instead, as it is significantly more efficient and should power from the generator acceptably from idle on up.

Computer stuff and a motor assisted bicycle

I got fed up of having a mismatched set of drives and a hole in the front of my TRS-80.

neat and tidy

This prompted me to go find some software and find a way to transfer files to and from the TRS-80. Turns out running an emulator, using it to convert binary files to hex, transmitting them across serial and converting them back works well.
Also, on a plus note, have managed to get a word processor software working and printing properly. Real proportional print on the old daisy wheel printer!

snow

It snowed. This prompted good “out in the garage” type work, as it was pleasantly cool.

pile of parts

I decided to try a bit of a fun project. Bolted an engine to my bicycle. A few things needed a bit of ingenuity- the sprocket at the back is clamped to the spokes between two discs of rubber. That pushed it too far out and didn’t let the brake work (hub brake on the rear wheel).

rag joint

An afternoon of adjusting and tinkering and setting up and I got it to run.

motorized

50cc, 1.5hp.. geared to do about 20-25 tops. Decided it needed a speedometer. Ordered an old-fashioned mechanical one. Decided I did not like the face that was on it so redesigned it, in the style of 60’s BMC Smiths gauges.

gauge design

Printed out rough draft and compared to the one it came with.

faces

The gears also had no lubrication, instead relying upon the nylon being inherently slippery- that only works for a short while, so added some silicone grease to try extend the lifespan of them a little.

face

Mounted the face, decided it looked well enough. Painted up the center of the needle with silver paint.

spray paint

Finish is acceptable. Not mirror but certainly shiny.

shiny

All finished up, looking better than it did.

speedometer

Took a while to calibrate, and it’s far from accurate but it’s good enough for the job it’s doing. Also, pulled the trip reset dial off and blanked it, turning it into an odometer.

black chain guard

Painted the chain guard up, made a few adjustments to the way the chains route.

lens

Bought a light set for it, the front lens was all hazy. Polished it up so it was a lot clearer.

clear

All back together it looks a fair bit better.

lamp

All attached to the bike, adding to the look and usefulness.

lights

Next up is an engine driven generator, switchable to the wheel generator. Might add a battery in there someplace but for now it’s all AC lights.

Processor and a monitoring panel (plus holiday oddments)

After the previous discovery that the -12V rail was collapsing under load, I read up on the datasheet for the 8080A processor. It states that the voltage rails must be brought up in a particular order (-5, +5, +12) and if the -5 is missing then there’s a very high chance of damaging the processor. The 8085 negated this and required a single, positive power source- the 8080 has strict requirements.
The 4116 RAM states that it should be brought up with the -5 first then the +5 and then the +12 but any of the rails missing should not cause damage to the chips. Bonus there.
So, I decided just to fling a processor at it. For $4 a pop, I decided that it was worth a shot, having fixed the power supply.

8080A

Same behavior upon power-up. At least I have a couple spares now.

repeating trash

Pulling the video RAM does show a different pattern on the screen so that at least is moderately positive- it initializes the memory in the same fashion each time it it switched on. Pulling the CPU and I/O cards and powering up the video card only liberates a solid beep, no crackling warbles.

voltmeter

Bought some little voltmeters from China- self-powered with internal self-regulated reference. They work from about 2.5 Volts all the way up to 30 which is impressive.

contrast

Also, bought some red transparent acrylic to serve as a mounting plate and to act as a contrast-improving device for the displays.

cut out

Marked up, cut with a hacksaw to size and sanded down smooth. Gently heated it up with my butane torch and bent it into a shape that stands up by itself.

measured

Measured up for the meter locations, drawing the positions on the front in Sharpie.

pva

Spread a thin layer of PVA glue on to each meter. It’s nice because it dries clear and doesn’t attack the plastics.

row of meters

Five meters stuck on and waiting for the glue to dry.

heat shrink

Trimmed the wires down to length and soldered on a length of multi-core wire, and using a spoon as a heat shield, added some heat shrink tubing to each join.

clips

Soldered some test leads onto the other end of the cable and marked them up as to which is which.

plugged in

Got everything hooked up onto the appropriate locations on the PSU.

meter on

With a few labels to show what’s what (and a couple others because I got carried away) the output of the PSU is monitored fully. Everything is in spec, all loaded down with all boards fitted. Now that I have this set up, I’m happier in the knowledge that everything is doing what it’s meant to in terms of power.

Next up, pulling it all out of the chassis to get the analyzer clipped on properly.

new light

Back to the house, I bought a new 4′ Lithonia light fixture to replace the junky Lights of America one that refused to light one tube and barely lit the other. Wired it up, fitted the old 25W tubes and flicked the switch. Nice bright light with instant start, too.

recapped tv

Recapped a TV for someone at work. The ventilation grilles at the back had become lodged with dust due to the location it was kept in (TV stand with no access to the sides) and as such, had cooked itself. Uprated the heat ratings of the replacements (all the originals were 85C, the new ones went in all 105C with a few in really warm locations at 135C) and ran it for an evening. Worked well.

Jeep

Traded the Challenger in against a new vehicle- Jeep Grand Cherokee. A bit more practical than ferrying the family around in a 2-door muscle car.

drip drip

Changed the ignition amplifier in the Renault and also a new distributor cap and arm, along with the crank position sensor. The CPS was at fault causing the non-running but the ignition amp appears to have been a bit marginal because it has a lot more torque now. Also, the power steering has stopped leaking and is holding fluid. The gearbox is leaking though, along with a weep of coolant onto the exhaust manifold that I need to find the source of because it smells when I start the car up. Other than that it is actually working moderately well.

Centrifugal.

The Renault had been making some unhappy noises from the engine bay recently, bad bearing kind of noises. I drove it to work and back and on the way home it decided to buck and jolt badly, feeling like a bearing jamming up (more on that later).

old pump

After having to purchase an 11mm wrench (not a real size, why it’s used is beyond me) I removed the water pump. Due to the design, it was impossible to remove by hand, as the bolts undo and the pump came off with a gentle tap, but the impeller got stuck in the aperture with the pulley wedged against the frame rail. A bit of wiggling and there was 1/8″ holding it back so a thump from the bottom of the mallet handle saw it liberated onto the floor.

coolant

I’m quite impressed by the coolant. It’s very clean, all things considered. This is a good thing.

water pump removed

Water pump aperture, including original gasket, which probably could have stayed, in hindsight. Note the really large space to work in (by general Renault standards, at least. I can get my hand in there and even see what I’m doing. Luxury).

gasket scraper

Spent an hour swearing at the old gasket, which was particularly awkward to remove.

no more gasket

Eventually it did come up clean. I’m just glad the block is cast iron because the angle I was forced to work at with the blade would have scratched and taken chunks out of any softer metal. Surprisingly also, the pump housing is remarkably rust free where the impeller spins, so I’m guessing this coolant does have some anti corrosion properties.

new pump

The new pump came with a new gasket (which didn’t fit very well, the holes didn’t line up properly) and has a different impeller design. Previous one was a pressed steel affair which was effective enough, had 4 vanes. This one is cast metal and has many more (and upon actually having run it now, pumps a much higher volume of coolant, particularly at idle).

sealant

Gave the gasket a coating of sealant and installed the bolts, which were held in place by the gasket (useful side effect of the holes not lining up well).

pump in place

There was a moderate period of jigsaw/Jenga type thought and experimentation that occurred before the pump went in. In the end, the bolts had to be in place, the pulley had to be on the shaft but not attached so the pulley could wobble about enough to allow access to put the pump in place. Thankfully there’s enough room to see one bolt past the frame rail and also space to stick a locking rod so the pulley bolts can be tightened.

alternator bracket

Then it was time to put things back on! Alternator and aircon compressor bracket assembly first.

alternator

Alternator with top adjustment bracket.

compressor

Finally, aircon compressor and belt, which took a while to remember which way round all the pulleys it goes.

battery

Finally, the battery tray and battery went back in. Filled up the coolant and let it burp as best it can with the engine off.

grubby

Been a while since I’ve had grubby hands, made a change from moving boxes and furniture.

running

Finally, all buttoned up, topped up and running. Aircon even works still, which is nice. There howling bearing noise is gone, but initially it was still bang thump, kangarooing and running intermittent badly on the test run. This was traced back to a rubber bungy that had split and fallen off one of the big spigots on the brake booster. Replaced that with a short length of pipe with a wire nut stuffed in the end because that shouldn’t split now. Normal, smooth running resumed. This fuel injection system really doesn’t do well with vacuum leaks at all.

It’s nice to have it back on the road, even if the front brakes are now sticking because they’ve not been used. Next job, that.

Wipe and wait

My car has a 4-position windshield wiper stalk; off, intermittent, slow, fast.

While the motor needs to be pulled and serviced because there’s little difference between slow and fast, the intermittent wipe had always been somewhat pathetic.

Selecting intermittent would make the relay click, and as soon as the wipers returned to the parked position, click again and they would almost immediately wipe again.

Pulled the dash shroud down and located the clicking box at the top left. (Top right is the key-in/seatbelt buzzer, bottom left the cruise control stalk, above that with the finned heat sink the dashboard dimmer control).

relay delay box

Took the circuit board out and drew up the circuit diagram by following the traces, to get a better understanding of the circuit and its method of operation.

board

Culprits were most likely the electrolytic capacitors. One had a high ESD and the other was meant to be 22uF, it measured in at about 100nF. Replaced them both. Now the wipers wipe and wait about 5 seconds before wiping again on intermittent, and added bonus, they now wipe 3 times after spraying screenwash onto the screen. Not bad for 45 minutes’ work and spares I had in stock.