Category Archives: Uncategorized

DIY RF Adaptor Set

So I was looking at commercial RF adapter kits and the prices shocked me so I decided to make up my own. The commercial ones I saw used a weird connector to join the adapters to each other. I decided I would use female BNC as the interconnect that way i could use male to male adapters to make short connectors or BNC patch leads for longer cables. Here is a commercial kit from element 14 it is pretty limited and is more than US$200.42421688

I put together a much larger kit with two of all the adapters as well as to 50 dummy loads just small ones to use to match the load when connecting to a scope to match the impedance, you use a BNC Tee piece. Anyway here is my kit… It has double of each connector and should cover all my needs it cost me about 120 bucks Australian to put it together.

rfadapt

Dust PC from Hell

So I rebuilt a friend of my sons PC. It was a mess it had water cooling and the radiator was hanging lose. It was overheating from all the dust and when he brought it over in the car the radiator ripped the CPU out and bent dozens of pins.

emp

It was one of the worst PC’s I had seen in a long time for dust and if it had gone to a shop they would have thrown the CPU in the bin and it was an AMD FX 8 core worth 300 bucks

Nearly an hour under a stereo microscope with tweezers that are so fine they are like needles was spent getting all the pins straight.

I pulled it all apart except for the motherboard, blew all the dust out, mounted the radiator to the top and put a HDD cage in as the hard drives were just hanging by the power cables.

emp_2

 

It took Angus and I about four and a half hours to get it from the first photo to the finished product in the last two photos, one of the back which has a case cover over the cables and one of the front side which is missing the cover.

Some people might think it is to much to repair a PC like this and rebuild it but I actually enjoy this type of work, I just wish I could actually do this as a full time job but my health wont let me

IMG_20160114_222123 IMG_20160114_222142

Geek

Okay I was a geek at school, .. Nothing has changed… Just ask my wife
I run Linux
I am a licensed Ham Radio operator
I Own 4 Oscilloscopes
I also own 8 calculators including 3 graphing
3 slide rules
I have a glass world globe on my desk
4 Ham Radios in my shack
3 Radios in the car
2 Handheld ham radios
5 Multimeters
My phone and tablet run custom android roms
My bookshelf in my man cave has the following books…
Machine Tool Operation Book 1
Machine Tool Operation Book 2
Taps and tapping by sutton tools
The Australian Amateur lapidary handbook
Meters for measuring water
RCA receiving tube manual
108 uses for an oscilloscope
Audio Handbook No2 “Feedback”
Phillips Valve data book
Electronics Made simple
Oscilloscope equipment
101 ways to use your signal generator
99 ways to use your oscilloscope
Aquariums
How to use grid dip oscillators
101 uses for your Vacuum tube volt meter
Transistor radios Circuits and servicing
The casio PB100 Computer manual
RCA Tube Manual
WIA Handbook Vol 1
Summary of lectures Automatic control systems
Faber castell slide rule manual
Hemi 40RK Sliderule manual
Icom ICT90a Manual
Transistor Transmitters for amateurs
Radio Data Reference book
Program Design
The boys book of crystal sets
ARRL radio Amateur handbook
Electronics Principles Integrated and discrete
GIMP Graphics Package User Manual (Linux)
Tech topics radio handbook
Radiotron designers handbook
High quality sound reproduction with valves
Temperature measurement
Novice Operators Theory Handbook
Tektronics Scope 314 Service Manual
1972 Melways (Street Directory of Melbourne) from my birthyear
The ARRL handbook 1995 (Theory)
Sourcebook of electronic circuits
Yaesu FT707 Service Manual
Ford Falcon EA-EF Factory Manuals (We own 2 falcons)
Running Linux
Linux Sys Admin
HEMA World Atlas
Oh and I own two domains, twistedsouls.com and hamshack.org
Geek and proud

Jaycar MP3086 30 Volt PSU Teardown and testing

Old MP3086

Okay so I bought a 30VDC Variable 3 amp PSU from Jaycar a few weeks ago. It is model MP3086 with CV and CC modes. I was expecting the one shown above with 3 pots, one for amps, and coarse and fine ones for volts.. Instead I got a new improved model, unless you like the coarse/fine pots!

New MP3086
So of course with anything new you need to follow Dave from EEVBlog’s advice.. Don’t turn it on tear it apart so that’s what i did..
Cover off, transformer looks nice doesn’t it ?
Okay so first impressions from the photo above.. Nice secure soldering on the mains connections, shake proof washers on the earth wire and extra covering on the mains feed, see that black rectangle on the right centre ? Here it is closer up…
Switch Close-up
It is a real clunking power switch on the mains, so no standby current usage, Yay a thumbs up..
IEC socket with integrated fuse holder, nice one !
Shake proof washer a point for Jaycar
Spring washers on transformer mounts with intake vent for fan, there is also vents on the sides with exhaust at the rear of the unit
Terminal block for permanent connections say a bench Multimeter and banana sockets

Okay now for the close-up internal shots, there are five boards

  • Rectifier board Power transistor board with Relays to switch taps from transformer to transistors
  • LCD Display board
  • Keyboard Board for buttons
  • CV/CC Control board
  • Connection board for front panel outputs with current shunt for amps readings

Rectifier Board with room for two more transistors


Is this a real Japanese Rubycon or a copy ? 
The Main Power board looks like it has a real Rubycon capacitor, the screen printing looks good and it does not look like a rip off

LCD Control Board all SMD, the bodge wires on the right run to the back light, keyboard board bottom left with ten turn pot for volts selection underneath
The Voltage and Current control board, there is nothing on the other side apart from a few through hole caps and a voltage regulator on a small heat-sink, notice the flux residue on the through hole hand soldered joints, not good how hard is it to clean a a board ? Here are some close ups of the cruft left behind after soldering. But hey the Ningbo QJE company gave us their phone number if you want to call and complain to them about it :p

NXP Chips a counter IC and a logic gate, some more quality parts to go with the Rubycon cap…

Nice SMD soldering, re-flowed not hand done ! This is one of the trimmers to calibrate it all
Nice thick bus bars to the connections on the front panel with shake proof washers as well, excellent job.
Thermal switch for the fan, wired in series with fan it is rated at 5 amps and 50 C cut in temperature but cuts in before that, 
Okay now for some testing…. 
The test set-up consisted of the following.
  • RS232 connected DMM logging temperature
  • Galaxy Note 2 Smartphone for dB readings (Not real accurate but okay) 
  • Incandescent 12V globe as resistive load
  • Digitech QC1932 25MHz DSO
  • Supply set at 6.9 Volts, this just switched to the second tap (6.8V) so max heat from transistors

12 Volt Light globe pulling 1.33 amps at 6.9 volts, this tested at about half of the maximum amps and the second tap on the transformer had just switched in at 6.8 volts so I was dissipating the most heat for this amperage in to the heat-sink. 
The test set-up, I connected the scope probe to the terminal block on the front directly, I just hadn’t done it here yet
Below is the capture of power on unloaded, there is a small HF ripple at power on then ramp up to full voltage (5VDC) with no overshoot, there is a small amount of ringing when it reaches the set voltage, from power on to stable voltage is about 10 milliseconds.
This is a close up of the spike at power up unloaded, about .5-.75 volts lasting 206 microseconds
Here is a capture of a loaded supply at 7VDC from turn on to full output is 76 milliseconds with no overshoot to speak of.
1.6mV ripple at 7 volts under loaded conditions
dB levels with phone acting as meter with smart tools app. The first bump is me pressing the power switch, the second is the mechanical temp switch clicking in, then you can see the fan ramp up to 69dB. the phone was sitting 10cm behind the PSU with the microphone sideways to the fan, the power switch click is quieter as it is at the front while the temp switch was closer to the rear. The ripples in the graph is just background noise in the shack.
If you look between the cursor marks on the timebase below you can see two little ripples lasting about a second, this was when the fan switched in but was brief and low in amplitude. It may have just been induced noise from the arcing in the mechanical temperature switch for the fan as its contacts closed.
Here is the temperature run at 7VDC 1.33 amps from cold (I did this test first after leaving it off overnight) Starts at about 26c the shack temp, ramps up to 43.9c in about 2 minutes then settles to around 34c and stays there. I ran it longer then this graph loaded and the temp was stable and didn’t run away at all which it shouldn’t pulling 9 watts from a 90 watt supply.

 All in all for the price I am very happy with it, well built steel case, the front panel is plastic but has steel rails running from it to the back panel for support.

So what don’t I like ? Well not much the only things are as follows.

  • Earth Connection is in the centre, so I cant plug a standard spaced dual banana plug adaptor in to the – and + rails, I may re arrange the banana sockets and move the earth to one side.
  • You need to short the rails to set the required amperage for CC mode, I am going to put a NO momentary switch on the front so i don’t need a lead to do it
  • Switching on CC mode is a bit hit and miss, I dont know if it is key bounce or a slow micro but you have to press the CC button a few times before it locks in to CC mode, it is a soft switch
Apart from that i really like it and it actually goes to 31.5 Volts
MP3086 Regulated lab Power Supply 30VDC at 3 AMPS
List price $199 AUD

Photos of the shack all setup

The Twisted Shack
The twisted Professor

Shack mascot Tux and Mr Bean teddy
My Pulse Jet

Tools in filing cabinet

Power tools in Filing Cabinet

Close up of my books

More books

Even More Books

Bits and bobs on display

A few more knick knacks and a dummy load project DC-1GHZ 250W

VIC Royal mail Service Morse Key circa late 1800’s

Small hand tools

More Small hand tools

Pocket Digital Scope and Function Gen from Velleman

Keyboard and mixinf desk at workstation side

Fishtank and tablet

Loose tools behind Drillpress

Storage bins

12VDC Shack battery backup

Gas storage Mapp/propane

Microscope, ultrasonic cleaner battery Charger, Pestle & Mortor and telescope optics

Flatbed scanner I get out as needed and storage draws

Breadboarding

Labeller, tacho and camera

Dremel and Hot Snot

Gaming PC in old 19inch Rack case and Fan/heater on top under the desk 
Air COmpressor Oiless with water trap for dusting electronics

Tool Bag for field work

Inside tool bag, I add the pocket scope and sig gen when i go out with the bag

Swing out lead rack

Test leads for field bag

Network cable tester and resistor/capacitor sub boxes

2nd Dremel and drillpress stand

Air tools

Measuring and scraping draw

Spanners

Metal Working, files snips reams

Screwdrivers

Drillpress

Hammers clamps and random tools

larger pliers, side cutters allen keys

Sockets

Handmade clock from old 240VAC clock that had broken glass and burnt out Mistral Desk fan

More Sockets Taps/Dies Drifts Wad punches

Under workbench storage and solder dispensper Atten Digital iron and Compressed air outlet

Digitech 2 Chan DSO, Powertech 30VDC 3A PSU Tek 314 Scope GW Freq Counter DMM with Cap/Ind/Tran test and cordless power screwdriver

Main Shelving with video feed from driveway and frontdoor so i dont miss the postie with goodies from eBay

Atten Iron (Base under desk) Digitech SMD rework station (air and iron) and small PCB hand tools in old makeup case with USB outlets to left and Power fail torch (Comes on when power goes out)

Drill press and visitor chair with storage bins, resistors in drawers to left

Asst small parts Caps/Semis/Screws etc

Overview of workbench side

Panning to left of workbench

Workstation, Desktop PC at top laptop with 2nd screen center and tough book laptop right, all linked with synergy remote software to use one keyboard and mouse to run it all as one virtual PC

Ham radios Mindisc recorder, 10 band graphic equalizer transmatch and 13.8PSU with 24VAC for weller iron (So I can solder power etc at radio side)

Sign my son made me for Christmas, just hung it up for the pics 🙂

The entry to the shack

Old fridge outside shack to use for chemical storage

The 2.4×2.4Mt (8×8 foot) garden shed that is the shack

The wire bin for scrap wire

Around the back of the unit is bins of larger parts and some tools

CB250N Cafe Racer The Hornet and the 5K wall

Here is a photo taken by the seller of me riding away from his house..

So now the saga..

Well I have spent the last few days rebuilding the carbs on the bike, had them off about 15 times, checking and rechecking cleaning and checking again.

A photo of my work area, I am in a small unit with no space..

I spent a lot of time reading blogs, forums and tuning guides and kept coming to the 5K wall that honda twins of this vintage had. This was the problem I was having with the CB250N it would not rev past 5k  and I now was pretty sure it was not the carbs.

Okay this led me to electrics, COOL…. I know but in a past life I did this as a job and my hobby is Ham radio and electronics so now I went from an area i was okay in (Mechanics) to an area I actually loved electrics.

I was able to get the bike running so the first thing i did was put a timing light on it to see if the high RPM pulser was triggering the advance, it was advancing but I noticed that as the bike surged and lost power it lost spark, okay so it really is looking like an electronics problem.

Okay next I pulled the wiring to the CDI on the left hand of the air box… WTF I just noticed that the frame has been resprayed with the bloody wiring loom on the bike, there is paint in the connectors, there is paint on the earth points and paint everywhere it should not be….

So out came the dremel (mini grinder) and I started to sand all the paint of the earth points for the coils and CDI. I removed some extra wire that had been spliced between the CDI and the stator and reran the loom to get an extra two inches to rejoin the loom.

A photo of the “new” rewired loom you cant see much but I replaced connectors in the harness and removed a 6 inch splice someone had added to the stator wiring (blue white CDI voltage wires) and reran the loom to allow for the shorter length

Gapped the plugs and cranked it,…. Its alive its alive it is revving to red line and just sounds heaps better.

I hosed the stator with with a dry silicon lube I use that repels water and doesnt harm wiring to protect it and stop corrosion.

So I have been over the bike and so far have a small list of things for RWC (MOT) they are as follows…

Replace Brake Lever (I broke it putting the bike in the car)
Re wire front brake switch
Plastic weld LH side cover crack
Lube Clutch and Throttle cables
Pull apart RH switch block and clean Hi/Lo switch
Replace Fuel line and add inline filter
Sync Carbs
Reweld header it has a small crack near the muffler

On the plus side the previous owner who could not get it to run well had done the following already…

New chain and sprockets
New Rear Indicators
New Brake pads and bleed brakes
Replacement seat from wrecker
New brake light

Anyway that will do for this post… but for those that didnt see the last post in the welcome section here is a rendering of what I want the bike to look like when done