Since M1-DA to VGA cable is quite expensive, we have decided to add extra connector to our Dell 3400MP Projector so we could just use common male to male VGA cable.
1st thing to do is to know the connector pin-out. For VGA connector we have 15-pin connector.
Cable = MALE and Projector = FEMALE.
Next, the M1-A connector (AKA M1-P&D Plug) A lot of pin. :-)
Cable = MALE and Projector = FEMALE.
Internet research tell me that only 7 connections are needed in order to make this work as below
>
VGA pin#
M1 pin#
Red
1
C1
Green
2
C2
Blue
3
C4
RGB
Ground
6,7,8 (join)
C5
Horizontal
Sync
13
5
Vertical
Sync
14
6
Sync
Ground
10
4
Now the hard work begin.... disassembling...
Soldering...
Testing...
Finally, the connector cut-out through the Dell 3400MP magnesium alloy chassis.
Last week, I came across 2 different model same brand dead ceiling fan. Both models are remote controlled model. Symptom quite similar.
The first model comes with 7 speed but I can only see only 5 TRIACs on the board. Not sure how it works.
Meanwhile the second model comes with 3 speed and 3 TRIACs available on the board. I assume 1 TRIAC for 1 speed.
While troubleshooting they look like their µC don't have enough power to start. The buzzer give something like repeating click sound. I did measure the µC Vdd/Vss and found out that the voltage is less than 5V.
After a quick search at Google, lead me to aztronics . Similar symptom. So I give them a try.
Desolder the capacitor and measure. Binggo! All caps (regulator part) value is less than they should be.
Replace them all and test with a smaller vent fan.
Done and pass them back to their owner to test with the their ceiling fan motor.
A friend of mine ask for a favor to take a look at his HP TX1000 Entertainment Tablet PC blackout LCD problem. I have no idea on how to fix this until I found below video.
Instead of using bulb, I used a heat blower to re-flow the chip.
From my observation, there is a the gap between the GPU and the heat sink was join by a burned thermal conductive silicone sponge.
I replace this with an aluminum foil folded a couple of times to get just the right thickness.
After reassemble it back together and now, the moment of truth, Hey! it works! :-)
Since I saw a several request for P16PRO40 strip board layout, so I decided to share it here.
My PIC programming tool is a strip board based (AKA Veroboard). It is not as compact & neat as the commercial programmer but guess what, It took only 2 hours for me to built it from my electronic junkyard, except the 74LS05 and of course the strip board it self. Use normal IC socket if you don't have a ZIF socket.
I have made some modification to the circuit to match what I can find on my electronic junkyard. I replaced BC557 with A1015 (PNP), note that both transistor don't share the same pin layout. Just be careful if you want to use the alternative transistor.
On the power supply circuit, I've remove 7808 regulator since I already have 13V power supply. I only use 7805 to produce the 5V Vcc and the 13V Vpp comes directly from the main power supply.
I've also remove Vpp40 on/off from my PIC programmer. I've no plan to use them in the near future.
The programmer has been tested to work with 16F84A & 16F628A.
The recommended software for this programmer is WinPicProg 1.91 from http://www.winpicprog.co.uk/. It is simple but reliable software for PIC programming.
If you are using 74LS05 or 74LS06, set your 'hardware' setting as below. They are both HEX Inverter Open Collector output ICs but 74LS06 has extra features = with Buffer/Driver and 30V output.
Below is my test circuit, just a simple blinking program to test it out.
Have you ever experience a bad optical mouse? It went double click action whenever you did a single click action? At first, I try to Google for answer but none of them help. I’ve tried every combination of settings but the problem doesn’t go away. I really suspected there must be something wrong with the circuit. After I made a conclusion that it is a mechanical related issue (maybe the switch it self), I replace the switch from an old mouse available.
Unfortunately the problem is still there. This is dangerous since you might drag a folder by accident and move it into another folder. This problem always happening to a first time touch-pad user with tapping function turned on.
So next I’m thinking it maybe related to a noise in the circuit. So without any calculation, I try to salvage a capacitor that l can find from an old circuit board and solder it parallel to the switch.
:-) Now it become “click and hold” for about 10 seconds. The capacitor value that I used to smooth the noise from the circuit is too big causing it to simulate “click and hold”. After measuring the capacitance it shows about 2µF. Too big maybe.
Next I try to find a capacitor with quite smaller capacitance value (~2nF). Maybe this will do. So I just replace it.
Walla! At last like a brand new mouse looks and feel. Good luck.
My 24kV high voltage "Jacob's Ladder" from DIY flyback transformer driver using 555 timer.
Creating an electric arc
I've always wanted to create an electric arc but don't know how. Then I come across the theory that air breaks down at about 1MV/m (Mega Volts per meter) (24kV/in). That mean you need 1kV in order to get 1mm arc. So you need a higher voltage. One of the method is to use a flyback transformer that can be found from an old TV or an old CRT PC monitor. It could generate about 10 to 30 kV. Other method is to create a "tesla coil" which is quite complicated. Maybe it will become my next project.
Flyback transformer and preparation
Flybacks can be found in all types of monitors and screens that use a cathode ray tube (CRT), e.g. TV sets, computer monitors etc. It has a big red cable with a suction cup. It looks something like below.
Next, you need to identify the primary and secondary pin out. Thanks to "Lab HV-PS page" for providing an instruction on how to find the pinout. The main HV out on the secondary coil is a big red cable with a suction cup. Now we need to find the 0V pinout for the secondary coil. The trick is to use a DC power supply. This is because the flyback secondary coil resistance is much too high. There is no way you could find it with ordinary digital multimeter.
So use your own understanding on the circuit below to find the 0V pinout. Give it about 12V and your meter should show some volts when you find the 0V pinout. For me, just to be safe, try to find a datasheet of the flyback transformer or try to find the TV or old CRT PC monitor service manual/schematics diagram to find the pinout like below. Most modern flybacks include built-in HV rectifier diode(s) and/or voltage multiplier (tripler) so output without additional components will be high voltage positive or somewhat smoothed HV DC. So, make sure your polarity is correct.
Unless you have one of these multimeter, you should get the resistance reading out of it. From my FLUKE 189 multimeter you can see that it shows more than a hundred Mega Ohm. That is why ordinary meter could not measure it because of it's limit. Below I test two types of flybacks with 112 Mega Ohm and the other about 522 Mega Ohm. Again, polarity is critical to get the reading.
To find the primary coil is a much simple than the secondary coil. The primary coil resistance is about 1 ohm and again I confirm this with a TV or old CRT PC monitor service manual/schematics diagram. In my case I could only get 0.45 ohm.
Creating the flyback driver (20kHz with 90% duty cycle)
Thanks to "Jonathan Filippi" for the idea. My circuit is quite different. I try to fix up the frequency and duty cycle with help from simulation software. I use "Electronic Workbench" to simulate the circuit which can generate about 20kHz with 90% duty cycle and I come out with this. Using 555 timer to generate 20kHz with 90% duty cycle. Next I try to put it on the breadboard and test the output from it. I get about 18kHz with 85% duty cycle. Jonathan Filippi is using 2N3904 and 2N3906 but I'm using c1815 (npn) and a1015 (pnp). I found out that you can use any multipurpose transistor and I could find it on my old TV board. For the MOSFET, Jonathan Filippi is using IRF840 but I'm using IRF630. You may try to find it's equivalent and experiment with it. Just make sure it is compatible if you want to use other types of MOSFETs. Find it's data sheet and compare the characteristic for both types of components.
Before assemble it, I test this circuit with a small transformer which I can find it on the same old TV board. Since I'm getting too excited, the quick test is to connect the output to the lowest resistance coil. I test it with a limit resistor and surprise, I can get a hundred volt out of that.
Next is to plan to transfer it to the stripboard/veroboard. Here is the stripboard layout and the assembled circuit board. Make sure you mount the MOSFET to a heat sink since it going to heat up while running/powering it up. Note that I put the 150 ohm "snubber" resistor and diode near the flyback. This is to suppress ("snub") electrical transients that might damage of the circuit.
Again, I test the assembled circuit board with the same small transformer and I could get a neon to light up. This mean I'm getting about hundred volts. Neon needs about 80V or higher in order to light up.
Test it out
Now it time to test it out. Get a high power supply for this test. Don't use an expensive lab power supply for this test. It might burn or damage. For me, I'm using a 12V DC battery charger that can give about 5 Amps. You may also try a car battery if you have one.
There is an arc!. At last, I could get an arc out of it. I try to measure the initial max. length and I could get about 24mm. Thus, it is about 24kV. Remember the theory 1MV/m?.
I measure the DC operating current. It is about 5 Amps. I've blown my DC power supply fuse in the process. Maybe I need a bigger power supply :-) . At least I've got some arcs.
07.04
Unknown
