Junebug Assembly Tips

[3v0]

I think it is just part of the injection molding process; it is the point where the plastic is injected into the mold for the casing.

You must be correct. Both work the same even though the marks differ.

 

[blueroomelectronics]

The BS170 appears to be an excellent replacement for the 2N7000.

 

[mvs sarma]

I ordered from mouser once, had to pay $35 in duties and broker fees. Digikey no problem. Might not apply to US orders.

In India, I just paid Rs.25?- (1$ at Rs.40/approx)

 

[mvs sarma]

(Priliminary step__ My DMM has been cross checked with another by measuring my PC's +5V. Both meters were reading 5.12V)

1. Oh God - I interchanged 2 transistors (Q1 and Q4)by mistake. Today I have restored them.

2.the resistor R17 has been increased to 680 ohms due to very high brightness and consumption too.

3. The consumption at 5V external feeding was measured at 130mA.
After removing the 18F2550 it has come to 65mA. Now with 680 ohms, and transistors normalled , the current with f2550 in socket is 70mA with 5V supply.

4. the USB is still at 4.71V.

5. a) The trouble shooting procedure, the Vdd is indicated as if 4.5V. I don't Know where this measurement was taken. I presume it as measured at pin3 (TG_T) of 18f2550.
5. b) the Vpp is indicated as if, it is 11.9V. But actual measurement at collector of Q4 is only 10.99.V

6. The specific test of red color LED blinking, when powered while reset key pressed , is OK.

Now I am sure until I manage this voltage to 12.5V , perhaps I can't use it.

I propose to tamper the feed back ratio by reducing the R6 to get the required Voltage. I have used a 1% Tol resistor of 2K7 here.

Please offer your valuable comments and help me .


Meantime I am also trying to see how to improve the USB voltage of my PC. here I wan to attach a link to an Intel document PDF. If you google for this link you will land in usb.org link with a pdf suggested. perhaps it may be of help to us.

"Power Delivery Design Issues for Hi-Speed USB on Motherboards"


In my case the PC USB socket, the series resistor on 5V supply line is marked x15 ( I presume it to be 0.15 ohm. I would try to manipulate this to .075 by paralleling another. It might take time.

 

[blueroomelectronics]

The 2N7000 and BS170 will both work, just depends on what part of the world you're in one will be more available than the other.

Preprogrammed 18F2550 comes with the kit, the firmware will update itself if it's older when you use MPLAB or PICKit2 software. You can even downgrade to 1.x if need be so you can recalibrate PIC12F chips (feature was removed in 2.x PICkit2 software)

DIY builders that have to supply their own 18F2550 will have to have access to a PIC programmer, sort of chicken before the egg problem.

Here's a useful tip for the MOSFETs (as they can be tricky to figure out DS)
* Use a multimeter to find the internal diode across D & S the Gate will be in the center.

 

[mvs sarma]

The 2N7000 and BS170 will both work, just depends on what part of the world you're in one will be more available than the other.

Preprogrammed 18F2550 comes with the kit, the firmware will update itself if it's older when you use MPLAB or PICKit2 software. You can even downgrade to 1.x if need be so you can recalibrate PIC12F chips (feature was removed in 2.x PICkit2 software)

DIY builders that have to supply their own 18F2550 will have to have access to a PIC programmer, sort of chicken before the egg problem.

Here's a useful tip for the MOSFETs (as they can be tricky to figure out DS)
* Use a multimeter to find the internal diode across D & S the Gate will be in the center.

Was it aimed at me (MVS Sarma)!!!-- I didn't see the context sir. i do have my MOsfets. no problem

 

[blueroomelectronics]

It was aimed like yours just to help anyone interest in building the Junebug or any other ICD type programmer.

As for your USB it's not likely serviceable. A powered USB hub should work fine and are often not current limited.

The VPP section is right out of the PICkit2 manual, it works perfectly using the values in the schematic.

 

[Krumlink]

I finally got my junebug working!!! (big thanks to 3v0, Bill for the board, looks awesome)

Heres a pic:

It is pretty "special", as in ride the short bus special. Reistors and caps too big, crystal too big, no DIP Switch but shorting blocks, Massive Toroid, Messed up Ferrite bead (found off old monitor board, it is all twisted up) and tiny switches. But hey at least it can recognize chips and work!

Any comments on my junebug?

 

[blueroomelectronics]

Looks great Krumlink, I'll have to get you a smaller inductor that ones a beast.

 

[Krumlink]

No, it makes mine that more special

 

[blueroomelectronics]

then it is special. You built it.

 

[futz]

I finally got my junebug working!!! (big thanks to 3v0, Bill for the board, looks awesome)

Heres a pic:

It is pretty "special", as in ride the short bus special. Reistors and caps too big, crystal too big, no DIP Switch but shorting blocks, Massive Toroid, Messed up

Hahahahaha!!! That fatty inductor is hilarious! You couldn't find a bigger one?

Hey, as long as it works, no problem.

 

[blueroomelectronics]

Krumlink, what does DON'T PRESS mean? The button?

 

[3v0]

While we were working on it Krumlink asked what the bootloader button was for. I told him that he would have to re-flash the chip if he hit it. Not exactly right but close enough, I did not want to get into bootloaders at the point. He promptly posted the danger sign on the unit.

 

[Krumlink]

Hey bill how do I get the demo to work? Do i follow the directions on the Hello world poster but instead put in its code?

 

[blueroomelectronics]

Hey bill how do I get the demo to work? Do i follow the directions on the Hello world poster but instead put in its code?

You mean the blinky program at the back of the Junebug manual?
Yes the instructions on the poster mostly apply, the poster is for version 7.x where 8.x has a release (normal) and debug selector on the toolbar but is otherwise similar to 7.

 

[thekyguy11]

Hey guys...

Just finished assembling my Junebug today, and I don't think its working quite right. I followed the directions to a T, and everything is identical to the picture. When I hook up to the USB cable, the green and yellow leds come on and the 3rd larger led comes on and goes off. I don't know where to start?

 

[thekyguy11]

o, and it shows 3.98 volts across U5V and GND

 

[blueroomelectronics]

Hey guys...

Just finished assembling my Junebug today, and I don't think its working quite right. I followed the directions to a T, and everything is identical to the picture. When I hook up to the USB cable, the green and yellow leds come on and the 3rd larger led comes on and goes off. I don't know where to start?

That sounds normal. LED 3 will come on when the 18F1320 is blank. The green & yellow are normal and the red may flash. Run the PICkit2 standalone software availabe in the PICkit 2 section of Microchips site.
3.8V seems too low though. Is that measured with a multimeter?

 

[thekyguy11]

o, so it is working, lol.

Yes, the voltage was measured with an old Fluke Multimeter. The only things I questioned during assembly was L1. All that was left that could go there was what looked like a larger resistor (1/2 watt?) than the rest. I think the colors were wrong for R6 also, but when I measured resistance of the one I installed in R6 it matched what the directions called for. Could either of these cause the low voltage?