Started to Build the MP

[SVEN1]

Just finished Step 2.
Just to make it clear testing for +5 volts, you attach multimeter probe Neg to TP1 and pos probe to TP2?
Then I get the 5 volts (4.95v)

[Qiaozhi]

Just finished Step 2.
Just to make it clear testing for +5 volts, you attach multimeter probe Neg to TP1 and pos probe to TP2?
Then I get the 5 volts (4.95v)

The reference point (0V) for all measurements is the +ve terminal of the battery (TP10). So you need to attach the multimeter neg probe to TP10, and the pos probe to TP2.

[SVEN1]

Thanks, made typo I should have written TP10

[multieagle]

Nice start. Keep us up on your progress Sven.

[SVEN1]

I noticed something in the instructions after loading up the board with parts from Step 3.
Should not R5 (20K) be included in step 3? I don't see it listed under any other steps.
That would complete the path from Cxx to U2.
I have already added Q2 to my step 3 instruction sheet.

I haven't powered up the board after loading up step 3 parts yet.

[Chet]

Hi SVEN1, when I built mine I submitted the following for updates to the build manual.


“A few minor suggested changes; add to Step 3, Q2 (2N3904), R9 (10k) and R5 (20k), add to Step 7, Short PL3 again, add to Step 8, connect 50k Reject pot to PL3.”


Hopefully they will update the manual someday.

[SVEN1]

Thanks just added R9 to step 3 and soldered it onto the PCB

[greylourie]

Hi SVEN1, when I built mine I submitted the following for updates to the build manual.


“A few minor suggested changes; add to Step 3, Q2 (2N3904), R9 (10k) and R5 (20k), add to Step 7, Short PL3 again, add to Step 8, connect 50k Reject pot to PL3.”


Hopefully they will update the manual someday.

R5/20K had me for a while. It wasn't in the instruction steps. But a look at the Rev C schematics showed it in place.

You will be fine Sven.

[Qiaozhi]

I've added both Sven and Chet's observations to the errata list here -> http://www.geotech1.com/forums/showt...lse-Plus-REV-C
These changes will be incorporated into the REV-D document when it gets released (probably in the 1st quarter of 2015).

[multieagle]

Thanks Sven. Will follow along behind you with my kit. Will be my first shot at a two-sided board.

[Davor]

I might have a revision of a GB add-in soon

[SVEN1]

Step 3 has now been completed.
Ready to build step 4.
Question regarding wattage of two resistors.
What is the min. watt rating I can use for R1 and R3?
I don't have any 2 watt on hand. Would have to go out and get some.

[Chet]

Hi SVEN1; peak power through these resistors during the transmit pulse and flyback pulse period is hundreds of Watts.
Because the pulses are very short in duration the average power through these resistors is less than 1 Watt.
Good engineering practice is to install higher wattage (2Watts in this case) resistors for reliability.
If you have 1 Watt resistors use them temporarily.
Otherwise temporarily you can use two ½ Watt resistors in series or parallel to dissipate 1 Watt;
for example a ½ Watt 220 ohm and a ½ Watt 270 ohm resistor in series = 490 ohms at 1 Watt;
two ½ Watt 1000 ohm resistors in parallel = 500 ohms at 1 Watt.
You can mix other values to achieve whatever value you need.
Chet

[SVEN1]

Thank You

[SVEN1]

Had a few parts come in so i was able to finish step 6. Everything looks good on the scope and thanks to Chet I was able to figure out how to hook up a mono coil.
Actually used a 5" coil around 300uh built for my Mirage PI for step 6.

Now to move onward to step 7