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Tbkahuna

00:25:17 Fri
Apr 15 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

I'm getting number 1! Now I just need to wait for Sergey to become even more famous.

I want to use the switch for voltage change and may remote the on/off too.

I'm doing some more testing in anticipation of 2000 rpm.

TBK

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camracer

00:22:07 Fri
Apr 15 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Quote: Sergey_new_pcb at 11:59:40 Thu Apr 14 2011

Quote:

we may have to do the capacitor mod I had to do to prevent the "run-away" motor issue I had on my prototype

We don't know yet if it's necessary. The voltage regulator on the new board can supply more current than the old DC-DC converter so there won't be bad voltage drop when motor starts up. If it's a matter of voltage spikes generated by the motor, the mag (not the board) will need mods - a small ceramic capacitor should be soldered to motor terminals.

Ok, That's good news Sergey. Easy to do!

---
2010 DROZD TACTICAL ASSAULT RIFLE: 2010 regular Drozd, 23" JimC tactical rifle barrel, JimC AR stock, Leapers 3-9x32 "Bug Buster" scope, Walther tactical laser/light combo, Fab Defense T-Pod tactical foregrip, Sergey's 2000rpm custom full-auto circuit board, Prototype AR style 9500 round dual drum magazine

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camracer

00:16:53 Fri
Apr 15 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

I call circuit board #3 For me Sergey! TBK beat me to the punch for #2!
Ready to send you payment! ---Cam

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drozdandconfused

13:52:33 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Excellent work Sergey. I think you nailed it by spacing out the ROF 4-6-8-etc. The new mag linear voltage regulator (15V) or jumper is a great set up similar to what I'm using now. I really like the idea of adding an external switch to toggle between the two settings. Can't wait to see video of 2000 rpm BB with the new TB Kam Hi-Cap mag feeding it!!!

Cheerz

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Tbkahuna

12:26:36 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

I'm ready!

I made the payment for the smaller board yesterday and will send the payment for this board today.

There is nothing like getting new toys!!

Thanks,

TBK

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Sergey_new_pcb

12:21:30 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Quote:

Let me know when you will be ready to ship one

How about this one?

When I become famous you'll show this #1 board to journalists. :smile:

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Sergey_new_pcb

11:59:40 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Quote:

we may have to do the capacitor mod I had to do to prevent the "run-away" motor issue I had on my prototype

We don't know yet if it's necessary. The voltage regulator on the new board can supply more current than the old DC-DC converter so there won't be bad voltage drop when motor starts up. If it's a matter of voltage spikes generated by the motor, the mag (not the board) will need mods - a small ceramic capacitor should be soldered to motor terminals. [1 edits; Last edit by Sergey_new_pcb at 12:01:38 Thu Apr 14 2011]

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Tbkahuna

11:56:47 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Sergey,

That is great! I can't wait to put one into use.

With the Nichibo motor we are using in the new electric mags, I will get over 2500 rpm at the auger. That should be able to feed sustained fire at 2000 rpm.

The same motor with a different wind should do over 4000 rpm at the auger. It looks like everything is lining up for this to be a successful new chapter in air machineguns!

Let me know when you will be ready to ship one and I'll send the money.

Thanks for putting this together, Sergey!

TBK

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camracer

10:49:58 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Forgot to ask: With the higher 2000 rpm mode The Blackbird may require a better motor. And since were breaking ground here, we may have to do the capacitor mod I had to do to prevent the "run-away" motor issue I had on my prototype. Is there anything that you have done to the new CB that can prevent that? ...Or just do a capacitor mod as needed only? ---Cam

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camracer

10:26:28 Thu
Apr 14 2011
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Re: Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 m

Fantastic work Sergey, put me down on your list I'll buy one very soon! Just gotta get some cash coming into my business for the season. Looks like CB #3 is going to be a real winner!!! ---Cam

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Sergey_new_pcb

09:16:48 Thu
Apr 14 2011
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Drozd Blackbird "Sergey's board - 2" (9-24V, 400-2000 RPM, Full auto, 4-12 ms)

Greetings Gentlemen.

Please welcome the board ver.3 (Sergey's board - 2).

What it inherits from the previous design:
1. The same size and controls positions.
2. Power supply range (9-24 V).
3. Drozd/backbird compatibility.

What's new:
1. ROF: 400-600-800-1000-1200-1400-1600-1800-2000.
2. Mag voltage is controlled with a jumper (see below).
3. Better transistor in mag control circuit.
4. Pulse: 4-12 mS.
5. It's $10 cheaper (no need for DC-DC converter).

Here's the ideology behind the design changes: let's say good bye to DC-DC converter, we don't need it any more. Originally, it was implemented because we needed to lower mag voltage from 24 to 9 volts with minimum losses. DC-DC converters are efficient when there is significant difference between input and output voltages. But then I had to increase its output voltage from 9 to 14 volts (so in-out difference was reduced). Now, achieving higher ROFs requires further voltage increase, plus higher voltage applied to the mag means the converter has to supply more current. This would mean less efficient and more bulky DC-DC converter. The processor and LED display draw only 5-12 mA so a simple linear voltage regulator can supply them with all they need. As for the mag, you have three options now:

1. If your batteries voltage is below 17.5 volts you can put the jumper in the position closer to the mag connector (there are two positions available, see the photo below). This means the mag voltage regulator is bypassed and all batteries voltage is applied to mag motor. The actual RPM you'll be able to achieve in this mode depends on your batteries voltage.

2. If your batteries voltage exceeds 17.5 volts and the jumper is in the position closer to the display, mag voltage is limited to 15 volts. This mode is safe for Blackbir

[ Continued ]
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[1 edits; Last edit by Sergey_new_pcb at 09:18:46 Thu Apr 14 2011]

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