Barracuda circuit.....

[Chris]

Hi

this is a redrawing from a very blur copy of the Baraccuda PI. If you are interested you can cross check the diagram and post the errors in this forum. Please read the note in the schematic.

thank's in advance....Chris

[Carl]

Re: Barracuda circuit.....

Here is what I have, from an older board:

R1 - 100k
R6 - 33k
R11 - 22k
R12 - 33
R13 - 100
R14 - 0
R15 - 150k
R16 - 100k
R17 - 6.8k
R18 - 39k
R21 - 330
R22 - 270k
R23 - 1k
R24 - 150k
R25 - 1M
R26 - 1k
R27 - 20k
R28 - 20k
R29 - 25k (?)
R31 - 33k
R33 - 2.2M
R34 - 100k
R35 - 270k
R36 - 100k
R39 - 33k
R40 - 27.4k

C7 - 100p
C17, C18 - 220u/25v
C19 - 0.1u

Q1 - TIP127 (Darlington PNP)
Q3, Q4 - 2N5485

7660 - pin 8 to B+, pin 6 N/C

Everything else matches. I'm sure there have been component tweaks over the years, so other boards may vary.

- Carl

[Carl]

Re: Barracuda circuit.....

Oops... Pawel caught another one... swap the inputs on U4a.

- Carl

[Chris]

Re: Barracuda circuit.....

Hi Carl

thanks for your kind support. Now it's a difficult task to adopt (some of) your component values. Because the board you mention is an older version of the Barracuda. I'm pretty sure that yours is an earlier version than Revision "D" because of Q1 (TIP127).
Why? If I would be the designer I would try first a PNP Darlington and in a redesign I would change it to a Power MosFet. I wouldn't do it the other way round. Ha Ha... and another thing confuse me where is the 7660? In the drawing is a 555 timer. Or am I wrong?
The input pins of U4a are correct drawn according the blur copy.
Is it in the original copy wrong?

Regards
Chris

[Pawel]

Re: Barracuda circuit.....

Hi Chris,

1. Q1: You have used IRF9410 - but it is an N-channel MOSFET. It should be an irf9530 (a P-channel one).

2. 7660: Yes, there is a 555 in the drawing - but this is an error. It will never work. Perhaps in a very early version a 555-based voltage inverter was used and somebody forgot to change the chip in the schematic. This is an almost correctly wired 7660 switched-capacitor voltage converter.

3. U4a: Next evident error in the "original". You should expect more bugs.

4. Lfe is brutal.

Regards,

Pawel

[Pawel]

Re: Barracuda circuit.....

5. Bug in point nr 4. Correct version:

4. Life is brutal

(quod erat demonstrandum)

Regards,

Pawel

[Chris]

Re: Barracuda circuit.....

Hi Carl & Pawel

Thanks for your support. I'll wait till the weekend and collect error messages. Maybe more are coming. On Monday I'll post an update of the schematic with all collected errors.

Regards
Chris

[Bill]

Coil Resistance

I think the coil measured 129 ohm's ?

[Bill]

Coil Resistance mistake

It should have been more like 1.29 ohms, not 129 ohms.