WB RC1 Fixes

[hahahehihoha]

I'm looking for feedback to the following fixes I have formulated. Are these correct?

A) TX/RX paths swapped: going from 4pin jumper to microcontroller. This is because of the TX/RX from the FT232 into the jumper makes it necessary.

B) Ring/Tip switch on the DC jack: The two pads in the image below need to be swapped with their connections maintained.

C) The 0.1uF caps on top of the 10K 1206 resistors in the PLL section can be placed in parallel somewhere BESIDE the 10K resistors on the board.

D) The MIC2506 voltage boost regulator rated for 7.5V max is receiving 13.5 V, as reported by another WB assembler. This can only be from pins 1 or 4 which are connected to the other voltage regulators and the microcontroller at pins 1 and 8 respectively. How do I fix this with the a resistor?





Ciao !

[budzeg]

i'm yet to build the ckt but as soon as i do, i'll give u a feedbk

[jc]

I have built 2 working wave bubles and here is how I overcame the issues you are having.

A) yea they are just swapped. All you need to do is cut the traces on the board and use some jumper wire to reconnect them. The simplest fix unless you want to edit the board before you ship it off for etching.

B) this is a little harder. I will refer you to my post on my site where I have a picture of how I cut what traces and where I reconnected them.

C) just stack the buggers. Solder the caps on then tack the resistors right on top of them. Any other fixes are just thinking too much and too much work. Remember KISS.

D) DO NOT USE THE R3 value or you will fry IC 10 (MIC2506 power switch) to overcome this voltage just swap out the resistor with a smaller value. Look to the datasheet for the equation to calculate it. I just changed R3 to 36.6 ohms at 1% and got 4.95-4.98 volts. Close enough.

http://corl.homedns.org/electronics/?p=21

John

[none_such]

You need to cut all the traces (three landings - two input values since to of the terminals are connected). Could you just reverse the polarity on the input charger?
Cheers

[none_such]

That is, reverse polarity and cut and jumper one trace

[jc]

no you cant just swap the voltage on the external PS. the pin gets shorted to allow the internal voltage to get passed thru.

John

[hahahehihoha]

Hat off to JC for the pointers, finalized PCB and sent off to APCircuits.

keeping it complicated:

C) resistors on caps preferable to viceversa?
D) R3 is reference to the mainboard component list ? (120 K ohm to 36.6 ohm seems a big leap and while I can obtain and read datasheets at a novice level, this I could not grasp).

Thanks,

outta here, and will report back with assembly.

[yopper]

D) DO NOT USE THE R3 value or you will fry IC 10 (MIC2506 power switch) to overcome this voltage just swap out the resistor with a smaller value. Look to the datasheet for the equation to calculate it. I just changed R3 to 36.6 ohms at 1% and got 4.95-4.98 volts. Close enough.

I assume you mean 36Kohm

(5.0 - 1.23) / 1.23 * 12K = 36.78K

What I don't understand is why the LM2733 is used as its web page states Output Min = 20 Volt Output Max = 40 Volt.

[adafruit]

D) DO NOT USE THE R3 value or you will fry IC 10 (MIC2506 power switch) to overcome this voltage just swap out the resistor with a smaller value. Look to the datasheet for the equation to calculate it. I just changed R3 to 36.6 ohms at 1% and got 4.95-4.98 volts. Close enough.

I assume you mean 36Kohm

(5.0 - 1.23) / 1.23 * 12K = 36.78K

What I don't understand is why the LM2733 is used as its web page states Output Min = 20 Volt Output Max = 40 Volt.

i think thats a typo: the example they give is for 12V!
http://www.national.com/pf/LM/LM2733.html

[yopper]

Hmm strange, still it seems the LM2731 is more appropriate. meant for a lower voltage range.

http://www.national.com/pf/LM/LM2731.html

[jc]

yea i typed that while i was a little tired. 36.6K Ohm Digikey part
311-36.5KFRCT-ND

Also in response to caps on resistors or resistors on caps. I found it easier to put resistors on caps because to the shape of the caps. your choice

John