Tweet
Here is a PDF with the schematic and PCB layout, including the 2 required mods. Mod 'A' is required, as it connects the TX drive to the correct PIC pin. Mod 'B' is optional, and is needed if you experiment with the "non-VCO" audio.
-
-
ADC Delay Pot Mod
Carl,
I plan on using the ADC input for connecting the wiper of a delay pot. I assume that the pads provided between IC5 and IC1 have been provided for this purpose. I believe that to use the ADC (IC pin 7, GP0) in this way, I need to make a modification to the board. I believe that I need to cut the trace that is going between IC5 pin 7 and the collector of Q6. Before I destroy my board (when I receive it), I would like confirmation of my assumtion. The attached PDF illustrates my intended modification. -
Q11 running warm
Finished my assembly of my HH2 board. During testing, I found that Q11 was running warm and that the battery drain was significantly higher than the original HH. I believe I found out why. The connection of the uPC PWM (IC5 pin 5) to the base of Q11 keeps Q11 always forward biased causing constant current (about half of peak) through Q11. You still get sound (though it is reduced and there is more background noise) because the forward bias current increases with signal. I broke the connection to the PWM pin (see attached image, change 'C') and audio was cleaner, Q11 ran cooler, and baterry drain is back where it should be. I am using the 555 constant tone option (option using R55, R49, and Q10), but I believe this issue exists with all audio options. If you want to use PWM audio, you need to jumper the PWM signal directly to R46 from somewhere behind (on the PWM side of) the break at 'C'.Comment
-
HH2 modifications
What a lot of ... is enough.
Welcome KingJL.
I read about HH2 - modifications.
I am interested in your version - or you may be the final version with all the modifications to the pcb with the PIC12F683. I am interested in version of the VCO.
PCB assembly in the figure are two jumpers / paths of the same / side R54 and R23. Jumper links side R54 IC5 - 7 pin collector of Q6 / according to the diagram /, while the jumper side R23 and R23 combines C16, R22 /? / What is not on the diagram.
Yours Gomos.Comment
Comment