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| Joined: | Mar 3rd, 2008 |
| Location: | Muskogee, Oklahoma USA |
| Posts: | 349 |
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Only got a small monitor here, but can follow what's going on. Do the transistors on the outputs of the 555's also negate the 'pop' spike sound, often heard as a 555 changes state ?
I managed to minimise that effect using a 104 ceramic capacitor and the diode to the former Reset switch of the radio (while there seemed to be a problem if the diode wasn't in place). I was probably lucky with this version of CMOS 555 though, it apparently generates less output current. A probable bane for many circuits, but for this simple trigger operation the less current is probably the better.
I haven't been able to do a schematic yet, my circuit is basically a hack and so the radio part is what's been altered. The basis though is the 555 to time a Reset of scan and the Mute bipass.
As a 4.5V circuit, your ideas there seem logical and functional, makes me wonder if simply adding another battery would have simplified all the late nights on mine lol ended up removing some ideas and yet the unit does what i'd intended, as somewhat of a trainee in circuit mods.
Thanks for posting it