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SammichFM - Control Surface Problems **FIXED**


Electric Ungulate
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Hello Forum,

I have never built a kit before, not even one of those "burgular alarm" ones you see in electronics shops. Perhaps I should have. I'm working on a sammichFM. It's been going quite well, having uploaded the firmware and the presets I am playing around with the FM sound, but unfortunately the control surface is not functioning yet.

Thus far I have:

* Performed the control surface power tests as prescribed in the build guide. Success. ~5V where required.

* Checked for continuity in the switches.

* reseated the three ICs on the control surface (presumably some kind of logic chips to handle all the lightyswitchiness?)

* checked all solder joints for good tenting etc (some of them have little bits of burned flux on the surface, I cleaned as much with alcohol as poss, should I be concerned?).

* Reflashed with latest MIOS and Midibox FM firmware (Sammich Version)

Any suggestions? Perhaps it is the 74HC595 IC at the bottom, as the four leftmost switches of this component are also non-functioning and these four don't appear to be connected to the dual 74HC165 at the top.

Thank you in advance!!

Ungulate

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Hi there,

could you provide us with high-res photos of the PCBs (front (with chips in) and backsides), so we can have a look?

Also, a description of what is not working (everything, only some switches/LEDs) would be great!

Greets,

Peter

Edited by Hawkeye
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Any suggestions? Perhaps it is the 74HC595 IC at the bottom, as the four leftmost switches of this component are also non-functioning and these four don't appear to be connected to the dual 74HC165 at the top.

IC1 (at bottom) is 74HC165

IC2 (in middle) is 74HC165

IC3 (at top) is 74HC595

Thus there is no "dual 74HC165 at the top". You probably have the 74HC595 at the bottom and a 74HC165 at the top, where they don't belong. Thus LEDs and switches don't work.

Protip: 74HC165 are for digital inputs (switches), 74HC595 is for digital outputs (LEDs). The 74HC165 usually has resistor networks on either side to "pull up" switches connected to ground.

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