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Here's a block diagram of caller id using 8051 as controller and mt8870 decoder mentioned by Ramussons There are more informations here if you are going to roll your own.
I'd suggest a 2 digit or 3 digit (for more challenges ) frequency counter that counts 00-99Hz or 999Hz.
Are you allowed to use a timer ic like 555 for the time base of the counter?
Allen
May be you're right; or it could be that something more important came out and he was distracted. Lets wait at least a week or two and see if he does come back.
Hopefully the problem was just a capacitor in the PA stage.:)
Yes the problem could be from the Main Amp board but it can be also from further up-stream.
When the expression pedal was at the minimum, is the loud tone still there?
Allen
Here's the block diagram of the Yamaha Model B4B.
Is there a similar block diagram for your BK7i model?
I used to have the BK4C service manual in hardcopy, but couldn't fine it anymore. The organ from this age used many small cards connected together with bundles of wires and was very hard to...
Yes and no.
The first timer is used to count the number of pulses from your generator.
The second timer will be the time base to reset the first timer. If it is set to 1000mS, then the counter value in 1st timer will be in Hz. If it is set to 10mS then the value will be in 100x Hz.
Allen
I have gathered some more info for your frequency counter:
So leave out Port3 for the inputs from the freq source and use Port0 for the LCD.
I also doubt that the 8051 is able to measure up to 20MHz without external prescalers.
Allen
Do you have a development board for 8051 or you just have the 8051 chip? What flavor is it? Intel, Atmel or STC?
I'd start with interfacing with the LCD display first. Learn how to display "Hello World" on the LCD.
Allen
Here are some more info for the samsung charger. The author also drew the schematic at 4:55
https://www.ifixit.com/Guide/Samsung+USB+Charger/17367
BTW, how did you measure the capacitors? Did you measure the ESR?
Allen
Using one 40106 to replace 3x LM555 was a big trade off and simplified the circuit much. I wish the OP has learned much from this thread. At least I have.:D
Allen
If you want the 74LS192 step down to work, you'd need a 1KΩ resistor at the DN pin of the chip like this
If using 74192, the resistor has to be lower.
Allen
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