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It can be activated through software, but I don't recall if the firmware made that available.?

Thanks Kerem, I’ll give that a try. Paul

It is louder if the Piezo speaker is not in contact with the chips below, and suspended in the air with the ground wires. [email protected]> wrote:

I have the same problem. ?If I put my ear to it I can hear a faint beep. ?Checked all the wiring and connections, everything looks right. Paul

Yes, it actually beeps on each key press. I just couldn't hear it. Is there anything else I can do with it? Mitch

Each key press creates a beep as well as turns on the led. If you don’t hear a beep, I would check to see if the opto coupler is installed correctly. [email protected]> wrote:

I finally added the piezo speaker to the Z80MC. It only took me 2 years! What I'd like to know is how is the speaker accessed? I half expected there to be a beep or something when the system booted up

I just did the same thing. Added a 22k resistor to R4 pins 1-2. Since my problem was intermittent, I'm hoping this resolves the issue. Mitch

Removed the SIO card, now I am getting in12 78 Is it possible that the SIO card interfering with input port 12? SIO card is a new one, assembled with great caution and seem to be working fine, except

When I use the instructions on page 24, Examine Input Port, Press 5 12, read in12 78, instead I am getting blinking FF. Is this normal? Does this indicate in have an HW problem?

The comment on TTL was a generalization. Also likely any Nmos chips and others will be dead. That will include most of the parts like the Ram chip, uSD is plugged in, and as mentioned already most

Thanks Allison. I have replaced the 74SL259 with a new one, but didn’t make any difference. [email protected]> wrote:

Any TTL (74LS259) will react very badly with overvoltage. Most of the CMOS may tolerate it. Allison

Now that the Front Panel is working, I need to fix the SIO card which I think accidentally destroyed during the troubleshooting of the Front Panel. SIO card received 9V instead of 5V now all LEDs are

I originally used FJN3303 transistors, which have internal 22k+22k resistors. When Mouser stopped stocking the thru-hole versions, I had to switch to FJN3305 with internal 4.7k+10k resistors. I

Hi all! To add another data point to the problem, I'm using DTC114ES for Q2/Q3, and DTA114ES for Q5 (all with 10k + 10k resistors) and R4 is 22k. Edit:? R4 is of course 10k.? I confused it with R4

Thanks Lee, a 22K resistor in parallel with R4 A between pins 1 and 2 solved the problem with S8. [email protected]> wrote:

Kerem Kapkin wrote: Correct. This provides a debounced pushbutton to clock counter U2A. Either is fine; you just don't want to leave a CMOS input floating. Or J2 pin 10 also works. With this setup,

Here is the recommended setup for standalone testing of the front panel, just to make sure it is the correct start. -J2 Pin 9 [/out] is connected to 3 components. 0.1uF cap other end ground, momentary

Nothing is actually getting hot on mine. Barely perceptible warmth would be a better way to put it. I'm powering it directly from the USB port on my laptop. Actually I just got a new laptop and it's