RC2014 Not Booting automatically

[John Sandlin]

I thought, or got it in my head without thinking.... that the Dual Clock & Reset board would hold the reset active for a short time for the RC2014 to get stable (voltages) and the release the reset to allow the CPU to run and boot. For me I have to hit the hard reset on the backplane to kick things off. And the reset button on the clock only seems to halt the system, it stays stopped until I press the backplane reset button.  

Is this how the board should work, or did I miss something putting it all together?

jbs

[Robb Bates]

I believe the intent of the circuit was to automatically reset upon power up, but I think it doesn't quite work as designed. I had to add a supervisor circuit to mine to get it to reset upon power up. There are plenty of options available, though I couldn't recommend one. Mine was an odd bird I just happen to have lying around. 

Robb

[Mark T]

The reset circuit on the dual clock would be better with schmitt trigger inputs but that would not work for the clock oscillators. You could try adding a resistor from pin 4 to pin 1 of U1, probably minimum of 10k but may need to experiment with different values.

[John Sandlin]

OK, I'll look into the resistor fix, it would be easy to "bodge in". And if it is acting normally, and the bodge doesn't do the job, I can live with pushing the button to start things running. 

[Pellatonian]

Not an electrical engineer by training or aptitude, so take this for what it is worth.

On several RC2014 kits I built which didn't start automatically I connected a capacitor between the ground and reset pins on the bus. With a high enough value capacitor that seemed to work OK wherever I tried it.

[John Sandlin]

The 10K resistor between pin 1 and 4 of the U1 Chip on the Dual Clock board didn't work - in fact the system wouldn't power up.    However a 47uF cap between Reset and Ground (Just pushed in on an empty socket) did the trick. I'll probably want to setup a cleaner way for the cap since it doesn't look very secure there. But it booted right to the "Boot [H=Help]:" prompt. 

Thank you all for the replies.

[Phil G]

DS1233 £1 reset mod:
https://www.mccrash-racing.co.uk/philg/retro/retro.htm#rc2014_reset

[Christer Karlsson]

I use the DS1233, the only thing I have noticed, is that the instruction to only use one in your system is there for a reason... 🙃

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[Sergey Kiselev]

On Monday, September 1, 2025 at 10:31:57 AM UTC-7 Christer Karlsson wrote:

I use the DS1233, the only thing I have noticed, is that the instruction to only use one in your system is there for a reason... 🙃

On Mon, Sep 1, 2025 at 11:14 AM 'Phil G' via RC2014-Z80 <rc201...@googlegroups.com> wrote:

DS1233 £1 reset mod:
https://www.mccrash-racing.co.uk/philg/retro/retro.htm#rc2014_reset

CPU supervisor is the way to go. 

Note that not all "Econoreset" parts support an external reset button.

Particularly, DS1233 parts do support it,  but DS1233D and DS1833 do not.

See https://www.analog.com/media/en/technical-documentation/data-sheets/ds1233.pdf page 6.