Sounds like something isn't clocking in the data on the 74LS76, or the clear is being kept low. That would be my next point of investigation.

How are you getting on with the tape interface?

Do think the zeners will be good enough stabilise it? Yeah, three 5W Zeners is 15 watts, that's over 2 amps at 7.5V. The current limiter would kick in well before that and bring the voltage down. Therefore three Zeners is overkill a bit but it's best to engineer for the worst case. Under test with ...

So what does the 1.37 represent? Amps? Yes, that's what the bulb is drawing. I don't like the regulation, it's a bit pants. As the load decreases the voltage goes up, levelling out at just under 9V. I think I'm going to have to put a large Zener diode clamp into the circuit to keep it stable, or ra...

The Direct from China eBay variable step-down regulator with current limiter arrived today. Of course, no instructions so getting the voltage to change etc. was very much trial and error. Anyway, it does work: IMG_3672.jpeg I have it on test at the moment. The regulation isn't massively great as the...

Actually, thinking about it, 1.5A at 5V is only 7.5 watts. It just seems a lot.

One and a half amps is quite a lot. I wonder what's burning all that electricity.

First of all, never try to upgrade a non-working machine as you never know if it's the system or the upgrade at fault. My first diagnostic, in lieu of a diag cartridge, is to do the basics, i.e. power, clock, reset and halt. However, the last one could be due to other parts of the system playing up....

Hehe... See, it's starting to fill up.


I may get another two "units" of 16 and put them on the left side.

Oh, and the label machine ran out of tape after only three labels.

I was off work with stomach problems today but used it productively this afternoon after feeling a bit better. I sprayed conductive carbon paint onto the insides of 24 of the 0.3L "Really Useful Boxes" and started moving chips into the storage. It turns out that 24 isn't sufficient to even...