8-bit acorn hardware • Re: Acorn ALF03 Data Recorder - Replacement LEDs???

It turns out the LED is actually fine .

I got myself a bit confused, because I replaced the original rectangular data indicator LED with a 3mm diameter LED, and the new LED would light up when I pressed the Play button. It turns out that pressing Play switches on the 6V supply to most of the PCB, and it appears that there was sufficient leakage through the NPN switching transistor, even when it was switched off at the base, to cause the LED to light up. I've not figured out what's actually driving the base of the transistor yet, but shorting out collector and emitter causes the original LED to light up once the play button has been pressed.
The manual for the cassette player states:

The Data indicator [12] will light up when blocks of data are being played back.

I'm not sure if this just means that the LED lights up when the Play button is pressed, or if it's a little bit more intelligent than that, and only lights up when data blocks are actually detected. But regardless, it's currently not lighting up in either case. The base of the transistor remains stuck at 0v at all times. Can anyone confirm the intended behaviour of this data indicator LED?

Unfortunately, I've not been able to locate a schematic for this player; only the ANF03, which doesn't have the three LEDs. Does anyone have a copy of the schematic for ALF03, so I don't have to completely reverse engineer the PCB?

TIA

Statistics: Posted by KenLowe — Wed Jun 04, 2025 1:20 am

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