A1200 LEDs schematics

[orange]

Does anyone have schematics of that little PCB holding power/floppy/hdd LEDs in A1200?

[Zac67]

You mean this?



It's not the PCB but apparently it just carries the LEDs.

[orange]

thanks, where do you get power/Vcc from CN14?
the other pin of diode is GND, right?

[Zac67]

What do you neec Vcc for? The LEDs just sit between their signal and GND. Oh well, on second look, you might need resistors in series with the LEDs or they'll burn. Not sure though, depends on the transistor types.

[Hodgkinson]

Agreed. I seem to remember seeing the resistors on a LED board.

Im puzzled about the 100R there on the _LED output...Maybe the idea is, rather than toggling the LED off and on, toggling the _LED line would cause the LED brightness to fluctuate between partial and full brightness. Am I mistaken or can this be seen on a warm-reset on the pwr LED?

Anyone know what that optional circuit would be used to indicate?

Hodgkinson.

[Hodgkinson]

Oooooh. I've got an idea. :-D

[orange]

@Zax67

but,  I got A1200 without that PCB or even the cable connecting it to motherboard.

so I want to make that little PCB in order to get info about hdd activity..

[Zac67]

The 100 Ohms is a bypass for the transistor, so the LED will stay dim and won't go completely dark when _LED is high.

Dunno where the _CC_ENA is coming from. Can you find its origin?

PS: 1000th post! Woohoo! :banana:

[Chain]

just a fast sketch in eagle
send me a PM if you also need exact PCB design



 8-)

[Doobrey]

Zac67 wrote:
Dunno where the _CC_ENA is coming from. Can you find its origin?

It's generated by Gayle whenever there's activity on the PCMCIA port.

My old PCMCIA activity LED hack :hammer:

[Zac67]

Cool! In C='s place I would've combined that signal with _IDE_LED, so the HDD LED would flash no matter what is accessed. Cheaper still. :-D

Could make an easy mod to get that though... :roll:

[Hodgkinson]

@Doobrey

Bugger. Someones already done what I was thinking of  :-D

Im having a look at your page now. Thanks for the info.

Hodgkinson.

[Eclipse]

This is interesting.
I might try a bi-coloured LED where the power one is. Green for normal like it is currently then another colour when the PCMCIA is used.
That resistor for the _LED is allowing it to be dim. I can't recall but does it ever flash? If it does it would explain why.

[Hodgkinson]

I've got an idea im working on with regards to the floppy LED (Since this is the least used of the three...).

I'd like to maintain the exact same colour scheme as the A1200 in terms of LED's and avoid adding additional LED's all over the place, so what im going to do is replace the dual-LED floppy indicator with a pair of rectangular yellow LED's, fill the gap between them with some special white plastic spacers which I should have made tomorrow, cut a track on the underside of the LED board, reroute ground a little, tweak the existing FDD led resistor, and get it so that the right most yellow LED (Which im going to have to add a extra wire for) will indicate PCMCIA access - And the left most LED will still indicate FDD activity.

I thought about adding a dual colour LED, but the problem is i’ve never seen them in rectangular LED packages, and getting the light output from a standard round LED to illuminate the slot properly is virtually impossible.

I’m still undecided whether to attempt to find and solder some SMD parts to the motherboard (The resistors should be easy enough to find as SMD, the 2N3904 will probably have to be discrete though...); or bring two wires off from either end of the pads for R637 to a little veroboard board with the discrete parts mounted on it.

Hodgkinson.

[Zac67]

Don't forget to adjust the Floppy LED's resistor - only one instead of two LEDs in line.

AFAIR the LEDs, you could even saw the LED in two halves, fill in the gap with some white plastic and with the trace reroute you'd have two independent lights.