Someone asked for the schematic of the LED driver. I did one up and
stuck it in the folder with the other LED pictures (Photos -> CS80
Renovation -> lights). The resistor values aren't that critical -
they're just the closest Radio Shack had to the ones already used on
the KAS. The transistors are generic PNPs that Radio Shack sells 15
for $2.60 (part # 276-1604). The little proto-board (with box) was
also from RS (# 270-283). Oh - and the 47k in series with the LED is
supposed to be 470 ohm.
David
--- In yamahacs80@yahoogroups.com, <barbara_Streisand@h...> wrote:
> Great thanks for the files!!!
> best david
> ----- Original Message -----
> From: David Rogoff
> To: yamahacs80@yahoogroups.com
> Sent: Sunday, October 31, 2004 8:15 PM
> Subject: [yamahacs80] Channel lights - was Re: Another CS-80 on
the overhaul bench
>
>
>
> New stuff:
>
> I just added some cool lights to my CS-80. When tuning the keyboard,
> or for troubleshooting, you need to know which voice card is sounding.
> There are eight TRG signals that go from the KAS board (which scans
> the keyboard) to the M boards (voice cards). I tried driving LEDs
> directly from these, but the load lowered the voltage too much. It
> still worked, but I was worried it would be flakey. So, I copied
> (with minor value changes) the same transistor drivers (the CMOS parts
> used in the keyboard circuits don't have much power to drive anything)
> used on the KAS to drive the TRG lines. The results are shown in
> Photos -> CS80 Renovation -> lights.
>
> I used tri-color LEDs so that they're green when idle and red when
> active. Because there's nothing blocking the light between the LEDs,
> an LED glowing red makes the green ones next to it look a bit orange.
> Right now the board is just loose, but I might mount it under the
> panel, with the LEDs to the left of the ribbon. I've also thought of
> adding some LEDs for the PWM rates, the ring mod rate, and the LFO
rate.
>
> One more thing: the CS-80 service manual came with great, huge,
> fold-out schematics and block diagrams for the whole unit. There are
> very good scans of these on synthfool at
> http://www.synthfool.com/schematics/cs80_1.jpg and
> http://www.synthfool.com/schematics/cs80_2.jpg. I tried printing
> these out in parts and taping them together, but it was a big pain and
> didn't line up. Last week I just popped the files on a CDR, went to
> Kinkos, and had them both printed on their large-format
> black-and-white printer. For both of them printed about 3 x 6 feet it
> cost $16. Great wall posters and invaluable for tracking down
problems!
>
> David
>
>
>
>
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