Vintage Synth Repair

----- Original Message -----

From: Quazimodo

To: vintagesynthrepair@yahoogroups.com

Sent: Monday, August 06, 2012 10:39 PM

Subject: [vintagesynthrepair] Re: Backlight Revisited...

Hello again,

OK I swapped the smoothing Capacitor C28.

No change... so to date I have checked the transistor, C28 and also the actual foil itself.

Stil getting 166 volts AC at around 2kHz.

I was thinking of changing C26 and C29 as well - could either of these be causing the symptoms?

Also, the transformer itself... it is obviously 'working' but do these either work or not - can they give different results?

I know you suggest going the LCD route - but as I have already got two new foils, I'd really rather get it fixed if at all possible... but this is fast becoming an epic saga!

Cheers,
TOM

--- In vintagesynthrepair@yahoogroups.com, "jammie" wrote:
>
> check the smoothing capacitor c28 the transformer is fixed uptransforms to the correct voltage for input
>
> so if the input ac voltage is wrong then it gets multiplied by the transformer
>
> so the input voltage to the transformer has to be wrong
>;
> the transistor switches the dc voltage of 5v into a small ac voltage
>
> its the same with all efoil invertors except on the korgs they have the components on board a lot use inverter chips which are the same but in a white box this is so if the invertor fails you can just swap it out
>
> on the korgs you have to find which parts are at fualt and change them
>
> i would just remove the invertor circuit and fit an led lcd instead
>
> then all you have todo is put a current limiting resistor to the manufacturers specs for the led back light from 5v line to the + of the efiol output pin on the psu
>
> then you can use the same cable for the back light as the original efiol cable
>
> the led backlights from rs work just fitted one to a kurzweil k2000
>
> which uses the same footprint as the wavestation but the negative blue ones are on back order until november
> ----- Original Message -----
> From: scott frye
> To: vintagesynthrepair@yahoogroups.com
> Sent: Sunday, August 05, 2012 2:49 PM
> Subject: [vintagesynthrepair] Re: Backlight Revisited...
>
>
>
> Is the rep rate of the AC frequency set internally on the transformer
> module?....If not, there must be an external timing component that's
> making the thing run too fast.
> A resonator?....A timing capacitor?
>
> --
> Scott Frye
>
> Audio-fixation.net
>
> Vermont
>