Vintage Synth Repair

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" <jammie.emma@...> 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
>