VB: SV: TB-303 original power supply - Answerfrom author

[*Star Project]

-----Ursprungligt meddelande-----
Från: *Star Project [mailto:ampe at swipnet.se]
Skickat: den 3 augusti 2000 21:13
Till: danial stocks
Ämne: SV: SV: TB-303 original power supply - Answerfrom author


ok, too bad you didnt have a scanner.
Are you saying i should replace the 3 PD444 chips
with one UM6104?
If you have eagle from www.cadsoftusa.com could
you please draw a quick schematic for me because
i didnt get much from your description there.
I dont wont to get anything wrong you see.
(the program also has a freeware version)
Thanks in advance / Andreas



-----Ursprungligt meddelande-----
Från: danial stocks [mailto:diode at hotmail.com]
Skickat: den 3 augusti 2000 20:10
Till: ampe at swipnet.se
Ämne: Re: SV: TB-303 original power supply - Answerfrom author



>I would really appriciate a schematic for that reply
>with a suggested IC and the lithium battery to back
>up the memory with.

Hi , I cant send schemo's unfortunately, no scanner you see.. anyway.. if
you look at the board print you'll see the mem chips are upd444c - these
have exactly the same pinout as the ancient 2114's - you can't use 2114's
tho, they draw heaps of current! un battery backable!.. but wire in a 6164
etc as a substitute for all the mem chips [replace by 1x6164], and you even
can have extra banks of mem.. to lithium back, a lithium batt [+] is
connected via a diode [1n4148 / BAW62] will do to the mem VCC terminal -
same idea as for the dry cell backup in normal 303 cct. - the [-] term on
the lithium goes to gnd.. a small button cell like a 2032 etc is fine, or
use a bigger one ..  might need to have a look at the 6164 datasheets - I
think there maybe something like another CS terminal that has to be selected
correctly to go into power down mode. I think UM6104 chips may have the same
pins as upd444c also but I'm not at all sure
Cheers,
Dan




>/       Andreas
>   -----Ursprungligt meddelande-----
>   Från: owner-synth-diy at node12b53.a2000.nl
>[mailto:owner-synth-diy at node12b53.a2000.nl]För Jeroen Proveniers
>   Skickat: den 3 augusti 2000 08:46
>   Till: '*Star Project'
>   Kopia: 'synth-diy at node12b53.a2000.nl'
>   Ämne: RE: TB-303 original power supply
>
>
>   > -----Original Message-----
>   > From: *Star Project [mailto:ampe at swipnet.se]
>   > Sent: Wednesday, August 02, 2000 7:08 PM
>   > To: DIY skicka Lista
>   > Subject: TB-303 original power supply
>   >
>   >
>   > Hi!
>   >
>   > As I am now getting started for real with my
>   > TB-303 clone project I need help with replacing
>   > the power supply. The thing with the real one is
>   > that the transformer coils are so impossible to
>   > get my hands on. There for i need to replace it
>   > and while doing this maybe modernise it a bit.
>   > However the battery supply still has to included
>   > so that it works the same way since the memory
>   > depends on the battery supply.
>
>   Are you going to clone the sequencer part too?
>   Why don't you take a look at http://www.techrepairs.freeserve.co.uk
>   There's a TB303 clone (only the synth part) complete with PCB and (good)
>documentation. It's more than just a clone, it also features a suboctave
>generator, HF modulation of the filter, adjustable slide time, a distortion
>unit etc. Check it out.
>
>   JJ
>

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