SV: TB-303 original power supply - Answerfrom author

[Trevor Page]

Hi Andreas and all,

Regarding the sequencer - just a reminder that the TB303's custom
microcontroller is no longer available, not even from Roland and therefore
it will not be possible to clone the sequencer exactly. New firmware will
have to be written for a modern device, eg PIC / Atmel. Since you mention
the memory circuit, I presume you are intending to clone the sequencer.

> However the battery supply still has to included
> so that it works the same way since the memory
> depends on the battery supply.

This will not be necessary, since a modern sequencer clone is unlikely to
use volatile static-RAMs. Rather, modern EEPROM devices will be used which
do not require the use of a backup supply. Your power supply circuit would
not need to provide a backup supply line from the battery.

Trev

=========

Trevor Page BEng (Hons)

----- Original Message -----
From: *Star Project <ampe at swipnet.se>
To: DIY skicka Lista <synth-diy at node12b53.a2000.nl>
Sent: Friday, August 04, 2000 6:13 PM
Subject: VB: SV: TB-303 original power supply - Answerfrom author




-----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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