[sdiy] Roland IC

[Dan Gendreau]

Gerry Dahl Wrote:
>What is a good Roland IC source? I need a BA662 VCA IC for my JX3P.
>Anyone have any leads on these?

Tony Allgood's TB3030 project calls for one of these chips, but it also has
provision for a substitute chip, the BA6110 which is easier to get.

http://www.techrepairs.freeserve.co.uk/tb3030.htm

To quote his schematics:
"The Original (TB303) Bassline used the Roland Part BA662. This is only
available from Roland and could be difficult to source. The BA6110 could be
fitted instead, but it is not pin compatible with the BA662. Because of
this, 2 spaces on the PCB have been probided."...

You can find it on page 2 of the TB3030 schematics (available on the URL
above). The part seems to have the identical function. Only the pinout is
different.

You should be able to adapt the part. The simplest way I can think of is to
use the "Dead Bug" technique(aka the "Dark Side" of synth repair :).

For those not familiar, "Dead Bug" is where you Hot-Glue the chip to the PCB
upside-down (so the pins point away from the PCB). Then you use Wire-Wrap
wire to route the leads to the appropriate holes. For more info, Search for
"Dead Bug Prototyping" on Yahoo.

-Dan Gendreau