[sdiy] Dynacord Boomer Sampler PSU

[Ken Stone]

sounds like a fairly standard requirement - 5V at 2 amps and +/- 15v at
pretty low current. There would also tbe a rom programming voltage which
could be 12.5, 21 or 25 volts.

the 2 x 7805 each supply half of the needed 5V current.

The diode arrangement you describe for the +/- 15V is half wave rectification. 
The 40V cap is probably associated with the eprom programming voltage, which
is probably 25V. 

Then of course, there is whatever the UV lamp runs on.

Ken


>Hi y'all...
>
>
>So I walked into this store, browsing for new gear, and came across a
>weird box. It says "Dynacord Boomer Digital Sound Programmer". I asked
>wat it was. They said all they knew was that it used eproms. They gave
>it to me for free. Joy! It turned out to be a sampler.
>http://www.synrise.de/images/dynacord-boomer.jpg
>
>Although its specs are rather 1984 (8 bit/12kHz/1.3 seconds of
>memory), I'd like to get it to work. It seems to be in good shape, but
>the transformer is missing. So, now I need one or two transformers. I
>traced the PSU board to figure out what I need. I got confused.
>
>It uses  4 pins of a 8 pin DIN type plug:
>http://pinouts.ru/connectors/din8cf.gif
>
>pin 4&5 and 1&3 go to the two ~ terminals of a great (diode rectifier ring)
>pin 2&8 go to the - terminal.
>The elcos here are 16volts and 24volts max.
>So far so good, but the odd thing is that the + is going to two 7805 ICs!
>
>Pin 7 goes to 3 diodes.
>diode one: goes via an elco to ground.
>diode two:  goes to a 7815
>diode three (in opposite direction) goes to a 7915
>The elco's are 40volts max.
>To me, this method of getting a symmetrical PSU is not familiar.
>
>All 78xx/79xx share the 0 as ground. And just to be sure, I checked
>that this 0 is the gound on the sound in/out terminals.
>
>
>Does anybody know what type of transformer I need?
>Or can anyone guess the voltages I need from this information?
>
>
>BTW: The machine has an onboard UV lamp to erase the eprom memory! :-)
>I'll look more healty with your help! ;-)
>
>thanks,
>
>Dave
>
>
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>