EKO Rhythm Maker

[pipdog]

I recently found an old EKO RHYTHM MAKER unit at a junk shop in reasonably good condition. Did a quick check and plugged it in. It made a bit of noise, albeit very quiet; went for a short time and then stopped.

Not being familiar with how these machines were supposed to work, and not finding any schematic diagram on the Web, I traced the PCB, and formed the schematic. This helped located a transistor (TR2 on the schematic) that was intermittently going into thermal runaway, thus dragging the DC supply voltage down, stopping everything else from working. I drew the schematic from right to left (input on right-hand-side), as the PCB is laid out with input on the right. It should not be too hard for others to figure out which component is where. Photo should help. Also found Elect capacitor on far left is wrong way around, but didn't seem to affect performance.

I only did the voice PCB, which is on top. The other PCB in the bottom of the box has the DC supply and the trigger circuits.

I drew the schematic in Excel, but I cannot post Excel on this forum as it does not accept the Excel format. I have posted PDF files that might help someone.

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Schematic.pdf
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Components.pdf
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Filename:	Components.pdf
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Photo.pdf
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[mosc]

to electro-music.com pipdog. Great to have you here and thanks for this informative post.

As for Excel, I don't think this issue has ever come up on this forum. I don't use that program. I just made a small change in the admin database for XLS file types. Maybe that will fix it. If you'd like to try again, it would be helpful.

Thanks

[pipdog]

Thanks mosc. The file extension is xlsx.

Going senile! Not Rhythm Maker, but RHYTHM BOX. Attached pic shows the box sitting on top of home built valve amp using Aussie "Lamington" circuit. I plugged my $10 guitar in that normally sounded like a string attached to a tin can, into the amp. The Lamington circuit made it sound unreal! My ears are still ringing. I assume the amp also enhances the Rhythm Box sound.
Also, I remember the seller telling me the box was originally connected to a Hammond organ.

Cheers.

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RhythmBoxSmall.jpg
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[PHOBoS]

Thanks for the schematics!

That almost looks too simple which makes it an easy option to add to something else and maybe experiment with the component values.
Do you have any sounds too ?

[pipdog]

Yep. Relatively straight forward.
Go to Youtube and type in Eko Rhythm Box. Someone else posted sounds - well done.