Help, Please, Wiring up Topp's Buchla 281 Function Generator

ericcoleridge · Joined: Jan 16, 2007 Posts: 883 Location: NYC

Ok, so, I have my boards assembled, and I've followed the wiring suggestion for the Attach, Decay, and 10V, all as illustrated in the PDF. I also follow the inter-board wiring.

However, I have no wiring example for the SPDT switch... and I'm not really understanding the schematic either. The PDF doesn't seem to be up anywhere anymore, so it's not in front of me as I write this, but the way I remember it, there are 4 wires connecting to the switch-- but aren't there only 3 tabs on an SPDT?

There's the gate input, transient, cycle, and "ms" out.

Obviously, I'm no electronic engineer, and frankly, I'm probably not too bright in general-- so can anyone help me here?

Also, if there's anything else confusing that's not specifically addressed in the PDF, I could use a heads up. pretty please?

I looked through the earlier post, but it's like 20 pages long now and impossible to find anything.

IMG_1903.jpg

Description:

Filesize:

85.5 KB

Viewed:

94 Time(s)

This image has been reduced to fit the page. Click on it to enlarge.

Ilanode · Joined: Sep 14, 2007 Posts: 80 Location: Berlin/FRG

It's true just 3 tabs but 4 wires! And 1 diode as well! Just send me a PM with your email I I'll send you the doc.

Blue Hell · Posted: Thu Jul 10, 2008 2:22 pm Post subject:

ericcoleridge · Joined: Jan 16, 2007 Posts: 883 Location: NYC

Thanks Ilanode! I PMed you.

Feel free, anyone, to drop some knowledge here too. Probably this question could come up again, I guess, or it might just be me. Embarassed

ericcoleridge · Joined: Jan 16, 2007 Posts: 883 Location: NYC

I got it.

I didn't realize that this was part of the original build doc PDF. I must have just missed it somehow. Got it now. Thanks again

numbernone · Joined: Aug 16, 2006 Posts: 476 Location: new york city

As always I am SO glad others are taking the plunge and guinea pigging all these great designs before I even dip my toes. I have 10 of the boards waiting and I havent even looked at any of the docs yet. I just KNOW that I could not pass up the opportunity for at least 2 full banks of these guys.

Best luck Eric, let us all know how it turns out.

Ilanode · Joined: Sep 14, 2007 Posts: 80 Location: Berlin/FRG

toppobrillo · Posted: Thu Jul 10, 2008 10:16 pm Post subject:

hey,

sorry yeah i added that diagram after i was asked about it early on- the middle terminal of the switch is the throw, so i guess the line should go straight through in the schematic. there was an error in the PCB for use with a 3-pos. mode switch as in the original- hence the redundant wiring. if you seperate the functions into 2 seperate inputs [trigger/gate] like i did in the new module i made, there is no error..

anyways, just follow that diagram and it should work fine. the diode [D11] is optional- it allows you to gate the FG when in cycle mode.

oh here is a new photo of the module i made pretty much done..

good work on yours by the way! Cool

josh

panel pic1.jpg

Description:

Filesize:

647.41 KB

Viewed:

105 Time(s)

This image has been reduced to fit the page. Click on it to enlarge.

ericcoleridge · Joined: Jan 16, 2007 Posts: 883 Location: NYC

OK, thanks again everyone.

But one other thing; I accidentally assembled the 'peak' circuitry on my 'A' boards. Will it be a problem for me to go ahead and use it as such? Or is it irrelevant which board it's on?

Pehr · Posted: Thu Jul 10, 2008 11:43 pm Post subject:

That doesn't matter as long as you have one on either of the boards Smile