LFO not oscillating

Luke51411 · April 15, 2014, 07:54:13 AM

I built the LFO from Grind Customs here: http://www.grindcustomsfx.com/forum/viewtopic.php?f=2&t=391 on the vero layout for the daughterboard here: http://tagboardeffects.blogspot.co.at/2014/04/grind-customs-fx-deprofundis-delay.html#comment-form The LED is at a constant brightness. The depth pot is controlling the brightness correctly but the led is not flashing. I've checked everything over for layout and shorts between tracks/cuts but I can't find anything. The shape switch doesn't change anything so I'm thinking the problem must be somewhere between where the rate pot connects to the board but I couldn't spot anything obvious. Maybe all this needs is a set of fresh eyes since it was late last night that I was trying to debug... Any suggestions are appreciated.

darron · April 15, 2014, 08:58:09 AM

That's not an LFO

It's an LF-NO

Expecting my account to be suspended in 3... 2... 1...

Luke51411 · April 15, 2014, 09:24:58 AM

LF-NO indeed. Hey I could always slap the depth pot into a wah shell and have manual modulation...

midwayfair · April 15, 2014, 10:32:54 AM

Just to be clear, you DID include the switch for sine-square wave, right? That's what those pads are.

-Are you getting varying voltage at pins 5 and 6/7?

-What op amp are you using?

-What are your voltages otherwise?

Luke51411 · April 15, 2014, 11:08:32 AM

Yeah I installed both switches. I'm using a 4558. I haven't checked voltage yet. Ill do that as soon as I get a chance.

Luke51411 · April 15, 2014, 12:42:54 PM

Voltages are all at half supply 4.6 other than 4 which is near zero and 8 which is 9.6. Pins 5-7 start a bit lower and slowly go up to about 4.64 where they stop. No varying other than that

Luke51411 · April 15, 2014, 12:50:22 PM

Here are pics of the board

Kipper4 · April 15, 2014, 01:55:51 PM

What LDR are you using?

Luke51411 · April 15, 2014, 02:01:40 PM

I haven't installed an LDR since I couldn't get the LED to pulse.

Kipper4 · April 15, 2014, 02:07:27 PM

I dont know if it makes a differance but there is an errata posted in the thread.

Luke51411 · April 15, 2014, 02:08:52 PM

It looks like there is an error in tagboard's layout. The 47u should go from power to ground according to the schematic.

Kipper4 · April 15, 2014, 02:16:20 PM

I cant see the layout my pc is playing up. I hope it works out for you,
Rich

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LFO not oscillating