Jeff C
Active member
Continuing from my tremolo thread here………
I recently built the Magnetron. I was delighted when it cranked right up on the first try (I am a rank amateur who makes lots of mistakes - as one can see from my comically epic Cobalt Drive thread and slightly less comical EA Tremolo thread…..). Then after I mounted it in the enclosure - nada. It was quite a struggle getting it into the enclosure so perhaps I damaged something in the process. So I hate like damn to have to start this one as I actually had it working!! The bypass works fine. But one of the LED’s just stays lit, whether the pedal is switched on or not. It does dim when I turn the level pot and flutters with the speed pot. The other LED never lights up - perhaps I burnt it out……. When I put my audio probe on the level pot, I get nothing. On speed and depth pots, I can hear the clicking of what the delay should be. And with feedback I can hear it distorting as it turns up, but no audio sound. I tried following the audio path. I get a clear signal from the in pad, so I don’t think it’s the switch. I also get audio to r1, r2 and r3, and c1 and pin 2 on IC1. No audio on the outgoing pin 1 (according to the schematic). I get audio on one pin on the gain trimmer pot. I tried three different op amp 2134’s at the IC1 slot with no luck (using a socket). Same with IC2 and IC3. (I was hoping my problem was that I had damaged one or more of them when I was wrestling the board into the enclosure - a very tight fit!) I went ahead and reflowed EVERY solder and inspected under good light with a magnifier glass - although my skills are questionable. I then did continuity tests on all points and reflowed solder where it did not ring out consistently. All ground connections have continuity.
But I still get nothing. On the schematic I’m not sure where the point is that connects the LFO to the depth pot and C8 cap, and from the LFO to R103. Nor do I know where the +5v point is that connects to IC3 and 4. On the power side, I get continuity everywhere but tomorrow (it’s late!) I’m going to reflow a few points that are a little hard to get to ring out (but eventually do).
Any suggestions in the meantime are most welcome!
I recently built the Magnetron. I was delighted when it cranked right up on the first try (I am a rank amateur who makes lots of mistakes - as one can see from my comically epic Cobalt Drive thread and slightly less comical EA Tremolo thread…..). Then after I mounted it in the enclosure - nada. It was quite a struggle getting it into the enclosure so perhaps I damaged something in the process. So I hate like damn to have to start this one as I actually had it working!! The bypass works fine. But one of the LED’s just stays lit, whether the pedal is switched on or not. It does dim when I turn the level pot and flutters with the speed pot. The other LED never lights up - perhaps I burnt it out……. When I put my audio probe on the level pot, I get nothing. On speed and depth pots, I can hear the clicking of what the delay should be. And with feedback I can hear it distorting as it turns up, but no audio sound. I tried following the audio path. I get a clear signal from the in pad, so I don’t think it’s the switch. I also get audio to r1, r2 and r3, and c1 and pin 2 on IC1. No audio on the outgoing pin 1 (according to the schematic). I get audio on one pin on the gain trimmer pot. I tried three different op amp 2134’s at the IC1 slot with no luck (using a socket). Same with IC2 and IC3. (I was hoping my problem was that I had damaged one or more of them when I was wrestling the board into the enclosure - a very tight fit!) I went ahead and reflowed EVERY solder and inspected under good light with a magnifier glass - although my skills are questionable. I then did continuity tests on all points and reflowed solder where it did not ring out consistently. All ground connections have continuity.
But I still get nothing. On the schematic I’m not sure where the point is that connects the LFO to the depth pot and C8 cap, and from the LFO to R103. Nor do I know where the +5v point is that connects to IC3 and 4. On the power side, I get continuity everywhere but tomorrow (it’s late!) I’m going to reflow a few points that are a little hard to get to ring out (but eventually do).
Any suggestions in the meantime are most welcome!
On the schematic it goes to the switch before going to ground, so if the switch is off, there is no route to ground……sorry to belabor this, just curious……….
hmm, I guess jumping to the pot would take the switch out of the equation and leave the LED on all the time. Never mind. But what about the other idea? Or putting a jumper between V+ and ground where the power pads on the daughterboard are?
