SOLVED Magnetron Very Low Output

[Spiff4565]

I had this working just fine but needed to put it in a different enclosure.

After removing it and hooking up power the Rate LED does not receive power and there is virtually no output.

Using a audio probe, on IC1, pin 2 I am getting a good strong signal. On pin 1 of IC1, the output is half of the signal going to pin 2.

Is this lower output on pin 1 expected or might there be another issue causing this?

 

[Locrian99]

Check your gain trim pot first. It looks like it could be at minimum volume.

 

[Spiff4565]

That is where I left it. I tried texting with it in various positions. No difference was made.

 

[Nostradoomus]

So it was working fine in box 1, but moved to box 2 it stopped?

 

[Spiff4565]

Yes, working just fine. So good my brother wants to buy it, but wanted in a different enclosure and LED's arranged differently.

Lit foot switch for on/off and rate light off when unit is off.

 

[Nostradoomus]

what

 

[Stickman393]

You're gonna need to follow along with the schematic as you probe your signal.

IC1 PIN 1 is the output of the OPerational AMPlifier (1/2 of IC1). A stronger signal here is to be expected.

Could be a connection came loose somewhere as you were re-boxing. I'd carefully inspect any offboard wiring, potentiometer solder joints, jacks, etc. Maybe one of the DC blocking 1UF caps got nudged and it's lead was dislodged.

Schematic:

 

[Spiff4565]

what

He wanted a foot switch that has a light around the base. He also wanted the rate LED to only be on when the effect is on.

 

[Spiff4565]

You're gonna need to follow along with the schematic as you probe your signal.

IC1 PIN 1 is the output of the OPerational AMPlifier (1/2 of IC1). A stronger signal here is to be expected.

Could be a connection came loose somewhere as you were re-boxing. I'd carefully inspect any offboard wiring, potentiometer solder joints, jacks, etc. Maybe one of the DC blocking 1UF caps got nudged and it's lead was dislodged.

Schematic:

View attachment 81886

Yeah, the weaker signal on pin 1 is what is throwing me.

But at the same time the rate LED isn't lighting up too.

Likely the two are related.

 

[Nostradoomus]

what voltages are you getting on IC1? Something is probably up with your power

 

[jimilee]

Yeah, the weaker signal on pin 1 is what is throwing me.

But at the same time the rate LED isn't lighting up too.

Likely the two are related.

Look for something grounded that is t supposed to be, like touching the enclosure.

 

[Stickman393]

Yeah, the weaker signal on pin 1 is what is throwing me.

But at the same time the rate LED isn't lighting up too.

Likely the two are related.

Ah, forgive me, I had read that backwards. I thought you had said that you had a weaker signal at 2, not 1.

I would check voltage at pin 8 of the op amp. I see that there is an LED on the bottom of that socket.

What did you do to make the rate LED switchable? Looks to me like the trick there would be to connect the anode of LED2 to the same point as where R102 meets the switch.

 

[Spiff4565]

what voltages are you getting on IC1? Something is probably up with your power

Bingo. I was using alligator clips to connect power. After I soldered on a proper connector the issue went away.

Lesson learned.