SOLVED Abyss rate led stuck on

[cniers13]

Hello everyone,

Just finished wiring up my abyss pedal. Sounded great and then I noticed the rate led stopped pulsing and is now stuck always lit up. I reflowed as many solder joints as I could and cleaned the board up too. Any ideas?

 

[zgrav]

is the pedal still working even though the rate led is always on?

 

[cniers13]

The level definitely works and so does the knob to turn the brightness of the led, I think that's the intensity

 

[cniers13]

I'll upload some pictures

 

[zgrav]

Are you still getting the rate function to work (hearing modulation when you change the setting on the pot)? I was asking to see if the problem is that the LFO is not working, or if it is only the LED that is stuck in the "on" position. when the title is "abyss rate LED stuck on" it could mean either one of those situations.

 

[cniers13]

The rate function did work but now turning that knob does not do anything

 

[zgrav]

so the rate LED is probably fine and is on all the time because the LFO has stopped working. fixing the LFO will probably have the LED working again. is the project in the enclosure? or was this all done out of the box?

 

[cniers13]

Here are some photos of the underside

 

[cniers13]

I tested both in and out of the enclosure and it still doesn't change

 

[zgrav]

can you post some pics of the top side and the wiring to the jacks and footswitch?

 

[cniers13]

Here's those!

 

[zgrav]

Take a close look at the wires coming into the board from the footswitch to make sure there are no accidental shorts. Also look at the connections for the dual rate pot (can't see the inner ones in the pic). since the rate control worked and then stopped working it is likely a bad solder joint or a shorted contact in the LFO section. what voltages are you getting on the transistor? do they change when you adjust the rate pot or the depth/intensity pot?

 

[Chuck D. Bones]

When you say "rate LED," you mean the LED in the middle of the LDR huddle? There is no Rate LED per se.

I do not recommend using aluminum electrolytics for C11 - C13 (especially C11). They are leaky and can stop the LFO. Use tantalum. Film would be better, but good luck fitting a film cap onto that footprint.

Measure the voltage on Q1-C.

 

[cniers13]

Yeah it's the led in the ldr group. I'll have to see if I have any tantalum around

 

[cniers13]

Alright, guys thanks for the help! I ordered some 1uF tant caps and will double-check the rate pot for cold joints and also no shorts on the footswitch wires. I'll get the caps replaced and report back after that

 

[Chuck D. Bones]

Measure Q1-C before changing anything.

 

[cniers13]

2.166V DC measured from Q1-C to the ground lug on the DC socket

 

[Chuck D. Bones]

The voltage on Q1-C should move around at the LFO freq. If it's not, then the LFO is definitely stuck. Since it was working and now it's not, the most likely suspects are a bad solder joint & conductive debris. Inspect everything, especially around the SPEED pot, R17-R22, Q1, C11-C14. Use magnification and plenty of light. Have you removed & replaced any parts during the build?

 

[cniers13]

I have not removed any parts, I did 2 reflows so maybe a piece so solder got stuck somewhere. I'll check the rate pot and those resistors and caps!

 

[cniers13]

I have continuity between the middle lug and right lug on the dual pot so I bet that's the issue (middle and the lug that is connected to the square pad)

EDIT I see that is correct on the schematic