SOLVED Angry Andy Plus Drive problem

[SteveScott]

I got this thing all together, the only thing not working is the drive pot. With it turned all the way down, everything else works as expected. When you turn up the drive even a little, all sound is lost. All three lugs of the pot ohm out correctly, it is a linear 100k pot. Can a pot be bad, even though the meter seems to indicate that it's OK? Or is there another angle I need to be looking at? Thanks for any help.

 

[SteveScott]

New item by Steven Scott

photos.app.goo.gl

 

[PJS]

The photo is not terribly large, but it seems from what is there that some of the solder joints are a bit dry. Maybe have a decent inspection and reflow/add solder where needed

 

[music6000]

The toggle switch looks like next to no solder, have you tried it in the middle position with the Drive pot.
There looks like quite a few spots have cold joints as PJS has noted.
Inspect and reflow
Try posting a picture from the Solder side.

 

[SteveScott]

I'll post a pic of the solder side in a bit. But please keep in mind, toggle switch works fine. Everything works fine except the drive pot.

 

[SteveScott]

New item by Steven Scott

photos.app.goo.gl

New item by Steven Scott

photos.app.goo.gl

New item by Steven Scott

photos.app.goo.gl

 

[SteveScott]

I reflowed almost all the solder points and replaced the drive pot. No change.

 

[SteveScott]

New item by Steven Scott

photos.app.goo.gl

 

[music6000]

Before all the other members jump in, You really need to clean the Solder side of the PCB, there is a lot of Flux & still questionable Solder pads.
I find Electrical Cleaner in a spray can & Tooth Brush is the cleanest way to get the crud off & will show your imperfections the best!

 

[SteveScott]

Before all the other members jump in, You really need to clean the Solder side of the PCB, there is a lot of Flux & still questionable Solder pads.
I find Electrical Cleaner in a spray can & Tooth Brush is the cleanest way to get the crud off & will show your imperfections the best!

Thanks. I'll take your advice and give it a good cleaning in the morning. The light should be better than for a better picture anyway.

 

[SteveScott]

2 new items by Steven Scott

photos.app.goo.gl

Sorry that took so long. My other life had some things going on.

 

[music6000]

2 new items by Steven Scott

photos.app.goo.gl

Sorry that took so long. My other life had some things going on.

Check for continuity with matching Colour rings:

 

[SteveScott]

All good on those.

 

[music6000]

What are the Voltage readings on the the Op Amp?

 

[SteveScott]

Help me out on this. I'm not sure where to place my meter leads to answer that. Sorry, still learning.

 

[zgrav]

Help me out on this. I'm not sure where to place my meter leads to answer that. Sorry, still learning.

I suggest doing a google search for some videos that show you have to use your digital multimeter. well worth the time to do so.

 

[SteveScott]

I suggest doing a google search for some videos that show you have to use your digital multimeter. well worth the time to do so.

Thanks for your input. I know how to use a multi meter. It's the op amp I'm unsure of.

 

[zgrav]

look at the schematic for the project in the build document to see if it shows you where the power connects to the IC. if it does not, look up the datasheet for the IC to see what the pinouts are.

or just do a google image search for the IC and you will probably get the info you need.

 

[SteveScott]

Ok. My power source (battery for right this second) is 8.68vdc. From pin 8 to pin 4 on the op amp (+ and ground) is 8.39vdc.
Pin 1 to ground is 4.8vdc.
Pin 2 to ground is 4.42vdc.
Pin 3 to ground is 4.05vdc.
Pin 5 to ground is 4.17vdc.
Pin 6 to ground is 4.175vdc.
Pin 7 to ground is 3.93vdc.

 

[music6000]

Check your Voltages again but put the Black probe to Ground on Input Jack.