Big Muff debug

[soggybag]

I'm debugging a Big muff.

- Q1 e: 0.0 b: 0.19 c: 9.14
- Q2 e: 0.15 b: 0.76 c: 4.83
- Q3 e: 0.14 b: 0.75 c: 4.75
- Q4 e: 0.93 b: 1.54 c: 5.17

I'm guessing I have a problem around Q1 the collector looks way off. Should be around 4.5v?

[Kevin Mitchell]

Man, this is like skipping dinner and reading a recipe as a bed time story.
The debug hunger is real.

What I mean is, you're on the right track! Now find the culprit!

[soggybag]

I'm just thinking out loud here. It helps me solve these problems!

[soggybag]

Just sitting here and looking at the numbers I'm thinking the real problem is 0v at The base. If there was a little current at the base it would allow something to flow between Collector and emitter, I'd have some divider action and the voltage would come down at the collector.

[soggybag]

Wait! I take that back misread my own notes! It's the emitter at 0v and the base seems too low still at 0.19v.

[antonis]

Q1 is at cut-off region..

Make it more happy by raising Base voltage at about 650 - 700mV..

[soggybag]

Fixed! Assembly error used a 10k instead of 100k for R14 (base to ground Q1)