Labrat issues

[Jebull]

Hello, I built a Labrat and I can't seem to figure out why I can't get it to work. The Bassdude I built next fired up first go, no issues. The only modification I did was was my clipping switch is on-off-on, thinking I could add no clipping. Hopefully that isn't somehow the problem. I first had a metal can lm308ah and somehow managed to plug it in with the pins all rotated 1 slot. Could this have fried something? When I tried it again, rotated correctly, all I got was a high pitched whine sound and the irf740 got really hot. I tried it again after checking it for other issues, with all new ne555, 2n3904, irf740, and an Op07. I also tried one of the 12ax7s from the Bassdude that I knew was working. Same problem as before, high pitched whine is all I get, and the irf740 gets very hot.

 

[Mentaltossflycoon]

I had one where the regulator was getting hot and it ended up being a bunk ne555. Have you already reflowed that socket?

 

[vigilante398]

Any particular reason you left the pins for the IRF740? Any chance those are hitting the enclosure and shorting? Also, can we see some better shots of the tube daughter PCB? That's one of the prime suspects in non-working builds.

 

[Jebull]

I had one where the regulator was getting hot and it ended up being a bunk ne555. Have you already reflowed that socket?

I tried reflowing that the socket, and a fresh 555, still the same.

 

[Jebull]

Any particular reason you left the pins for the IRF740? Any chance those are hitting the enclosure and shorting? Also, can we see some better shots of the tube daughter PCB? That's one of the prime suspects in non-working builds.

I just forgot to clip them after I swapped it. I clipped them and reflowed several things, swapped out to another 555 and 2n3904 set, still the same. Here are some more (hopefully better? Sorry) pictures. If needed, maybe I can get my photographer girlfriend to take some better ones lol

 

[vigilante398]

Alright, nothing really looks amiss there. Can I ask what power supply you're using?

The next step is probably going to have to be taking voltages and seeing if we can pinpoint anything.

 

[Jebull]

Hmm. Dang, I was hoping it would be something obvious that I was overlooking. I'm using a OneSpot CS12. Looks like I was using one of the 9v 250mA outputs, should I try one of the 500mA ones?

 

[Tassieviking]

You should use the 500mA outputs, 250mA is not enough.

 

[Jebull]

Tried with 500mA, no change. Just a whine, bypassed or not and the Mosfet gets hot.

 

[Twrog]

IRF740 looks back to front (Edit: Nah, trick of the light I think).