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Hi Guys,

I built a TC-15 ~5 years ago (red board) and it has always had a little more hum than I thought it should but I never went so far as to digging in until the past few days. The amp has been sitting for probably 2 years and I decided to fire it up yesterday to begin digging into resolving the hum issue.

Description of Issues
1. The Hum still persists but if I move the "cut" knob the frequency seems to change. (Not sure if that helps)
2. While turning different knobs to try and find out more about the issue, the amp started to make a terrible noise (nails on a chalk board maybe?). It was very loud but with the master volume engaged I could decrease the noise. I ended up turning the contour knob and that made it go away. I couldn't reproduce the noise, not that I would want to.
3. Per the troubleshooting sheet I checked the grounds and every thing came out around 0.5. I did find a few wires that could use a little more solder so I hit them up. Later tonight I went to check the voltages. I turned the amp on and when I turned up the master volume the fuse blew.

I've uploaded a few pictures of my amp (warning, not the cleanest build out there).

Any ideas where to start with the blown fuse?
Any ideas on the terrible screeching noise that might be related to the contour knob?


Once those are taken care of, I should be able to move on to checking voltages. Thanks for all the help in advance. Let me know if any other pictures / descriptions would be helpful.

Best Regards.

One quick update, one of the things I changed yesterday before the fuse blew was GROUNDING the white wire out of the transformer. Looking at schematic, pretty sure I wasn't supposed to do that. Is that the possible source of the blown fuse?

(Thanks in advance for helping out a rookie)

Removed the white transformer wire from the ground and replaced the fuse. Turned on and played normally. The cut knob is very "sticky" and the tone controls are definitely impacting the "sound" of the hum / hiss.

Any thoughts / comments are appreciated.

"Turned on and played normally" means it sounds normal But you have hum / hiss?

The white wire should never have been connected to ground.

_________________
Stephen
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