Yep. A pair of wires, one brown and one black, feeds from the main circuit board into the linear to key the relay.
Looked, and can't find a picture for this, but if you can find the driver transistor at the left (your left) rear corner of the main circuit board, a small tan plug has the brown/black wire pair plugged into the circuit board. It's just to the left of the bias-test (mirror) jumper board, directly in front of the 2SC2166 driver transistor.
One of the two wires is hot, the other is ground. Rather than worry about which is which, you could just pull the plug. This will leave you with a barefoot 1-final radio that runs out of steam below 20 Watts PEP.
You could put a toggle switch in the hot wire of that pair, but they have changed the color once or twice. Sometimes the brown wire is hot, sometimes the black. You can use a DPDT switch to break both wires, and not worry about which one is which.
The power supply will run pretty cool with the amplifier turned off, so you can turn off the fan.
And if it doesn't have a fan, it's miracle the thing hasn't gone KABOOM already from the heat.
The problem with the power knob may be a trimpot set wrong. VR19 sets the lower end of the RF Power control's adjustment range.
73
I recently had my 2995DX modified by a tech , he got her doing around 50dk swing 150 on AM.. Cannot turn it back on the RF variable knob.. He has since left the country and I would like it turned back to normal so I can run a ext. Amp.. 