The problem was not the 'goo', which was supposed to be there.  Rather, the insulator pad must have been cracked or damaged and allowing the transistor case to short to the heatsink.
There are 2 types of transistor insulators.
The mica type are easily cracked and use heatsink grease.  The sil-pad type are flexible like rubber and do not use heatsink grease.
If you had to cut it to size, chances are it is the sil-pad type.
Otherwise, you need the grease like J M Fahey stated above.

There are some pictures and a gut shot here:  http://inspireformation.blogspot.com/2012/08/electro-harmonix-freedom-brothers-photos.html

I can't say whether the schematic is the same as the Mike Mathews Freedom amp.

Probably won't matter, depending how small the current is.
If you are really concerned, you could just put a resistor across the negative rail to draw a little current and balance it out.

Yes, they would likely be 1/2 watt resistors.
It's a bit odd they are using 5 band color code (usually precision) resistors.  With a green band in there it would be 2570 ohms.  I would have expected regular 4 band color code with red-violet-red and gold for tolerance.

As far as the additional testing, you should never try to do resistance measurements when unit is powered up.  You could damage the meter, and the readings are meaningless anyway.  Also applies to batteries or capacitors that are charged.  Or anywhere voltage is present.  Resistance measurements are only done when power turned off, and power supplies given time to discharge.

The voltage readings on the bias string indicate something is wrong with R47 or it's connections.  36V across it (points F to G) would mean 13mA through that string, That in turn would cause approx. 20V across R46, which you do not have.  What does R47 resistance measure?

Measure DC voltages (no signal) at points A through G.

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That string of parts marked in red sets the bias for the drivers and in turn, the output transistors.
Was D6 the same type as D4 and D5?  Black plastic like 1N4001 rectifier diode, or glass type like 1N4148 signal diode?
Replace with same type it was (signal or rectifier).
While you are there I would resolder all connections in that bias string.

That sounds normal for the thermistor.  Make sure neither of it's legs are touching the heatsink.

Quote from: DrGonz78 on June 06, 2024, 01:20:00 PMI don't know what Q11 & Q12 actually do but it never stops me from guessing. Are they current limiting the circuit in case of overload?

Correct

Unfortunately, this is one of those 'flying rails' designs which makes things a lot more confusing.  The output transistor emitters go to ground, and the positive terminal of the output jacks connects to the center point of the main filter caps (marked 'CC' on schem.)
So a bit of reverse logic as far as how the speaker fits in the circuit.
As long as you make your voltage measurements to ground, they should be ok.
At the input to the power amp, shown to the left of U1B, there are 2 diodes, D1 and D2.  You should measure 0VDC at D1 anode/D2 cathode.
Is U1 in a socket by chance?  If so, clean it.

Ok, if it's your own amp you can leave it like that.
Just mentioned in case it was going to someone else.  Don't want to have to change your name from mr. to Dr.   

Q14 doesn't seem to be turning on, probably resulting in cross-over distortion which Dr.Gonz suggested.
Check through the components (and connections) on the path shown in red here:


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It would be preferable to mount the other way if possible, with less exposed wiring.
The 2 black wires are carrying the 120V and you don't want any chance of a user being able to come in contact with them, or for them to get damaged.  Also, if those wires are not going through an original hole, the new hole can not have any sharp edges.
If you can, flip it over and mount so the 2 black wires are closest to the hole the wires route through.
Aside from that, the FM65 transformer is a great match for voltages and power capability (for Bandit 65).

Yes, that is where to check.
If no DC there, check DC volts at e,b,c of Q6,Q7,Q8,Q9.  No signal, no load.

That's great you didn't have to do any drilling, and no excess hum.
What transformer did you end up using?

Those seem good.  Can you do the same checks (DC volts, no signal) for e,b,c of Q13 and Q14.