Realistic MPA-100

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Time to play with this one

Had to borrow a fuse holder cap and a fuse and put it on the big ugly DBT with 60w bulb

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Next input signal 1Vp-p and hooked scope probes to input and (16 ohm) output
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Input channel one and output channel two

Amplifier power off (ch 1 at the bottom)

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Next amplifier power on and had aux volume at half and master volume at half
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Not much amplification going on 
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Next I tried to max out both volumes and see the result but it started flattening out the top of the output

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The most output I could get is about four Vp-p

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Now...granted there are a bunch of switches on the back so who knows
And...idk what I'm doing 
So there's that but it looks like it works to me idk 

One really wierd thing that happened...I could hear a very faint hum with the power off.  I leaned in to listen better and thought wow is that my 1 khz signal ?! So I reached up and changed the frequency and yes it was my signal I could hear it with the amp power off 

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I'm gonna propose that the above is probably not SOP for amp testing   

I'm gonna connect a speaker and see if I can get ear bleeding 1 khz   

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Alright well either
-im not doing this correctly
-or this amp is putting out one watt 

So I -connected an 8 ohm speaker
-Scope leads across speaker terminals
-Maxed out aux and master volume
-increased signal until output started clipping (about 2.8 Vp-p)

Did math
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So I guess I have a sick one here 

Meanwhile it cut off a few times I could hear a distinct click whenever it did.  It was not intermittent it wouldn't come back until I turned it off and turned it back on after s moment.
And the fuse is good.
I guess that explains why all the cover bolts were missing

A couple things I noticed about this amp is there is no relay click maybe it's not supposed to have one because it "works" with out it.
Also I noticed the bottom panel gets warm
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 but I saw a video pointing out that the output transistors are attached to the bottom panel
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So right off the bat I suspect a bad voltage regulator