R.S.R. Electronics 3010

[saturated]

We have the technology 

Knobs at zero

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And increased

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Time to play with some op-amps

And later pop the hood off and have a look

Thanks to everyone helping me earlier in a different thread I have an idea how they did it

[saturated]

Before proceeding with op-amps I figured it would be appropriate to take the lid off and have a look-see

Looks very nice inside

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First notable configuration was the array of TO-220 devices

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Identified as follows

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Of course a schematic would help but I can't help but wonder why have such low valued resistors 

Something else I noticed was the itsy bitsy ceramic capacitors (?) bridging each pair of outputs

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Last but not least I noticed some chewed up wires but with the lid on no way mice could get in so I presume this was accidental soldering iron contact

Also I wondered what the little covers on the back are they appear to be covers for the heat sink tab fasteners

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And in the midst of all the excitement I found another TO-220 hiding but can't read it

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Time to put it to work 

[g1]

It looks like under those covers is set up for TO-3 type metal transistors, mounted on the outside.
They may be using that same case for other higher current models.

[Loudthud]

I would assume that 3 terminal regulators ICs (LM317 and LM337) are being used as pass elements for the bipolar supplies. These usually require a small capacitor across the output to insure stability. Also note that because the Voltage adjust pots are only using two wires, the Voltage output can not be adjusted to zero. I don't have my data book handy but I think 1.25V is as low as you can go.

The 7805 (an IC) and MJE2955 (a PNP transistor) are used to form a high current 5 Volt supply. The low value resistors are part of that circuit.