Vintage 1960's Kay Model 703 Tube Combo Guitar Amp, Signal w/Loud Hum from Cap

Description

Vintage Kay Model 703 tube guitar combo amp, smaller practice/performance amp from the 1960's. All three tubes were removed and tested, and all are in great functioning shape (see pic of testing in vintage guitar shop, Demont Guitars in Oswego, IL) Amp powers up, gets a very noisy signal, so the analysis is that the capacitance is flawed as well as the two-prong plug should be converted to a three-prong plug due to the noise of ungrounded sound and safety in grounding in general. Needs a capacitor replacement for which schematics can be found online.
Basic specs of this Model 703: "All-tube design (18GD6A Preamp, 60FX5 Power, 36AM3 Rectifier)
3.8 Watts
6" speaker
3 instrument inputs (cascade with patch cable for extra gain)
Volume and Control pots
Control pot acts as tone rolloff and on/off switch
Dimensions: 15" W x 12" H x 7" D
Weight: 8 lbs. "