Has anyone seen inside Magnatone Vibrato module, V130 amp

[cgoepel]

I am I am repairing a Magnatone V130 amp from 60's. Customer complains that vibrato effect is weak. Intensity modulator consists of a single light bulb and two photocells from the schematic. Each photo cell modulates the gain of two cascaded intensity modulator stages. Being over 50 years old I'm sure the light bulb may be weak and the photocells as well. These items are located within a small drawn aluminum can.