Vermes
Advanced Member level 4
How it works:
The principle of operation is simple. One pulse which control the relay of warning lamp, coming from the driver, switches one of the relays on the board for the duration of the pulse. This is the relay of the warning lamp. That pulse also charges the electrolytic capacitor C1 through the transistor Q2. Charge stored in the capacitor C1 saturates the transistor Q1 for about 5 seconds after the failure of the control pulse. Transistor Q1 switches the supply of the relay K4 coils. Its contacts switch a large transformer powering motors and lamp.
The board was home-made, tinned with soldeing iron and a piece of tin-soaked braid.
Pictures:
Link to original thread (useful attachment) – Rozbudowa Bramster'a o moduł sterujący transformatorem