555/Repairs

As with any vintage instrument, capacitors needs to be checked. Electrolytic capacitors are used in both power supply and indicator unit for filtering.

Also multi-section electrolytic capacitors C1093 and C2093 are used for low frequency compensation in vertical Amplifiers. All of these caps needs to be checked for leak and may require replacement/reforming.

Any paper capacitor used also need to be checked/replaced, for eg. C793 in Power supply AC Regulator section.

Two fuses - F1054 and F2054 - are used in the plate line of distributed vertical amplifiers (Underside of the chassis) If they are blown, it can load the screen bias resistor R1218/R2218 and potentially cause it to blow open. This can lead to loading the grid line driver cathode follower and V1033/V2033 resulting in no vertical sweep for the affected beam. Check the plate voltage of the V1033/V2033 and for a working VAmp, it should be ~178V DC.

It is also advised to check the HV oscillator tube 6CZ5 and capacitors in the HV section