Ekco Radio Continued, Model AC85 Chassis

This page will allow us to take a close look at the chassis of the AC85.  The receiver is a five valve plus rectifier circuit, with a valve line-up of FC4, AC/VP1, V914, 354V, AC/PEN, IW3.  A particular feature of this receiver is the “Noise Suppression” control.  It had three settings, “All Stations”, “Medium” and “Strong”, but is continuously variable between all three.  When the control is in the “Strong” position, only the most powerful stations are received, and the control can then be adjusted until all stations too weak to be heard satisfactorily above local interference are suppressed.  This control is often found to have no particular effect on receivers that turn up nowadays, as the circuitry is quite difficult to get working.  A tone control is fitted to the rear of the cabinet, and the receiver also incorporates AVC.  Sound was amongst the best available from receivers of the period.

Shown above right is the underside of the chassis.  Here it looks near identical to the day it left the factory.  However many components, mainly capacitors, have been replaced.  Too ensure the chassis remains original the new components have been built into the casings of the old components.  Rebuilding capacitors is a very slow procedure.  If a receiver is already largely original though, it can be worth it. 

The chassis underside pictured is from the black and chrome AC85, and only the mains smoothing electrolytics had been replaced when I obtained the receiver.  That replacement would probably have taken place in the 1950’s, and the original wax paper blocks had been removed.  I therefore obtained wax paper block capacitors from a scrap set, re-building new components inside and then resealing, and mounting the newly restored components under the chassis.  As the paper block capacitors are not from another AC85 they are therefore not quite the same shape.  

The chassis in my brown bakelite cabinet receiver is also totally original, in fact it is still using the original (non-rebuilt) wax paper block electrolytic smoothing capacitors!  Performance is understandably not too good on this receiver, but it seems a shame to touch it until the capacitors have totally broken down.  Mind you, I operate that receiver infrequently as using old and leaky capacitors does present a risk to some of the more difficult to replace components such as the output transformer and valve etc.

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