Success with an Australian Healing model 308E from 1939.

[petervk2mlg]

While this is not an English set, I hope my first success story posting might be acceptable and could provide some exotic reading for members.
I had paid quite a lot of money for this radio, so I was keen to have it going.
Removing the chassis from the cabinet was straightforward, paying attention not to damage the large celluloid disc that is part of the tuning mechanism. A friction drive rotates this disc in front of the stationary dial on which all the stations are marked.
The friction drive needed retensioning to effect a smooth movement of the disc when the tuning knob what turned.
A quick visual inspection revealed a dusty and dirty chassis which appeared original with no evidence of service work having ever been performed on it.
A circuit diagram was located and this indicated a very simple circuit for 1939:
An EK2 frequency changer – an EF5 IF amplifier and an EBL1 detector and audio amplifier. An 80 rectifier completed the glassware.
One diode in the EBL1 was used as detector, but there was no AGC in the set – the volume control was a 2.5K pot in the cathode circuit of the first 2 valves. Very primitive for 1937
In fact in my set there was no EF5. Instead a more common 6U7G took the place of the IF amplifier valve. This appeared original as the type number was clearly marked on the chassis as were the numbers for the other valves. Healing must have made some modifications reflecting availability of valves.
After various parts of the dial drive were removed, cleaned and tightened up. I turned my attention to the tuning gang. It was mounted very close to the power transformer. Indeed the tuning gang could not be fully operated as the moving plates fouled the power transformer case. This must have been the case for some time as the side of the transformer was scored where the plates of the tuning condenser had rubbed against it. Replacing the rubber mounting grommets on the gang restored it to a fully vertical position and the moving plates could now open and close freely, clearing the transformer by only a millimeter or so.
I set about performing my usual restoration procedures – fitting a three core power cord, replacing electrolytic capacitors and other critical components.
On powering up the set and fitting a decent length of wire as an antenna, I was disappointed not to hear any stations coming in. The radio was dead across the entire band. High tension voltage was high and did not come down after the set warmed up. I figured that some or all of the valves were not drawing proper current. There was audio present however as a audio signal injected into the grid of the EBL1 resulted in a healthy blurt of sound from the speaker. Similar results resulted when the signal was injected into the diode load resistor (0.5 megohms.)
Nothing, however was heard when the signal was transferred to the grid of the IF amplifier.
No IF signal was present when the signal generator was tuned to the IF (455KHz) and attached to the grid of the frequency changer.
A quick check of the volume control indicated it was open circuit – these wire wound controls are prone to breakage in the resistance wire.
Indeed that was the case here – a small tin plate shim slipped into the control bridged the break with a loss of only a couple of ohms and now the control did its job of varying the bias on the first 2 valves. Disappointingly , no stations could be tuned.
Now, the EK2G was oscillating – I could detect a small negative voltage on its oscillator grid, but no signal would pass through the set.
I began to suspect the 2nd IF transformer. The primary winding was ok with healthy high tension on the plate of the 6U7G, but perhaps the secondary was open circuit. A check with the ohm meter confirmed my suspicions. Damn! A replacement IF transformer for this radio would next to impossible to find and a non original replacement in would spoil matters.
I unsoldered the 4 connections below chassis and removed the transformer from the set. Removing the 2 knots from the can enabled me to slip the winding out of the can and make a closer inspection of the windings. As mentioned, the primary was fine, but no continuity could be found on the secondary, although as I handled the unit, the meter needle gave a kick – the connection on the bottom of the secondary where the fine wire was soldered to the lug of the adjustable mica capacitor was intermittent. A fresh dab of solder with the iron restored the connection and all now appeared OK – I was lucky!
The repaired IF transformer was installed back into the set and this time on applying power to the set, I was rewarded with a healthy response from the speaker – stations could be tuned in across the band.
Realignment showed only minor drift in the tuned circuits. The set was ready for the final cleaning touches and reassembly.

[paulsherwin]

That's a very handsome radio.

Could you post a closeup pic of the tuning dial?

Paul

[petervk2mlg]

My camera is not so good, but here goes.

[Steve_P]

Fascinating set and well done. You were lucky with the windings! Also, the EBL1 is getting rare now over here, so heaven knows over there!

Don't worry about it not being a British set by the way. I've posted Polish, Yugoslav and even a Turkish set.

Cheers,

Steve P.

[petervk2mlg]

Only a few Australian sets used the EBL1 valve in the late 1930s.
Later on in the 1950s there was another much more common output valve with diodes in it - the 6BV7

Peter

[howard]

Well done Peter

I always find it interesting to see radios from other parts of the world and
that's a very good looking art deco set from 'down under'.

Howard