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 Healing 401 H Valve portable radio restoration - sourcing new oscillator coil etc
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 Return to top of page · Post #: 1 · Written at 4:30:38 PM on 11 January 2016.
Martyjames's Gravatar
 Location: Sydney, NSW
 Member since 11 January 2016
 Member #: 1851
 Postcount: 2

Hi All

I just joined this forum. I'm 55 and started collecting and restoring late 1950's early 1960's transistor radios. I 'inadvertently' bought a Healing 401 H Valve portable radio which is in need of repair. I'm not a valve man (dont like high voltages!!) but will try and get this going. The first obvious fault I found is the oscillator coil ( transformer / double wound) is broken - one of the 4 wires seeems to be snapped off at the coil and I dont think its salvageable - does anyone have any suggestions where I might get a replacement in Australia? I found a US based radio restoration supplies place that has what may be a replacement.... any ideas appreciated thanks

As I'm new to restoring radios (sofar ive fixed 2 1950's transistor radios - I enjoy faultfinding them) I was thinking I would approach this valve set faultfinding in the initial stages as:

1. replace all old electrolytic caps
2. make up a 7.5 v supply for the heaters and a 90 v ht supply from 10 x 9v batteries
3. apply 7.5 v first and see if heaters work then apply 90v
4. go from there

is that reasonable?

thanks



 
 Return to top of page · Post #: 2 · Written at 12:19:54 AM on 12 January 2016.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

In case you don't have the schematic and service data, here it is:

http://www.kevinchant.com/uploads/7/1/0/8/7108231/401h.pdf

I note that is a mains/battery set and that it is transformerless. Heed the caution about correct polarization of the mains plug -- that is, ensure that active goes to the switch and neutral to the chassis. An active chassis, and anything connected to it, is a potential deathtrap.

Also of note in regard to mains power is that the 401H uses "dry metal" rectifiers, either copper or selenium. Such rectifiers have usually given up the ghost by now and are no longer available.

Normally, we would not apply power until a set has been given a good visual inspection for issues and only after electrolytic and wax caps have been replaced. Resistors should also be checked as you go as should wiring for bad insulation, etc.

As you might expect, and as I can attest from personal experience, the 1.5V and 3V filament valves can be destroyed easily if their filament voltages are exceeded so be very careful with your battery connections, etc.

AI think you best chance for a replacement oscillator coil would be a donor parts 401H. However, not sure how many of those would be around, especially in Sydney where it seems portable sets are not as well loved these days as they may be in other states.

You might be lucky and she plays as soon as the restorative work has been done. Otherwise, proceed with diagnosis as you would with a transistor radio.


 
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