08-02-2018, 05:49 AM
Hi Gents Y caps are commonly only available up to 4N7, values much above this, when used on more than one appliance can cause nuisance tripping of RCD,s due to the current flow in them.
Ed
Ed
Pilot Little Maestro.
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08-02-2018, 05:49 AM
Hi Gents Y caps are commonly only available up to 4N7, values much above this, when used on more than one appliance can cause nuisance tripping of RCD,s due to the current flow in them.
Ed
08-02-2018, 08:53 AM
Hi.
Oddly enough I have only used one "X" type cap in an AC/DC set. The set in question nearly caused a house fire but lived to tell the tale. It is a Luxuri Japanese micro valve set, no doubt intended for 110v areas but sold here with the addition of a 2.2uf cap dropper. The radio was 100% original nothing had been changed as all caps were fine with no leakage currents and resistors were as marked. A visit from David Boynes a few years ago brought out the set and it was playing away on the carpet, we adjourned into the shed with set on (volume was low) after an hour we came back in to a rather odd smell, yes the dropper cap had shorted but the set was still playing away. quickly it was disconnected and put in the kitchen sink, it was literally so hot, even the pile on the carpet was flattened. A few days later I replaced the 2.2uf dropper cap and all was well, the valves were still fine as was the main smoother and all resistors were still OK with unchanged values, the only notable damage was the wax from the output transformer had long gone. There was no room for a motor run cap so an "X" type was fitted. The radio is rarely used but it does get a very occasional airing, a 200ma fuse is fitted in the set now, normal mains consumption is 190ma so I'm sure if the cap shorted it would blow the fuse. I think I'm correct in saying, motor run caps are more reliable in this application the ones I use are rated at 440v ac.
Cheers.
Trevor MM0KJJ. Member of, RSGB, GQRP, WACRAL, K&LARC.
17-02-2018, 10:38 AM
Refer back to post No.23. Today, I intend to make a start on the electrical restoration of the Pilot T66.
See first attachment. Those TCC waxies are useless and will be replaced. There's evidence of previous service work having been carried out to this set and it's possible the set was still in use well into the seventies. Second attachment: note the push and turn waveband selector. A simple dog clutch mechanism. Geordie McBoyne.
17-02-2018, 11:39 AM
The push and twist wave change saved a knob at manufacture. I am amazed other manufacturers did not spot that idea.
17-02-2018, 03:27 PM
(This post was last modified: 17-02-2018, 03:28 PM by Geordie McBoyne.)
(17-02-2018, 11:39 AM)Refugee Wrote: The push and twist wave change saved a knob at manufacture. I am amazed other manufacturers did not spot that idea. I don't think there would be any production cost savings by using the push and turn waveband switch, especially when one considers the Little Maestro series of radios were sold at the low end of the marketplace. Nevertheless, it's a neat idea. Useful sales gimmick. The set works, not much was required to get the set going. The two leaky waxies have been restuffed but in fact the set would have worked even with those capacitors in the original condition. The capacitors function as decouplers in the AVC circuit. The IFs need peaking up and it's likely further adjustments will be necessary in the aerial and oscillator circuits. Geordie McBoyne.
KB had a push and twist wave change on the tuning knob on a few sets around 1935, the KB 426 was one. You can see the method in the under chassis photo.
Mike
17-02-2018, 11:11 PM
My 1955 Philips AM/FM set has a similar set up using a concentric knob. Only snag is the poor quality zinc casting that had disintegrated. Fortunately I only use the set on VHF
Cheers.
Trevor MM0KJJ. Member of, RSGB, GQRP, WACRAL, K&LARC.
03-07-2018, 05:15 PM
Been looking for the correct paint colour for the Pilot T66 "Little Maestro" Finally found it in the PlastiKote range of spray paints. This paint takes longer to become fully hard so it's best to prepare and spray the surfaces and put the item away for a week or so.
The colour chosen for the T66 is "Antique White". Did try Lada cream but it didn't look right. Also Rover Arum White but again not the colour for the set. The same colour can used on the Airline radio. Geordie McBoyne. |
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