EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Greetings

I am restoring an AW23 tuner, PS and base speaker.

I got a few good tips from Kent and Dave a while back.

1. Use test lead wire to replace bad rubber wire

2 Use .047 for all the wax caps including the .1 wax caps.

I dont have a good way to test the micas because of the low value any thoughts on reliability of those.

I am replacing all wax caps, bad wire, all electrolytic, safety caps, for power inlet and any resistors out of tolerance. 

Checking and replacing any bad tubes. Do have 1 bad NE-42 bulb.

The cloth wire tuner cable needs cleaned has some nasty areas on it not sure best way to clean that.

Is it rubber wire inside the cloth?

Need to pull the antenna tuner switch apart to replace bad rubber wire.

Have everything marked any tips on that?

Made a wood stand for the tuner that really helps.

S# on tuner is Q-458 think that makes it a version 1.

Got all the info in the AW23 set folder (Thanks Kent) also have the Rider 44 XIV.

Hopefully thats all I need data wise. Happy to have anything else recommended.

I bought all my parts from mouser think I have everything. I went overkill but what the heck.

Went with the Illinois caps pp mpw  .047s

Nichicon electrolytic s, Pomona black test lead wire ( its perfect) One thing I like about it is the insulation is very thick giving you good rf interference spacing from metal its next to.

https://www.mouser.com/ProductDetail/Illinois-Capacitor-CDE/473MPW6...

Using  1 watt metal oxide to replace any bad 1/4 watt resistors. 

The units are complete. Here is the tuner I have torn down to bare bones and have started the restoration. 

Any comments or tips are appreciated.

Thanks in advance!

John

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The resistors used in that set are quite reliable.  I would not replace them unless well out of spec.  The plate resistors to the IF coils were designed to fail open if the plate circuit were to be shorted thus protecting the plate winding.  Replacement with a modern resistor may result in failure of the IF transformer in the event of a short.

I have never encountered a bad mica capacitor in a Scott receiver and only one bad one in another receiver in my many years of restoring radios.

Norman 

Thanks Norman

On the photo with the if diode assembly. the 1k ohm (#367) is a dog bone measures 1.6k 

The other resistor looks like a large brown carbon one but marked like a dog bone it should be 10 k (#373) and shows 8700. I assume thats the type failed to open?

Maybe Ill replace the dog bone and leave that one alone especially since its lower and not higher in value.

John

Norman S Braithwaite said:

The resistors used in that set are quite reliable.  I would not replace them unless well out of spec.  The plate resistors to the IF coils were designed to fail open if the plate circuit were to be shorted thus protecting the plate winding.  Replacement with a modern resistor may result in failure of the IF transformer in the event of a short.

I have never encountered a bad mica capacitor in a Scott receiver and only one bad one in another receiver in my many years of restoring radios.

Norman 

The dog bone resistors used by Scott in the earlier AW-23 sets are very unreliable.  The cylindrical resistor is a carbon film resistor that is usually very reliable.  The carbon film resistors fail open.

Norman

Ok thanks

Maybe I will just replace the dog bones and leave the others if they are reasonably in tolerance.

Norman S Braithwaite said:

The dog bone resistors used by Scott in the earlier AW-23 sets are very unreliable.  The cylindrical resistor is a carbon film resistor that is usually very reliable.  The carbon film resistors fail open.

Norman

That is reasonable.  That is pretty much what I would do.

Norman 

When replacing the 3 wires running from the switch assembly in the center can to the SW coils...I find it is easiest to carefully remove the switch rotor, unscrew the phenolic plate and unsolder/replace the wires away from the set, then pass them through the 3 holes and reassemble the switch. Much easier than trying to solder new wires in with the switch assembled and screwed down. Just be sure to get everything back as it was and try not to move the bandswitch throughout the process. 

Also, the antenna wires...can't be easily removed, and unsoldering could melt the old insulation in the sheath. If they aren't shorting right at the ends, I leave them alone. If they are shorting to the sheath, I've had some luck cleaning it up and pushing some spaghetti over the ends and sealing off with shrink tubing.

Kent

Thanks Kent

I will follow your advice.

John

Kent King said:

When replacing the 3 wires running from the switch assembly in the center can to the SW coils...I find it is easiest to carefully remove the switch rotor, unscrew the phenolic plate and unsolder/replace the wires away from the set, then pass them through the 3 holes and reassemble the switch. Much easier than trying to solder new wires in with the switch assembled and screwed down. Just be sure to get everything back as it was and try not to move the bandswitch throughout the process. 

Also, the antenna wires...can't be easily removed, and unsoldering could melt the old insulation in the sheath. If they aren't shorting right at the ends, I leave them alone. If they are shorting to the sheath, I've had some luck cleaning it up and pushing some spaghetti over the ends and sealing off with shrink tubing.

Kent

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