Caps under Coil shields on Philharmonic?

[jonathan dollimore]

The McMurdo Silver sets have caps above chassis, under the chrome coil shields. Do the Scott Masterpiece sets have them also, or are all the caps on these sets underneath the chassis? I ask because I’ve never looked under the coil shields.

[Kent King]

Some do, some don't...I usually remove the shields for cleaning anyway, then replace anything under them that needs replacing. I know that's not super helpful...

Kent

[Alex R. Whitaker]

The few Scotts that I've had apart (AW-12 two and 1 dial, AW-15, AW-23, and the Philharmonic) all have components (i.e. resistors and paper capacitors) under the coil shields.  As Kent said, you need to remove the shields anyway, to clean the contacts at the bottom to make sure they're making contact with chassis ground, and to inspect things.  Come to think of it, the only one, that I know of, that doesn't have components under the shields is the 800B, which is about 10 years newer than your Masterpiece. 

[David Zrout]

My FM and AM are inoperable on my 16A. I am just working my way through the FM signal path and most of the 6200pf mica capacitors are out of spec. But I ran into this also, should I take the covers off and replace the caps inside? Will they cause the radio to not pull in any stations? How do you remove the covers?

[Kent King]

The 16A is MUCH newer and generally you won't have any components inside those smaller units to worry about - generally they are just adjustable coils, which can be trimmed without removing the covers (which is hard on that set). So...don't worry about those for the 16A.

Kent

[David Zrout]

I did pull one of them, the first one wasn’t so bad. Both resistors under it were 20% out of spec, both caps were Mica. 

other Mica caps in this set were out of spec but haven’t pulled these to check them. 

Kent King said:

The 16A is MUCH newer and generally you won't have any components inside those smaller units to worry about - generally they are just adjustable coils, which can be trimmed without removing the covers (which is hard on that set). So...don't worry about those for the 16A.

Kent

[Scott Seickel]

When you say the mica caps were out of spec, were they just measuring low?  Did you test for leakage?  Just curious as I don't find too many that are out, but leakage in these is becoming more common as the silver migrates. 

[David Zrout]

Haven’t tested the caps yet, the resistors are out of spec. 47k measures 58k, 56ohm measuring 67ohms. 

Scott Seickel said:

When you say the mica caps were out of spec, were they just measuring low?  Did you test for leakage?  Just curious as I don't find too many that are out, but leakage in these is becoming more common as the silver migrates. 

[David Zrout]

The other mica caps that I tested in the set were measuring low. 6200pf caps measuring 5200-5800pf

Scott Seickel said:

When you say the mica caps were out of spec, were they just measuring low?  Did you test for leakage?  Just curious as I don't find too many that are out, but leakage in these is becoming more common as the silver migrates. 

[Norman S Braithwaite]

The higher value domino type capacitors in the Metropolitan 16A expander circuit are really wax paper capacitors, at least in the Metropolitan 16A set that I restored.

Norman