Common Transistor Radio Faults

Thanks for the input, Cliff.

 Also I should have mentioned a nifty & cheap piece of test equipment you can build for testing battery draw. It will take you maybe 5 minutes to make.

 Just take a small rectangular piece of double sided thin PC board and solder a wire on each side.
The wires go to your ammeter.
Slide it in between the end of a battery and the contact & BAM! instant current draw test.

On battery corrosion:
After using Vinegar, Then I end up using Baking Soda to neutralize the vinegar then flush with water.
I prefer using distilled water (No Minerals).

Also, You can Put a current meter in series 
with the battery to see how much the circuit is draining. Normally a range up to 15 Milliamps unless it's a power Hog then 25–30Ma.

These are some of the common faults I have found over the years.

1. No Sound:
Look for open coupling cap to volume control. Also check the earphone jack. The switching contacts get dirty or bent. plus dead battery or it has come out of the holder and contacts not making.

2. Battery dies quickly or gets VERY hot: There is a cap across the battery leads (decoupling) after the power switch. They short. (This is true even in remote controls, and I have seen it in car radios also).

3. Motorboating: See [You must be registered and logged in to see this link.], same solution. Also can be main filter caps.

4. Volume control very scratchy: Clean or replace control.

5. Volume won't turn down: Look for bad ground off the volume pot.

6. Dead:    See [You must be registered and logged in to see this link.]. 
 Look for bad batteries or leaking batteries that have corroded the battery contacts. If alkaline batteries, clean contacts with white vinegar, clean water, & dry. 
  Note: Don't always  believe the customer when they say " I just put new batteries in the radio a couple of weeks ago". 95% of the time the batteries were put in there months/years ago, and are dead/leaking.

  Also some brands of batteries are just plain crap. I saw brand new batteries for flashlights that only worked for 1-2 minutes before failing, being sold to the State of Washington back in the 70's . Purchasing for the agency refused to get good quality ones. Test all  "New batteries" before installing. New does not in any way mean they are good batteries.