Radio symptoms and Logical repair

I would suggest that in order to repair radios you need to develop a cross reference chart. This will make your job a lot eiser than going willy Nilly to find solutions to problems you encounter.
Design it as a Table.

Here's a suggested list of Symptoms of trouble.
( I would apply these Titles across the top of the Chart)

A. Dead receiver

B. Intermittent reception

C. Fading

D. Weak

E. Excessive Hum

F. Oscillation

G. Noisy

H. Distortion and Rattling
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Possible Trouble sources
(I would put these in order starting at the top and going down on the left row edge)
1. Antenna System

2. "A" Battery (if used)

3. "B" Battery (if used)

4. Tubes

5. Receiver Circuits Proper

6. Rectifier and Filter circuits

7. Loud-Speaker

8. Miscellaneous
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Example:

___A. |B. |C. |D. |E. |F. |G. |H.
----------------------------------------------------------------------------------------------------------------
1.
2.
3.
4.
5.
6.
7.
8.
--------------------------------
Use the letters and numbers to pin point solutions as an Alpha-Numeric reference.
each solution is also numbered.
So each block has a number also
The reference would be : E-5-1
So E = Rectifier and filter circuit
and -5 = Excessive Hum
and -1 = hum control or "balancer" out of adjustment Examine; readjust

I am adapting this from Radio Troubleshooting Handbook by Ghrirardi

1. First thing is to recognize the trouble by doing a Symptom Check.
2. then look for causes of Probable Trouble
3. Then follow a repair procedure called a Remedy.

A. Dead-

1. No “B”plus voltage across one section of filter condenser.
2. Probable Trouble- Open field coil or filter resistor or connections thereto.
3. Remedy- Change resistor, speaker, or repair connection.-
------------------------------------------------------------
B.
1. No “B” plus voltage at filament or cathode of rectifier tube.
2. Probable Trouble- rectifier filament open or transformer windings open (Check with ohmmeter with power disconnected.)
3. Remedy- test tube and replace and check and replace transformer if necessary

C.
1. No a-c to the pilot lights, tube filaments or rectifier plates.
2. Probable Trouble-open switch or transformer (Check with ohmmeter with power disconnected.)
3. Remedy- replace switch or transformer

D.
1. Rectifier plates get red hot.
2. Probable Trouble- Shorted electrolytic condenser (Check with ohmmeter with power disconnected.)
3. Remedy- replace condenser.

E.
1. Loud Hum
2. Probable Trouble-open electrolytic condenser (Check with ohmmeter with power disconnected.)
3. Remedy- Hum stops when like electrolytic is substituted across filter condenser. Change electrolytic condenser.


F.
1. Note: A-c voltage reading on a-c voltmeter not equal within about 10% as measured from B minus or chassis to each plate connection on rectifier tube.
Probable Trouble- Shorted windings in power transformer or open
Remedy-Replace transformer

G.
1. Low reading across filter resistor on Ohmmeter.
2. Probable Trouble-Resistor changed value from overheating due to other troubles such as a shorted tube.
3. Remedy-replace resistor, and check rectifier tube, and electrolytic condenser for shorts

H.
General
1. Power transformer excessively hot or smoking.
2. Probable Trouble-Shorted or partially open section of power transformer. (Check with ohmmeter.)
3. Remedy-Check for shorts-Change transformer.


I.
1. Hot or excessively warm electrolytic condenser.
2. Probable Trouble-shorted or partially shorted condenser.
3. Remedy-Change electrolytic condenser.