Zenith Royal Sent To RRF For Repair

Couple months ago, I go t this email:

After placing his order for repair and service here, the customer and I emailed each other:

Working on portables is more difficult because everything is so compact. It's hard to find issues and troubleshoot.

 

 I got the radio. It looked like this:

 

 

Upon initial disassembly, nothing was obviously broken. I put in a set of new batteries but the radio did not work. No sound. Totally dead.

The speaker looked good:

Order some replacement transistors:

ECG103A NPN GERMANIUM TRANSITOR TO-1 REPL NTE103A

I discovered a resistor had come loose. After resoldering it, the radio still did not work.

The capacitors looked fine. I tested the resistors and none of them were open. I performed a voltage test from the battery pack, and there was voltage going through the on/off switch.

A few weeks later, I decided to check the connections one more time before I started replacing transistors, and I happened to resolder one of the capacitors that was sticking out higher than the others on the board.

Voila! It worked!

YouTube video here

Here is the capacitor that came loose:

After I reflowed the solder points around this capacitor, the radio fired right up and sounded great.

I performed an alignment and the radio was good to go.

 This radio has a flap with two clips for the battery compartment. Unfortunately, the radio circuitry and components are exposed during battery replacement. It seems likely that the closing of the flap at one point pressed up against the capacitor and pushed the solder joint loose on the other side of the circuit board.

To avoid this damage in the future, close the flap and press the clips lightly so the flap does not push against any of the electronic components. I'll bet there was a cover or baffle at some point probably cardboard that has gone missing over the years.