Recently overhauled a Browning Mark 4A base station that had a blown power transformer. Some genius had "upgraded" a tripped fuse with one rated at 20 Amps. Needless to say this let out all the magic smoke from the power transformer. Made this an expensive repair, even more so than normal for a 45 year-old tube-type base.
Sent it home, and in a week the owner reports a problem. The lights behind the dial and meters are dark, and all the heaters in the tubes are dark. Since all of these are powered by the same 6.3-Volt winding on the power transformer it was a quick task to identify the problem. No juice coming out of that winding. All the rest of them were running okay, but not that one.
Long story short, ordered a new transformer. The guy who sold it to me had not seen this fault in that part, so it seemed a safe bet to just buy another and send the customer home with a working radio.
Couldn't resist playing Sherlock Holmes with the failed unit. Removed the end bells and found that the failed winding is the outer most layer of them all. Unwrapping insulation tape exposed the winding.
Sure enough, the blue pigtail wire just wasn't soldered securely to the end of the secondary's enameled wire.
It worked well enough to travel 80 or 90 miles and run for a week. This one will get repaired and reassembled. Never can tell when you'll need a power transformer for this model.
73
Sent it home, and in a week the owner reports a problem. The lights behind the dial and meters are dark, and all the heaters in the tubes are dark. Since all of these are powered by the same 6.3-Volt winding on the power transformer it was a quick task to identify the problem. No juice coming out of that winding. All the rest of them were running okay, but not that one.
Long story short, ordered a new transformer. The guy who sold it to me had not seen this fault in that part, so it seemed a safe bet to just buy another and send the customer home with a working radio.
Couldn't resist playing Sherlock Holmes with the failed unit. Removed the end bells and found that the failed winding is the outer most layer of them all. Unwrapping insulation tape exposed the winding.
Sure enough, the blue pigtail wire just wasn't soldered securely to the end of the secondary's enameled wire.
It worked well enough to travel 80 or 90 miles and run for a week. This one will get repaired and reassembled. Never can tell when you'll need a power transformer for this model.
73
