The Tram D201A has no shortage of quirky "gremlin" issues that crop up the first few days or week after a routine overhaul. Only after replacing the list of "usual suspects" will you find out how many other aches and pains the radio has.
Some of the most aggravating quirks are the "scritch" and crack/pop noises caused by one or the other kind of electrical connector. For now, we're focused on the 9-pin tube sockets mounted to the pc boards. The one 9-pin socket mounted to the metal chassis almost never goes bad, unless someone spills his drink on it.
But the sockets on the circuit boards are different. A glance at the spring contacts reveals a totally-different shape to the spring contacts. The factory tube sockets just lose spring temper and get loose. Don't know why, doesn't matter. You can't "fix" a loose tube socket and expect it to last very long.
For a while we were taking the metal ring loose from tube sockets built to mount in a steel chassis hole. Bending the pins would permit them to line up with the holes in the circuit board. A quarter-inch drill bit would countersink the center of the socket to make a #4 flat head screw lay flush, and serve to secure it to the circuit board.
The original sockets used the circuit boards's foil pads to hold them in place. Those foil pads are most likely coming loose from the G10 laminate once the old socket is removed. A screw down the center of the socket, secured to the center hole in the pc board will remove all the mechanical strain from the circuit board foils.
This socket from somebody on chinabay has a hole down the center, already countersunk just the right size for a #4 screw head. Can't remember who sold them to us. Finding an obscure electronic part on Ebay typically requires that you turn over a hundred rocks before finding one with the desired item under it.
Gotta get the old socket out first. Best to minimize the heat exposure to the foil pads. They tend to just peel away from the board's G10 laminate. Most efficient way I have found to do this is to simply crunch the brittle black plastic at each pin position with the tip of a diagonal wire cutter one by one.
In some cases you may have room to just leave a socket's metal chassis-mount saddle ring where it is. But for V602 on the radio's audio board it's better to remove it first.
Once all nine pins have had the plastic "crunched" it should be simple to pluck out the fractured plastic so the individual spring contacts can be gripped one by one to unsolder and pull loose. I have found the small dikes best tool to grab the spring contact that's being unsoldered.
This tube, V602 is only half-used in the 40-channel radio. The triode section was driving the S-meter in the older models. Those three pins are just not connected to this socket. If the foils fall off, it won't cause any trouble.
To date, since we started using chassis-mount style sockets to replace the original 9 and 7-pin pc board sockets none of them have come back with noise or intermittent troubles.
So far, so good.
Unless one of these radios has under a couple thousand original miles, it's a safe bet that at least one of these sockets will prove to be noisy after the radio runs a couple of days.
The higher the mileage, the more of them will have to get changed.
73
Some of the most aggravating quirks are the "scritch" and crack/pop noises caused by one or the other kind of electrical connector. For now, we're focused on the 9-pin tube sockets mounted to the pc boards. The one 9-pin socket mounted to the metal chassis almost never goes bad, unless someone spills his drink on it.
But the sockets on the circuit boards are different. A glance at the spring contacts reveals a totally-different shape to the spring contacts. The factory tube sockets just lose spring temper and get loose. Don't know why, doesn't matter. You can't "fix" a loose tube socket and expect it to last very long.
For a while we were taking the metal ring loose from tube sockets built to mount in a steel chassis hole. Bending the pins would permit them to line up with the holes in the circuit board. A quarter-inch drill bit would countersink the center of the socket to make a #4 flat head screw lay flush, and serve to secure it to the circuit board.
The original sockets used the circuit boards's foil pads to hold them in place. Those foil pads are most likely coming loose from the G10 laminate once the old socket is removed. A screw down the center of the socket, secured to the center hole in the pc board will remove all the mechanical strain from the circuit board foils.
This socket from somebody on chinabay has a hole down the center, already countersunk just the right size for a #4 screw head. Can't remember who sold them to us. Finding an obscure electronic part on Ebay typically requires that you turn over a hundred rocks before finding one with the desired item under it.
Gotta get the old socket out first. Best to minimize the heat exposure to the foil pads. They tend to just peel away from the board's G10 laminate. Most efficient way I have found to do this is to simply crunch the brittle black plastic at each pin position with the tip of a diagonal wire cutter one by one.
In some cases you may have room to just leave a socket's metal chassis-mount saddle ring where it is. But for V602 on the radio's audio board it's better to remove it first.
Once all nine pins have had the plastic "crunched" it should be simple to pluck out the fractured plastic so the individual spring contacts can be gripped one by one to unsolder and pull loose. I have found the small dikes best tool to grab the spring contact that's being unsoldered.
This tube, V602 is only half-used in the 40-channel radio. The triode section was driving the S-meter in the older models. Those three pins are just not connected to this socket. If the foils fall off, it won't cause any trouble.
To date, since we started using chassis-mount style sockets to replace the original 9 and 7-pin pc board sockets none of them have come back with noise or intermittent troubles.
So far, so good.
Unless one of these radios has under a couple thousand original miles, it's a safe bet that at least one of these sockets will prove to be noisy after the radio runs a couple of days.
The higher the mileage, the more of them will have to get changed.
73
