Now there's a sexy title for ya.
The job of re-capping a D201 has its boring side. And expensive side, especially if you want to buy an "authentic" 4-section twist-lock "can" capacitor for C624.
We quit doing that some time ago when the price shot out of reason for us. The price of four single 10uf 450-Volt capacitors is a lot less. The labor to put them in place of the one 4-section part might be more than installing a new "can", but not enough to keep it from looking more economical.
C624 in a Tram D201 has a single wire each attached to three of the four positive-side lugs. The fourth one supports two 1.5k 7 Watt resistors. We solder the foot of a single-lug tie strip to the metal saddle of C624, move the two resistor leads over to it, and attach the single 10uf cap there.
For the other three sections, each single wire comes loose from its lug, and followed to the other end.
Forgot to note the wire color at each section. Oops.
A single orange axial 10uf cap C6 is right next to C624. We put a radial part on the front side of the tie strip just to reduce the heat exposure a bit. Those two 7-Watt wirewound resistors run pretty hot.
This solution has worked for us for some time. I have found that caps rated for 105 degrees C seem to hold up better during a cold power-on than the cheaper 85-degree parts. The B+ voltage in a D201 jumps a bit above 450 Volts between power-up and the tube heaters reaching normal temperature. Once they warm up and load down the power supply, it will fall to a safe 410 Volts DC or so. But that surge while the tubes are cold makes the 500-Volt rating we use for the three-section cap C5 just common sense. This stress doesn't seem to affect C624 as much, but I don't think we have seen one of the single-section radial replacements we use fail since we settled on the 105-degree part.
Just be careful and check your work when soldering radial-capacitor leads directly to the foil pads around the edge of the audio board. Too easy to leave a tiny solder bridge in the wrong spot.
73
The job of re-capping a D201 has its boring side. And expensive side, especially if you want to buy an "authentic" 4-section twist-lock "can" capacitor for C624.
We quit doing that some time ago when the price shot out of reason for us. The price of four single 10uf 450-Volt capacitors is a lot less. The labor to put them in place of the one 4-section part might be more than installing a new "can", but not enough to keep it from looking more economical.
C624 in a Tram D201 has a single wire each attached to three of the four positive-side lugs. The fourth one supports two 1.5k 7 Watt resistors. We solder the foot of a single-lug tie strip to the metal saddle of C624, move the two resistor leads over to it, and attach the single 10uf cap there.
For the other three sections, each single wire comes loose from its lug, and followed to the other end.
Forgot to note the wire color at each section. Oops.
A single orange axial 10uf cap C6 is right next to C624. We put a radial part on the front side of the tie strip just to reduce the heat exposure a bit. Those two 7-Watt wirewound resistors run pretty hot.
This solution has worked for us for some time. I have found that caps rated for 105 degrees C seem to hold up better during a cold power-on than the cheaper 85-degree parts. The B+ voltage in a D201 jumps a bit above 450 Volts between power-up and the tube heaters reaching normal temperature. Once they warm up and load down the power supply, it will fall to a safe 410 Volts DC or so. But that surge while the tubes are cold makes the 500-Volt rating we use for the three-section cap C5 just common sense. This stress doesn't seem to affect C624 as much, but I don't think we have seen one of the single-section radial replacements we use fail since we settled on the 105-degree part.
Just be careful and check your work when soldering radial-capacitor leads directly to the foil pads around the edge of the audio board. Too easy to leave a tiny solder bridge in the wrong spot.
73
