Robyn T-123B power cord diode ?

[bevis]

Does anyone know what kind of diode was used in the Robyn T-123B AC power cord ?
The schematic calls it out as U50B but i cant find that number so far.
I bought a really nice specimen in great shape with no power cord.

I've looked all over the place and all i can find for sale is the ac cord for the T-240 which does not have that diode in it. The diode supported the T-123 instant on feature. All of the cords being sold on ebay / other places on the web support both the T-240 and the T-123 but not the T-123's instant on feature because of no diode in the radio end of the power cord.

One seller claimed that it was a special diode thats no longer available and he was only able to build cords that did not include the diode. Im not really buying that.

I wanted to order a female octal socket and make my own cord but i don't know if this is just a rectifier diode or what.

As you can see in the pic, it's not there for DC use.
Maybe it's some kind of double secret special alien diode.

Anyone know ?
Thanks

 

[DoctorAudio]

Looking at the schematic it looks like a silicon diode large enough for the current demand is all you need. To be safe I'd use a 6 amp, 200V diode.

 

[bevis]

Looking at the schematic it looks like a silicon diode large enough for the current demand is all you need. To be safe I'd use a 6 amp, 200V diode.

Thanks. I was thinking it was just a silicone diode also but thought i should ask anyway.
Thanks for your respose.

 

[bevis]

Looking at the specs, it shows pulling only 80 watts in the AC mode ?
That does not sound correct.
They show xmit current in DC but not in AC

 

[Dmans]

That should probably be 800 watts or between 6.5-8 amps on AC.

On 13.5Vdc, 80 watts would equal about 6 amps.

73
David

 

[nomadradio]

It's the "instant on" diode. Looks like it feeds the tube filaments rectified AC from the power transformer's 12-Volt winding. There is no filter cap, so the effect is to cut the filament voltage roughly in half. A diode between the front-panel lights and the tube-heater circuit D14 blocks this polarity so the lights only get power when the Instant-On switch gets closed, jumping around the diode in the power socket.

Kept the tube filaments warm, and reduced the time for the radio to come to life. Would take better part of a minute from a cold start.

73

 

[bevis]

Thanks for all the help. I ordered some Octal female receptacles and im going to build a couple of cords instead of paying $30 for one on fleabay that does not have the diode.