Wireless of the Week - week 45

[Patrick Johnson]

Hi Bruce,
Thanks for posting this information, it's great news to me since I recently bought a CPP-2 to power my 19 set. Any chance you could post the pages of the manual for all to enjoy?
Regards, Patrick

[Bruce Parker (RIP)]

Originally Posted by Patrick Johnson

Hi Bruce,
Thanks for posting this information, it's great news to me since I recently bought a CPP-2 to power my 19 set. Any chance you could post the pages of the manual for all to enjoy?
Regards, Patrick

Happy to. First batch:

[Bruce Parker (RIP)]

Second batch:

[Bob Carriere]

....for the important information that I can keep on my files.

Bob C

[David Dunlop]

Oh boy! Just before Christmas and now I have two more manuals to look for to compliment the equipment I have on hand.

A number of the 19-Set items have shown up out here over the years. All but one worked when found. Two others quit within a year or so never to be resurrected. They both developed a progressively louder hum before passing on. Three others are still alive and well, but see minimal use. Without detailed schematics or design info, the root cause of the failures is tricky to pin down but the 'failure' seems to result in the main transformer unit becoming electrically inert permanently. A recurring suspicion is they were very finely designed for the 110V AC world with minor cycle fluctuations. In the postwar upgrade to 120V, they were not happy and slowly packed it in. Who knows.

My CPP-2 is my main wireless set supply, covering 2 19-sets, C-42 and vehicular PRC 77 setup. I will post more on that later. It is Serial No. 1319, also dated 1952.

Thanks again for the heads up on these manuals, Bruce. If you ever run across any spares, keep me in mind.

David

[Bob Carriere]

....according to my PS computer power supply my input varies from 112v in the day time and up to 123v right now.....

I use a variac and can dial in my input at exactly 110 or 112v..... when using the CPP 2

We also have a lot of 2 or 3 second blips on our power almost weekly.

cheers

[Bruce MacMillan]

The rectifier #1 uses several 6X5 tubes which are notorious for developing heater to cathode shorts. This grounds the B+ lead and burns out a winding. The power transformer & chokes are all encapsulated in one unit. If one winding goes open then it becomes a small boatanchor.

I always use a variac to bring the power up to 110V and no more. This ensures I don't exceed the input voltage but also allows the filaments to completely warm up. A line voltage of 120+ volts is a 10% increase in output voltage. The 540V B+ to the xmtr is now close to 600V and may stress the rectifiers resulting in a failure.

My unit has been in use for about 10 years with no problem and it's much quieter that using a CPP2 to power the dynamotor. (also much lighter )

[Bob Carriere]

My unit has been in use for about 10 years with no problem and it's much quieter that(n) using a CPP2 to power the dynamotor. (also much lighter )

....that you have a one of a kind power supply that feeds directly the HT and LT to the rec/transmitter without using the dynamotor???

Cool....... was it homebuilt?

cheers

PS..... Duh ...read your email again..... you are using the rectifier #1 which is supplied by your variac...... never actually ever seen one.....

....so, I assume, the regular power supply unit fed by the CPP 2 has the same 6x5 (3) tubes and susceptible to also being fried if the tubes go wrong........ will need to test my tubes and spares to make sure they do not have a grid short .......