Prototype set is here

[miniman82]

Several requests have been received for me to label the back panel controls, so here it is!

[Zenith6S321]

Since there does not seem to be any main power transformer or power rectifiers present, is the 7 pin male plug on the lower left chassis back panel where a separate power chassis plugs in?

[Zenith6S321]

Perhaps the two pin male plug is a power on/off circuit to allow the TV chassis to remotely control the power chassis? And the is two pin socket above it a convenience power outlet to plug your VTVM in?

[miniman82]

Originally Posted by Zenith6S321

Perhaps the two pin male plug is a power on/off circuit to allow the TV chassis to remotely control the power chassis? And the is two pin socket above it a convenience power outlet to plug your VTVM in?

I looked at the 2 pin thing, and it's wired into the heaters of all the tubes with some really thick wire. I suppose it's possible that the heater circuit is the 2-pin, and the rest is B+ type stuff on the 7-pin one.

[Zenith6S321]

There are some pictures, by Harry Poster, of an RCA prototype set that looks like this set showing the CRT mounted. It even shows the black tape. Link: http://www.earlytelevision.org/rca_color_prototype.html

[Mal Fuller]

Originally Posted by Zenith6S321

There are some pictures, by Harry Poster, of an RCA prototype set that looks like this set showing the CRT mounted. It even shows the black tape. Link: http://www.earlytelevision.org/rca_color_prototype.html

Isn't that interesting? Is the CRT serial number a match to your prototype, Nick?

[miniman82]

Originally Posted by Mal Fuller

Isn't that interesting? Is the CRT serial number a match to your prototype, Nick?

They are one and the same.

[MelodyMaster]

Originally Posted by miniman82

I looked at the 2 pin thing, and it's wired into the heaters of all the tubes with some really thick wire. I suppose it's possible that the heater circuit is the 2-pin, and the rest is B+ type stuff on the 7-pin one.

So you don't actually have the power supply for this set? Did it go missing? And won't that slow down getting it going?

[Zenith6S321]

It should be possible to make a replacement power chassis. If a schematic could be found it would help.

[MelodyMaster]

Originally Posted by Zenith6S321

It should be possible to make a replacement power chassis. If a schematic could be found it would help.

However that puts to rest the question of whether to recap it or leave in non-working survivor condition. The whole bottom chassis is going to be all-new.

[miniman82]

Originally Posted by MelodyMaster

So you don't actually have the power supply for this set? Did it go missing? And won't that slow down getting it going?

No, and there's no reason to expect it will ever turn up. No one knows where it is, so it is assumed missing. Something like that would be very common looking anyway, so it probably was either tossed or repurposed for something else. It won't really slow anything down, other than the time it takes to build a new one. It's easy to trace the wiring, and figure out what voltages need to go where. I figure I'll start with an old console amp chassis, install a suitably large power transformer, and use the sockets for the rectifiers. Maggie chassis are plentiful, so that's what I'll probably use. That, or I'll strip the old organ chassis in the next room.

[miniman82]

Found the heater string connections: the 'main' part of the chassis, that is, everything that is not tuner/IF related, gets it's 6.3 volts from the small male 2-prong plug on the back. The tuner/IF strip is powered from pins 1 and 6 of the 7-pin round plug, with pin 1 connected to chassis ground.

[miniman82]

Originally Posted by Zenith6S321

Since there does not seem to be any main power transformer or power rectifiers present, is the 7 pin male plug on the lower left chassis back panel where a separate power chassis plugs in?

Most likely, since the early prototypes had a lower chassis which supplied power to the whole shebang.