Hi All,

Thanks for having me in the forum.

I have just bought an radiogram, its got a couple of cables that I am not sure what they are for.

The majority of it is obvious, there is the main power input, then power out that runs the turntable, a red and white radio antenna. Speaker output to the cabinet. In-between the speaker output and the radio antenna there are two separate cables, both are white, no distinction between them. internally they are like co-ax cable (outer shield, weaved wire, tough plastic, then inner core wire).

I would like to know what they are for, I have a feeling that it is RCA cables that have been cut at some point.

Any help would be much appreciated,

Thanks,

Nick

I have a feeling that it is RCA cables that have been cut at some point.

Yes, possibly an AUX input, and if so there should be an input selector switch on the radiogram with a position for that, also such inputs usually have RCA type sockets on the chassis to which coax cables connect.

The turntable itself, as well as having power go to it, should have a coax cable coming from the cartridge to the chassis forming the GRAM input path.

However, we're flying blind so a well-lit in-focus photo or two of the front and rear would help. You can email image files to Admin (Brad).

Thanks for the reply, I have sent some photo's in, hopefully they will be up shortly.

I am not sure if the picture is clear on the front, but the controls are on/off(tone), Volume, radio/gram switch, and tuning.

So with that on the front the only inputs seem to be radio and the record player, so maybe not Aux in, potentially aux out?

There seems to be a separate bank of valves that have the input cables from the turntable going to them.

Currently its in pieces as I am restoring the cabinet, all going back together in the next couple of days hopefully.

Thanks for the help.

There seems to be a separate bank of valves that have the input cables from the turntable going to them.

Probably a preamplifier stage.

As for the mystery cables, let's see what those photos show us when Brad inserts them. Had I known that the chassis was out of the cabinet I would have suggested an under chassis photo, too.

Photos uploaded.

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A valve a day keeps the transistor away...

Hard to say from the photo, other than they appear to be exiting the chassis on the output side and the grommets appear to be the same as the others so it may may be original wiring.

As mentioned above, given that you have the chassis out of the cabinet, a good photo of the underside of the chassis might help shine more light on the situation.

Also, what is the full valve line up? From the label I can make out 6AV6 and 6BV7, but the other 3 are not clear.

All the wiring bar the white flex appears original. Three core 'figure 8' cable was more common in the 1960s. I've seen it on a few radios of the time. As mentioned the picture doesn't show the full story but I am guessing one of the brown three core cables is power in and the other is power out to the turntable.

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A valve a day keeps the transistor away...

Have sent some photos in of the underneath of the chassis and the valves. Hopefully that will help us shed some light on what the cables are. Is there a sensible way to test them?

Thanks,

Nick

Valves can be tested to some extent in a valve tester, but the true test of a valve is how it performs in the equipment itself.

However ... that only applies to equipment that has been checked for other faults (such as bad capacitors, bad resistors and bad wiring) before power is applied to it.

Powering up old equipment that hasn't been used for a time can lead to the otherwise avoidable destruction of parts, some of which are either difficult or impossible to replace these days.

Oftentimes the valves themselves are okay; it's other components that need serious attention.

PS: Your avatar image displays as a black square on my monitor. Is that your intention?

Your avatar image displays as a black square on my monitor. Is that your intention?

I'd say so, it is a Gravatar-hosted image. It's his national colour too.

The thin red wire is the antenna and the thin black wire is the radio earth.

The red and blue wires go to the transformer just above the socket on the chassis so they will be for the speaker.

The thick black wire is a shielded pair and would go to the gramophone pickup coil for the stylus.

The second brown figure 8 cable looks like it is a parallel pair for the motor on the turntable.

This leaves the two thick white wires, they appear to be shielded pairs too. Not sure what they are for.

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A valve a day keeps the transistor away...

One white cable would be for the phono pickup and the other could be for a microphone. I have a Kriesler from the 60's that came with a microphone.
What brand is yours? The nameplate is obscured by the wires in your photo.
Made in Auckland by the looks. Is it a Columbus and Courtenay branded radio from 1934? http://www.nzvrs.pl.net/aaa/Radioltd.htm
Can you post a clear closeup picture of the dial and knobs?

As per the thread title and the chassis sticker in the second photo of post #3, it's a Dominion Radio Tallboy 5V. (Dominion Radio & Electrical Corp.)

The phono pickup connection would appear to be the black coax terminating on the mode switch.

NickW: per my earlier request (post #6), let us know the valve types listed on that sticker, please.

Hi Nickw, I believe I can help you, I have the exact same radiogram in mint condition, a LaGloria 1060S, will post pics & valve lineup etc... soon. The amphenol coaxial connecter under the record player is for a mic.

The photo shows "wax paper" caps, if they are still in there, they should be replaced.
Mains cable has knots in it: No longer allowed.
Do check that mains cable, I have seen some with failing insulation.

Photos uploaded to Post 13.

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A valve a day keeps the transistor away...