Alba 3003 RadioGram Uneven Volume

[Station X]

That sounds generally correct, but normally the Black and Green wires, along with the screens of the cables going to the amplifier are connected to the centre tag of the tag strip which is grounded via its fixing screw. The red and white wires go to the outer tags and connect to the inner conductors of the cables going to the amplifier.

Do you have electrical continuity between the Black wire, Green wire and the deck.

What happens if you do the buzz test at the tag strip?

[Station X]

Just seen the picture. It would be better if the centre tag and the 4th tag from the left were bridged. The short bit of wire under the screw head doesn't look right.

Bridging the tags won't necessarily cure you problem, but it will make diagnosis easier.

Alternatively shift the Green wire to the tag with the Black wire.

[ms660]

Maybe the black is open circuit?

Lawrence.

[ekjdm14]

Originally Posted by ms660

Maybe the black is open circuit?

Lawrence.

I did think maybe black was floating, but why would that cause a buzz on touching it, unless it was coupled somehow to a +ve?

[Station X]

Doing a buzz test at the tag strip would give a clue. I don't know whether the OP has a meter.

[StuckInThePast]

Evening,

Buzz test at the tag strip.

Red & White give a buzz

Black and Green give Nothing.

Station X I do have a meter, its a Hilka 90030064

[ekjdm14]

Sounds more and more like damaged wiring, or perhaps touching around the tag strip dislodged a whisker of wire that was causing an issue? Is the left channel still low if you play a record now?

As you have a meter it would be worth checking, in my opinion, that you have good solid continuity between black and green (and between these and the chassis) both at the headshell and at the tag strip, and that there is no short between red/white and black (there may be resistance but not a dead short).

[Station X]

Yup. The next step should be to prove continuity of all four wires and that there are no shorts between them other than those applied by design at the tag strip.

Once that's done we can move on to swopping over wires on the cartridge to prove that both its channels are working.

[StuckInThePast]

Evening everyone,

Well just out of interest I put the cartridge back in as I had it dangling and looking at the tonearm the wires bend down before they go below deck as it were and there is a metal plate screwed inside the tonearm.

looking at this it looks like an ideal candidate for chafing of the wires.

Though with a light and my watchmaker eyeglasses I could not see any damage.

I decided to try the Turntable again and all of a sudden I have sound from both speakers when a record is playing.

My thoughts are either;
a) I have re-disturbed something and it's now making contact as it should.
b) The Stereo Balance control was dirty and my operating from lock to lock as it were a few times whilst metering for centre has cleaned up the contact and its now functional.

I have played a MONO LP with both speakers now functional.
A Stereo LP with the same.
And also a 78rpm record with the same.

So at the moment all is working.

I think I now need to give the unit a good workout tomorrow night playing many records and see if it keeps going. I will ( not when playing a record ) give the turntable some good nudges on its springs to see if I can cause any clicks or pops and see if the sound disappears again.

This should prove a bad connection somewhere.

So at the moment I thank everyone for their help in diagnosis, I have got the urge again to expand on my basic electronics knowledge so will be reading these boards with great interest.

Just need to now try and identify the low hum that is always present either with radio or turntable.

Though my mother said that she always remembers this radiogram having a hum right back into the early 70's and maybe before.
I have swapped out all the caps, so might just call it a nostalgic warm sound.

Thank you all again.

Rich.

[ms660]

If the cartridge connectors are crimped connection only to the wires I would be tempted to solder them as well but not while attached to the cartridge (heat can ruin a cartridge) The fact that you got a buzzing sound when you touched the black connector on the cartridge would be symptomatic of a poor connection there, the buzzing coming through via that section of the cartridge and the white wire due to the cartridges impedance.

Lawrence.

[ekjdm14]

Ah, yes it could. I was envisioning the buzz test carried out with the cartridge removed.

Does sound like perhaps a bad connection or wire strand out of place though, I had a feeling it might suddenly work when there was no "black buzz" at the tag strip. Glad we have progress even if the cause is annoyingly unclear, I think the workout/provocation idea sounds grand. If nothing else it's an excuse to listen to some good music.