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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 17th Feb 2019, 10:51 am   #1
StuckInThePast
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Default Alba 3003 RadioGram Uneven Volume

Good morning everyone,

I have an Alba 3003 RadioGram that has been in our family since early 60's

It has been passed down to me about 30 years ago and has remained dormant for much of that time.

I decided recently to renovate it as I always remember the the deep rich sound that it had.

Removing the chassis I found, as expected, that several of the electrolytic's had started to swell, mostly the 125uf Sprague's , the large 3000uf had actually burst a small pinhead hole in itself, with all others looking externally fine but obviously very old.

I have successfully re-capped the chassis with as close-to values that can be sourced today and on a positive it did not go bang or issue white smoke on startup!

FM reception, as always could be better but the internal FM aerial does a good job.

When using the radio function the volume is good and balanced equally between both front speakers.

However, when I switch to the GRAM the right channel is noticeably louder than the left which is pretty non-existent.

There is a "Stereo Balance Control - Set On Mono Record" pot on the rear of the unit.
With a MONO record playing altering this makes no difference to the left speaker, but the right one does get louder/quieter when adjusted.

So in summary, radio is fine and evenly balanced, but the gram only appears to be playing through the right speaker.

Bad Balance Pot on the rear? or broken wire from the tonearm?

The turntable is a BSR UA 25

I appreciate any thoughts on this.

Thank you.

Rich.
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Old 17th Feb 2019, 11:34 am   #2
Edward Huggins
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Default Re: Alba 3003 RadioGram Uneven Volume

Firstly, I would check for any oxidisation on the 4 cartridge pins/connectors.
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Old 17th Feb 2019, 11:46 am   #3
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Default Re: Alba 3003 RadioGram Uneven Volume

Cartridge problem? Try swapping L-R conns at the cartridge. You could try a buzz test from each too. Use an insulated tool if the gram is live chassis- a floating meter lead or some such.

Are you sure it isn't an 8003? Can't find a 3003 anywhere but the PW 38 chassis which looks promising is in an 8003.
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Old 17th Feb 2019, 11:49 am   #4
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Default Re: Alba 3003 RadioGram Uneven Volume

Welcome to the forum.

I think the most likely cause of this is the pickup cartridge has failed and has no left output.

It's worth checking the connections to it of course. If you post a picture someone will be able to identify it.

You could do a "buzz test", touching a screwdriver blade on left and right catridge terminals alternately; don't forget to put the balance control back to mid-way first.

Last edited by Simon Gittins; 17th Feb 2019 at 11:52 am. Reason: Typo
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Old 17th Feb 2019, 1:38 pm   #5
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Default Re: Alba 3003 RadioGram Uneven Volume

It may be a type 42 chassis according to this incomplete thread: https://www.vintage-radio.net/forum/...d.php?t=140230
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Old 17th Feb 2019, 2:09 pm   #6
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Default Re: Alba 3003 RadioGram Uneven Volume

Good afternoon everyone and many thanks for the quick replies.

The unit is indeed a Alba Model Number 3003 and Chassis Type 42 with a BSR UA 25 turntable.

I have just now unclipped the phono cartridge and re-seated all 4 wires to the cartridge, though this made no difference.

Altering the Stereo Balance Control does boost one speaker if going in one direction, but in the other the strong speaker gets weaker ( as expected ) but the other speaker makes no improvement.

I can discern sound from the weak speaker, though it is low and muffled.

As said before, when in radio mode both speakers are fine and of equal strength.

Could someone explain the 'buzz test'? is that just a continuity test from the cartridge to where is connects on the chassis?

Have 'hopefully' included a few pics of the unit.

The view of the chassis, I have also now replaced the Gold 1000uf Capacitor.

Thanks.

Rich.
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Old 17th Feb 2019, 3:07 pm   #7
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Default Re: Alba 3003 RadioGram Uneven Volume

'Buzz test' just means touching the LH and RH cartridge connectors with a screwdriver while keeping a finger on the blade. You should hear an equally loud buzzy hum from each of the channels. Equal volume means the cartridge is bad; unequal volume means there is a fault elsewhere.
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Old 17th Feb 2019, 3:19 pm   #8
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Default Re: Alba 3003 RadioGram Uneven Volume

Good afternoon again,

Thank you for that explanation Paulsherwin.

Can you tell me which pins to touch as there are obviously 4 to choose from.

I am no expert in electronics, just have reasonable grounding in it, but have been a mechanical engineer for 35 years.

Thank you.
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Old 17th Feb 2019, 3:37 pm   #9
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Default Re: Alba 3003 RadioGram Uneven Volume

Two of the wires will carry the signals and two are earth connections. The earth connections will do little or nothing if you touch them. Just try all four wires and see what happens.
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Old 17th Feb 2019, 4:16 pm   #10
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Default Re: Alba 3003 RadioGram Uneven Volume

Good afternoon Paulsherwin,

Ok done the test,

I have 4 wires;

Right + Green ( No hum at all ) , Red ( Low Hum )

Left - White ( Louder Hum ) , Black ( Louder Hum ) ( both these hums were the same )

The Cartridge I guess is original, its a BSR Type SXIM

Thanks,
Rich.
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Old 17th Feb 2019, 5:46 pm   #11
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Default Re: Alba 3003 RadioGram Uneven Volume

Paul will correct me if I'm wrong, but surely the usual arrangement is Red +, Black -, Green -, and White +. The black and green wires should be common, and were normally earthed at the tagstrip or phono socket strip on the underside of the deck plate, so equal volume level should be obtained from the red & white wires. These in turn should be connected to the + terminals on the cartridge, whilst the black & green wires should go to the -ve terminals.
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Old 17th Feb 2019, 6:03 pm   #12
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Default Re: Alba 3003 RadioGram Uneven Volume

Hi Livewire?

Taking a closer look at the cartridge, and I believe I am reading the pin assignments correctly we have for the wire terminations;

RIGHT -- GREEN(-ve) -- RED(+ve)

LEFT -- BLACK(-ve) ------WHITE(+ve)

Thanks.
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Old 17th Feb 2019, 7:39 pm   #13
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Default Re: Alba 3003 RadioGram Uneven Volume

I'd be inclined to look at the tag strip under the deck and see how the wires from the arm are connected to the amplifiers.
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Old 17th Feb 2019, 8:11 pm   #14
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Default Re: Alba 3003 RadioGram Uneven Volume

You need to make sure that the balance control is set exactly at the mid point position and that the volume control is turned up. If the balance control is set to one side then the test will be pointless.
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Old 18th Feb 2019, 7:46 pm   #15
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Default Re: Alba 3003 RadioGram Uneven Volume

Good Evening all,

Just an update.

I tried earlier to get the Stereo Balance control to its 'mid point'

This is somewhat vague if going by the slot in the head of the knob as the dial travels an uneven amount each way from vertical.

Anyway, I managed to meter across the pot measuring resistance and found that at each end of the travel the resistance was lower than in the middle setting.

So after establishing that the reading was the same at both extents, I set the dial at its highest resistance reading which I am taking as centred.

I re-done the buzz test with the volume set higher and I got an even loud buzz from the Red, White and Black wires on the cartridge.

The Green Wire gave no buzz at all.

So from that are we talking a dead cartridge?

I also re-traced and checked connections at tag-strips each end and could see no defective joints.

Thank you.

Rich.
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Old 18th Feb 2019, 7:56 pm   #16
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Default Re: Alba 3003 RadioGram Uneven Volume

Your results are odd, because if standard colours are being used, I'd expect nothing from Green and Black, but a buzz from Red and White.

That's why I suggested checking the tag strip under the deck to see IN WHAT ORDER the wires from the cartridge are connected. I'd expect Green and Black to be earthed at the tag strip with Red and White going to the amplifier.

The tag strip is visible in your fifth picture in post #6, but I can't see how the wires from the cartridge are connected to it. A close up picture would help.
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Old 18th Feb 2019, 8:26 pm   #17
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Default Re: Alba 3003 RadioGram Uneven Volume

Perhaps the black wire (left -ve as I read it from the OP's description) has become damaged/partially shorted to a +ve and this is why there's a buzz on 3 wires? Also makes sense a problem in the black wire as it's related to the poor left channel...

Could it be as simple as a stray hair of wire at the tag strip, or even insulation rubbed through somewhere?

Agree a close up of the tag strip would be very useful so as to confirm wiring order.
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Old 18th Feb 2019, 8:35 pm   #18
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Default Re: Alba 3003 RadioGram Uneven Volume

Good evening Station X & ekjdm14

Looking at the tag strip under the deck I see;

White - to main radio chassis Tag strip

Black - bridged across 2 tags that join the 2 radio chassis signal cable shields together.

Green - connected directly to the Record Deck chassis

Red - to main radio chassis tag strip.
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Old 18th Feb 2019, 8:47 pm   #19
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Default Re: Alba 3003 RadioGram Uneven Volume

Here we go, got an image.
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Old 18th Feb 2019, 8:50 pm   #20
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Default Re: Alba 3003 RadioGram Uneven Volume

Seems strange, I would have expected green, black and shields to be bridged together and connected to the TT chassis?

Edit-: on looking at the photo it would appear that they are, in a convoluted way... Is there good continuity between green and black at the tag strip? Still leaves a potential short in the leads somewhere.

Would I be on track suggesting desoldering the red/white/green & blacks from the tag and redoing the buzz test directly at the tag strip? (or measuring ohms between the thin wires to check for problems there?
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