Heirloom item help please

[samjmann]

As you're getting radio on both channels, the speakers and amplifiers are both working. You may have lost output from the pu cartridge. A Simple 'buzz' test with a bent paperclip on the cartridges terminals should bring a healthy buzz from each of the speakers in turn with the volume about halfway.

If there's still no output whilst on gram, then it could be that the rotary function switch needs a shot of cleaner that you have. It's best to spray the switch contacts and rotate the function knob to 'wipe' the contacts. Mains plug removed before starting any work!!

Let us know how you go on. Rather like the grey finish. Does look rather stylish. Purists would prefer the wood-look, but we're all different.

SJM.

[FrankSinatra]

Thanks both, could you detail the buzz test for me please in layman's terms?

[FrankSinatra]

Sorry assume if I do need a new cartridge it will have to be another SX5M or would another one be compatible?

[Edward Huggins]

Touch all 4 of the cartridge wires (best with a paper clip) where they connect to the cartridge. If you get a healthy BUZZ from both channels then the cartridge has failed. If you have to replace the cartridge, we can advise. Thr connectors may just be oxidised.

[samjmann]

Dont go replacing the cartridge just yet, it may well be blameless.

A buzz test is simply using your finger or the tip of a screwdriver etc to inject a tiny signal in to the Gram's input terminals. The buzz bit is in fact mains that is picked up by your body then connected to the amplifier. If you get the same buzz on both speakers (one at a time of course) then this proves that the function switch, both amps, and most of the rest of the amplifier is working.

Follow what I posted on #101 and see. If you only get one speaker working the the function switch may be at fault. Does it crackle when changing functions?

The way to fault find is to logically make a test and then act upon the results. Don't jump to conclusions, it's tempting to do so I know, but it's seldom the best way of working.

Regards, SJM.

[FrankSinatra]

Thanks Gents will do that tonight and let you know, was just a little worried about touching terminals,

[FrankSinatra]

Done the buzz test gents, results as follows.

Out of interest I swapped red and white wires in the first instance and the output from the gram then switched to the right speaker which didn't previously have output. The left which did have output then didn't so reversed the problem.

Tried the buzz test, only one of the top two wires produced the buzz the other didn't, but again when I switched them the opposite speaker buzzed.

On radio I get output on both.

Have tried some cleaner on the function switch will report back shortly.

[FrankSinatra]

Cleaner hasn't changed the above.

[samjmann]

As the fault appears to change sides, it would seem that you have lost one output from the cartridge.

Can you check if there is a ground on the Left (blue) and the Right (green).

As a test you can link the white and red leads together with short length of very fine flexible cable. Both channels should play the one working output. Hence proving the amps are ok.

Have you got a basic test meter to use?

SJM.

[FrankSinatra]

Sorry I don't know what you mean by ground, I am an amateur with this work.

On linking white to red do you mean leave them connected to the pins but Bridge them with fine wire?

I don't have a meter unfortunately but could perhaps borrow one from someone at work.

[Refugee]

Testing without a meter.
First buzz test all the pickup wires and establish the inputs to the amplifier and the ground wires With no wires on the pickup.
Put one input wire on one pickup terminal and buzz test all the others on the pickup making a note of the loudness of the buzz. Repeat for each pin.
You should find two pins that buzz louder in both directions. These are the ground pins and should be connected to the ground wires to the amplifier and the other two to the amplifier inputs.
If you scan the pickup with a magnifying glass you might find some markings.
I suspect that there is a link inside the pickup between the two ground pins just lurking there to confuse you. The pin-outs are often not logical on pickups.

[FrankSinatra]

OK thanks will try that this evening, take it you mean wires may have been switched at some point?

[Edward Huggins]

"Ground" means Earth. It's important that both the LH and RH channels are working on your cartridge. You can be easily fooled by linking (aka bridging) the one working channel to give output from both speakers. For example if the LH channel is still working but the right hand channel is dead, by bridging incorrectly you can make the LH channel come from both speakers which may suggest that you have stereo, but you don't. Please confirm you understand this before moving on. Also do be aware what each coloured wire represents. For example the Red wire is RH channel positive (+) and the White wire is the LH channel positive (+).

[FrankSinatra]

Thanks Edward, understood. I am expecting to need a new cartridge but will do as suggested above.

[FrankSinatra]

Struggling for time to do the testing here, managed whilst prowling ebay to spot a sx6m for a tenner so have ordered that also so I can give that a go alongside this with little expense. Assume from what I have read the sx6m and sx5m can both be used here?

[Edward Huggins]

That BSR SX6M seems rather cheap. I hope it is fully working. By and large, the BSR SX6M and BSR SX5M will suit your amplifier.

[FrankSinatra]

Thanks Edward I offered half of the asking price as it had been up a while, not lost much of if its no use.

[FrankSinatra]

Would a ceramic sc5 or sc5 work also please Edward do you think?

[Edward Huggins]

A BSR SC5M would work if you can find one. A BSR SC5H might overload your amplifier. Which version have you seen/found? Search "Stereo Cartridge Wiring" to show show to connect the Red/White/Green/Blue wires. Use tweezers.

[FrankSinatra]

Looks like bsr sx6m man letting me down although could still arrive tomorrow, we will see

In the meantime managed to source a bsr sc5m for a similar cost, would this be a better option anyway than the sx6m?