Rotel RP-5300 - no sound

[mking007]

Hi all.

I've got a Rotel RP-5300, which has been in the family since the 70's.
It's electrically safe (AFAIK!), the motor works fine but there's a problem with sound or lack of it.

Until recently (maybe a few months ago) it was producing sound via an amp to 1 speaker but not both. We have just moved it to a new location and it now seems to be producing no sound at all.

When I plug it into the amp and turn the amp volume to max I can hear a buzzing but no music. When I turn the amp volume to max for another input (the CD say) then I don't hear buzzing.

When I put my head near the cartridge I can hear the music from the needle on the groove, but nothing is going to the amp.

I'm OK with a soldering iron, but definitely not an electrical expert.

Any advice on where to start appreciated.

Thanks

Michael

[Records]

It could be your cartridge, the part that holds the needle/ Stylus, has died.

[mking007]

Thanks.
Yes, i was wondering that.
How do i check? Just get a new one?

[SiriusHardware]

It may just be worth checking to see if the stylus is sitting correctly centred in the 'V' gap in the rubber pickup cushion and not skewed off to one side. If it is splayed out to one side it will produce virtually no output. This seems like a possibility as the arm may have come off its support and scraped across the turntable during the move, unseating the stylus.

If that seems OK, disconnect the wires from the cartridge - take photos or draw a diagram of which colours go to which pins on the cartridge - connect it back up to the amp and with the Amp set to phono, volume about one quarter, balance centred, gently pinch each of the cartridge connector wires in turn between your finger and thumb. If the deck wiring is OK you should hear a healthy buzz as you pinch two of the three or four wires - pinching one wire should give you a buzz in one speaker, pinching another should give you a buzz in the other speaker.

If this works then your problem is probably the cartridge.

[Michael Maurice]

I think Sirius is getting confused between magnetic and ceramic cartridges.

Magnetic cartridges which is almost certainly the type fitted to the O/P's deck don't have a V gap.

[SiriusHardware]

Apologies, I don't know this particular deck. The advice was generic. But presumably the buzz test still applies?

[barretter]

The headshell which holds the cartridge is removable so it may have worked loose. Try tightening it by pushing the headshell gently into the arm and turning the ring on the arm anti-clockwise. If it's not that it might be the leads between the back of the cartridge and the back of the headshell. Make sure they are tight on the cartridge pins and the pins at the back of the headshell with some needle-nose pliers. Gently. If it's not that it could be that the stylus is loose in the cartridge. Very gently push the stylus into the cartridge body. Be very careful. If it's none of these, you may need a new cartridge.
The only soldering that might be necessary is if one of the cartridge leads is defective but I wouldn't get involved with that unless you are very confident about soldering ; just buy a new set of leads. Keep any heated soldering iron far away from the cartridge.

[Edward Huggins]

There may be oxidation on the cartridge pins/connectors. It might just need the connectors removing (one at a time!) and re-fitting, just use tweezers.

The fact that one channel was lost and then later, the other, suggests this.

If the cartridge has failed, the very good Audio Technica AT91 is only £19.00. It might even be an improvement on the original.

[mking007]

Thanks for all of the replies.

I have taken out and then re-applied and tightened the cartridge - no change.
I've looked at the wires in the cartridge and they all look good connections, but I can't say if they've oxidised.
I looked at the 4 receiver pins in the arm that connects to the cartridge and I can't see any problems. I touched each of them with a neon tester and all of them showed some power, so I'm assuming that is a positive?
I'll try replacing the cartridge. I see Richer Sounds are offering them for £16.95:
http://www.richersounds.com/product/...audi-tech-at91

Thanks for all the ideas. Hopefully the AT91 will solve it.

['LIVEWIRE?']

Why would a neon tester light when touching cartridge connections??

[stevehertz]

Well yes, that's a good question, leakage of some sort I guess, but in any case using a neon tester to 'test' a cartridge does not seem like a good or useful idea to me. The best way to test this, given the technical level of the OP would be by substitution I reckon. Either a new one or maybe borrow a spare one off a friend if that is possible.

[jamesperrett]

Did you hear a buzz from the speaker when you touched the pins on the arm? If not, I'd suspect either the arm wiring or the wiring from the deck to the amplifier.

[peter_sol]

You need to get someone who knows what they are doing to help you before wasting money on things like cartridges.
Are the phono plugs from the turntable plugged into the correct sockets on the amp?

[mking007]

Hi all

Thanks again for the replies. Here's my progress so far.

I bought an AT91 and substituted it fine. But no improvement - still no music coming from the speakers.

@jamesperrett there is a buzz from the speakers and when I touch the arm or the metal "pickup" on the side of the cartridge to lift it off the record then the buzz changes tone in response to me touching it and removing the touch.

@peter_sol yes I'm sure the plugs are connected to the right amp sockets. I'd guess the buzzing above supports that? I'm open to finding someone with expertise who can look it but I haven't found anyone yet. Any suggestions welcome. I'm in Liverpool.

Any further ideas appreciated.

[Edward Huggins]

Originally Posted by mking007

I bought an AT91 and substituted it fine. But no improvement - still no music coming from the speakers.

My suggestion to go buy an AT91 was on the basis that you found that the original cartridge had failed and as the AT91 is a good value replacement.
The problem still seems to be in the wiring continuity from the cartridge to the amp. Have you removed and re-connected the phono plugs on the amp?

[SiriusHardware]

mking007, do you have a test meter or multimeter available to use? You can buy basic ones for less than £10.

If you have one, we'll try to guide you more specifically through checking the connections. This is not going to be an insurmountable problem. As you have at least one good cartridge and neither of them makes the unit work, it can only be a wiring / connection problem.

As always, detailed photos of the cartridge wiring to the headshell and anything else you think relevant would be helpful.

Is the audio connection out to the amp via a lead which is hardwired to the deck and has phono plugs at the amp end, or are there phono plugs at the deck end of the lead as well, plugged into phono sockets on the deck?

[mking007]

Thanks again for the help.

@SiriusHardware yes I've got a multimeter. I'm not an electrical engineer but I'm comfortable with arduino / raspberry pi and low power stuff, so I would be grateful for pointers on what I should look for.

I've uploaded 5 photos.

Two show the top of the turntable. I've taken the cartridge off and tried to capture the 4 pins inside the arm.

The other three show the underneath and I've removed the wooden base. One is zoomed in on the cable out to the speakers. I'd checked this before and don't see any obvious loose wires etc.

It's unplugged from the mains.

Any advice on where to test appreciated

Thanks

['LIVEWIRE?']

Two or three things occur to me , are all 4 wires in the headshell connected to the correct pins on the cartridge, and, when the headshell is plugged into the arm is the locking collar screwed up correctly, and is there continuity between the connections at the base of the arm and the RCA leads/sockets connecting the turntable to the amplifier. These connections can be easily checked on the lowest ohms range of a multimeter (Analogue or Digital).

[SiriusHardware]

OK, that's helpful information. From the image of the audio wiring tag trip especially, it looks as though

Thin red wire from arm = left channel signal from cartridge.
Thin green wire from arm = left ground from cartridge.

Thin white wire from arm = right channel signal from cartridge.
Thin blue wire from arm = right ground from cartridge.

The following suggestions are based on the assumption that red usually equals right and white usually equals left. I'm also assuming that the plugs on the amp end of your audio output lead are coloured red, and either (white, or black).

For now, leave the headshell unfitted.

With your meter (which I assume is digital?) set to buzzer / continuity, first check that the meter is really in the right mode. Touch the probes together, it should buzz or beep.

We'll do this in steps - so first the audio output wiring.

Check to see if the following pairs of points are connected together by putting the red probe on one point, and the black probe on the other.

First check between
Tag connection with thin red / thick red wires on it
Centre pin of red phono plug at the amp end of the audio output lead
(Should buzz).

Second check
Tag connection with thin green wire / cable screen on it
Outer ring of red phono plug at the amp end of the audio output lead
(Should buzz).

Third check
Tag with thin white wire / thick white wire on it to
Centre pin of white (or black) phono plug on amp end of audio cable.
(Should buzz).

Fourth check
Tag with thin blue wire / cable screen on it to
Outer ring of white (or black) phono plug on amp end of cable.
(Should buzz).

The next two checks assume that the headshell / cartridge are NOT fitted. This is a check for unwanted signal-to-ground shorts on both the output wiring and the arm wiring.

Fifth check
Tag with thin red wire / thick red wire on it to
Tag with thin green wire / cable screen on it - should not buzz

Sixth check
Tag with thin white wire / thick white wire on it to
Tag with thin blue wire / cable screen on it - should not buzz.

Let us know if all those checks pass, and we'll continue with checks on the wiring from the end of the arm to the tagstrip.

Could we have some closer shots, one looking into the socket receptacle on the arm, and one or more close ups of the current wiring between the cartridge and the headshell?

[mking007]

First I connected a multimeter (with the meter on ohms and resistance) between the cartridge wires and the RCA phono cables but this seemed to give no readings most of the time but sometimes it seemed like there was connectivity.

So I decided to go further back and looked at the connectivity between the cartridge wires and where they connect on the base of the turntable to the DIN cable. Photos attached.

I seem to get connectivity across all the wires e.g. if I touch white on the cartridge then every connection on the base of the player shows connectivity except the black one in the middle.

So I've got some sort of leakage or crossover somewhere?