Bringing an SL-23 back to life... can you assist?

[damager]

Hello all my fellow vinyl enthusiasssssts....

I just inherited a Technics SL-23 which I'm currently bringing back from the dead.... and I'm *ALMOST* there!! My last outstanding issues are:

• pitch seems to warble every now and then, maybe every 20-30 seconds I'll get a slight dip, and you can even SEE it on the strobe. For this, I'm planning to replace all the caps as they are the originals, waiting on the order now. Please let me know if I'm not on the right track there or if this could be something else.
• I'm getting some snap crackles and pops on the playback, even though I have a brand new cartridge / stylus, and a brand new record. And this is the one I'm a bit mystified on right now.

I'll admit I'm not the knowledgeablest vinyl guy on the planet. I've scoured the webs and found a lot of excellent videos specifically on the SL-23 in terms of maintenance and upkeep. And what've done so far is:

• replaced belt (it was horribly worn)
• replaced a fuse (motor wasn't moving)
• lubed up switches and pitch controls and worked em in
• replaced old stylus (which was an AT2000XE, and used to sound great) with a new AT85EP on a recommend.
• removed spindle and cleared out all the old grease, cleaned thoroughly as well as the shaft hole until perfectly clean, then replaced with some grease. Worked it in.
• Cleaned the table and all parts, man the thing looks like I just took it out of the box now!!
• Obviously, set the balanced the counterweight, set to zero, and then set the counterweight to 1.5. Adjusted anti-skate accordingly.

Beyond this, I really am mystified as to why I'm getting the snapping and popping. Everything else seems kosher. This is more than 1 brand new record by the way, that I hear this on. Hopefully I'm not missing something stupid, so I'm here at AK consulting the experts.

Thanks anyone and everyone for your expertise and advisement. Peace!

 

[sregor]

Maybe need to ground the main platter bearing,or may be the motor assembly. Static buildups due to bad grounding is only thing I can think of...my two nickels

 

[sound hound]

Maybe the snapping and popping be an electrical connection problem in the circuit from the cartridge to the phono input. Is it only when a record is playing? Do you have another cartridge/headshell that you could try? It is on both channels?

 

[damager]

Maybe need to ground the main platter bearing,or may be the motor assembly. Static buildups due to bad grounding is only thing I can think of...my two nickels

ok thank you Steve I will check this!

 

[damager]

Maybe the snapping and popping be an electrical connection problem in the circuit from the cartridge to the phono input. Is it only when a record is playing? Do you have another cartridge/headshell that you could try? It is on both channels?

Yes, the snapping and popping is only when a record is playing, and it's on both channels. And, I should add that it doesn't occur in mono, straight down the middle. It occurs all over the stereo sprectrum. A pop or two in the left, a snap or two on the right. This is why I'm thinking it's got something to do with the balance of the tonearm, or maybe it's pressing the needle down too hard. But that's not the case as I've tried it at ALL weight settings.

it sounds like I'm playing a dirty record, and I know for a fact the ones I'm using to test are pristine, one of them I just took out of the original plastic!

 

[EdBacon]

There's really not much that can go wrong here. From the stylus-cartridge then the wiring to the output. It sounds like static build up or something.

As far as the unstable speed goes, I would start by cleaning the pitch control and speed trimmer potentiometers with a good contact cleaner. You said you lubed and cleaned them. Does this mean you used an electrical contact cleaner? Use a good contact cleaner on each potentiometer and work them all the way from one side to the other, then return them to their original positions. Start with that and see if it resolves your issue.

 

[dankik]

Yes, the snapping and popping is only when a record is playing, and it's on both channels. And, I should add that it doesn't occur in mono, straight down the middle. It occurs all over the stereo sprectrum. A pop or two in the left, a snap or two on the right.

If it were static discharge, it would be heard in both channels since there is only one stylus but two sets of cartridge coils. but what you hear is separate L & R pops so I don't think it is static. Do you think that the record is skipping grooves or is the music continuous but with pops?
Check to make sure that the solder connections look good from the tonearm to the RCA cable (see photo below).
Are you sure that the problem is not with the Phono input of your amplifier? Try another amp to verify.
Also, as @sound hound points out, maybe the problem is with the cartridge and not the turntable. Try another cartridge (What make/model cart is installed?)

 

[damager]

There's really not much that can go wrong here. From the stylus-cartridge then the wiring to the output. It sounds like static build up or something.

As far as the unstable speed goes, I would start by cleaning the pitch control and speed trimmer potentiometers with a good contact cleaner. You said you lubed and cleaned them. Does this mean you used an electrical contact cleaner? Use a good contact cleaner on each potentiometer and work them all the way from one side to the other, then return them to their original positions. Start with that and see if it resolves your issue.

I'm sorry, I guess I did not specify. I used contact cleaner that I got from RADIO SHACK (yup, i just dated myself) years back. I used this on all pots and worked the SH1T out of em. I figured there'd be a lot of buildup over the last 40 years.

 

[damager]

If it were static discharge, it would be heard in both channels since there is only one stylus but two sets of cartridge coils. but what you hear is separate L & R pops so I don't think it is static. Do you think that the record is skipping grooves or is the music continuous but with pops?
Check to make sure that the solder connections look good from the tonearm to the RCA cable (see photo below).
Are you sure that the problem is not with the Phono input of your amplifier? Try another amp to verify.
Also, as @sound hound points out, maybe the problem is with the cartridge and not the turntable. Try another cartridge (What make/model cart is installed?)

View attachment 3530390

All good points here... to reply:

I actually AM now suspecting the amp. Not thinking that there's anything wrong with it, but perhaps it's REALLLLY pushing the bright high end, and picking up even the slightest flaws?? It's a Yamaha RXV6A. And I definitely have the grounding wire hooked in as well.

In terms of the cart, I suspected that too, and swapped with the old one just to check. Same result. pops and snaps still exist.

I'm also wondering if, maybe this is just inherent in the vinyl world?? But, jeez man, I gifted a brand new Victrola from Best Buy to a friend of mine a year back to get her in to vinyl. and when I hear records at HER place, they sound so pristine, it sounds like CD. Like, eerily flawless.

This is why I'm suspecting the amp. May try to bring my SL23 over to her place and test it.

 

[painttoad]

I would start by cleaning the pitch control and speed trimmer potentiometers with a good contact cleaner

this

there are 2 trimmers on the pcb that need replaced. don't try to clean them. just replace them.

these roughly adjust the speed. the controls up top do fine adjustment.

replaced belt (it was horribly worn)

make 100% sure that you used a proper replacement.

this is what i used

Technics SL-23 [silver] Model Uses Our Flat Drive Belt Stock Number FBM23.6

www.turntableneedles.com

the previous owner had replaced the belt ..with the wrong one.

 

[BmWr75]

Deoxit on the speed control pots fixed the speed issues on the SL23 I bought new circa 1976.

 

[damager]

there are 2 trimmers on the pcb that need replaced. don't try to clean them. just replace them.

these roughly adjust the speed. the controls up top do fine adjustment.

Are you referring to the two tiny ones on the bottom on that small PCB? I'm really afraid to mess with those thinking I'll screw up the pitch like, for good. haha!

But if you insist I'll do it I'm very handy with a soldering iron. Where can I source good replacement parts for those?

 

[damager]

make 100% sure that you used a proper replacement.

So, for this, I simply went on to Amazon, and searched SL-23 belts. I found a set of 5, and one of them was intended for the SL-23. It was the only one that even remotely fit. It seems like a nice snug fit that isn't too tight. and CERTAINLY better than the one that was in there which was just about falling off.

 

[painttoad]

So, for this, I simply went on to Amazon, and searched SL-23 belts. I found a set of 5, and one of them was intended for the SL-23. It was the only one that even remotely fit. It seems like a nice snug fit that isn't too tight. and CERTAINLY better than the one that was in there which was just about falling off.

i would not trust amazon for belts. i posted a link to a legit belt from a reputable seller. make sure that you loop the belt around the platter evenly, in a straight line. don't have it looking like a sine wave.

Where can I source good replacement parts for those?

mouser, digikey.

i'm not even sure where i got mine from or the part number. most likely i had them in stock and just automatically replaced them knowing that they need replaced.

 

[EdBacon]

All good points here... to reply:

I actually AM now suspecting the amp. Not thinking that there's anything wrong with it, but perhaps it's REALLLLY pushing the bright high end, and picking up even the slightest flaws?? It's a Yamaha RXV6A. And I definitely have the grounding wire hooked in as well.

In terms of the cart, I suspected that too, and swapped with the old one just to check. Same result. pops and snaps still exist.

I'm also wondering if, maybe this is just inherent in the vinyl world?? But, jeez man, I gifted a brand new Victrola from Best Buy to a friend of mine a year back to get her in to vinyl. and when I hear records at HER place, they sound so pristine, it sounds like CD. Like, eerily flawless.

This is why I'm suspecting the amp. May try to bring my SL23 over to her place and test it.

An SL-23 is a good turntable. I've completely rebuilt one before. Totally taken apart, reassembled, new tonearm wiring, etc.

It should not be producing bad sound reproduction like you're describing. Unless the cartridge or tonearm wiring were somehow damaged, or the record is damaged.

The issue could be in the pre-amp stage of your Yamaha although I would not suspect that first. I would start to suspect a wiring or contact issue with your p-mount adapter. It might be where I'd start looking first. That and the solder connections to the RCA out. Like I said, there isn't really much between the stylus and the output on any turntable. You are just producing the signal transmitted mechanically by the movement of the stylus into the cartridge, then straight out the turntable. There is nothing else going on in the turntable itself electronically (apart from the motor control stuff, but this is separate from the audio). So the issue has to be there: stylus, cart, wiring.