macfan

Help diagnosis a problem with LP12

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Issue: Intermittently loosing right channel only when playing LP12. 

Symptoms:

  1. For instance, plays fine on Monday then on Tuesday the right channel does not work from the get go
  2. Swapped cables from left to right - both channels have audio - swap back everything is good until the problem materializes again.
  3. Can go several days at a time without the issue coming back
  4. Recently, the issue started happening more and now it seems here to stay.

What I have tried:

  1. Swapping cables no longer works
  2. Dealer sent me a replacement phono stage for my SDSM - swapped it out but it did not help - problem persists

Next steps:

  1. What would you do next?
  2. Spoke with dealer who is out of town. Might just try to do current promo and tackle problem at same time.

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I don't get quite enough info from your Wigwam info and your fault description to fully diagnose but from what you have provided you likely have an issue either with the right channel plug (rca or din or whatever) that fits into the phono input on the phono stage/amp or with the cable to the plug.

Normal diagnosis of a channel fault would involve swapping channels both at the cartridge tags and then into the amp to locate where the problem lies but nothing you have provided suggests the problem is with the deck itself or cartridge.

Not clear if the replacement phono stage plugged into different sockets on your amp. If it did then that would probably rule out the sockets on the amp as having an issue.

The problem is with the signal channel but not ground channel (no humming mentioned) on the right cable which may be down to a bad solder joint in the plug or with a break in the signal wire that fixes and unfixes itself when you jiggle the wire during plugging in and unplugging the cable.

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Would bet money on a broken connection in one of the cable connectors. With the volume LOW try wiggling the cable near the connector and see if that breaks/makes the connection and sound stops/starts coming out of that channel.

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I had a similar problem, loosing one channel from my LP12 intermittently. There could be days, weeks between faults.
I tried the usual things, moved the output cables to another input on the amplifier, swapped cables left/right. Nothing helped to fix the problem.

Then, I removed all wires from the cartridge.
Some were a little loose on the arm contacts, so, I tightened the terminals a little with a tweezer and installed them again. 
After weeks the problem showed up again. Then, I phoned my dealer and we decided to send my Urika to Linn (via dealer).
The unit was returned a couple of weeks later. There was no repair needed, because there wasn’t a problem found.  

When the problem reoccurred, weeks later, I decided to remove the cartridge wires again and take a closer look at them. 
This time I have put them under the 12X magnifying glass.
It is hard to believe but one of the crimp terminals wasn’t crimped tightly enough on the very small stripped, cartridge bare wire. 
I could see the wire moving in the terminal crimp area when I pulled carefully on the terminals. Why didn’t I see this earlier?
I ordered a new set of cartridge wires.

Since I installed the new cartridge wires, the problem did not occur again. Solved!
I hope this helps. There can be little problems with big impact. 

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@ErikH Thanks for the detailed reply. I will take a look. I have started to believe the cartridge is the issue. I really do not have the skill to repair or replace it but will take a close look.

@CJ1045 Tried the wiggle procedure with no luck.

@cre009 When the problem 1st started swapping channels brought both channels back. Swapping back resulted in both channels being there...until the problem happened again. The swap procedure worked until last week. Also the phono stage is a daughter card inside the Select DSM. We swapped it as it was easy to do and a good test.

I have inspected the solder connections on the the RCA plugs and they look OK. No clear signs the right channel connections are loose.

Thanks for thoughts. Hopefully can get it resolved sometime soon.

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@macfan  Need a little more info here. To add to what has already been contributed, there is a possibility that the phono stage might have an intermittent issue. If you are switching out the phono stage when playing another source and therefore the Linn is not playing, I would check the phono stage.

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@Daveyf Thanks. The phono stage has been swapped out. Same results.

Question: When looking at the phono cartridge lead wires there is a blue on top of a white an a green on top of the red. Which combo is the left and right channel? If the green/red is the right then this might be a clue. I can see the red wire is not push firmly all the way on the connection point where the other three are. You can see just a bit of space -where the others have none. If you are standing behind the cartridge the green/red wires are the right pair.

Trying to get a good photo but not success thus far. 

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Hello macfan,

    I am not sure if this is going to help but I tried. I have taken pictures of my Kandid connections to see if they show you something different. The right side (image attached) is very clear but the left is a little dark (I couldn't get the flash to trigger for some reason) (image in next post).

I hope you get this solved soon,

Chris.

IMG_1304.jpg

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4 hours ago, macfan said:

@Daveyf Thanks. The phono stage has been swapped out. Same results.

Question: When looking at the phono cartridge lead wires there is a blue on top of a white an a green on top of the red. Which combo is the left and right channel? If the green/red is the right then this might be a clue. I can see the red wire is not push firmly all the way on the connection point where the other three are. You can see just a bit of space -where the others have none. If you are standing behind the cartridge the green/red wires are the right pair.

Trying to get a good photo but not success thus far. 

The red wire is the right channel signal wire so could be the problem. The green is the right ground.

Will the red wire push all the way in? You can apply a bit of pressure to push it. It should be a snug fit. If it is a loose fit then it may need to be crimped a little.

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Hi all - thanks for the continued responses. Red wire is definitely part of right channel and it does appear to be different from the others. I will try and attempt to push it on a bit more. Being small am a bit nervous but will try later tonight.

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So new symptom - 

Since the preamp board swap in the Selekt DSM did not solve the issue I put my original back in and send the replacement back to my dealer. BTW, very easy to work on a SDSM. Anyway, hooked everything back up and this time right channel was there. However, something seemed amiss where the left channel seemed slightly louder than the right. 

Pulled out my Analog Productions test LP and confirmed the left is in fact slightly louder enough to make a balance difference where the center image shifts to the left ever so slightly. but definitely noticeable. Checked the tracking weight and it was at 1.75g. Do not remember if 1.74g or 1.75g is correct for the Krystal. Then to check anti-skate I placed the stylus on a blank plateau and it more or less remained in place with little movement to the center - but it did eventually move toward the center.

I did try and push the red wire onto the cartridge pin - but it was very sung so I did not apply to much force as I did not want to cause damage. At this point I tend to think it might be the cartridge or a connection somewhere. Looks like a profession is needed to sort it out.

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Posted (edited)

I still think it is bad a connection.

The right channel has an interruption or a contact resistance somewhere in the wiring, possibly.
You said the left channel is louder, if so, it is still a problem with the right channel. 

There are so many contacts in the circuit, the Krystal coil + and - are soldered to the cartridge pins which is quite good. The cable to the amplifier is soldered, also good (under the arm is, of course, a push connection - but I have never seen a problem with that). The 4 cartridge wires have in total 8 slip-on terminals and 8 crimp terminal-wire connections. Potentially, 16 contact problems. If one of them is causing a few ohms resistance, eg a slip-on terminals not tight enough, you may already have a channel imbalance, because the Krystal is very low impedance, may be 10 ohms, and the moving coil amp in the Selekt DSM may be set to low, eg 30 ohms. 

Of course, there may be something wrong with your Krystal, but why don’t you try (just to test) to set your Selekt DSM MC amp to the highest cartridge load resistance available, eg 1000 ohms (1 Kilo Ohm) with the Konfig settings. This load is so high that an additional resistance in the wiring, which may be low too, eg 10 ohm, is not noticeable. A low cartridge load setting in the MC amp is causing a bad contact to loose more signal than with a high load.

This may help you in your analysis.
If with a high load resistance in the MC amp the left and right channels both work (almost) equal in output, then you can possibly say Krystal oké and wiring ‘ a bad contact somewhere ‘ . If setting back to the Krystal selection with Konfig (and not touching any LP12 wiring in the mean time) the problem shows again, it is a contact somewhere. 

I have a Krystal too on my LP12, I set it to 1.75 grams weight with my digital scale, and that works fine for me. 

EDIT: reading from the Selekt DSM manual, the MM and MC inputs are fixed load resistance. MM is 47K-ohm, much higher than the MC input 100 ohm. MM is lower amplification (-14dB) but with somewhat more volume the test can still be done.

Edited by ErikH
Correct text

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Posted (edited)
2 hours ago, macfan said:

Anyway, hooked everything back up and this time right channel was there.

I did try and push the red wire onto the cartridge pin - but it was very sung so I did not apply to much force as I did not want to cause damage.

I can only go with what you describe which suggests to me that the red wire terminal tag may not be properly fitted onto the pin.

If it was already a snug fit then I would have expected it to move all the way in to the pin with moderate pressure applied using finger or finger nail. It is a tight space to work and you don't want to over apply pressure because that would risk either jolting the arm or breaking the red wire tag. If the red wire tag is over crimped so it will not push onto the pin properly then that could lead to intermittent connectivity and occasional drop out of the right channel.

Edited by cre009

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