Groove Controller Souri Problem

[Discomo]

Today I found out my Groove Controller of Souri's Vinyl Recorder is not working properly anymore.

It sometimes cuts to narrow, in comparison with the same music cut before. Resulting in faulty cuts.

Is the Controller broken? Or can I somehow adjust it? (I saw there's a turning-knob at the back, but don't know what it's for...)

Anyone have a suggestion to solve this big problem please?

[SueDenim]

The knob at the back has nothing to do with the groove control motor (it's for gain attenuation of the input audio signal).

I suggest that the first thing to try is to clean the groove controller knob's potentiometer.
Take the lid off the main unit and squirt a little cleaner such as DeoxIT F5 into the small gaps in the potentiometer's metal body.
Then twist the knob back and forth a few times to work the cleaner into the tracks.
Give it a few minutes to dry, then replace the lid and power up.

Whilst DeoxIT F5 isn't the cheapest, I highly recommend you invest in at least a small can as it's one of the absolute best on the market for pots and faders.

[Discomo]

Thank you Sue! I will try to do this.
However, the knob turns fine... very smoothly (not too smoothly) in fact it turns like it always did. I now have the VR about 20 months by the way.

I find it strange that in cut 1 it goes how it should go: normal groove spacing; but in the next cut the grooves are much tinier... Then when I try again later after having it turned off, it goes fine again, the first cut...

Seems to me it's something else than oxidation in the potmeter??

[SueDenim]

Do the cleaning of the pot first, then at least you can eliminate that as the source of your problem.
We can move on from there if you're still having issues.

[Discomo]

Many thanks, I really appreciate it.
It's night here now, but in 8 hours I'll buy the liquid. Will post an update.

[Vinylfan]

Properly fixed the screw on the left side at the spindle wheel?
Cutterhead moves smoothly from the outside to the center by turning the spindle manually?

[Discomo]

Do the cleaning of the pot first, then at least you can eliminate that as the source of your problem.
We can move on from there if you're still having issues.

Your advise was perfect... It seems to have done the trick! Wasn't expecting it to be solved so easily. So, many thanks!

The DeoxIT F5 they don't sell here in the Netherlands. Instead I used Kontakt IPA as cleaner and Kontakt 61 as protection against oxidation.

[Discomo]

Do the cleaning of the pot first, then at least you can eliminate that as the source of your problem.
We can move on from there if you're still having issues.

Unfortunately, the problem didn’t go away. I’ve thoroughly cleaned it... I’m now going to clean and oil the inside of the iron bar where the cutterhead moves.
Do you have aan idea what to do next of this doesn’t work?
Is it necessary to send the aparatus back to souri if its a problem with the electronics? Or can it be done by any average technician?

[Discomo]

NB:
I've checked also the movement of the cuthead only; when I switch on the green knob, there is an electric sound at the right rear end of the bar (where the electric wire enters the bar). When I then turn the groove spacer dial from 0-100 there is first an increase in the electric sound, then it stops. When I then repeat this, there is only still a very faint electric sound. This corresponds with the increase of movement (when the sound increases) and then almost no movement (faint sound).
What does this mean? That the electronics work properly but that it's a mechanical problem inside the cuthead-bar?

I haven't yet cleaned the inside of the bar. When I run my finger along the inside, it's still oily. The top of my finger has then a greyish oil on it. No clean oil, but also not black. Just a middle grey colored oil.

[markrob]

Hi,

I have some limited experience with that unit. I repaired one for a friend some time ago, so this may help. The controller is just a variable DC power supply that uses a LM317 adjustable voltage regulator to drive the motor. There is an RCA jack on the rear that has a shorting jack installed. This I believe was added to allow an interface to and external pitch controller. With that in mind, here are a few things to check:

1. Make sure the shorting jack is not making a bad connection. Might be a good idea to re-seat it and if possible give it a spray with some contact cleaner like De-Oxit.
2. If that does not solve the problem, measure the voltage at the motor using a DC voltmeter. Make sure the voltage is stable at any position on the pitch control pot. Its possible you have a bad pot or a bad connection someplace.
3. If the motor voltage seems stable, then I think you are on the right track as far and mechanical issues go. Don't rule out the motor as an issue.

Hope that helps,

Mark

[Discomo]

Hi,

I have some limited experience with that unit. I repaired one for a friend some time ago, so this may help. The controller is just a variable DC power supply that uses a LM317 adjustable voltage regulator to drive the motor. There is an RCA jack on the rear that has a shorting jack installed. This I believe was added to allow an interface to and external pitch controller. With that in mind, here are a few things to check:

1. Make sure the shorting jack is not making a bad connection. Might be a good idea to re-seat it and if possible give it a spray with some contact cleaner like De-Oxit.
2. If that does not solve the problem, measure the voltage at the motor using a DC voltmeter. Make sure the voltage is stable at any position on the pitch control pot. Its possible you have a bad pot or a bad connection someplace.
3. If the motor voltage seems stable, then I think you are on the right track as far and mechanical issues go. Don't rule out the motor as an issue.

Hope that helps,

Mark

Many thanks Mark...

I'm a total newbe where it comes to measuring anything...

Can you please tell me what will be good spots (-/+) to measure the voltage?

[Discomo]

Just to be prepaired for the worst;
Is there anyone in The Netherlands, preferably in the vicinity of Amsterdam, who could repair the unit?

[SueDenim]

Sorry that you're still having problems mate!

One thing I'd try first before measuring voltages is this:
- unplug the shorting phono plug markrob mentioned, located at the rear of the main control unit
- turn the motor switch on
- does the pitch motor (the one located at the end of the feed screw bar, where the wires enter) sound like it's running flat out at full speed?

[Discomo]

Sorry that you're still having problems mate!

One thing I'd try first before measuring voltages is this:
- unplug the shorting phono plug markrob mentioned, located at the rear of the main control unit
- turn the motor switch on
- does the pitch motor (the one located at the end of the feed screw bar, where the wires enter) sound like it's running flat out at full speed?

Yes, the sound is very faint. the same as when it's turned at 0.

[markrob]

Hi,

I'd try to measure at the motor terminals first. If you are not getting good readings there, work your way back to the controller and see if a bad connection is the cause. If you see a reasonable range of voltage as you adjust the pot, then either the motor is bad or you have some sort of mechanical issue. I can't recall the actual voltage range (maybe 2-12 Vdc??) as the pot is adjusted. Maybe somebody here can supply that info.

Mark

[Discomo]

Hi,

I'd try to measure at the motor terminals first. If you are not getting good readings there, work your way back to the controller and see if a bad connection is the cause. If you see a reasonable range of voltage as you adjust the pot, then either the motor is bad or you have some sort of mechanical issue. I can't recall the actual voltage range (maybe 2-12 Vdc??) as the pot is adjusted. Maybe somebody here can supply that info.

Mark

Sorry for this stupid question but do I need to power the controller on for this? So, connected to the mainspower? And where do I measure? On the naked contact points of the wires (without insulation, so in contact with the metal wires)?

[Discomo]

I've measured the voltage at the controller (because it was very hard to get to the metal wires to the motor inside the iron bar- it's covered in a kind of glue/plastic as insulation and I need to scrape it off to get to them)

I've measured it at 3 points: (see photo; forget nr4 please) 1. measured at 13.75 / 2. measured at 13.02 / 3. measured at eratic nr's between 0.26-0.36 constantly changing, independent from setting at green dial.

Can I conclude from this that the fault lies at the controller?

[markrob]

Hi,

Does the connector marked 3 go to the overhead motor? If so, that looks like a good place to make your measurement. You need to place your probes on both connections (Motor + and Motor - terminals). You might need to have somebody adjust the front panel pot while you hold the probes in place. Make sure your meter is set to read DC Volts. If you do not get any reading, try removing the DIN plug that runs to the motor to make sure its not shorting out the supply. If still no decent readings, then you probably do have a controller issue. The LM317 (probably the device mounted on the heatsink) is a good candidate for replacement, but you should take some additional readings to prove that its the problem. It might be time to find a local service tech to help you solve the problem.

Mark

[SueDenim]

Agree with markrob - sounds to me like the LM317 voltage regulator has died.

With the shorting phono plug pulled out at the rear of the main unit, the pitch motor should be running as fast as it can.
However, if the LM317 isn't working, there's a good chance that almost no voltage is being put across the pitch motor terminals.

[Discomo]

Many thanks, @markrob @SueDenim
Yes, "3" goes to the motor...

I'll see a tech tomorrow.

Alternately, if it's only the LM317 is it possible to simply replace the LM317 myself?