Technics 1210 MK2 powers on but not turning.

turning japanese
RoyRoundBelly
junior member
junior member
Posts: 12
Joined: 19 May 2018 22:08

Technics 1210 MK2 powers on but not turning.

Post by RoyRoundBelly » 20 May 2018 02:45

It powers up but start button does nothing.


Service manual has a check list:

1. Check Test Point 5 (TP5) looking for 20v
2. Check voltage and waveform on IC201.
3. Check voltage and waveform on IC101
4. Check voltage on Q201 looking for 10v


#1 - I measured TP5 and it was 20v.

#2 - IC201 - I don't have an oscilloscope to check the waveforms but I checked the voltage. The schematics lists voltage for pin 9 at 9v and this measured at 9v. I'm not sure on what the voltage at the other pins should be but my readings are noted below in case someone out there knows what the other pin voltages should be:

IC201 voltage at pins:
pin 1: 2.5v
pin 2: 2.9v
pin 3: 2.9v
pin 4: 1.9v
pin 5: 3.3v
pin 6: 3.4v
pin 7: 0v
pin 8: 0v
pin 9: 10v
pin 10: 9.3v
pin 11: 0.5v
pin 12: 0v
pin 13: 0.1v
pin 14: 0.6v
pin 15: 8v
pin 16: 2v
pin 17: 5v
pin 18: 2v
pin 19: 8v
pin 20: 6v
pin 21: 0v
pin 22: 3v
pin 23: 3v
pin 24: 2.8v


I also followed the start button press switch on the schematics and tested the continuity to IC201 pin 19 and confirmed this is good when the start button is pressed.


#3 - IC101. Again no oscilloscope and the schematics didn't list the expected voltages. The actual voltages measured are listed below if anyone can spot an issue?

voltage at pins:
pin 1: 0v
pin 2: 1.9v
pin 3: 0v
pin 4: 1.9v
pin 5: 0v
pin 6: 6.5v
pin 7: 0v
pin 8: 5v
pin 9: 0v
pin 10: 0v
pin 11: 0v
pin 12: 15v
pin 13: 15.6v
pin 14: 15.4v
pin 15: 15.6v
pin 16: 0v
pin 17: 15.6v
pin 18: 20.6v
pin 19: 20.7v
pin 20: 20.7v
pin 21: 20.7v
pin 22: 0v
pin 23: 20.7v
pin 24: 2v


While on IC101 I checked the coils resistance and continuity. All looks good.
Continuity between AC - A1, AC - A2, AC - A3, PCOM - P1 etc. all good.
pins 1, 2, 24. measure 24 ohms each, pins 11, 13, 15 measure 9 ohms. and pins 18 and 20 measure 24 ohms each.

#4 - Q201 - this measured at the expected 10v at Q201 pin B



Any ideas on what to test next?

Spinner45
long player
long player
United States of America
Posts: 2035
Joined: 01 Mar 2017 18:21

Re: Technics 1210 MK2 powers on but not turning.

Post by Spinner45 » 20 May 2018 04:44

Up against a wall, eh?
The tools needed (oscilloscope) should be in your possession if you intend to play technician, particularly with complex electronics.
Without the proper tools, a car mechanic can't fix the car, either.

RoyRoundBelly
junior member
junior member
Posts: 12
Joined: 19 May 2018 22:08

Re: Technics 1210 MK2 powers on but not turning.

Post by RoyRoundBelly » 20 May 2018 08:57

Yes after 4 hours troubleshooting the pcb yesterday and getting nowhere you could say that...

I think I'll put it away and go shopping for a 1200GR.

cafe latte
vinyl addict
vinyl addict
Australia
Posts: 10084
Joined: 11 Oct 2009 04:27
Location: Cattle property near Ravenshoe Qld Australia

Re: Technics 1210 MK2 powers on but not turning.

Post by cafe latte » 20 May 2018 10:19

Did you check protection ic's?
Also dont discount the obvious maybe the on off switch is stuffed..
Were are you located?
Chris

RoyRoundBelly
junior member
junior member
Posts: 12
Joined: 19 May 2018 22:08

Re: Technics 1210 MK2 powers on but not turning.

Post by RoyRoundBelly » 20 May 2018 10:31

Start/Stop button switch looks good. I followed the schematic for that (continuity test of yellow and orange wires passed when button pressed). I followed it all the way to the IC201 (pin 19) and it's showing continuity with the button pressed.

Do you have more info on the protection ic's? I'm unsure about what they are.

I'm in Ireland. Nowhere here does servicing.

cafe latte
vinyl addict
vinyl addict
Australia
Posts: 10084
Joined: 11 Oct 2009 04:27
Location: Cattle property near Ravenshoe Qld Australia

Re: Technics 1210 MK2 powers on but not turning.

Post by cafe latte » 20 May 2018 10:47

RoyRoundBelly wrote:Start/Stop button switch looks good. I followed the schematic for that (continuity test of yellow and orange wires passed when button pressed). I followed it all the way to the IC201 (pin 19) and it's showing continuity with the button pressed.

Do you have more info on the protection ic's? I'm unsure about what they are.

I'm in Ireland. Nowhere here does servicing.
Another option is buy a whole main board on ebay or even try Kabusa. I have a spare (not for sale) which I picked up for 60 bucks I think, they will cost more now, but the whole turntable electronics minus the power supply and slider is on the main board. Just make sure you check stuff like switches first though.. The protection ic's are Q2 and Q3, they are 2 of 2sd637's Q201 can cause no power too.
Chris
Chris

RoyRoundBelly
junior member
junior member
Posts: 12
Joined: 19 May 2018 22:08

Re: Technics 1210 MK2 powers on but not turning.

Post by RoyRoundBelly » 20 May 2018 22:51

Thanks for all the advice.

I have access to another working 1210 mk2, so today I did a test main board swap and everything worked fine confirming the issue is a fault on the main board. I even put the bad board into the other 1210 and the platter doesn't start spinning either. 100% it's a board fault.

As advised, I swapped the following components from the working board to the faulty board (and vice versa):
Q2
Q3
Q201

I tested these transistors with the multimeter once they were taken out and they looked good but I swapped them anyway. Sadly the faulty board is still faulty and not reacting to the start button.


The good board is working fine with the Q2/Q3/Q201 swapped from the faulty board so I'll leave the components swapped.



I've ordered a replacement PCB on Ebay for 100 euro but I'm still curious as to what component is causing this "platter will not start" issue.

Based on the troubleshooting steps I've done so far, are there any other components that could cause this issue and I'll swap them too?

Tom_Technics
member
member
Posts: 54
Joined: 20 Aug 2016 12:54

Re: Technics 1210 MK2 powers on but not turning.

Post by Tom_Technics » 20 May 2018 23:36

How old is the 1210? If it's over 20 years old then it could very well be an electrolytic capacitor issue, and I also recall reading that a batch of 1200's/10's were made with cheaper components to cut the cost of production. You have a multimeter so you could just pull them out and test them one by one. The thing is though that sometimes a cap will measure good out of circuit but won't work in circuit. I'd re-cap it, it's the logical next step after ruling out all that you have.

cafe latte
vinyl addict
vinyl addict
Australia
Posts: 10084
Joined: 11 Oct 2009 04:27
Location: Cattle property near Ravenshoe Qld Australia

Re: Technics 1210 MK2 powers on but not turning.

Post by cafe latte » 21 May 2018 01:13

Check the rectifier (black thing near the protection ic's) and check q203 which is an 2sc1328
Fingers crossed..
Chris

RoyRoundBelly
junior member
junior member
Posts: 12
Joined: 19 May 2018 22:08

Re: Technics 1210 MK2 powers on but not turning.

Post by RoyRoundBelly » 21 May 2018 15:35

Thanks again all. I probably wont have time to do more work on this until the weekend but will report back on any progress.

Just a quick one though - I read on kabusa.com about testing for expected voltage on the IC's and compare when the start button is pressed.

This looks like a great way to troubleshoot an IC issue but is it safe to press the start button with the platter off???
If you need to keep the platter on before pressing start, how do you get the probes under the platter to measure?

cafe latte
vinyl addict
vinyl addict
Australia
Posts: 10084
Joined: 11 Oct 2009 04:27
Location: Cattle property near Ravenshoe Qld Australia

Re: Technics 1210 MK2 powers on but not turning.

Post by cafe latte » 22 May 2018 00:02

RoyRoundBelly wrote:Thanks again all. I probably wont have time to do more work on this until the weekend but will report back on any progress.

Just a quick one though - I read on kabusa.com about testing for expected voltage on the IC's and compare when the start button is pressed.

This looks like a great way to troubleshoot an IC issue but is it safe to press the start button with the platter off???
If you need to keep the platter on before pressing start, how do you get the probes under the platter to measure?
You need to email Kevin on that one as I understood platter must be on, Kevin will clarify for sure.
Chris

djrichie_t
broken record
Posts: 1
Joined: 14 Mar 2014 16:56

Re: Technics 1210 MK2 powers on but not turning.

Post by djrichie_t » 22 May 2018 02:05

I have had this scenario when servicing, all with different faults. Most of the time it has been down to a faulty AN6680 but its worth checking the 4011 aswell. Only once has it been due to a fried AN6675.

All of these faults can most likely be caused by a faulty regulator circuit - check Q201 is properly soldered in place as these often become loose, most often causing the motor to spin very fast and putting extreme stress on AN6675 causing it to fail.

Spinner45
long player
long player
United States of America
Posts: 2035
Joined: 01 Mar 2017 18:21

Re: Technics 1210 MK2 powers on but not turning.

Post by Spinner45 » 22 May 2018 02:54

RoyRoundBelly wrote:Thanks again all. I probably wont have time to do more work on this until the weekend but will report back on any progress.

Just a quick one though - I read on kabusa.com about testing for expected voltage on the IC's and compare when the start button is pressed.

This looks like a great way to troubleshoot an IC issue but is it safe to press the start button with the platter off???
If you need to keep the platter on before pressing start, how do you get the probes under the platter to measure?
Per Technics service, never power the turntable without the platter in place.
warning note.jpg
warning note.jpg (26.14 KiB) Viewed 209 times

RoyRoundBelly
junior member
junior member
Posts: 12
Joined: 19 May 2018 22:08

Re: Technics 1210 MK2 powers on but not turning.

Post by RoyRoundBelly » 27 May 2018 23:38

The spare ebay main PCB arrived. After swapping, the platter spins but it slightly "judders" and is not smooth. The dots are vibrating back and forth when pitch is at 0.

I took the PCB out and put it into the known good turntable and confirmed it has the same judder issue.

Looks like a got a bad board from ebay.

I was thinking since I have 2x bad boards now - one that doesn't spin and one that judders, perhaps I can make one good board out of them.
The one that doesn't spin I was pretty sure the AN6675 that's faulty since the work last weekend. So I de-soldered the AN6675 from the chugging ebay board and soldering it on to the original non-starting board. Installed it, powered it up and pressed the start button - it started to spin. Delighted at first, until I noticed it was juddering too. The same judder that was apparent on the ebay board. At least I know the AN6675 was the cause of the not spinning fault and it looks to be causing a judder fault too. 2x boards with a bad AN6675 though... are these chips really prone to failing?

Thankfully they are cheap enough at the moment so I'll order some and see how it goes next weekend.

cafe latte
vinyl addict
vinyl addict
Australia
Posts: 10084
Joined: 11 Oct 2009 04:27
Location: Cattle property near Ravenshoe Qld Australia

Re: Technics 1210 MK2 powers on but not turning.

Post by cafe latte » 28 May 2018 01:08

RoyRoundBelly wrote:The spare ebay main PCB arrived. After swapping, the platter spins but it slightly "judders" and is not smooth. The dots are vibrating back and forth when pitch is at 0.

I took the PCB out and put it into the known good turntable and confirmed it has the same judder issue.

Looks like a got a bad board from ebay.

I was thinking since I have 2x bad boards now - one that doesn't spin and one that judders, perhaps I can make one good board out of them.
The one that doesn't spin I was pretty sure the AN6675 that's faulty since the work last weekend. So I de-soldered the AN6675 from the chugging ebay board and soldering it on to the original non-starting board. Installed it, powered it up and pressed the start button - it started to spin. Delighted at first, until I noticed it was juddering too. The same judder that was apparent on the ebay board. At least I know the AN6675 was the cause of the not spinning fault and it looks to be causing a judder fault too. 2x boards with a bad AN6675 though... are these chips really prone to failing?

Thankfully they are cheap enough at the moment so I'll order some and see how it goes next weekend.
Not really, most Technics faults are abuse or people trying to mod and dont know what they are doing like the trend of installing led strobe, when it is done wrong things get fried.. DJ slowing and speeding up by hand will stress drive components too. Then there is drinks spilled or DJ turntables getting rained on on way to car or just condensation moving from cold car park to hot night club then turntable fails when powered up. Home use you should never have issues as these turntables survive unbelievable abuse from DJ's..
Chris

Post Reply