Record Player Turntable Motor not self starting

[spike1947]

Hi
I have a Sony DJ9000 Record Player and the problem is that the Turntable ( Platter) will not self-start, I have to give it a nudge then it will turn ok.
Anyone any idea as what the problem could be, have checked the motor winding's and they all show the same reading's, have re-oiled the bearing, it just seems that it just needs that initial power surge to start it turning, will attach a schematic and some pics of the underneath of the Turntable .

Cheers

Spike

[spike1947]

Pic 1

[spike1947]

Pic 2

[spike1947]

Pic 3

[rvalente]

Looking the provided service manual, did you check the motor coil and the hall sensors?

Checked voltages? Is the IC01 well supplied?

[fzabkar]

https://docs.rs-online.com/c720/0900766b80998f6d.pdf

Have you checked the 3.9 ohm 1W motor current sense resistor on pin #5 of IC01?

If you are game, you could add a second resistor in parallel and increase the current limit for the motor, if only for testing purposes.

[shakalnokturn]

I'd check the power supply voltages and ripple because it can be worth the time spent.
First suspects would be C12, C14, C15 next IC1. I remember having to replace TA7259P's in Numark turntables that had mysteriously lost their punch.
Interesting to see that there are no Sony IC's in this turntable, is it a rebrand?

[shakalnokturn]

After checking the motor PCB looks very similar if not identical to that of the Numark TT-1650.
Doubtful it is a Sony design and most likely you'll need a TA7259...

[Haenk]

I'd start with measuring the 3 caps at "C03". I assume they are for one phase of the motor driver each - that's how Technics did it, and those caps often fail. Hall sensors and driver IC should be OK, as the unit runs...

However the fault might also be in the other caps (so check at the same time as the C03 ones) or motor driver IC (I would check out that one as last resort).

[spike1947]

Thanks for all your replies, will check those recommendations out tonight, and come back on what I find out ! .
Cheers

Spiike

[Gyro]

Yes, my bets would be on C02, C03 and C04 on the motor board having lost their pep too. That would definitely reduce motor torque.

[spike1947]

https://docs.rs-online.com/c720/0900766b80998f6d.pdf

Have you checked the 3.9 ohm 1W motor current sense resistor on pin #5 of IC01?

If you are game, you could add a second resistor in parallel and increase the current limit for the motor, if only for testing purposes.

Hi
Thanks for your reply, Re the IC 1 , can you tell me if all the numbers on that IC1 are voltages !.

cheers

Spike

[spike1947]

Looking the provided service manual, did you check the motor coil and the hall sensors?

Checked voltages? Is the IC01 well supplied?

Hi
Thanks for your reply, are the numbers on the sides of the IC01 voltages ! .

cheers
Spike

[fzabkar]

Yes, they would be voltages.

[shakalnokturn]

Any luck with the capacitors?