WM-D6c after 1 minute on correct speed

Hi @rahul_unde and welcome to Stereo2go.
I cannot talk you through a step by step fault finding, there are a few things which you need to check with the new chip in place.

Firstly, what are you using to power the D6C?

Have you replaced all the wires around IC601 in the correct places?
Check that the wires to the FG coil are not damaged and that they are soldered in the correct place. Check the resistance of the FG coil, it should be about 620 ohms. Sometimes the wires can be pinched and damaged if the back cover is not fitted correctly.

Check all the solder joints on the new chip. Check that there are no cracked PCB tracks or damaged pads.

Is the walkman running fast with the speed tune switch on?

Check the voltages on the pins of IC601 against those shown in the service manual.
Do you have 1.65V on pin 5?. If it is low, then check C606 to see if it is short.

If your D6C is a later model with the mostly surface mount board, then check C601, C602 and C603. I have seen these go high ESR and cause the motor to run fast.

 

Hello @Deb64, I shared these instructions to a local tech expert and he was able to resolve the problem. There was some resistor which was fried. Got it replaced and now the D6C runs good. Thank you for this help Deb!.

 

Thanks for the update @rahul_unde . I'm glad to hear that it's working again.

 

Hi, please tell me which resistor, I have the same problem.

 

Good day! Just wondering if this apply to the later model which I was helping my friend fix. His unit as the exact speed issue when starting to play for about 1 minute or so, then it recovers on its own.

 

If yours is the later, mostly surface mount, model then it could be C601, C602 and C603, as stated in the last line of my original post.
The symptoms sound as if one or more of these capacitors have gone high ESR. The best bet is to replace all three at the same time as they are difficult to get to. You will need to remove other components to get to these capacitors. As you will need to remove C607, it is a good idea to replace C607 as well.

 

Hello. Did you eventually solve the issue?

 

Appreciate your quick response! Where are those caps located, and what are their respective values?

 

Cap values and locations attached.
This information is all in the service manual, along with the setup procedure, which you need to carry out after the repair.
If you don't have the service manual, you should find it on-line and download it before you go any further.

 

Thanks for this valuable advice! I have downloaded your shared image and also the service manual.