Strange phenomena with SUPERCDROM2 (PI-CD1) CD drive does not stop

[hiro]

I am repairing a SUPERCDROM2 (PI-CD1) that cannot read CDs.
The capacitor has been replaced and the CD drive is now operational.

A strange phenomenon occurs in music CD playback mode.
Normally, the CD is stopped when the CD exchange button is selected or when the controller is reset with RUN+SELECT.
However, even with these operations, the CD does not stop and the music continues to play.
Is the CD drive system IC faulty?
Has anyone else experienced a similar phenomenon?

[Keith Courage]

I've never seen that behavior before but I would look for old capacitor leakage under the two BA6290A chips. This is a common area caps leak and wreak havoc on lens function.

This is just where I look first if there are any issues after a capacitor change for Super CD-rom2 drives.

[hiro]

Thank you Keith.
I will check.
Is the BA6290A chips responsible for the functions related to starting and stopping the rotation of the CD drive?
Is it likely that other chips are faulty?

[hiro]

I removed the BA chip to check it and found no evidence of decay or other abnormalities.
I could also check continuity with a multimeter.
I installed a new BA chip and checked the operation, but the symptoms remained unchanged.
What other possible causes could there be?

[Keith Courage]

I'm sorry that wasn't your problem.

I honestly can't say for sure as I've never come across that exact problem in a super CD ROM2 drive before.

I've seen something similar in Duo systems though.

Does the CD drive have any issues loading games? Also, just curious if you've also tested a different PC engine or core grafx with the CD-ROM to see if that makes any difference.

if games are actually working perfectly fine, then it sounds more to me like it's not getting the correct signal from the system itself when you reset the console. Maybe there is a bad trace or resistor for the data lines coming from the expansion port in the CD drive?

[hiro]

Thank you.
Although there are sound problems (sound quality is degraded), both games and music CDs can be played.
I have used other units and the music CDs continue to play even if I perform a reset in the same way.

Are you saying that the reset signal from the controller is not being received correctly?
Do you know which pins of the expansion bus the reset signal from the PC-ENGINE unit to the SUPERCDROM2 console is sent to where (IC?)?

[hiro]

After trying various things for a while.

When the RUN button is pressed to start the CD, a voltage change was observed on pins 3 and 4 of the (P3) where the CD drive's green connector is connected.
This voltage change seems to start the CD drive spinning.

I perform a reset operation with the controller on another normal unit, the voltage returns to the voltage before the CD drive starts to rotate. This causes the CD to stop rotating.
However, on my unit with the problem, there is no change in voltage on reset and the CD continues to rotate.

（I followed the trace (P3) and reached the BA chip and the 4558 op-amp in IC107, so I tried replacing both of them, but the CD still does not stop.

It seems that the reset signal from the controller is recognised somewhere, which controls the voltage of the BA chip and op-amps, but I have no idea where that is. Does anyone have any ideas?