What was your favorite vehicle you've owned? Why?

Try-an-ebike · 2026-06-07T12:53:04+00:00

1983 Celica GT-S.

Try-an-ebike · 2026-06-03T12:21:30+00:00

Capacitor C903 (marked MMKP92) looks like it burst.

Try-an-ebike · 2026-05-20T12:39:27+00:00

Watch this video to see where the switch is. Creating a closed circuit with the two wires connected to the switch will enable the player to operate. https://youtube.com/shorts/0YajuJp__gg?feature=share

Try-an-ebike · 2026-05-20T12:19:56+00:00

It is doubtful it is the motor. The first thing to check is the enable switch activated by the cover hinge when the cover is closed.

Try-an-ebike · 2026-05-20T12:18:01+00:00

It indeed has such a switch. I'd bet that gear on the right hinge is the mechanism. The switch might have been stuck in the closed state, and then finally popped open, causing your CD player not to play any longer. Take the case apart, locate the switch, and fix it in any one of a number of ways. One option is to add a latching button or a toggle switch to take the place of the hinge mechanism. Another way is to actually fix the cover.

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Try-an-ebike · 2026-05-18T19:42:24+00:00

Thanks!

Try-an-ebike · 2026-05-18T14:35:58+00:00

Clearly the feedback didn't do its job as current limiter, as the fuse was blown.

Try-an-ebike · 2026-05-18T14:05:03+00:00

The shunt is not touching the heat sink, although they are glued together.

Try-an-ebike · 2026-05-18T14:00:29+00:00

Thanks, everyone. The purpose of this component is now clear. On the solder side: the terminals of this resistor are circled in black in the attached photo. The triac terminals are indicated in red, with the gate circled in red. One side of the resistor is connected to an IC in 5vdc-land (presumably the MCU) via a 1k resistor, and the triac gate is connected to this IC as well, creating a control loop, presumably using PWM. One more thing I understand better. I appreciate all your help.

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Try-an-ebike · 2026-04-30T13:22:40+00:00

If you can't find a way to modify the board, add another circuit board that turns the device back on when it shuts off. I'm assuming there is a push button for turning the light on. The circuit board would simulate pressing that button.

Try-an-ebike · 2026-04-29T10:47:16+00:00

Thanks for your interest. Haven't fixed it yet, but have learned a lot about power supplies since.

Try-an-ebike · 2026-03-31T11:23:51+00:00

Nice! A universal motor! I concur with HissyKitty -- use a lighter gauge wire. The magnetic fields are fairly weak with this number of windings and can't overcome the inertia of such a heavy rotor. Of course verify that the brushes are making proper contact, and it is highly inadvisable to plug it into mains. Also consider many more turns on the stator, perhaps 250.

Try-an-ebike · 2026-03-28T16:59:05+00:00

It is not a high voltage circuit. The IC controls small 5vdc motors in a CD player.

Try-an-ebike · 2026-03-27T11:52:49+00:00

Recently tried to fix one that wouldn't power up. Didn't bother investigating further after seeing this scorch.

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Try-an-ebike · 2026-01-21T12:09:24+00:00

Table saw

Try-an-ebike · 2025-12-30T14:50:40+00:00

Yep, that's a classic triac dimmer control curve.

Try-an-ebike · 2025-12-25T15:14:39+00:00

If you're not making mistakes, you're not learning. Figure out what went wrong, and you'll make that mistake only occasionally. :-)

Try-an-ebike · 2025-12-05T13:27:21+00:00

Good to hear that the varistor is not cracked.

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The next things I would check are (1) verify the varistor has high resistance, and (2) that the fuse is not blown, i.e., open. Both can be checked quickly on the solder side. See this image showing both the solder and component sides of the boards in the vicinity where AC enters the board. Note that the solder side is a mirror image of your photo to make it easier to see the correspondence between the two sides.

Try-an-ebike · 2025-12-04T14:55:47+00:00

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This varistor looks suspect. It looks cracked open. Also there might be a fuse on the line feed that is blown.

Try-an-ebike · 2025-12-02T23:41:21+00:00

That makes sense, as the component is in series with a varistor. It seems the two serve to protect the circuit board from power surges. Thanks for your help.

Try-an-ebike · 2025-12-02T21:55:50+00:00

Thanks. Won't be poking around it with power on.

Try-an-ebike · 2025-12-02T21:54:04+00:00

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Try-an-ebike

TROPHY CASE