Hi everyone,

I’m working on restoring a vintage Yonezawa Wild Champs (also known as Wave Hunter) from the 80s and could use some advice.

the problems is:
the front wheel turn right and left when i activate the remote => this is ok
but when i activate the remote to go foward / backward this does not work, sometimes the wheel start to roll with no reason briefly when i dont touch the remote,
so i thought it was a transistor problem i replaced them (see below) but it's still the same

What I’ve already replaced:

• Q1 was a C380 transistor, replaced with a C1815.
• Q2 and Q5 were 945P transistors, also replaced with C1815.
• Replaced the large capacitors (not sure of their original values, but they were visibly bulging).

Current status:

• The car powers on, but I’m still troubleshooting the motor and steering controls.
• I noticed that the white and blue wires seem to be connected to the rear motor (propulsion)

please find photo of the car

if you have any idea of what i could do next it would be very helpfull

best regards

this is the model :









remote inside

remote

main board of the car

main board of the car