Help repairing an old toy RC dump truck

[AnthonyC]

Hi,

I am hoping that someone will be able to give me some advice on what to try next in the restoration of an old RC dump truck (1980s vintage). I started this as a project to try and advance my electronics knowledge.
With both the remote and car powered up nothing works and unfortunately I do not have access to anything that would be able to measure the RF output.
Unfortunately the truck does not have any indicator lights to show it has powered up ok.
I have probed the circuit as best I can and it seems to be getting power to the chip, but as mentioned above I have no way of measuring the RF output.
I have checked the motors and they are all working (steering, tip mechanism and wheel drive).
I have cleaned up the battery compartment, desoldered and resoldered, as it was a bit crusty from holding some old batteries.
I have replaced all of the electrolytic capacitors, though they all tested fine out of circuit.
The main chip is a TA7557P.
Let me know of any other info you need.
What would people suggest is the next best step?
Maybe this is the excuse I need to purchase a scope 
Thanks in advance for any assistance.

[ledtester]

Do you know what frequency the car operates at? It'll either be 27 Mhz or 49 Mhz.

One option is to find another known good controller that operates on the same frequency to troubleshoot your car. Check with your local hobby store to see if they can help you out.

Another is to order a new controller and receiver board -- e.g., like:

https://www.aliexpress.com/item/33009973632.html

Yet a third option would be to convert the vehicle to use bluetooth and control it from your phone or computer. This will give you a much more robust and reliable communications channel .

This kind of conversion has become a very popular diy project, and there are many examples of how to do this on the web -- i.e. search for "convert rc car bluetooth". And there are car control apps available for both Android and IOS, e.g.:

https://play.google.com/store/apps/details?id=braulio.calle.bluetoothRCcontroller&hl=en_US

[AnthonyC]

Ah, great ideas! It is 27 Mhz. I will see if I can find a controller that I can test with.
Very tempted by the bluetooth option though! I think I will give that a go.
Thanks for your help, it may be a few weeks, but I will let you know how it goes.

[AnthonyC]

Tried with another controller and no luck.
I went with the new controller and receiver board and it works perfectly!
My three year old is now having loads of fun shnew toy!
Thanks for the tips!