MK194 Digital Radio - Need circuit diagram please


I just assembled the radio but can´t get it running. Everything has been already checked: position, solder joints, voltage on each part.
It is extremely difficult to isolate the mistake without a circuit diagram…

It would be nice if you could provide this anyhow.

Thank you very much in advance and have a nice day,


I have just built this radio and thanks for pointing me in the direction of the circuit diagram. My question is although the radio seems to work, the operation of the digital switches confuses me.
Top one searches for stations fine
2nd one is supposted to increase volume, mine changes frequency similar to top one
switches 3, 4, 5 6, 7 seem to work as indicated.
Any ideas where to look for solution
Chris G0EYO (radio ham)

Most likely a soldering error.
Both switches are most likely paralleled due to solder joints which are touching each other.

Thanks Velleman
Can you tell me which switch on the circuit diagram relates to which function:
Vol up
Vol down
Preset 1
Preset 2
Preset 3
Preset 4

This would help me where to look on the pcb
Chris G0EYO

Top to bottom:


Sorted I had RA1 the wrong way round. Had not appreciated it had dot on end (should have read the instructions more carefully).
Thanks for the support. It is very good
Chris G0EYO

Happy to read that it works!

Hello every one .I am just constructing the mk194 digital radio on a bread board instead of the circuit pcb you get with the kit.I have had a look at the circuit diagram.thanks uploader for the circuit diagram couldn’t get it anywhere not even .maplin didn’t even have it.any way to my point on the circuit diagram there’s an arrow pointing to GPIO2 does any one know what this is .thanks for any help anyone can provide.

Yes, it goes to pin12 of the PIC microcontroller. Please check the diagram.

Thanks velleman don’t know how I missed that .thanks for your help

Dear velleman support,

Is it possible to reupload the schematics for the MK194 kit?

Hereby the link to the diagram:

Please allow 1h for server update.

The link doesn’t work over here…
What do you mean with allow 1h for server update?

That you will have to wait 1h before the link will work :slight_smile:

Ok thank you, sorry for the unnecessary post.

Hello again,

Is it possible to insert a new pic, or is it programmed?
If it is programmed is it possible to share the program inserted in the pic?

Sorry, for copyright reasons we never supply source code or .hex files.

Isn’t it possible to explain the way the pic works because i need to replace the pic with a Cpld (its for school).

Sorry, circuit descriptions are not available.
Basically, the PIC just sends serial data to the FM front-end.
Complete protocol can be found in the front-end manual.
Please allow 1h for server refresh.

Is it possible to get the tuner seperatly?
I live in Belgium