Yamaha DX & TX Forum • Re: Yamaha DX7 problem "r8" on the seven segment

The battery voltage is 3.10v. I think the clock signal is missing (my logic probe will arive tomorrow). Would you advise which pins should i check for the clock signal please.

Ok - the battery voltage is fine.

Re the clock signals - see red circles in pic: (please refer to the complete schematic).
Clocks 1.gif
The best schematic on the web can be found here :
download/file.php?id=13360

Hi Miks,
Thanks for the reply.
As per the logic probe. IC5 pin 11 receives a pulse ( red and green leds on my LP1 logic probe.)

But output of the IC5 pin 9 seems undefined (red,green and yellow led.)

So i replaced the original ic (74LS74) with 74HC074. But the issue is same. I dont know whether the replced ic is not compatible, the replaced ic is already blown or the is in somewhere else.
Please help. Thank you.

Statistics: Posted by Janku97 — Sat May 11, 2024 11:00 am

---