Noritsu QSF 430L-3 relay board

[Balázsovics]

Hey, i have this 430 that i'm restoring, First time i powered it on everything gone fine untill the machine asked me to take it out of timer mode, i flipped the switch, lights flickered and a cloud of smoke, quickly i flipped main breaker and started investigating
Resistor R13 on relay board J303567-blank white square is burnt, it reads 76.2 ohms and i'm getting 7.45V and 22.10V from connector P18, i have no ida what original voltages or resistor values should be, i'm guessing i need 12V instead of 7.45 and 24V instead of 22.whatever

Any information is welcomed

[Balázsovics]

One more important thing i left out, on the operation/timer switch two legs were swapped, i sadly noticed that after it blew up, swapped back and now the machine boots, it beeps and when i hit keys it does something but the screen has some artifacting, nothing close to what it should show, that happens when voltages are not correct
I have the diagram if that helps, it does not say resistor values

[Balázsovics]

430L-3 Wiring Diagram.pdf

[Dave S]

Basically you put mains voltage on to the 5V line that is used to tell the CPU that the switch has been turned on to operation mode. You may have damaged the CPU board.

All the voltages are written on the circuit drawings.

Check the voltage tappings for the transformer TR1 are correct for your mains voltage supply.
On Plug J/P19 between Pins 11 & 12 you should have approximately 18V AC. Between pins 3 & 4 you should have 8V AC

On J/P18 Pin 1/5 +24V pin 6 GND and on Pin 2 +5V pin 6 GND.
If the +24V is low and the 18V AC input is correct maybe the capacitor C1 is tired.
If the +5V is too high probably the voltage regulator circuit is bad or there is no load on the circuit.

There is a separate 5V supply for the CPU PCB, check J/P1 Pin 1 +5V Pin 2 GND 

[Balázsovics]

Voltages are correct, 18 VAC is a bit high i think at 22 VAC but the 8 VAC is good, the problems start when i plug in the J2 connector into the cpu board, 22 VDC stays but 8 VDC drops to 1.4 at most.
P1 is getting the correct 5 VDC, but P3 is getting nothing at all
The two capacitors under P2 on CPU board are shorted, optocoupler PC24 also might be bad

[Balázsovics]

[Dave S]

I'd be suprised if that optocoupler isn't damaged! Hopefully it's done it's job and saved the rest of that board from damage.
The +5V supply coming from the 8V AC should be able to supply 2A, if it can't the 5V regulator or capacitors are probably bad. The +24V supply voltage isn't critical.