Problem with astro city PSU

[kernelchagi]

Hello. I have this weird issue were i cannot get my jammatopi to work on my astro city.
The psu is measuring 5.25v exactly when i load it with a PGM pcb, but if i connect nothing, the voltage fluctuates somewhere between 4.4 and 4.8v.
If i connect a raspberry with the jamma to pi the 5v voltage fluctuates between 2v and 5.25v very fast and i dont know whats happening.
The psu is fully recap, i tried to change the potentiometer and the IC3 with same result.
The raspberry and the jamma to pi are working because they work perfect on my blast city.
And this same cabinet worked good before with the jamma to pi and the pi3.
The model of the psu is the 400-5198-01Y wich is known for having incompatibility with cv1000 games but i dont know why¿?

Any ideas? Probably the next i will do is check the transistors.

 

[kikaso]

The psu is measuring 5.25v exactly when i load it with a PGM pcb

That’s way too high. You can damage ICs with any voltage above 5.1v.

Is IC3 the 5v line voltage regulator?

 

[kernelchagi]

That’s way too high. You can damage ICs with any voltage above 5.1v.

Is IC3 the 5v line voltage regulator?

I dont have the schematics but the ic3 is a voltage regulator that is connected to the potentiometer.

 

[nem]

The model of the psu is the 400-5198-01Y wich is known for having incompatibility with cv1000 games but i dont know why¿?

Because like your Jamma to Pi, the CV1000 doesn't draw enough power for the PSU to function reliably.

 

[JohnRambo'sKnife]

Would a resistor on a switch help here?

 

[nem]

Easiest would be to just throw some cement resistors on the pi jamma hat. Problem solved.

 

[Enskynet]

yep. You can put a high resistance directly on the 5V line of he PSU
A friend soldered a car lamp on his PSU and it worked with Cave and Pi carts then

 

[JohnRambo'sKnife]

Would a 5V LED also work the same here?

 

[nem]

No, because LEDs draw very little power.

 

[nogoodnames222]

New to this forum and happy to see someone else ran into the exact same issue I'm having on my new-to-me NAC. Same power supply (400-5198-01y), fresh recap, adjusted to 5.05V and functions perfect with a PGM plugged in. Trying to run a JAMMAizer w/ a Sega Saturn.

Is there a non-intrusive solution here, or a picture/diagram showing how I can wire up some load? I'll most likely run dedicated PCBs in the future so I don't want to solder a resistor to the board if it causes issues down the line, but I may just be misunderstanding what you guys were suggesting.

Thanks for any help!

 

[kernelchagi]

New to this forum and happy to see someone else ran into the exact same issue I'm having on my new-to-me NAC. Same power supply (400-5198-01y), fresh recap, adjusted to 5.05V and functions perfect with a PGM plugged in. Trying to run a JAMMAizer w/ a Sega Saturn.

Is there a non-intrusive solution here, or a picture/diagram showing how I can wire up some load? I'll most likely run dedicated PCBs in the future so I don't want to solder a resistor to the board if it causes issues down the line, but I may just be misunderstanding what you guys were suggesting.

Thanks for any help!

Hello. I solved the issue powering up my sound amp from the jamma harness. I bought a male-female jamma and soldered a wire to power the amp from there. You can also solder a resistor or an hallogen bulb (they work with 12v) there and it will work the same but it will heat it up a little.