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Title: Qbert+5v is low Post by: qrulz on October 20, 2015, 01:23:07 pm I just rebuilt the power supply on my qbert and have low +5v. Even after cranking the potentiometer, I can't get more than 4.65v at the board. As a result I am having sound issues. What can I do to kick the voltage up to closer to 5?
Title: Re: Qbert+5v is low Post by: John's Arcade on October 20, 2015, 07:34:26 pm This is a tough one...
Does the 5V affect the audio? I though audio was like 18V? What are your input voltages? My Q*Bert was flipping out and it was my transformer. Did you replace the filter caps on the bottom? Just guessing here... Title: Re: Qbert+5v is low Post by: iankellogg on October 21, 2015, 07:28:31 am Have you tried measuring at the power supply? What is the voltage at the power supply when the board isn't connected? Have you checked that the pot even works? Measure from the middle terminal to one of the ends with your multimeter on Resistance, turn the pot back and forth. does the pot resistance change?
Audio issues are very common and probably not caused by low 5V in this case. 4.65V should be enough, but maybe a sensitive chip is not happy. Sound needs 30V and +/- 12V. Title: Re: Qbert+5v is low Post by: qrulz on October 21, 2015, 08:21:49 am I ended up cleaning the edge conector and was able to get it up to 4.9v. I will have to look deeper into the sound issue. Thanks
Title: Re: Qbert+5v is low Post by: John's Arcade on October 21, 2015, 09:21:20 am I ended up cleaning the edge conector and was able to get it up to 4.9v. I will have to look deeper into the sound issue. Thanks That makes total sense. Resistance at the edge connector. Good work! |