Dragon's Lair Fans - Arcade Lifestyle

General Chat => Technical Area => Topic started by: level42 on December 20, 2013, 06:18:29 PM

Title: Asteroids PCB....overload on the +5V, where to start looking ?
Post by: level42 on December 20, 2013, 06:18:29 PM

When I connect my (once fully working) Asteroids PCB to an AR-II and power it up, the +5V LED only lights up very dimly on the PCB. The +5V is drawn down to only about 2,3 V and R5 on the AR-II starts to overheat very quickly (so I disconnect it quickly).

I have a feeling there is a short somewhere, but about each and every chip is connected to the +5V....where the heck so I start ??

This is a sense modded AR-II, yes I'm normally against it but this is my test-unit.

Title: Re: Asteroids PCB....overload on the +5V, where to start looking ?
Post by: Capt. Kirk on December 20, 2013, 07:28:26 PM

Hi André, have you checked/replaced the 2N3055 Transistor on your ARII-Board?
The Voltage-Drop under Load suspects that.

Title: Re: Asteroids PCB....overload on the +5V, where to start looking ?
Post by: level42 on December 21, 2013, 11:07:46 AM

AWESOME tip Dirk, why didn't I think of that !

I tried another AR-II and it's fine so you're probably correct !! :)

I already thought it was strange because there wasn't any problem in the section that is powered by the regular +5V before (there is on the other powered sections (D/A stuff).

But at least now I can work from here, thanks ! :)

Title: Re: Asteroids PCB....overload on the +5V, where to start looking ?
Post by: level42 on December 21, 2013, 03:02:21 PM

Yup 2N3055 kaputt !

Replaced....now test :)