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**Reel Slots** Gaming Machines => IGT S and S-plus Reel Games => Topic started by: RILaw on March 23, 2014, 08:50:50 AM

Title: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: RILaw on March 23, 2014, 08:50:50 AM

Picked up this S+ project recently, had a 65-3 code (After I replaced a bad CC and coin optic I'm at this stage).  Found one of the large diodes chilling on the bottom of the machine.  So I soldered it back in (D3) and still had a 65-3.... turn key, 65-1, press reset, 65-0 and smell of burning....D3 unsoldered itself again  :duh:   So I just looked closely at the cpu pcb to see if a quarter or anything was shorting anything...Nothing.  Checked wires etc.....  Soooo, any ideas??

Thanks

Title: Re: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: Crash0 on March 23, 2014, 09:19:54 AM

Is D3 anywhere near the transformer?  If so, may want to check output on it, see what kind of voltage it's putting to the board.

Title: Re: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: RILaw on March 23, 2014, 09:26:25 AM

Quote from: Crash0 on March 23, 2014, 09:19:54 AM

Is D3 anywhere near the transformer?  If so, may want to check output on it, see what kind of voltage it's putting to the board.

No, its the one big diode by itself near the top of the pcb, not one in that group of large diodes.

Title: Re: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: LINDAM on March 23, 2014, 09:37:18 AM

It sounds like your D3 is part of the power supply bridge and may be bad. have you check it to see if it's still a diode?

Title: Re: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: RILaw on March 23, 2014, 09:39:48 AM

Quote from: LINDAM on March 23, 2014, 09:37:18 AM

It sounds like your D3 is part of the power supply bridge and may be bad. have you check it to see if it's still a diode?

Sorry, yes, tests good on DMM.  Thanks

Title: Re: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: LINDAM on March 23, 2014, 09:45:08 AM

By looking at one of my S+ PCB's, it looks to be the regulator for the +5 Volt supply for the board. Should be a 1N6373.

Title: Re: Sooo, what would cause D3 to unsolder itself off the MPU?
Post by: Crash0 on March 23, 2014, 09:45:52 AM

maybe try testing transistors, they often regulate voltage
Lol what he said^