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Title: 3902 Board issues Post by: MrBellMan on August 08, 2009, 03:30:32 AM I have a 3902 board go belly up on me and I was wondering if someone might know what to look fir to fix the issue.
As soon as I put the board in the game and turn it on I get screen garbage (see picture). All of the LEDs on the front of the board are on and the red one blinks. I have tried different games, games with and without SIMMs, with and without the sound board, but it doesn't make a difference. It there a 3902 manual anywhere that has trouble shooting ideas? Thanks, Rob Title: Re: 3902 Board issues Post by: slotsteve on August 08, 2009, 10:28:50 AM leg out on chip or bent pin on plug or plugs on back of board
Title: Re: 3902 Board issues Post by: Flexpipe on August 08, 2009, 12:12:40 PM Could be bad EPROM, as well, have seen that before.
Title: Re: 3902 Board issues Post by: Slotmaster on August 08, 2009, 12:34:56 PM or a cut trace under the eprom socket (ends) due to a screw driver getting under the stocket instead of between.
Title: Re: 3902 Board issues Post by: MrBellMan on August 08, 2009, 01:39:41 PM Thanks for the ideas.
I went over the board this morning with a magnifying glass to see if I could find the "screw driver" scrape and found this (see picture)... I assume this is my issue. If not I have other issues now. There are two missing transistors I believe. The ones next to them are marked "T5D" and have what looks to be a "08" listed sideways. The print is so damn small I can barely read it. :186- Does anyone know if they make a full size replacement component for these micro ones? Thanks, Rob Title: Re: 3902 Board issues Post by: Slotmaster on August 08, 2009, 02:05:02 PM Thanks for the ideas. This was the reason I said cut trace or really something similar like a few chips knocked off. You had said you tried different software so that ruled out what it normally is when you see snow. This is aside from putting the GME1 and GM2 in the opposite socket, bent pin or a miss match. I went over the board this morning with a magnifying glass to see if I could find the "screw driver" scrape and found this (see picture)... I assume this is my issue. If not I have other issues now. There are two missing transistors I believe. The ones next to them are marked "T5D" and have what looks to be a "08" listed sideways. The print is so damn small I can barely read it. :186- Does anyone know if they make a full size replacement component for these micro ones? Thanks, Rob Title: Re: 3902 Board issues Post by: Tilt on August 08, 2009, 02:11:21 PM Thanks for the ideas. I went over the board this morning with a magnifying glass to see if I could find the "screw driver" scrape and found this (see picture)... I assume this is my issue. If not I have other issues now. There are two missing transistors I believe. The ones next to them are marked "T5D" and have what looks to be a "08" listed sideways. The print is so damn small I can barely read it. :186- Does anyone know if they make a full size replacement component for these micro ones? Thanks, Rob You're missing CR9 and CR15. Both are common 1N914 switching diodes. They are available as a full size component, but it will be difficult to mount/solder in. Your local rad shack should have them. Title: Re: 3902 Board issues Post by: MrBellMan on August 08, 2009, 02:28:47 PM 1N914 Switching Diodes. Sweet!
I will pick up some, install and report back with hopefully some good news! Wish me luck! :5- Rob Title: Re: 3902 Board issues Post by: Slotmaster on August 08, 2009, 03:19:44 PM Good luck and if RS has them I will be super shocked, I have found that most of their stores do not carry these anymore or similar items.
As noted it will not be easy to solder in but give it a shot. Title: Re: 3902 Board issues Post by: MrBellMan on August 08, 2009, 10:53:17 PM RS did have them. $2.79 for 50... :103- :103- :103- (anyone need some diodes?)
Anyways, I was able to get them soldered in place, but no change. Still snow and no boot. Thanks to everyone for there help. I guess I will just look for a replacement board. Rob Title: Re: 3902 Board issues Post by: CommTech on August 08, 2009, 11:55:59 PM RS did have them. $2.79 for 50... :103- :103- :103- (anyone need some diodes?) Anyways, I was able to get them soldered in place, but no change. Still snow and no boot. Thanks to everyone for there help. I guess I will just look for a replacement board. Rob How did you determine which direction to install them? Title: Re: 3902 Board issues Post by: MrBellMan on August 09, 2009, 12:00:02 AM I got a copy of the schematic.
Rob Title: Re: 3902 Board issues Post by: CaptainHappy on August 09, 2009, 04:44:15 AM RS did have them. $2.79 for 50... :103- :103- :103- (anyone need some diodes?) Rob,Anyways, I was able to get them soldered in place, but no change. Still snow and no boot. Thanks to everyone for there help. I guess I will just look for a replacement board. Rob It is hard to tell from the picture, but the trace (The small "wire" in the circuit board) may have been broken as well causing the problem to continue. Also I did spy some bare copper there as well which after soldering the new parts on may cause a short. Not sure to what level of board repair you are comfortable with? May be worth some more effort, but then again, maybe not. :103- CaptainHappy :95- |