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Title: Super Off Road Track Pack Help. Post by: ArcadEd on March 04, 2011, 04:20:25 PM I have started a few threads at KLOV asking for help repairing my PCB. However, I tend to get side tracked and just start posting all kinds of information. What I would like to do in this thread is ask someone like RJ to simply walk me through trying to fix my PCB. I enjoy fixing PCBs and I am willing to spend some money on equipment if I need it. I have most of the equipment now.
I am going to start off by giving a little bit of detail on the PCB from CAESAR. cpu: 80186, 16MHz cpu: Z80, 6MHz cpu: Z80, 6MHz audio: AY-3-8910A, 1.666666MHz audio: AY-3-8910A, 1.666666MHz audio: Leland 80186 DAC I have Schematics via the Manual. Master CPU is Z80 at U99 Slave CPU is Z80 at U1 80186 Handles Audio I presume? The PCB is setup with a top and bottom board, with Ribbon cables going between the two. The actual Z80s are on the Top board. I have tried replacing ribbon cables. With that said, I am going to walk through RJs pcb repair tutorial 101 and 201 and report back my findings here, and nothing more. :) Thanks upfront to anyone willing to help. Title: Re: Super Off Road Track Pack Help. Post by: ArcadEd on March 04, 2011, 04:37:54 PM I have visually inspected the board and I don't see any missing parts, scratches, trace breaks, etc.
I pressed down on all ICs, no change on screen. Here is a picture of the screen currently. Power Supply reading on Power Supply is 5.55v On top board it's 5.16v (Recommened for this game is 5.20) Bottom Board is 4.96 I have removed the 12v from the PS because cranking the PS up to high to get a good voltage on the board makes the 12v in the 15v range. I am pretty sure the 12v is just for sound. Title: Re: Super Off Road Track Pack Help. Post by: ArcadEd on March 04, 2011, 04:50:36 PM Probing the Z80s CPUs.
Master CPU Halt - LOW Clock - LOW/HIGH Reset - HIGH Slave CPU Halt - HIGH Clock - LOW/HIGH Reset - LOW Same measurements on the bottom board where the CPU ribbon cables plug in. I will wait for instructions/advice now. I have my schematics showing me where the Master CPU PROM/RAM are located if that's next. Title: Re: Super Off Road Track Pack Help. Post by: jay on March 04, 2011, 05:47:51 PM I am certainly not RJ
Are you certain the problem is not with the monitor. Title: Re: Super Off Road Track Pack Help. Post by: ArcadEd on March 04, 2011, 05:57:15 PM Yes, monitor is fine. It's my test bench and I have another super off road board that boots up just fine with it.
Title: Re: Super Off Road Track Pack Help. Post by: ArcadEd on March 04, 2011, 06:45:59 PM I don't know if this is relevant at all, but thought I would share.
I replaced the 4 4464 RAMs on the bottom board and it changed my picture. I have my garage door open so there is more light coming in, but he pattern is completely different now. Title: Re: Super Off Road Track Pack Help. Post by: ArcadEd on March 05, 2011, 01:52:38 AM Well, to add complication I found out that the power supply on my test bench was wack. It was putting out almost 15v on the 12v line. I was trying to fix another off road board with just a sound problem and couldn't figure out why one of the sound ROMS kept getting corrupted.
So now I will recheck all roms on my board with a new power supply and see what's up. Title: Re: Super Off Road Track Pack Help. Post by: ArcadEd on March 05, 2011, 05:34:57 AM All Roms are good.
As far as I can tell, the master CPU is booting up and running. With my probe I can see the address and data lines sending data moving from nothing, to high and low. I assume now is to get the slave cpu up and running? That one shows RESET as LOW right now. |