Purity Posted July 9, 2014 Share Posted July 9, 2014 Hi guys, I've been looking at a Konami Mikie and not got very far. This is what I have at the moment: Any thoughts on area to look in? Link to comment Share on other sites More sharing options...
Homepin Posted July 9, 2014 Share Posted July 9, 2014 Great to have a video but some of us can't see that.. how about you bother to describe the problem....... Link to comment Share on other sites More sharing options...
Purity Posted July 9, 2014 Author Share Posted July 9, 2014 I've always thought a picture tells a thousand words? How come you can't see it? The PCB shows weird lines that look to be constantly scrolling up and down. So looks like there's a sync problem (amongst probably other problems with the board). I can coin the game up and hear the sounds of the game playing Link to comment Share on other sites More sharing options...
Homepin Posted July 10, 2014 Share Posted July 10, 2014 How come you can't see it? Because I am in China and Youtube is blocked here along with Facebook, most of Google and numerous other sites. Sounds like possibly an earth to the monitor type of problem? Maybe try connecting the monitor earth (the one bundled with the RGBS) to the correct earth specifically for the monitor on the edge connector? - - - Updated - - - How come you can't see it? Because I am in China and Youtube is blocked here along with Facebook, most of Google and numerous other sites. Sounds like possibly an earth to the monitor type of problem? Maybe try connecting the monitor earth (the one bundled with the RGBS) to the correct earth specifically for the monitor on the edge connector? Link to comment Share on other sites More sharing options...
Purity Posted July 10, 2014 Author Share Posted July 10, 2014 Hi, this is a test setup so is fine with other Konami boards, using the same adaptor. The problem is with the PCB somewhere. I will try and put the video somewhere else where you can see it. Cheers! Link to comment Share on other sites More sharing options...
Womble Posted July 13, 2014 Share Posted July 13, 2014 Defo a PCB fault, as you can hear the game running and you can coin up and hear it playing it rules out a lot of the board, but you have a fault in the video generation section, almost certainly bad Fujitsu TTLs. Link to comment Share on other sites More sharing options...
Purity Posted July 14, 2014 Author Share Posted July 14, 2014 Any ideas which areas of the board I should look in please? Link to comment Share on other sites More sharing options...
immortal Posted July 14, 2014 Share Posted July 14, 2014 There is a board diagram available online for this PCB Link to comment Share on other sites More sharing options...
Purity Posted July 14, 2014 Author Share Posted July 14, 2014 There is a board diagram available online for this PCB Thanks I have the schematics. I've looked around the sync area with my logic probe - so the LS244 @ 13G, the LS241 @ H16, and LS273 @ F15. Not found anything yet. Any specific areas you think I should look at would be helpful - - - Updated - - - Link to comment Share on other sites More sharing options...
immortal Posted July 14, 2014 Share Posted July 14, 2014 can't use a logic probe for that sort of fault as might look ok on probe but signal is incorrect better off with a scope thats atleast 20mhz Link to comment Share on other sites More sharing options...
Purity Posted July 14, 2014 Author Share Posted July 14, 2014 I thought you may say that. Unfortunately I currently do not have a scope in my arsenal :-( Link to comment Share on other sites More sharing options...
immortal Posted July 14, 2014 Share Posted July 14, 2014 there would be no point going any further with it IMO as you would be just shot gunning it (randomly replacing parts) Link to comment Share on other sites More sharing options...
Purity Posted July 14, 2014 Author Share Posted July 14, 2014 Yeah, I'm not shot gunning. I'll look at getting hold of a scope. Thanks for the advice Link to comment Share on other sites More sharing options...
caius Posted July 14, 2014 Share Posted July 14, 2014 As I said on UKVAC forums I think your faulty is located in video timing circuit.Usually ICs involved in this part of circuit are counters 74LS161/163 so I'd check them for first. Link to comment Share on other sites More sharing options...
Womble Posted July 14, 2014 Share Posted July 14, 2014 What he said, you don't have a video sync issue. Link to comment Share on other sites More sharing options...
Purity Posted July 14, 2014 Author Share Posted July 14, 2014 Apologies caius, I've not updated the thread on UKVac. I did take your advice and look at the LS163/161's and did not notice any obvious issues. I will take another look Link to comment Share on other sites More sharing options...
caius Posted July 14, 2014 Share Posted July 14, 2014 No problem.How did you check the counters? Link to comment Share on other sites More sharing options...
Purity Posted August 12, 2014 Author Share Posted August 12, 2014 No problem.How did you check the counters? I'm trying to get to grips with a Logic analyser to check the counters. Not sure I'm having much luck understanding what's going on Link to comment Share on other sites More sharing options...
Womble Posted August 12, 2014 Share Posted August 12, 2014 You will struggle to check a counter with a logic probe, especially if its a Fujitsu chip and suffering from a lost input pin internally. The outputs can still be firing but they are firing in an incorrect pattern as the circuit inside the chip is only seem some of the inputs you can see on the external leg. Your only option for those is to use a logic comparator, desolder them and test them in a modern EPROM burner, or just replace them if they are Fujitsus. Link to comment Share on other sites More sharing options...
Purity Posted September 14, 2014 Author Share Posted September 14, 2014 Made some progress! Found two broken 74LS373's @ A8 and C6 on the gfx board and I now have this: Link to comment Share on other sites More sharing options...
immortal Posted September 15, 2014 Share Posted September 15, 2014 Looking good :) how many faulty ones have you found/replace so far i got one here off wombles spares pile i need to look at one day Link to comment Share on other sites More sharing options...
Purity Posted September 15, 2014 Author Share Posted September 15, 2014 Looking good :) how many faulty ones have you found/replace so far i got one here off wombles spares pile i need to look at one day I've replaced two 74LS373's Link to comment Share on other sites More sharing options...
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