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About arkleyjoe

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    Space Invader

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  1. Hi, I wonder if anyone can help. I have a faulty Virtual Boy and it needs a replacement mirror servo board. Does anyone have one they could spare and would like to sell or maybe a faulty VB I can use for spares?
  2. Hi, I wonder if anyone can help. I have a faulty Virtual Boy and it needs a replacement mirror servo board. Does anyone have one they could spare and would like to sell or maybe a faulty VB I can use for spares?
  3. So some progress. I have removed and socketed the 74LS logic chips near the battery. I do not have replacements on hand, have ordered them today. However if I remove u13 the 74LS373 the halt line comes up and I see activity on the other lines. So my hope is that when I replace this it will be ok, or alternatively it will be a problem with the ram.
  4. I would like to buy a virtual boy servo board as I have a faulty one on which the mirrors do not sync. If anyone has one they could spare I'd like to buy it
  5. @Daedalus2097, I am pretty sure there is no brief period where it is high. I see nothing more than a tiny flicker on the line but more like low level interference rather than activity by design. here are the are some behaviours of the halt line in different scenarios. 1) gary / cpu in place = halt low. 2) gary out / cpu in = halt low. 3) gary out / cpu out = halt high. 4) gary in / cpu out = halt high. So I think this rules out a short on the halt line between Gary and CPU?? But both chips are known good. So as @Daedalus2097.suggested previously maybe the CPU is halting because it finds a fault elsewhere?
  6. Reference: try to boot with Gary removed and the Halt line stays constantly low, then the CPU is potentially the issue. If I boot with Gary removed the HALT stays low. However halt also stays low in my known good machine with Gary removed.
  7. Hey, I have since managed to remove the agnus and I have replaced the socket with a new better quality one.
  8. Hey, IIRC lol I have been scanning schematics for that This one is turning in to a real puzzle. So I did have some broken traces around that resistor pack near Gary and I have repaired and thoroughly tested again all of the traces right though to their final destination. Gary, CPU and ROM have been tested in a known good machine. I get close as damn it 4.7k ohms between halt and ground / 5v. That resistor pack did have a little corrosion around it but I suppose if I am getting 4.7k ohms on Halt it is functioning correctly? I have also reflowed the CPU socket just incase there is an issue there and still no joy
  9. Hi Daedalus2097, thank you very much for your help. Sorry for the slow reply. So in reply to your specific points: You don't even get a very short burst of bus activity, no?: No nothing at all that I can see. I would check the ROM socket, including the alignment (the ROM socket should have an empty row at the pin 1 end. : Rom socket and alignment it in seems fine. Tested the rom in another machine, all good. What is the halt line doing? My halt line is stuck low. Not even a twitch. Continuity is fine between Gary and the CPU on the halt line. What is the IIRC?? I am pretty sure if I can work out the cause of the low halt line it will point to my cause. Any tips on causes of that? My Diagrom does nothing but I guess that it is not even attempting to read that?
  10. Perfect I will get in touch thank you.
  11. Hi, I have a couple of faulty A500+ Rev 8A boards both with battery damage. One is a total mess the other had 2 /3 broken traces which I have fixed, but I need some advice as what to try next. What I have done so far: On both boards, I have tested and fixed any continuity issues, focussing on the usual area around Gary, Replaced Gary's socket. replaced the 74LS244 in U12 Swap tested all of the ICs with known good chips / board. Tested clocks / power. So this is the current state of play with each board. Board 1 (the lightly damaged board): I get black screen and the power light stays dim. There is a sync signal to the monitor albeit no pic. I have tested with a diagrom. No difference still black screen. I have scoped around and there does not seem to be any activity on the address lines. Reset lines on CPU / Gary seem to behave normally low for a moment and then stays high. I am not sure what to try next on board 1? Additionally, Agnus is welded in to its socket on this board. Later I plan to replace the socket with a better one but can not get it out. For now I plan to leave it alone unless it is likely / potentially part of the fault? Board 2 (the horrendous board that now has so many botch wires it looks like a breadboard project : This board amazingly is getting to a green screen which I know indicates a ram problem. I tried piggy backing the ram but this did not change anything. My question here is simply I am not sure if I should start desoldering the ram OR is it more likely to be the other 74 logic chips near the damage? Joe
  12. I had a similar problem with my screen and it turned out I had attached D0 and D1 to the wrong pins on the Lynx. They were both 1 pin off where they should have been. I would check the wires and pins are all correct.
  13. Hi I have just upgraded an old lynx 2 with a McWill LCD. That has worked out fine. However every time I reassemble the lynx a different selection of the buttons on the front are not working. I wonder if my ribbon cable is knackered. It is possible to get replacements? Or is there else going on maybe? Joe
  14. Hi, Please add me to your pre order list.
  15. Perfect thank you for your help.
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