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Jomac

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Everything posted by Jomac

  1. I have a couple left atm and quite a few used spares for 25" tubes. Those tubes that @Autosteve has would be gold, Toshiba only made "A" tubes and I have only ever seen a couple of the ones Steve is talking about from AMF, the chassis they come out with as he mentioned were terrible things so most of the tubes left over were still like brand new.
  2. The firmware update disk has Version 4.01 , all the disks always come with the security chip , the same chip come with upgrade disks for Naomi, Chihiro and TriForce but as the Chip is locked there is no way to read it, the Zero Pic doesn't work.
  3. Try to re-initialize the pots, While holding the test switch push the service button which should bring up an initialize screen. When you start don't touch the bike or controls because initialize also centers the bike left /right pot , when you are in that new screen it will ask you to move the controls to find the pot lower and upper limits.
  4. A lot of people ask me this, It's used as an over voltage clamp, an add on we did here in Australia for any chassis that used the STR-S5741 after there were a stack of failures caused by the B+ going way to high. When C610 ( 10uf 160v ) and C609 ( 33uf 200v ) start to fail it causes the output frequency of the chopper circuit primary winding ( for the switch mode transformer ) to increase meaning the output voltage would increase proportionately and could go up as high as 180vdc. Pin 8 is an unused "ref" pin so we put a 120K resistor from here to the positive side of C610 Pin2 , this monitors the frequency and stops it exceeding 130vdc. Obviously when the caps are new there is no problem for a little while but this even changed as the operating temperature changed, so that one little resistor saved a huge amount of these being destroyed.
  5. Awesome work Trav, I know how much effort you have put into this for the benefit of many ! Not to forgot Shane either, always awesome! ( he definitely needs the default white background or he thinks the monitor is in standby 🙂 )
  6. I should have replied to this sooner, That is a TV tube not an arcade tube, Horizontal Yoke with this value 1.9 ohm & 1.118 mH is designed specifically for CGA ( 15.75Khz ) use, it can be used with certain chassis modification to operated on 25K EGA but it can't be used for VGA at all, if you try a VGA on this tube is will burn out the horizontal deflection circuit in most cases instantly. Thomson tubes like this are quite often mistaken for the Thomson tube used in arcade machines with Wells Gardner 27D9200 or 27D9400 chassis which are CGA, EGA, VGA and EVGA (15~38K ) . These tubes and chassis are failing or have already failed at an alarming rate, the D9200 was a disaster from the start, the D9400 Pure Flat screen version was a nice looking monitor when they were released but 9 out of 10 now are way past their design life and beyond repair.
  7. Some good points there Steve and valuable feedback. Shane gets to see what comes in everyday, all sorts of 5v power supplies with adjustments turned up to the maximum, plenty with broken pots because they couldn't be turned up any higher and then the resulting damage to boards. Not saying you or people in the know are going to over voltage things but trust me if there is an adjustment people can play with they will play it long before pulling out the multimeter. The original LM323K has always been a problem but so much worse now due to there being so many fake ones on eBay etc, just like the LM338K they are rebadged T03 packages with 7805 regulators soldered internally, Shane has some pictures of packages we opened up because they failed way under maximum current specs.( The LM338K rated at 5 amps all failed at maximum 2.4 amps ) We talked tonight about having an adjustment up to 5.2v but the most important thing is making this bullet proof so it's going to be tested in every way possible and work all day at quoted specs not just for short bursts at maximum claimed specs.
  8. Sorry mate I didn't notice you had responded to this, if your boards were repaired by me there will be a Jomac sticker on them with a serial number, we do that to keep track of what was done and who for because for some reason people often claim someone has sent something to us on their behalf when they never did at all. Not saying Norman would do this but from memory there were some boards that sat for months after being repaired. If it turns out these are the ones and you are still having problems I will take care of them under warranty for you.
  9. Now that is next level restoration, amazing mate you should be proud of that effort!
  10. Sega Rally doesn't have voice, the voice data is part of the music data EG: at the start or end of music. You can call in anytime if you want to test ROMs or need new ones for anything.
  11. There is a guy over there I know well and does a great job rick@niemandisplays.com , while he doesn't do everything we do he does specialise in monitor repair.
  12. I haven't seen any ManxTT boards for a couple of months, are you sure they were sent to Jomac ? @Andyj965 , He is talking about whoever he had look at the machine from how I read it. Yes this is totally off topic and should be posted in the technical section.
  13. They would be a nightmare to reverse engineer, I can understand why he doesn't make them anymore he would be lucky to sell one a year these days. There is no other compatible board, that's why he first made these.
  14. Locate PC101 , it looks like a resistor next to the only INTEL IC on the main board, measure across this and you should get 5.0v , I am assuming this machine is a twin, if so swap the main board to the other side and see if the fault follows the board, if it does you have a board fault, it the fault doesn't follow then it's a power supply issue. The power supply is the black unit in front of the main board, the images you have shown are only the Audio Mixer and Sub Amps, they are nothing to do with the power supply, the silicon is factory and put there by Sega to stop the caps vibrating out. It's amazing how many of these still have original untouched power supplies in them, the caps are rated to last between 8 to 10 years, the machine is 26 years old so if they are untouched the caps will have completely leaked all their contents and dried up into empty shells, The game needs very clean 5v DC , even with all the caps completely gone you will still read 5v but it will mostly be unfiltered AC passing through which damages the boards and of causes freezing or no boot. Yes they can be rebuilt and the boards can be repaired if they are not corroded.
  15. Just trying to work out if the tester can test ram with 4 legs, although I think Shane already has his own testing algorithm :) Have to mention that this tester actually tests RAM how it needs to be tested, I have a few Eprom programmers, a couple of expensive ones and 9 times out of 10 they show faulty RAM as good. With Shane's tester it's been incredibly accurate, with this I actually do know 100% if it tests good it is good. We have a pretty good collection of all types of different RAM that test good on other testers even when they clearly show all types of different issues , this tester fails them first time every time.
  16. The chassis is a Nanao / Kaga KZ-20EN , that chassis is normally matched with a Mitsubishi tube but as it's 12 pin and all arcade 12 pin tubes and chassis are interchangeable someone has ditched the old Philips chassis and fitted the much better Kaga. Definitely worth repairing good 12 pin chassis are pretty hard to find and as mentioned it will work on any 12pin arcade tube.
  17. Sounds like you have a chassis fault, give Stuart a call 0437 370 274 he will be able to call out to diagnose and carry out necessary repairs.
  18. Hi Charlie , Yeah I realised it was you that called. With the chassis now the fuse has been blown it often damages the B+ regulation , you can only really test with when connected to a working tube, with your multimeter set to DC Volts put the Black lead on the metal frame and the Red lead to either side of the 1amp fuse, it should be 110V DC , over 125v means damaged or below 90v . If damaged it's no problem to repair., the 4 amp fuse is the primary section of the chassis , the 1amp fuse is the regulated secondary section. The Dot in the middle of the screen mean that both coils in the yoke are open circuit , basically the same as not having the yoke connected ( never leave a monitor on for longer than it takes the dot to appear ) . That chassis will work on either 14 or 20" without any mods , when looking at tubes TV or Arcade in 12pin , simply measure the yoke , Horiz ( Red & Blue ) should be 2.2ohms , Vert ( the other two wires ) can be anywhere from 36 to 60 ohms , forget anything outside this because the chassis can't be modified reliably to suit. It's rare to find 12 pin TV tubes but when you do at least 80% of them were high impedance yokes like the Orion so totally usable , the other 20" 12pin TV's we old balls usually euro imports. If finding another 12 pin tube turns out to be to be to much trouble then you can start searching for a 10 pin type 19"~21" and in most cases I can sort out a chassis to suit.
  19. Sorry I meant to respond to that question, What most people are talking about with controls refers to a very common 26" Kortek that is really bad for this issue , it's not the issue with yours but it is caused by interference. That machine was originally made with a nanao MS7-20L monitor but as most failed a long time ago they have all been replaced with what was available, to stop this interference on the Nanao they had the input cable to the chassis wrapped around a ferrite bead, you see them all the time on computer monitor VGA cables except they are moulded into the cable, if you google "Snap On Ferrite Bead" that is what you need. You simply make a loop with the wires going into the chassis from the game ( about 150mm from the chassis ) and the ferrite bead snaps over where the loop meets, the will filter out the EMI the chassis is picking up. There are of course other things that can cause this issue but this is the most common and very easy to try.
  20. Definitely send it back if it hasn't long ago been repaired, it is still under warranty :)
  21. Hi Charlie, That sticker indicates I worked on that 21 years ago :) so just out of warranty Yep that yoke is history, the chassis should still be ok as long as the secondary 1amp fuse hasn't blown ( they rarely ever blow without other damage happening first ). Fortunately that chassis will work on any 12 pin arcade tube, they all have the same specs , most common was the Mitsubishi tube used for the Kaga KZ-20EN but the same tube was used for the very first Kaga Denshi monitors, Most monitors in that time here in Australia were 12 pin types , Orion , Kaga , AWA, Philips, Toei and a few other obscure no brand name tubes. , Orion were the only 12 pin tubes that had this yoke issue , the very same issue happens with another Korean made "Samsung" tube used with 10 pin Kortek chassis. Basically what you are looking for is a replacement 12 pin arcade tube because donor yoke and ring assembly to suit then setup isn't an easily achievable option on this particular tube. Just to add , Yokes for arcade tubes were never available as spare parts, all yokes that do become available have to come from broken tubes etc so with this being a very common issue for at least 20 years now there are at least 60 times more tubes sitting around without yokes than yokes sitting around waiting for people who need them.
  22. By far the most brutalized boards I see are pinball related but I certainly get a lot of chassis where some people aren't even capable of replacing a single cap without destroying the pads, unfortunately seeing how much damage some people are doing they are not discouraged and continue on until there is nothing left to wreck anymore. We see the results of failed attempted repairs daily it's a far bigger problem than most people could ever imagine, it's a problem growing at staggering rate due to so much internet advice. I have some customers that ask me to change an IC for them because they know their limitations, they don't have the correct tools, experience or confidence, but there are more people that get on youtube and after a 10 minute video decide it's easy, these pictures posted by Shane are a perfect example of the average results, some are far worse I have even had boards where the components have been cut off and the holes drilled out. The saddest part of most of these attempted repairs is that people remove or attempt to replace parts they have no idea whether they are faulty or not so a heap of un-necessary damage. I know a lot of people will look at the above pictures and think it's not to hard to run jumpers etc to where tracks are broken, to us that is a last resort option, we try wherever possible to return the damage back to as close to original as possible, running wires etc is not a repair it's patching over damage much like putting electrical tape around a broken hose. The mess on that pictured board would take several hours to restore to a reasonable level, it's painful and should never be necessary, it may not in any way be related to the fault the board still has before it was brutalized. Using Shanes mechanic analogy above,this would like taking your transmission apart by drilling the screws out, pulling some parts out and throwing it all in a box and handing it over to the machanic. Seriously if people drop in knowing exactly what a fault is wanting an IC or something removed properly, I would gladly let you use my tools or do it for you, we could have removed both those AMP's and the IC in less than five minutes with zero damage, we do this sort of thing countless times to help people out, even people not in this industry.
  23. Great post Shane, This is one of my pet hates ! Safewash is by far the best cleaner on the market, it's not toxic and doesn't leave behind any visible residue. Not only is what Shane has pointed out important I have to add that you should never clean boards for no reason, especially if want them repaired by someone else because washing removes a lot of very helpful signs of where to start looking, drink, liquid spillage or cap leakage while easy to wash off you can't see where it may have gone under components. I prefer getting boards, chassis etc in their raw form as they were removed from the cab. A huge amount of boards I have seen over the years have been destroyed by corrosion due to nothing other than them being washed incorrectly with the wrong products and or methods. What a majority of people that do this don't understand is the purpose of those thousands of tiny little holes ( called Via's ) are for all over the boards, by far these are the things that suffer the worst damage from washing. Shane has some great close up pics of these via's damaged by corrosion and hopefully can explain their purpose and why water causes them so many problems.
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