Dragon's Lair Fans - Arcade Lifestyle
General Chat => Technical Area => Topic started by: joeks on September 07, 2015, 09:34:49 AM
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Guys, I am having a problem with my Robotron :(
Fired it up and now I get slow vertical blocky lines during boot and a short sound effect.
After that, nothing. Just black.
It actually started a couple days before with "Ram error 31" and sometimes other random numbers.
Had something like this before, back then I just reseated all the connectors and the error went away.
But this looks a little more serious.
Haven't really tried to find the cause, if it's not a connector thing I hope it the ram.
I still have the older 4146 ram chips. Time to upgrade to 4116's.
Does anyway here have a load of them? No time to order from the US considering I want to bring this to Eurocade next saterday!
As a backup, I can always bring my DK Jr.
EDIT. Found this http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=Williams-hardware.txt (http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=Williams-hardware.txt) online.
Will try tonight!
EDIT2. My screen kinda looks like a "rug pattern" screen...
The text below is what I found on the link above.
By far the most common failure of these machines is the DRAM (type 1
failure). This usually will produce a very organized "rug pattern" on
the screen and the game will not "boot". Sometimes you get really weird
video or else none at all. The solution is simple, get new DRAMs!
These are type 4116 (450 ns access) 16K x 1 Dynamic RAMs
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4116 Rams seems to fail very often.
i recommend a small hack for williams boards to use the 4164 rams - which seems to be much more stable
actually it is very simple hack. look here: http://www.robotron-2084.co.uk/techwilliams4164.html
afaik after changing to 4164 - future ram probs should be solved
(i already did that on my defender)
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Thanks for your reply Jochen!
Good to hear about the hack!
Now I need to find the ram chips and connector online.
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Uh, you have to go the other way around....there are now 4116s on the board (if it's original).
Checked my inventory list (man I am so organized these days ;)) and sadly have neither.....well not in sufficient quantity....send Robin a PM he may have some stock.
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if it is not a hurry, i could bring those rams to the eurocade...
i bought some 4164 NOS (>200 pieces i guess) - so i have a lot as spare
i made the hack without a connector by (afair) soldering pin 5 and 6 of the male connector (on the main pcb) together and removing the +12(pin 5) and -5v(pin 9) wire from the female connector
i am not 100% of this - i need to check it...
the 4164 could be plugged into the sockets without bending or wiring any pins.
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Uh, you have to go the other way around....there are now 4116s on the board (if it's original).
Oops, thanks :) wrote down the numbers wrong.
@Jochen,
The hack without using a connector seems an easy way of doing it. Will probably go that route.
If you could bring those rams to Eurocade, would be great.
Except for the fact that I wanted to bring my Robotron to Eurocade :)
I could bring my DK Jr instead of course, don't know if that's ok with the Eurocade crew.
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Yep that should work fine. It's a simple mod but some people prefer to use an adaptor connector like that so you can "go back to original". Whoever would want to go back to original RAMs that need three voltages and die by the bunch though ?
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Yep fine, we can always play Robotron on my Joust/Robotron cab, in fact....it's better as Robotron since the 2 player is still not hooked up on Joust...
I'd prefer to have the Jr. that really add a game :)
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Ok great! I'll bring DK Jr instead.
That way it gives me some time to fix Robotron.
So, please Jochen, if you could bring the 4146 ram chips to Eurocade I appreciate it very much :)
Paypal ready, or cash.
Here's a photo I found on my phone of the chips in my Robotron.
Weird thing, only the top one in the middle row says "4116"..
(https://farm6.staticflickr.com/5803/21221099921_89045dfbbf_b.jpg) (https://flic.kr/p/ykeFF8)Untitled (https://flic.kr/p/ykeFF8) by barrybuise (https://www.flickr.com/photos/35165513@N04/), on Flickr
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i will bring 4164(!) on friday
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i will bring 4164(!) on friday
Thanks! Are you there on saturday as well?
Our plan is to be there from saturday morning till late evening. So not friday evening.
Oh by the way Andre, I'll bring my brother John along if that's ok.
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i'll be there from friday evening 'til sunday morning
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Yes no problem as long as he also pays :) (kids of paying guests are free though). There's still plenty of room for more people, we are only at about 35 now.
The 9016's are compatible or equivalent to the 4116. different manufactures sometimes used different numbers for the same thing.
I bet that Texas one is the dead one ;) try to feel for heat ...
At least that one is the oldest seeing the date code of 1980.....
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Thanks for info on the 9016's. Looking forward to replacing them for proper 4116's though :)
Didn't have a chance to test yet, forgot we had a cinema-evening with work.
Will test tonight.
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It's definitely recommended to upgrade to 4164 RAMs, but I'd first try and exchange the possible faulty 31 RAM with one from another position, for example RAM 15. If the errors then says 15 you have a faulty RAM.
Usually the 131 error is not necessarily RAM-related (it's just the first one that gets tested) and could mean nearly everything. Hope you're lucky though. :)
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Hope I am lucky too :)
Will reseat all connectors and check for error codes on the LED tonight.
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Thanks for info on the 9016's. Looking forward to replacing them for proper 4116's though :)
Hellllooooooo, McFlyyyyyyyy.....
You need to replace the XX16s with 4164's....
But you MUST mod the board first, unless you like fireworks....
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Haha! I must be dyslectic or something :)
Must have been busy at work.
I will mod the connector first, thanks for the heads-up.
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;) :D
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Replaced the ram tonight.
So all new 4146's on board. Soldered pins 5 and 7 together of the male connector on the main board and removed wires 6 and 9 from the female connector. Had no materials laying around to build an adapter, and I didn't feel like cutting traces and soldering on the board itself. So this was the easiest method.
I had high expectations, but it still doesn't boot up :(
Same vertical scrolling blocks of garbage and error code 1-3-1.
Tried moved the ribbons cables around a bit, but made no difference.
Measured the voltages at the new 4146 ram.
Pin 8 = 4.85v
Pin 9 = 4.9v
All the other pins have about 1.5v or so.
At least no accidental 12v anywhere.
(https://farm1.staticflickr.com/684/23535148061_b618bc9059_b.jpg) (https://flic.kr/p/BRHMyR)Untitled (https://flic.kr/p/BRHMyR) by barrybuise (https://www.flickr.com/photos/35165513@N04/), on Flickr
Removed wires at pin 5 (+12v) and pin 9 (-5v).
(https://farm6.staticflickr.com/5656/22990488333_db85d3fc07_b.jpg) (https://flic.kr/p/B2AgcT)Untitled (https://flic.kr/p/B2AgcT) by barrybuise (https://www.flickr.com/photos/35165513@N04/), on Flickr
Here you can see I soldered pins 5 and 7 together to connect the 5v to both pins.
(https://farm1.staticflickr.com/695/22803176664_0f053f7e8f_b.jpg) (https://flic.kr/p/AK3eYm)Untitled (https://flic.kr/p/AK3eYm) by barrybuise (https://www.flickr.com/photos/35165513@N04/), on Flickr
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Do you have a spare ROM board you can swap to see whether the fault is with the ROM board or the CPU board?
If not, remove all ROMs except ROM 12, and just reseat ROM 12 (this is the self-test ROM) and see if you get the normal rug pattern. (You probably won't get the rug but at least it removes the ROMs from being the problem)
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Hi Phil, thanks for your help.
Don't have spare boards, wish I had.
By removing ROMs, you don't mean removing the 4146 ram on the main board do you?
Do you mean the larger eproms with the windows in them?
What do you think of the way I did the board's connector mod, should be ok?
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are the horizontal black lines there or a cause of the pic....
if there are permanet (not moving) there, it could be an adressing problem...
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Hi Jochen,
The black lines are there. These lines (black lines and garbage lines) scroll smoothly from top to bottom.
Like a slow vertical sync type scrolling. Tried making a video but the smooth scrolling wasn't that obvious then.
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By removing ROMs, you don't mean removing the 4146 ram on the main board do you?
Do you mean the larger eproms with the windows in them?
What do you think of the way I did the board's connector mod, should be ok?
Yes the EPROMs with the windows on the separate board, they should be labelled with numbers (if not, take the ROM board with the ribbon cable facing up, ROM 12 is top left, just next to the 74154)
Also if you disconnect the interface board and the sound board for now
The connector mod looks just fine
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I could test the pcbs if you want. At least you'd know where the problem is located.
BTW: Is pin 6 also bridged to +5v? It looks so on the picture.
BTW 2: Once I realized that 95% of the problems are caused by shitty plugs I changed all plugs (and I mean ALL of them). Never had any problems since. You can buy them at most pinball shops, costs are around 50 Euros for everything.
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Hi Wurstkopp, thanks for your input!
If you could test the pcb's, that would be really helpful too. Will keep that in mind.
Pin 6 is also bridged to +5v indeed. Only 5 and 7 needed to be connected but on the solder side of the pcb I could see pin 6 was also connected to them, afaik.
So I didn't see any problem with it, or am I wrong?
About the original connectors and pins, maybe it's time to replace them all indeed. Can't hurt.
I have read lots of posts about bad connectors on these Williams cabinets.
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Ah, didn't know that pin 6 is connected to +5v, should be no problem then.
Connectors: It takes some time, but it's worth it. One shoud also resolder all metal pins of the plugs on the pcbs and it's certainly not a bad idea to clean/sand them either, as they usually suffer from corrosion.
Feel free to send the pcbs (RAM and ROM board) to me anytime, I'd be happy to test them.
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Thanks for the offer Wurstkopp! The connectors and solder joints are probably the next thing to look into.
Will let you know.
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Please don't swap out the connectors yet. They're something to look at once you get the game working and for reliability, not just to get it working. You might cause more problems trying to do this.
If checking voltages, replacing RAM and trying the self-test ROM on its own don't get it booting then it's going to need a proper repair :(
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Will try your suggestion with the self-test rom chip first Phil.
Thanks, will let you know!