(Topic ID: 183913)

They're not kidding about NVRAM on WPC!


By goingincirclez

2 years ago



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  • 31 posts
  • 18 Pinsiders participating
  • Latest reply 2 years ago by goingincirclez
  • Topic is favorited by 6 Pinsiders

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    #1 2 years ago

    Over the hundreds of threads I've read here, are many passing references to NVRAM installs gone wrong, specifically on WPC: Too easy to screw up, too easy to ruin a board, don't attempt it unless you know what you're doing and even if you think you do, just send it off to be absolutely sure. Better yet just stick to batteries in the first place. This is a mod for the manliest men, not the wannabes.

    Well I'm a stubborn bastard, teaching myself by fire in this hobby (with great assistance from awesome folks here when needed). I've progressed from board repair with the metaphoric hair dryer and blowtorch, to better tools like a Hakko 808. Since then I've repaired several board issues with a great first-success rate, and more challenging items. On the NVRAM side I progressed from Sys6 to Sys9 and Sys11, successfully.

    So last night I approached Dr.Who for the NVRAM attempt... Ho. Lee. Zeushit. I am still shaking!

    WHY are those traces and thru-holes so stupidly fine and close together? WHY in seemingly this one and only case did Williams feel compelled to fuse a DIP chip against a board like that? WHY is that one location crammed between the ASIC and game ROM sockets to impede emergency/secondary topside access?

    The SRAMs on my other games fell out with a quick wave of the Hakko FR300, but that WPC SRAM was a fugging surgical nightmare. The chip legs fully plugged the thru-holes so the desolderer couldn't open them, even as the "pin" part of the leg was floating centered. Adding flux and new solder didn't help.

    Nippers couldn't get "behind" the legs or "under" the chip because the legs were bent flush against the chip, and the chip was fused against the board. So I had to snip them against those @^&^! hairline traces. Get one side of the chip free, then bend and break it off the other side (so much for salvage). Clip the remaining leg bits. Desolder the top side, be careful of those tiny pads!

    Which I checked 6 times, and all seemed well until I installed the new socket and pins toned together. AUGH are thru-hole traces completing the paths elsewhere? Gah, but they go under the ASIC and ROMS so I can't see to verify! Schematic shows shared address and data lines but... gah, at this point there's nothing to do but put the NVRAM in and...

    SUCCESS!

    So I could breathe and play and all was well even after turning the game off and on, so hooray, I graduated. But damn, I don't know if I want to do another one again for a long while.

    Are they all really that treacherous?

    #2 2 years ago

    i've done every one of my games that accepts NVRAM with no issues.
    If you don't have a desoldering gun, I wouldn't even bother trying.
    If this is your first time holding a soldering iron; back away!
    Send it to a professional.

    Or better yet. Keep your off-board batteries. They don't hurt anything.
    Maybe wait till you need to send off for another issue. Not one you create by messing up an NVram install.

    #3 2 years ago

    Yes...the idea that this is an easy task is BS. I pulled traces with my Hakko. If you're sure you want to do this then cut the chip off and remove the legs one by one. The only games that is plug and play for me was the Whitestar board set.

    #4 2 years ago

    Congrats!

    (But Borygard just threw out your application.)

    #5 2 years ago
    Quoted from Blackjacker:

    But Borygard just threw out your application.

    Ha! Yeah, I saw that post *this morning, after* I had my little battle last night. I knew better than to apply! But man, that would be an awesome opportunity and I love working with and learning from old-schoolers like that. I'm not so young anymore myself, but always willing to learn.

    Ah well, even if I've a way to go to be master-class, at least I was careful & conservative enough to not screw mine up, and get it working right on the first try. I'm sure it gets easier with practice and technique.

    #6 2 years ago

    Congratulations on taking a step back, admitting your (current) limitations and not damaging the board. You wouldn't believe the amount of boards I repair that have no failure other than someone got in over their head, wouldn't admit it, and trashed the board.

    #7 2 years ago
    Quoted from goingincirclez:

    AUGH are thru-hole traces completing the paths elsewhere? Gah, but they go under the ASIC and ROMS so I can't see to verify!

    This is where having a blank board or good pictures of a blank board can come in handy, and is essential for the work terryB is talking about

    CPU-ASIC (resized).jpg

    #8 2 years ago

    If you own an $8000 game, you should be able to send the board off for NVRAM.

    Here's one from a MB that just came in. Not much OEM solder to work with. It's a must to add solder to allow more even and complete heating before trying to suck it out. Here you can see that I've added solder to the first three pins. The rest of them will get more solder now.

    The pics below show the clean removal. No tell tale bits of copper through-hole stuck to the RAM legs.
    --
    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact/
    http://www.PinWiki.com - The new place for pinball repair info

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    #9 2 years ago
    Quoted from terryb:

    Congratulations on taking a step back, admitting your (current) limitations and not damaging the board. You wouldn't believe the amount of boards I repair that have no failure other than someone got in over their head, wouldn't admit it, and trashed the board.

    Yeah but if you are a real techie you have already been through the "school of pulled though holes and broken traces!" Its not if but when? One way to do this easier is to preheat the board but thats another learning lesson and so is an air rework station ! too much heat input or too hot an iron and/or for too long is usually always what wrecks things. After vacuum desoldering try pusing the chip side to side very hard, this will break the little solder left where a pin touched the through hole wall or doing the same with each pin on the solder side. This is only good if you were able to remove the majority of solder... SOOO many variables so many different sidtuations. Many times with hard to vacuum desolder I will use every method. The one thats safest is to remove the socket leaving pins or cut the chip from the pins and the vacuum desolder and if its still stuck then use and iron with tweezers and pull gently from front side until remaining solder melts. Alway be mindful working fast as possible with heat and try to focus tip on the pin and with little pressure on the pad. And lastly, some pcbs are just CRAP. no matter what you do the pads come off pulling the trace along with it.

    That being said a general preheat works best and if you have had practice an air rework station can get you there but then again older solder had higher melting points than surface mount.

    And for those that pull traces.... buy some thin 30 gauge wire wrap wire, strip and place end in padless traceless hole, bend over and run a repair run to the trace which you scrape off the shield from and use a fine soldering tool to attach! Then use and exacto to score the attached trace leaving the xacto on the scored trace while gently rocking the long end until it breaks off. Voila a beautiful trace repair Simple but magnifying lamps make it easier on my old eyes. Sometimes a stereo microscope is required. WIth a little practice you will be amazed how thin a trace you can repair this way.

    Every circuit board and who made it with what material is different, sometime through holes in pads (which are plated through) just pull out no matter what. You then need to make sure that if its also being used as a circuit through hole to run somewhere else that both sides of the pin are soldered to the pad, thats if its only a dual sided board!

    I always say One can't know everything, the only thing that matter is how fast you can fix the shit you just got yourself into!

    And lastly yes I agree this is not for the faint of heart, if in doubt leave it to a pro.

    #10 2 years ago
    Quoted from ChrisHibler:

    If you own an $8000 game, you should be able to send the board off for NVRAM.
    Here's one from a MB that just came in. Not much OEM solder to work with. It's a must to add solder to allow more even and complete heating before trying to suck it out. Here you can see that I've added solder to the first three pins. The rest of them will get more solder now.
    --
    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact/
    http://www.PinWiki.com - The new place for pinball repair info

    Chris, yes but you forgot that if you have a poorly designed board (which most are) where a large shield (ground) layer or power layer is a heatsink to pins that are bonded to it. In that case heat heat and more heat before vacuum desoldering, thats where I heat up that area with an air rework or a large iron on the area on the shield/ground/power. That makes sure all the solder from top to bottom is removed. and not just from the pin side.

    Another thing is if you are using a hakko or weller vaccum desolderer it just as important in not killing pads that the tip matches the pad size and hole diameter then using a circular motion with mostly sideways pressure to move the pin from side to side to remove the liquid solder.

    #11 2 years ago
    Quoted from ibjeepin:

    Chris, yes but you forgot that if you have a poorly designed board (which most are) where a large shield (ground) layer or power layer is a heatsink to pins that are bonded to it.

    That's a good point for some desoldering tasks, especially the older WMS 3-7 boards. It sometimes takes a LOT of heat to melt the solder when it's on a large copper trace.

    Fortunately, both WPC and WPC-95 MPU designs don't use large traces to the RAM locations, so this isn't an issue with the specific act of installing NVRAM.

    I remember the first 40-pin interconnect headers I desoldered....wow.
    --
    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact
    http://www.PinWiki.com - The Place to go for Pinball Repair Info

    #12 2 years ago
    Quoted from ChrisHibler:

    The pics below show the clean removal. No tell tale bits of copper through-hole stuck to the RAM legs.
    --

    Whoa... Having done some circuit board repair, and having dealt with the fine traces on the WPC boards...

    That last picture is almost pornographic.

    #13 2 years ago

    I use a Pace solder/desolder station. Makes short work of ic extractions. These system 80 daughter boards can be challenging without one.

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    #14 2 years ago

    Heh... more proof I'm an idiot: while doing more work last night I realized mixed up my Hakko model numbers... the desolderer is the FR300, not the 808. Oof! Woe be to anyone who tries this stuff with a basic iron (808)/ without at least a good desolderer (FR 300)! I amended my first post to clarify.

    Appreciate all the info, tips, stories, and pics. This is work I enjoy but it's definitely not for the weak willed. Always appreciate the knowledge that skilled folks are willing to share so generously!

    #15 2 years ago
    Quoted from yfz450:

    I use a Pace solder/desolder station. Makes short work of ic extractions. These system 80 daughter boards can be challenging without one.

    Nice work yfz450 ! Very clean removal.
    System 80 solder pads are pretty delicate after all these years.

    --
    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact/
    http://www.PinWiki.com - The new place for pinball repair info

    #16 2 years ago
    Quoted from goingincirclez:

    Heh... more proof I'm an idiot: while doing more work last night I realized mixed up my Hakko model numbers... the desolderer is the FR300, not the 808. Oof! Woe be to anyone who tries this stuff with a basic iron (808)/ without at least a good desolderer (FR 300)!

    Is the FR-300 really that much better than the 808? I might have to pony up for the FR-300 sometime. And then not jack the heating element tube up like I did on my 808 thinking it was like my Aoyue desoldering gun where the tip is welded to the tube

    Quoted from ChrisHibler:

    Nice work yfz450 ! Very clean removal.
    System 80 solder pads are pretty delicate after all these years.

    After seeing mostly horror pictures of those removals, it sure does win the award for the cleanest removal I've ever seen.

    #17 2 years ago

    Printed circuit board technology has come a very long way since these boards were designed and built.

    These 20+ year old boards have tracks that are very narrow and the through hole plating was, at best, adequate as long as you don't disturb them.

    Add to that the somewhat random design relating to hole sizes for components and you are left with very delicate PCBs .

    These really should only be worked on by experienced techs with the correct tools.

    If you want to practice soldering please do it on a junked stereo or something like that not a (comparatively) rare game board.

    -1
    #18 2 years ago
    Quoted from acebathound:

    Is the FR-300 really that much better than the 808?

    No.

    #19 2 years ago
    Quoted from Homepin:

    These really should only be worked on by experienced techs with the correct tools.

    Agreed! Here is my setup, IMO hard to beat the PACE MBT-250 solder/desolder station. Although, I do most soldering with the Metcal SP200. Using the right tip/temp for the various solder points is also critical.

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    #20 2 years ago
    Quoted from goingincirclez:

    Get one side of the chip free, then bend and break it off the other side (so much for salvage).

    Doing this can actually pull a through hole if there happens to be a cracked solder joint that's half holding a leg and it gets moved around. Just saying. Last big repair I did was replacing the ASIC socket on a WPC board, that was fun. I've never owned a desoldering gun at all, never used braid. Just me and my trusty almost-6-year-old soldapullt...

    #21 2 years ago
    Quoted from Frax:

    Doing this can actually pull a through hole if there happens to be a cracked solder joint that's half holding a leg and it gets moved around. Just saying.

    Yeah, I was fearful of exactly that. Which is why I nipped as much as I could of every leg all around the chip... I was simply unable to get the nippers to get complete full cuts on the ROM side of the chip - I guess maybe I need new ones. But they did cut enough to essentially score and create a weak relief point on the legs that was easily broken before any pad damage was done. Since the game runs afterward I'd say I got away with it... this time

    Oddly enough, that revealed the next weak link in that my 5V is only outputting 4.88 at the driver board, so I have more work in the future but nothing this bad.

    Man, doing an ASIC socket with a pult? You da boss! I did plenty of board work (including multiple 40-pin sockets) successfully with a bulb torch previously, but then that aggravation and time was enough to make me move on too. Even a good tool won't save you from lousy technique so I'd say you're better skilled than I... a tip o' the hat to you sir!

    #22 2 years ago
    Quoted from goingincirclez:

    Man, doing an ASIC socket with a pult? You da boss!

    Agreed. That would be torturous!
    --
    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact
    http://www.PinWiki.com - The Place to go for Pinball Repair Info

    #23 2 years ago
    Quoted from ChrisHibler:

    Man, doing an ASIC socket with a pult? You da boss!

    hmmm....I'm confused are you saying that using a de-soldering station isn't the way to go when replacing the ASIC socket? Hot air station?

    https://pinside.com/pinball/forum/topic/wpc-89-cpu-repair-log-tz-cpu#post-1516678

    #24 2 years ago
    Quoted from scooter8416:

    hmmm....I'm confused are you saying that using a de-soldering station isn't the way to go when replacing the ASIC socket? Hot air station?
    https://pinside.com/pinball/forum/topic/wpc-89-cpu-repair-log-tz-cpu#post-1516678

    Oh no. Definitely not. A desoldering station is absolutely the way to go. I was referring to the chap who used a soldapult to suck the solder out of 84 pins of an asic. Now that, would be tedious.
    --
    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact/
    http://www.PinWiki.com - The new place for pinball repair info

    #25 2 years ago
    Quoted from Frax:

    Last big repair I did was replacing the ASIC socket on a WPC board, that was fun. I've never owned a desoldering gun at all, never used braid. Just me and my trusty almost-6-year-old soldapullt...

    opps....Sorry, totally missed that post. Yea that is just crazy, I wouldn't have even tired. Hats off to you frax

    #26 2 years ago

    When things do go wrong... this pinout guide will help you when testing for open or shorted traces, Note that not all of the upper address lines are common between the EPROM and RAM. I relabeled those as BANK signals on the RAM.

    Buzz out aid (resized).JPG

    Just check continuity between the pads on the bottom of the WPC board.

    Mac

    #27 2 years ago

    It really wasn't that bad. I dunno why people haterade on soldapullts so much LOL. If you don't have 300 bucks to drop on a desoldering tool, they're awesome, and mine's lasted through working on 40+ games. I call that a win. There's nothing about replacing an ASIC socket that ISN'T tedious, soldapullt or 808...either way it's still a bunch of holes.

    #28 2 years ago

    Yeah, Soldapult on an ASIC sockets isn't fun, but it's certainly doable. I still carry mine with me in my tool case, along with a Hakko. Both great tools for what they are, but Metcal is the bomb.

    --
    Rob Anthony
    Pinball Classics
    http://LockWhenLit.com
    Quality Board Work - In Home Service
    borygard at gmail dot com

    #29 2 years ago

    A few years ago I demonstrated a very primitive method with a 0,8mm needle, worked perfect without destroying anything (ignore the noises of my little children in the background )

    #30 2 years ago

    That's awesome Ingo. I've mostly put together a presentation to do at shows that uses a similar technique. It actually goes over two different methods. One with professional equipment, done "the right way", and one done with just a soldering iron. Both get the job done with no damage to the board.

    Of course one costs upwards of thousands of dollars in equipment and one, well...just needs a soldering iron.

    Just putting some final touches on it, and waiting for a show to want to add it to the schedule.

    --
    Rob Anthony
    Pinball Classics
    http://LockWhenLit.com
    Quality Board Work - In Home Service
    borygard at gmail dot com

    #31 2 years ago
    Quoted from Borygard:

    waiting for a show to want to add it to the schedule

    Curses, the Louisville Show was just a couple weeks ago! But that's not too far away by distance, so if you are generally free in the first weekend of March, you should reach out to the organizers (I can give you their info) as I'm sure they'd love to have you for 2018. I know myself and a couple others would be grateful for the chance to learn from a master on the spot!

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