Defender Cabinet

[Gilrock]

I acquired my first real arcade machine tonight.  Operationally the only thing I need to fix is it doesn't save high scores.  He said he replaced the battery and that didn't fix it.

[Howard_Casto]

Looks good man!  Not a lot of damage to it... I dig it. 

[Jimbo]

Very nice!

Pffffff... finding anything over here in the UK anywhere near that quality is nigh on impossible    

[ark_ader]

I acquired my first real arcade machine tonight.  Operationally the only thing I need to fix is it doesn't save high scores.  He said he replaced the battery and that didn't fix it.

Bah! stick a pi in it.  Nobody will know and your high scores will stay on until you power it down. 

[Mike A]

Your journey to the dark side is almost complete. Nice cab. I love my Defender cab. I throw a quarter in and it kicks me in the balls. I throw another quarter in and it happens again.  You would think I would learn, but there is something about the game I really like.

[leapinlew]

Big Defender fan here! I've built two cabinets just for Defender.

I'm also in the "it kicks me in the balls" club.

[wp34]

Nice grab.  Looks to be in great shape too.  Everybody needs a Defender in their kitchen.   

[yotsuya]

Defender is one of those games that I wish I was a lot better at. Gamefixer from Texas, when he comes out to ZapCon, routinely puts over a million on the game like it’s nothing.

[jennifer]

That machine almost looks too nice for its age, nice score!...I would venture a guess at a bad cap on the board for that high score issue, a reputable service guy (like Eldorado) could probibally nail that down if your not comfortable tearing into that.

[opt2not]

Fantastic condition on that Defender!

When you power-up, does it go into the game after the test patterns, or to the setup menu? If it always goes to the set-up menu, you have a CMOS problem, which could contribute to the high score saving.

Also, is it running on the original Linear PSU?  Or a newer switcher?  I've read that switching PSU's have a different timing pattern that messes with the 5101 CMOS memory.

Is the board still on the 3x AA batteries?  If so, I would highly recommend converting it to the Lithium Battery upgrade.

There's also a NVRAM upgrade, eliminating the need for battery backup at all.  But I've been sceptical of these NVRAM replacements, as I have one similar on a Gyruss board, and it's power hungry so I had to either run the board at a higher voltage to get it to work, or tap a 5v line from the jamma edge and power the NVRAM before the 5v gets too much load.

Lets see some pictures of the boards, and PSU.

[Gilrock]

Thanks for the info.  Yeah it seems to be booting to the setup menu every time.

Here's a few pics inside.

[opt2not]

Yeah, sounds to me to be a CMOS static RAM failure. You're using the original Linear, so we can eliminate the switcher shenanigans.
But apparently the 5101 and 6114 CMOS's is a common failure point, from what I'm reading up on KLOV. Especially if the board suffered some battery damage in the past.

Go into the test mode, and see what the CMOS test says.

also, just for fun, replace those AA's there. I don't trust second-hand batteries...

[yotsuya]

I put the NVRAM in my Pole Position and jumpered it to 5 volts. Rock solid ever since.

[Gilrock]

I put in new batteries and the CMOS RAM check passes but it still boots to the settings.

[Gilrock]

I downloaded the manual and found the schematic for the CMOS circuit so I might poke around and check some voltages.

[Gilrock]

Ok I figured out that problem.  I pulled the board out and 2 of the batteries were not making contact to the clips.  At first I thought I could just sand the ends to clean it up but that didn't work.  Trying to put some solder on the ends didn't work.  So I hacked a 4 position battery pack I had into a 3 position and soldered it to the +/- terminals and now the scores are saving across power cycles.  So that's only temporary.  I'll either do the Lithium battery or NVRAM mod to fix it.

[Mike A]

Nice work.

[opt2not]

Ok I figured out that problem.  I pulled the board out and 2 of the batteries were not making contact to the clips.  At first I thought I could just sand the ends to clean it up but that didn't work.  Trying to put some solder on the ends didn't work.  So I hacked a 4 position battery pack I had into a 3 position and soldered it to the +/- terminals and now the scores are saving across power cycles.  So that's only temporary.  I'll either do the Lithium battery or NVRAM mod to fix it.

Good stuff! Love the easy fixes.

Yeah, if I were you I’d do a bit of reading on the battery upgrades on KLOV. some people say the lithium upgrade on defender boards isn’t great because the battery gets drained quicker. I haven’t noticed this, though I’m not running any Defenders, just Robotron and Joust.

[Gilrock]

Well before I figured it out I already ordered the NVRAM cause it was only $18 so I figured get it if I need it later.

[yotsuya]

You won’t be sorry with the NVRAM

[Gilrock]

I feel like the monitor on this thing could look a lot better.  It seems to have a red tint across the whole screen but if I turn down the red drive it just seems to lose too much red for everything else.  I also noticed the radar area at the top there seems to be a some red offset from the blue lines like red and blue are not aligned.  Anything green seems to be sharper.  I see in the manual there are alignments but I haven't been brave enough to mess with that yet.  I'd hate to break a monitor that's running.

I also can't figure out how to adjust horizontal size.  This monitor doesn't have what I'd call normal control knobs like the other one I bought.  From the diagram on the monitor it appears they are pointing at something that looks like an inductor coil but I don't see how it can be tuned.  I read for a similar monitor that its supposed to be a hex nut adjustment.  I tried a hex socket but didn't get anything to change so I either had the wrong size or didn't really know what to do.  I was being delicate cause I didn't want to snap something off.  Here's some photos of the monitor and I marked where I believe its saying the horizontal size adjustment is located.

[Zeosstud]

Great Find.. You know, if you wish to punish yourself for all of eternity.. Defender is hard, but it sure is fun.. :-)

[Gilrock]

Great Find.. You know, if you wish to punish yourself for all of eternity.. Defender is hard, but it sure is fun.. :-)

Yeah I was hoping to get a lot better having the machine but its going slow.  I can't believe how quick a wave can spiral out of control.  Usually the first wave is easy with no drama.  Yesterday I don't know what happened but I delayed a little trying to save one guy and next thing you start hearing that sound of someone being picked up and then hear it like 3 more times in 5 seconds and I'm killing half the people trying to save em.  Wave 1 ended and I had 1 person left and I was like are you freakin kidding me.

I've watched videos of good players and they make it look so easy.

[Mike A]

They should have just put one of those cartoon boxing gloves behind the coin door. When you hit start it should spring out of the door and punch you in the nuts.

[Drnick]

They should have just put one of those cartoon boxing gloves behind the coin door. When you hit start it should spring out of the door and punch you in the nuts.

Instantly made me think of this advert 

[Gilrock]

I removed the 5101 chip and soldered in a socket and inserted the NVRAM chip.  It seemed to be working without adding any +5v wires but after playing a while I noticed a couple characters switched to "?" so I guess its needs a +5v line.  The schematic in the manual I found is terrible to read.  I don't even really see the 5101 chip in the manual.  Guess I'll probe where the wires enter the board looking for 5v.  Seems like its usually a gray wire on the schematic.

[PL1]

I removed the 5101 chip and soldered in a socket and inserted the NVRAM chip.  It seemed to be working without adding any +5v wires but after playing a while I noticed a couple characters switched to "?" so I guess its needs a +5v line.  The schematic in the manual I found is terrible to read.  I don't even really see the 5101 chip in the manual.  Guess I'll probe where the wires enter the board looking for 5v.  Seems like its usually a gray wire on the schematic.

Here's a 5101 datasheet.

https://www.jameco.com/Jameco/Products/ProdDS/42198.pdf

Pinout on page 2 shows Vcc on pin 22.   


Scott

[Gilrock]

Haha...yeah I know where the power pin is located on the chip.  I was more interested in a good spot on the board to grab it from.

[Gilrock]

Ok I pulled the board and I see where the +5v power rail goes all over the board coming in from pin 7 on and edge connector.  Almost every chip's vcc pin rings a short to that pin except the CMOS.  I found the spot on the schematic where the CMOS is located.  Problem is it was right down the middle where they split the page.  The area circled on the right is where the batteries are shown and it looks to be diode-or'ed with +5v power.  So when running the chip is basically losing the 0.7 voltage drop across the diode so I imagine the chip is seeing ~4.3v.  So if I jumper +5v directly to pin 22 on the chip its short circuiting the diode.  Not sure if that's an issue or not since it sounds like what some of you have done.  Seems like a better solution would be for me to just remove D13 and install a jumper which would provide the +5v directly off the power rail.  Does that sound right?

[Gilrock]

Ok just to close the loop I did my plan and it works.  I removed both D13 and D14 and cut the lead from a resistor to use as a jumper in the D13 slot.  This gives +5v directly to pin 22 of the CMOS and removing D14 prevents a problem if someone down the line sticks batteries in the clips.