neo geo cd toploader fixes and things

jetblue

Crossed Swords Squire
Joined
May 6, 2006
Posts
184
hi,had some adventures with the neo cd toploader and thought id share.

first is the power on but black screen fix i posted earlier in the year:
http://www.neo-geo.com/forums/showthread.php?240188-neo-geo-cd-black-screen&highlight=
found many more neo cd's with the same thing but different shorted L filter diodes or whatever they are called. i think there's five of them,L1,L2,L3,L4,L5 in various areas on the board and either one of them shorted will give black screen. so if you have black screen check with a meter any of those filter diodes with an L in front of them. volt or continuity,power will not go thru it when checking if its dead.

second is the annoying clicking sound that many neo cd's have. its caused by a switch wich stops the laser in center. they tarnish or get dirty not allowing the switch to activate so the laser keeps trying to go thru the board. no idea what these switches are called or where to buy usually getting a whole new mechanism solves this but im cheap. ( i think the mechanism is HPC-1L,30 bucks on ebay)
usually the clicking lets you play the game but on some the clicking stops it or makes mysterious resets making the neo cd unplayable. the fix is a bit complicated but cheaper than buying a whole new mechanism.

you need to desolder the 2 blobs holding the switch to the mechanism but be careful not to melt the plastic:
IMG_20130915_164114_zpsae3c063b.jpg
the plastic switch should just come off if not it has 2 tabs that you can untab with your finger
IMG_20131215_212751_zps695ea783.jpg
now thats its removed gently push the bottom part between the solder pins with something like a smalls screwdriver or toothpick and it will slide out from the top
IMG_20131215_213142_zpsa8f423bb.jpg
now that its released you can see how it works. just 2 strips of metal when pressed make contact
IMG_20130915_164151_zpsf8975f6c.jpg
here you can see a small square or triangle that is the part that makes contact. it is black with tarnish and dirt not allowing electricity to go thru. you need some sandpaper or a needle to scratch it clean till its shiny.
IMG_20130915_164237_zps857192b2.jpg
IMG_20130915_164216_zps47a319d6.jpg
now that its its clean slide it back in gently,if you bent it a bit scraping off the crud bend it back to its original way. the engineers who made this were kind enough to make a slide hole so use a toothpick as shown to lock it back in place. you will hear a click when its in all the way.
IMG_20131215_214136_zps4078d158.jpg

now that its all together put back on the mechanism and make sure to have the contacts completely surrounded by solder like before. it anchors it to the board more securely than the plastic tabs. if you only use a little solder the switch will wobble and wont work.
if it still clicks redo the scraping or if the switch wobbles make sure the center part of the switch with the 2 strips is in its plastic housing all the way till you hear the click.
done this fix many times and should last till another 20 years of tarnish and crud accumulates on it again

third fix is still in the works and maybe you can help. alot of neo cd pads loose the clicking sound of its d-pad switch and stop functioning all together. there is a metal concave thingy,i think the technical name for it is a tactile metal dome:
IMG_20131220_220243_zps92413988.jpg
here it is removed from the switch
IMG_20131204_175536_zps97ca8173.jpg
once it goes flat the switch is dead or extremely hard to activate.
ive ordered multiple switches similar to it and made prototypes:
IMG_20131220_220109_zps289148a7.jpg
prototype worked but the click to press ratio was off so i resorted to buying tactile switches and harvest the metal from them as a replacement. there are none that have the exact same size but i found one that's 75% the size and its working but takes a bit more force to activate making the rhythm off a bit. to make it flawless i would have to replace all of the concave metal if they are working or not with the new ones to get it in rhythm. i also harvested the concave metal from nintendo 3DS and they didn't work at first being too weak but messed with it again and seems to be working at almost the same pressure as an original. i will continue testing and let you know the results later on.

fourth is an oddity. the protection inner shell is a weird material almost like bakelite than plastic. also it has unused pegs that can hold its laser:
IMG_20131215_200057_zpse88a95ac.jpg
IMG_20131215_200036_zps85cd3007.jpg
IMG_20131215_200042_zpse4cc56ae.jpg
was it supposed to have been there originally? or perhaps an entirely different laser mechanism was meant for it cancelled due to costs but the mold was already made. that inner shell shouldn't even be there. such mystery.

i didn't mention pot tweaking for weak lasers as anyone can do this or region switch as there are plenty of tuts on it. here my simple region mod done with a radioshack slide switch:
IMG_20131001_140030_zps5683a900.jpg
http://img.photobucket.com/albums/v238/jetbue7/IMG_20131001_134321_zps31e982ca.jpg
http://img.photobucket.com/albums/v238/jetbue7/IMG_20131001_134253_zps0ab75a22.jpg
i lost my notes on pot readings but will provide later on. if you have a weak laser just tweak the pot on the laser not the motherboard pots unless you suspect they have been changed.
update,found notes. i used a multimeter set to ohms at 200k. use the black led on the top prong of the pots and use the red to check the other 2 prongs. i say top as they are like a triangle. to lean what ohms your pot is for replacement put both black and red leds on the 2 bottom prongs and the reading is the full measure of how many ohms it has max. the mainboard pots have initials next to them probably indicating what they are. one has FG so i think its focus gain,TG tracking gain etc. you will see them when you take it apart. these are the readings for 2 units i had:
unit 1 pots
vr101 44.0 39.0
vr102 05.7 09.2
vr103 16.9 17.6
vr104 01.9 000
vr105 00.9 000
laser 17.2 04.5
unit 2 pots:
vr101 42.0 36.9
vr102 08.3 10.6
vr103 17.0 17.2
vr104 01.3 000
vr105 01.0 000
laser 14.9 06.0
if games don't load or take a while tweak the laser pot only shown here:
IMG_20131221_175204_zps9f043e76.jpg
laser is a sharp H8147 i think,20 25 bucks on ebay.
the little blue pot. careful its fragile so use a small flat head screwdriver. you can take readings with it in the mechanism hooked up wont change the readings at all. same for taking pot readings from under the board where the 5 pots are.
http://img.photobucket.com/albums/v238/jetbue7/IMG_20131221_164350_zps919b4c5b.jpg
sometimes if the laser does read but has a hard time seeking and resetting after adjusting the laser ohm to like 20 or 25 then adjust the main board pots but as always remember what readings they were so if you have to you can set them back. usually i don't get to that point and just get a new laser.

forgot to ask,is there anyway to tell the difference between a USA and JP model? i found one where the owner has no idea where he got it. the metal jumper looks factory and semi clean but all the inside boards are stamped with this:
IMG_20131106_133007_zpsf3b532e1.jpg
IMG_20131106_133001_zps56e62dbb.jpg
same on the motherboard.
even the ribbons look different from all the JP units ive seen:
http://img.photobucket.com/albums/v238/jetbue7/IMG_20131221_164203_zps9d167122.jpg
http://img.photobucket.com/albums/v238/jetbue7/IMG_20131221_164306_zps765fe1c9.jpg
http://img.photobucket.com/albums/v238/jetbue7/IMG_20131221_165452_zps8bf61f17.jpg
its serial is JA0042124
if anyone has info on how to tell them apart proof positive that would be most helpful.

hopefully il get a cdz and a front loader and provide fixes for these.

that's it. if you can add to it or link other threads that have past fixes as i cant find them. hopefully this will help many keep there neo cd's running for many years to come.
 
Last edited:

Pope Sazae

Known Scammer, DO NOT DEAL WITH!, The Management.,
Joined
Dec 9, 2007
Posts
3,480
This is all great info. Thanks for sharing.
 

xsq

Thou Shalt Not, Question Rot.,
Joined
Jan 17, 2013
Posts
7,415
indeed. Maybe someone should make this one sticky.
 

Pope Sazae

Known Scammer, DO NOT DEAL WITH!, The Management.,
Joined
Dec 9, 2007
Posts
3,480
If someone could post up a clear picture of the laser pot for people to adjust that would also be very helpful since the questions comes up. My CD system is put up somewhere that I'm having trouble locating.

I agree with xsq, this would make a very good sticky since even though I love the NeoCD I fully admit it can be a touchy system at times.
 

NEO G-TRON

Marked Wolf
Joined
Mar 15, 2004
Posts
212
Great read on some quick fix it solutions for the Neo Geo CD. Very informative ...
 

DeusVult

Another Striker
Joined
Dec 18, 2013
Posts
319
I just opened my Japanese top loader to do the region mod and your bottom 3 pictures are the same as my system
 

dremcast

Timid Neo Newbie
Joined
Oct 19, 2013
Posts
2
Hi mi trying to check pictures of ur instruction to fix my neo geo cd but all of then said I don't have permission
Could u please help me on that ? Could u told me how u see the pictures here. Thank u a lot I will began toufic the Black screen tomorrow but I need the pictures to fix the click sound of the laser . Pleas could u also told me if the sound u said is this one http://youtu.be/SRPfFa8KH20 I record from my sistem thnank u
 

jets10

Timid Neo Newbie
Joined
Feb 3, 2014
Posts
8
Continuing our discussion from the Recent Purchases thread...

Pope - thanks for the info, I will try that then.

Chico - nope, I'm not getting any track numbers. When I first put a game in, it says 01, then goes to 00 when the disc stops spinning. I didn't think it was reading the cd anymore once the disc stopped spinning. Also, I'm sorry, but for some reason it's telling me access denied when I try to view your pic.
 

Kid Panda

The Chinese Kid
Joined
Jun 13, 2010
Posts
12,507
Continuing our discussion from the Recent Purchases thread...

Pope - thanks for the info, I will try that then.

Chico - nope, I'm not getting any track numbers. When I first put a game in, it says 01, then goes to 00 when the disc stops spinning. I didn't think it was reading the cd anymore once the disc stopped spinning. Also, I'm sorry, but for some reason it's telling me access denied when I try to view your pic.

Your account may not let you view attachments just yet, sorry bout that.


If your CD screen doesn't look like this, then I would think your laser might need some adjusting at the very least. Funnily enough in this very thread is the info you need for adjusting said pot. :D
 

jets10

Timid Neo Newbie
Joined
Feb 3, 2014
Posts
8
Yeah, it definitely doesn't look like that haha. Everything is just blank, except track of course which is 00. I've tried adjusting the blue pot attached to the laser. I've tried it from one end to the other, moving it slightly and then testing it and get nothing unfortunately. The only thing that happens is, when it's turned completely counter clockwise, even with a disc in, it won't detect it and will bring up the please insert cd message.
 

jets10

Timid Neo Newbie
Joined
Feb 3, 2014
Posts
8
So I tried hitting select at the cd player screen with and without a game in and nothing happened. What do you guys think, laser probably shot? If there's any more info you'd like me to provide or pics please let me know.
 

Pope Sazae

Known Scammer, DO NOT DEAL WITH!, The Management.,
Joined
Dec 9, 2007
Posts
3,480
You can try putting a replacement CD drive in the system to see if that helps.
 

Jibbajaba

Ralfredacc's Worst Nightmare
10 Year Member
Joined
Apr 30, 2009
Posts
5,612
My CD system just started doing the clicking routine. Followed OP's instructions and it fixed me right up. Thanks!
 

DemickXII

Timid Neo Newbie
Joined
Jan 29, 2013
Posts
1
Hi all. I own a JP version of a Neo Geo CD myself. Took mine apart to make an albeit messy language switch mod, which to my surprise actually took! :multi_co:

Why I am replying: I found out that one can actually get back to the "sweet spot" on a POT you previously altered on the CD's board. You will feel a tiny click when you turn the thing. Where it clicks is where the sweet spot, or the default setting, is. Found this out after days of frustration trying to get one of the POTs I moved around to go back to default settings that came with my unit. Using a tiny flathead helps out tremendously to feel said click, which is very minute but can still be felt if you pay attention. Almost like cracking a safe, except more obvious than that.

My personal preference: for me to get a damn multimeter so none of this bullshit guesswork is ever done again. :blow_top: Still, a pretty cool discovery nonetheless.

For the record, everything works like clockwork now.
 

Jibbajaba

Ralfredacc's Worst Nightmare
10 Year Member
Joined
Apr 30, 2009
Posts
5,612
That's interesting.

When I bought my Neo CD, the guy I bought it from had just replaced the laser, but any time he put a burned game in the system that it wouldn't read, his solution was to just mess with that pot (which you shouldn't really be doing.) So the first thing I wanted to do was to dial it back down. So what I did was turn the pot down pretty far, then try to play a music CD, which of course was skipping like crazy. So I just kept incrementally turning the pot and then trying to play the CD. As soon as the music played perfectly, I quit messing with the pot and put the system back together. I don't know if that's a kosher way to tune a laser pot, but I haven't had a problem since.
 

Jumpingmanjim

Cheng's Errand Boy
Joined
Dec 7, 2016
Posts
114
I just performed fix #2 on my Neo Geo CD yesterday and it has stopped clicking and games are loading properly now, thanks so much.
 
Top