View Full Version : Sega CDX laser calibration without opening the console
After a long wait I finally got my auction Sega CDX in the mail today. Seller described as half working, the Sega CD part did not load games. It was dusty so the first step was to give it a good cleaning. After my cleaning I powered it up for the first time using Van Halen's 1984 and some fresh AAs to see how it performed. I had a little bit of early success, the first track played wonderfully for 33 seconds! Very cool! I am still searching for a $10 or under AC adapter (thread pimping). I have an A/V cable and controller sitting around already along with some known good Sega CD games.
Anyhow, what got me started down this road was a YouTube video by a console repair hobbyist. On one of his videos, he bought a Sega CDX and mentioned how he lifted up the lip of the CD assembly and was able to calibrate the laser using a small screwdriver and a visible pot. This is my next step. Is there a tutorial online somewhere, or is this completely undocumented?
I'll be using legitimate pressed CDs and game discs (no CDR media in my consoles).
Alright, after some tech work last night, I say this laser is a lost cause, toast, dead and buried. I'm going to order a replacement Sanyo 10 pin laser and see how it goes.
I also found that my knock off slim PS2 was outputting a healthy 9.32V, which is right around spec for this machine. Not sure if it will harm it, but it's at death's door already. If none of this works out, time to fork over the funds for one that is already working 100%....I hate doing that :(
raylydiard
09-05-2012, 01:56 PM
Guys please use 9.5v power pack
and as for the laser replacement take care on replacing that.
and good luck.
Tokimemofan
09-05-2012, 02:04 PM
My second one had a shorted spindle motor, check that before trying an expensive laser replacement, BTW the PS2 power supply will work.
APE992
09-05-2012, 02:28 PM
Taking apart a CDX is something not to be remotely taken lightly. These things are compact little guys and there are a bunch of parts easily broken or lost in the process.
As for calibrating the laser, twisting the POT is not proper "calibration" anymore than tightening spark plugs in your car's engine without a torque wrench is proper tightening. There are tools to aid the process of calibration and shortcuts typically lead to something dying. But don't take my word for it.
Thanks for the advice folks! I would like to do some tests on the output voltage once the CDX is under a load, in other words, playing a game. I think I will try this next time I have the bottom metal cover off. My guess is that it isn't drawing many amps, at a max 1.5 versus the 5.65 the PS2 brick is capable of providing. It's all pretty new to me, but that's why they make multimeters to test things like this. But anyhow, simple math says not under load it is outputing 98% of the volts of a stock unit. That seems to be within tolerance to me.
I am going into the laser replacement with a digital camera and the CDX faq, and a lot of time. It is very advanced disassembly. I am going to be drawing from my arcade tech work, certainly. I have all of the tools for it on hand and some good experience.
I think the $13 lens replacement is wise. The old laser seemed to be flooded with dust specs, hair, etc. I did all the cleaning I could, but it wasn't enough. I have done this type of operation before, on my TurboDuo. That seems like a cakewalk compared to what I am about to face with this unit. I figure the poor bugger was worth another $12 to try and get it refurbished properly before I banished it to a dusty box somewhere.
Tokimemofan
09-06-2012, 09:52 AM
Thanks for the advice folks! I would like to do some tests on the output voltage once the CDX is under a load, in other words, playing a game. I think I will try this next time I have the bottom metal cover off. My guess is that it isn't drawing many amps, at a max 1.5 versus the 5.65 the PS2 brick is capable of providing. It's all pretty new to me, but that's why they make multimeters to test things like this. But anyhow, simple math says not under load it is outputing 98% of the volts of a stock unit. That seems to be within tolerance to me.
I am going into the laser replacement with a digital camera and the CDX faq, and a lot of time. It is very advanced disassembly. I am going to be drawing from my arcade tech work, certainly. I have all of the tools for it on hand and some good experience.
I think the $13 lens replacement is wise. The old laser seemed to be flooded with dust specs, hair, etc. I did all the cleaning I could, but it wasn't enough. I have done this type of operation before, on my TurboDuo. That seems like a cakewalk compared to what I am about to face with this unit. I figure the poor bugger was worth another $12 to try and get it refurbished properly before I banished it to a dusty box somewhere.
Just be careful, there are to minor variants inside these things, some of them have a pair of grounding wires between the controller ports. This is one of the hardest to open for a newbie. I consider myself to be an expert and the first one was a pain in the ass.
I got my replacement laser in the mail yesterday, the company must have sent it express. After about two hours of work, I had it in and the unit reassembled. There was one gotcha in the CDX faq. One was the connection to the power board, it slides away from the genesis board and not up, and I caught that before it got me into trouble. Everything else went okay. It really paid to take pictures of the laser assembly and rail before disassembly due to a tiny spring and the orientation of everything.
Sadly, after all this I am still stuck like all of the other CDX owners, at the "no disc" prompt. I can defeat the tray close mechanism and see the laser travel along the rail, and it attempts to focus on the start of the CD tracks, but that's it. I also found out how to properly turn the pot cog on the laser, and tried all possiblities. No luck. Welcome to my $85 smaller genesis :( Time to save for one that works 100% I guess. Lame-o.
Tokimemofan
09-08-2012, 05:41 PM
I got my replacement laser in the mail yesterday, the company must have sent it express. After about two hours of work, I had it in and the unit reassembled. There was one gotcha in the CDX faq. One was the connection to the power board, it slides away from the genesis board and not up, and I caught that before it got me into trouble. Everything else went okay. It really paid to take pictures of the laser assembly and rail before disassembly due to a tiny spring and the orientation of everything.
Sadly, after all this I am still stuck like all of the other CDX owners, at the "no disc" prompt. I can defeat the tray close mechanism and see the laser travel along the rail, and it attempts to focus on the start of the CD tracks, but that's it. I also found out how to properly turn the pot cog on the laser, and tried all possiblities. No luck. Welcome to my $85 smaller genesis :( Time to save for one that works 100% I guess. Lame-o.
Did you check the motor? I fixed one earlier this year that had a shorted coil, remove the motor from the unit and test it with a ohmmeter, there are 3 coils, rotate the spindle 1 full turn to test all 3 of them, if you get 0 or infinite resistance or the numbers don't are off by more than a point or 2 between coils replace the motor.
yep, no problem with the motor, it's fine. It's all in the laser calibration that I don't have the equipment to do. There are also a bunch of small pots on the Sega CD board that I could see once it was out. For all I know, Sega mated each laser with the unit, so even with a correct part it's not fixable without specialized equipment. This may be why no one repairs these beyond a simple cleaning. Right now it's desk art :( Time to look at auctions 24/7 again and get one working this time. Or find a really bad looking one that could use a new case. I saw a few of those before I bought this one.
Tokimemofan
09-09-2012, 08:43 PM
yep, no problem with the motor, it's fine. It's all in the laser calibration that I don't have the equipment to do. There are also a bunch of small pots on the Sega CD board that I could see once it was out. For all I know, Sega mated each laser with the unit, so even with a correct part it's not fixable without specialized equipment. This may be why no one repairs these beyond a simple cleaning. Right now it's desk art :( Time to look at auctions 24/7 again and get one working this time. Or find a really bad looking one that could use a new case. I saw a few of those before I bought this one.
My unit works, want me to take some readings on each of them? I was able to re adjust a Turbografx CD from scratch so I do have experience with this.
I got this oddball response from the seller when I asked if this worked or not for other CDX owners. What the heck?
"However before you install the item there is an anti static solder ball on the item that you will have to remove before the item will work...It is a silver round ball usually near the connector. This item i am not sure where it is but it should be near the connector. If you are not familiar in this field. The help of an experienced technician is strongly advised."
My TurboDuo laser was a really easy install (drop in and go), but this is an odd bit of information. Clueless seller, or clueless me?
FABombjoy
09-10-2012, 11:54 AM
It's anti-static protection. It's real, and all SF-C93s have them.
Jeez, of course there was no mention of it on the box, on the site, or anything. Anyone have a picture of what to look for? Maybe I can get excited and this is my holdup?
FABombjoy
09-10-2012, 02:14 PM
You can see where it has been removed in this pic:
http://www.microlend.ru/original/SF-C93%206710.jpg
About 1cm to the right of the "N" in the serial number, where there is a cut in half silver circle.
Edit:
Here's a better pic: http://tectronelectronics.eu/images/detailed/6/SF-C93DETAILS.png
I know what I'll be doing tonight.
Quick poll: if I screwed up the unit by adjusting the pot too much, do you think the company owes me a replacement unit due to this not being documented anywhere? Or am I on the hook for another $13?
I'll bet money this is where everyone gets hung up when it comes to laser replacement on the CDX. I've seen post after post of "I've replaced it and nothing happens." ...and I never bet money on anything....
APE992
09-10-2012, 05:59 PM
I know what I'll be doing tonight.
Quick poll: if I screwed up the unit by adjusting the pot too much, do you think the company owes me a replacement unit due to this not being documented anywhere? Or am I on the hook for another $13?
"If I put diesel in the tank rather than regular unleaded 87 does the rental company have to cover the cost even though they didn't tell me not to put diesel in?"
If you screw it up you get to foot the bill. All new lasers will have such a solder blob and it is common knowledge amongst anyone who replaces these things.
Though I'd be willing to bet messing with the POT didn't do anything since the laser doesn't work unless that blob is removed.
FABombjoy
09-10-2012, 08:51 PM
I think people have problems because many "new" lasers are complete POS's. I have dozens and dozens of bad lasers, all bought as new. They move and have beam, but the CDX can't read discs. There is something different about some new SFC93 lasers, beyond the sensor pin count. I have piles of HOPM3 with the same results.
I stopped selling lasers because I couldn't find a reliable source. I spot test and certify new products, but I doubt that a laser distributor has the facilities to check all of their different lasers under such a wide variety of circumstances.. I'd be interested in finding a vendor that could provide them but my patience ran out after the last chargeback. Sanyo doesnt help much either with their 8 or 10 pin variants and no data sheets to speak of. There may have been more undocumented revisions along the line.
Alright! I am now very close and can get it to play tracks from an audio cd in small snipits. It gets into trouble when switching tracks and further into songs. Still, I feel I have the problem on the run!
EDIT: I got this calibrated as good as it will get with the laser pot. It is better than when I got it at auction with the new laser, but it still plays halfway through a song when one is accessed. Strangely it likes to go from sone 5->4 to properly start song 4 instead of 3->4. Odd. But I think this laser needs more power sent to it and it will read discs properly. I really started to have fun with this little project tonight. The calibration song for tonight was 'Hello I Love You' by the Doors.
Fixed. Working through some games.
segasonicfan
01-17-2013, 04:12 PM
ifkz, could you post some more info on this? I would love to know:
1) where you bought your laser (some ebay sellers are selling bad ones)
2) what was the resistance of the pot after adjusting
3) what specific behaviors should I look out for on my laser?
I spent a couple hours toying with my dying laser and a "new" SCF93 which turned out to be an 8 pin model I bought last year (doh). Took a while before I figured out I was wasting my time with it. One thing I did learn was that the POT is actually rhetostat, i.e. its only connected with 2 pins. So the best way Ive found for adjusting these (and it is amazingly less hair splitting) is to remove the POT, solder two wires to the points it was at, and solder a precision POT externally in its place. Then you can adjust it while its looking for the disc to see its behavior. Also hookup an ohm meter easily for real-time readings.
I have 2 old lasers (one from another broken CDX I have) and the 8 pin one. The dying (but working one) measured 675 ohms before making any adjustments. However, after adjusting a little and putting it back to that, it no longer works :( Im not sure what I did wrong or if these lasers are just terribly fragile. It just spins, stops, spins, stops, etc.
Anyway, if you could offer more detail on your successful fix it would be great :) I hope to make a video when my new laser comes in the mail to help people fix this great system.
-Segasonicfan
I sent you a PM on this.
Basically, I did post technical help for the CDX but found members were fixing their systems and then asking for places to download ISOs of the library to rip off games. I'm a hardcore purist, with 2/3rds of the original Sega CD library, I got majorly pissed and took the info down. Unintended consequences of trying to help the community.
Anyhow, back to your CDX, you should not have to adjust the pot from a new NOS 10 pin laser. You've seen the ebay seller that everyone uses (Danyalbi ...may be spelling that incorrectly), so I would buy one for $18 and you should be good. Once the pot on this laser is adjusted, it's a real big problem to get it right again. Took me months with several different condition CDs!
If the laser doesn't fix it, it is going to be something else. For one of my repaired units, it was careful, minute measured adjustments of a couple of the pots on the main topmost CD motherboard that got it working again.
One of my others had multiple problems: someone had gotten into it and royally screwed it up. The ribbon cable was disconnected from the topmost CD motherboard, they had lost the small spring that pushes the CD track into the toothed gear, the "new" laser had a broken off pot connection, the copper shielding had a rips along the solder tabs, a cap on the powerboard was bad. Now it's my main unit until I get nutty enough to buy another broken one.
Anyhoo, probably said too much here; I hope this helps the purists that actually collect and cherish the Sega CD hardware and retail pressed games.
One more tip. Be sure to clean the laser rod that it travels on and put some new white lithium grease on it. Some of my games would randomly crash on one of my repaired units, but has been perfect with the new grease. You can get it at any hardware store or ebay.
sonicfan
01-25-2013, 08:26 PM
Hello ifkz, I'm kind off in the same wagon. Do you happen to remember which cap you replaced for the fix? Any tips adjusting the board pots? thanks.
I only play original Sega cd games too. but apparently the previous owner abused the system with CDr's :roll:
Hello ifkz, I'm kind off in the same wagon. Do you happen to remember which cap you replaced for the fix? Any tips adjusting the board pots? thanks.
I only play original Sega cd games too. but apparently the previous owner abused the system with CDr's :roll:
Well, I can tell the cap was on the small power board, and was buldging and leaking, so I took it out. It was only something that would happen if a wrong power supply is used. My guess is someone had used an under-amped Genesis 2 adapter with it, but that's just a guess. If your powerboard caps look fine, they likely are fine.
Under most normal circumstances the main top board pots should NOT be adjusted. That particular unit was still having seek and track playing problems after a NOS laser and the board pots were a last gasp chance at getting it working again. Thankfully it worked.
segasonicfan
01-27-2013, 09:58 PM
Thanks for getting back to me and *wow* sounds like you really know your stuff! I'm currently doing some extensive CDX documenting right now, including researching the chipset, fixing all the video noise problems, and installing Tiidos crystal clear audio mod. As far as I know, no one else has traced out the audio signals to do it, so you might dig this if you love CDX like me:
http://nfggames.com/forum2/index.php?topic=3719.msg33023#msg33023
I'm much more active on that forum and sega-16 so I did not get your message until just now.
I sent you a PM on this.
...Once the pot on this laser is adjusted, it's a real big problem to get it right again. Took me months with several different condition CDs!...
This is what I would love to know more about. While I did order a new laser I still have 2 others. One was partially working (would skip sometimes) but after adjusting the pot on it, it no longer reads anything >_< The original measurement was 675ohms (its a rhetostat actually, not wired in as a real pot) and setting it at that value did nothing. Bringing it down to ~350ohms it will spin the disc and search but I never get a "01" track listing on the display. So it really isnt seeing much. I've fiddled with it for hours and nothing seems to work. How did using different CDs help you? What behaviors other than spinning did you look for? Would adjusting the pots on the CD board help at all ?
Thanks for the headsup on the greasing. I figured that would be wise when I was looking in there. And that darn spring! One of em flew off into the abyss of my room. Found a good replacement though.
I think you'll be interested in some of the mods I'm doing, I'll post back here when I get things finished up. Going to install a CXA2075 among other things too :)
-Segasonicfan
P. S. Legit CDs are always the way to go. I'm pretty sure burns damage the laser and all the dumps online have audio in MP3 format-- to hell with that!
My knowledge comes from more trial and error than anything, it sounds like you are well on your way to discovering repair techniques I don't know about!
You'll have to get that pot on the laser back in adjustment before you do anything else to it, I hope you haven't messed with the other top motherboard pots (T.Gain, T.OFF, etc). Basically, when I threw my laser pot out of adjustment, I had to re-assemble the bare circuit board sandwich back together (leaving that large sheet of main copper shielding off) and soldering all normally soldered connections back together. Basically running the unit completely de-cased on a non-conductive surface (my wood desk). After that, it was easy to get to the laser pot adjusted to where it would start to spin the disc and read audio tracks.
On another unit, I had to do the same de-cased madness only to find that a solder tab had broken off of the pot, rendering it useless. It would work with presure from my screw tip, but as soon as that went away, the connection was lost.
The other Sega CDs I used had varying levels of scratches that would react to anything but a perfectly dialed in laser pot. My copy of Shining Force CD will skip midway through the introduction audio unless the laser is perfect.
I have a stable of broken ones I've bought from ebay and fixed, and they have all needed new lasers. So far they've been at or near three figures when I'm done with repair and making complete, so I had to stop spending so much money on them.
I've become an active member on Sega-16, it is more in line with my collecting interests. Feel free to hit me up there, I just finished a post defending the Sega Cd with a best of list attached too. That and unearthing Genesis 3 compatibility restoration thread.
And good for you to collect the retail games. It's a hard road (there are a lot of damaged discs out there) but well worth it in the end IMHO. Heck, I have a few games with pinpricks of light that are placeholders; better than a CD-R anyday. And for some with these pinpricks, the Sega CD handles it and skips over the spot with no trouble (if it's in the audio track, for example). My copies of Panic! and Keio FS are like this and I still treasure them and their reproduction boxes. And games like Keio would cost hundreds to replace nowadays.
segasonicfan
01-29-2013, 02:57 AM
Thanks for the reply, I left you a message over at sega-16. Tried the Dalbani laser but it was a no-go. You ever bought one that didnt work from them? Or where do you buy your lasers from?
segasonicfan
02-19-2013, 02:54 PM
Fixed my system!
Thanks to the pictures & guide here:
http://www.briconsola.com/esp/cdxxesp.htm
and the service manuals for Mega CD 2 here:
http://www.sega-16.com/forum/showthread.php?23228-Sega-Service-manuals-16bit
I learned how to adjust the pots on the daughter board to allign the laser right. Interestingly, you shouldn't need to adjust the pot on the laser itself-- Sega made pots on the boards that (in theory) do the same thing. I haven't found the "eye pattern" point on a CDX yet but I will soon...Basically you can use an oscilliscope to get the pattern right while adjusting the "E/F, B" pot. and once you get it to boot you can fiddle with the tracking gain "T. Gain" pot.
I also took measurements of the correct pot positions if anyone is interested. Works great with the 2 Dalbani lasers I bought! Plays Silpheed flawless...which is the most demanding on the system of any game I think :)
-Segasonicfan
onetunafish
04-21-2013, 02:08 PM
Hey segasonic!
First congratulations on fixing the cdx, is no simple task! I have one I'm tring to fix but no luck thus far. No luck at all, even the new lasers I bought from liberty electronics were DOA. That was a few of months ago and and as I just saw your posts on the subject, perhaps there is some hope for me too.
Would you have the measurements for the motherboard pots? That would be amazing info for me, the one I bought came in all messed up and I have no idea how to try and adjust those. I also track down a couple of new lasers and try again, I'd love to see this unit working like it should.
ED!
Fixed my system!
Thanks to the pictures & guide here:
http://www.briconsola.com/esp/cdxxesp.htm
and the service manuals for Mega CD 2 here:
http://www.sega-16.com/forum/showthread.php?23228-Sega-Service-manuals-16bit
I learned how to adjust the pots on the daughter board to allign the laser right. Interestingly, you shouldn't need to adjust the pot on the laser itself-- Sega made pots on the boards that (in theory) do the same thing. I haven't found the "eye pattern" point on a CDX yet but I will soon...Basically you can use an oscilliscope to get the pattern right while adjusting the "E/F, B" pot. and once you get it to boot you can fiddle with the tracking gain "T. Gain" pot.
I also took measurements of the correct pot positions if anyone is interested. Works great with the 2 Dalbani lasers I bought! Plays Silpheed flawless...which is the most demanding on the system of any game I think :)
-Segasonicfan
dylbob42
06-14-2015, 09:06 AM
Fixed my system!
Thanks to the pictures & guide here:
http://www.briconsola.com/esp/cdxxesp.htm
and the service manuals for Mega CD 2 here:
http://www.sega-16.com/forum/showthread.php?23228-Sega-Service-manuals-16bit
I learned how to adjust the pots on the daughter board to allign the laser right. Interestingly, you shouldn't need to adjust the pot on the laser itself-- Sega made pots on the boards that (in theory) do the same thing. I haven't found the "eye pattern" point on a CDX yet but I will soon...Basically you can use an oscilloscope to get the pattern right while adjusting the "E/F, B" pot. and once you get it to boot you can fiddle with the tracking gain "T. Gain" pot.
I also took measurements of the correct pot positions if anyone is interested. Works great with the 2 Dalbani lasers I bought! Plays Silpheed flawless...which is the most demanding on the system of any game I think :)
-Segasonicfan
hi, thank the google i found you!
i just spent my weekend trying to calibrate a cdx to a new laser and it been hell. I tried using a multimeter reference but that didn't work, been doing it by hand ,trial and error. adjust the pot, put cd on, turn on, turn off, take the cd off, adjust pot, put cd on, turn on....over and over. Got it from not reading to playing but not being able to load the next level (golden axe on the classics cd) to being able to load the next level. last issues are that the soundtrack wont play consistently and when i upscale the component signal there seems to be interference between the blue and green.
so in frustration i have decided that its time i got a oscilloscope, can i please get the measurements of the correct pot positions off you? Also do you have and advice on what to look for in a hobbyists oscilloscope?
cheers! :D
dylbob42
06-18-2015, 07:26 AM
hi, thank the google i found you!
i just spent my weekend trying to calibrate a cdx to a new laser and it been hell. I tried using a multimeter reference but that didn't work, been doing it by hand ,trial and error. adjust the pot, put cd on, turn on, turn off, take the cd off, adjust pot, put cd on, turn on....over and over. Got it from not reading to playing but not being able to load the next level (golden axe on the classics cd) to being able to load the next level. last issues are that the soundtrack wont play consistently and when i upscale the component signal there seems to be interference between the blue and green.
so in frustration i have decided that its time i got a oscilloscope, can i please get the measurements of the correct pot positions off you? Also do you have and advice on what to look for in a hobbyists oscilloscope?
cheers! :D
btw ive got my heart set on a Rigol DS1054Z
paulera
04-06-2016, 03:41 PM
Fixed my system!
Thanks to the pictures & guide here:
http://www.briconsola.com/esp/cdxxesp.htm
and the service manuals for Mega CD 2 here:
http://www.sega-16.com/forum/showthread.php?23228-Sega-Service-manuals-16bit
I learned how to adjust the pots on the daughter board to allign the laser right. Interestingly, you shouldn't need to adjust the pot on the laser itself-- Sega made pots on the boards that (in theory) do the same thing. I haven't found the "eye pattern" point on a CDX yet but I will soon...Basically you can use an oscilliscope to get the pattern right while adjusting the "E/F, B" pot. and once you get it to boot you can fiddle with the tracking gain "T. Gain" pot.
I also took measurements of the correct pot positions if anyone is interested. Works great with the 2 Dalbani lasers I bought! Plays Silpheed flawless...which is the most demanding on the system of any game I think :)
-Segasonicfan
Hi folks.
First of all thanks for the info. It is so cool to mess with these old systems with all the info online thanks to people like yourselves.
Could you please share the measurements of the correct pot positions ? I am absolutely interested.
I just bought a Sega CDX and I tried burning some games at different speeds, with different writers and different CDs, but no matter what I try I couldn't succeed yet. I went so far as buying old Pioneer recordable CDs which some sites state to be the best there was, with no luck.
I have an Ecco the Dolphin official cd which loads just fine, it just skips some songs, so my guess is the laser is fine.
On my tests, most cds won't even turn, some of them do, the sega logo and music even stops, which seems it is about to load, but then it doesn't.
I'm getting this feeling I may get lucky just by adjusting the POTs, as was the case for my Game Cube.
Thank you.
paulera
04-06-2016, 03:51 PM
Fixed my system!
Basically you can use an oscilliscope to get the pattern right while adjusting the "E/F, B" pot. and once you get it to boot you can fiddle with the tracking gain "T. Gain" pot.
-Segasonicfan
This is golden info. Since my CDX is booting and playing stock games just fine, my guess, by reading this is that I should only try and change this T.Gain pot. I'll measure it as it is with a multimeter and then try messing with it. Hope that works.