Briefcase system cd-rom woe

Snow Crash · 05/13/2012, 05:37 PM

Hello again, it's been a while since I've been here. A while ago I got a defunct CD-ROM unit to repair and put in my pc-engine briefcase set up. After finding the gear had turned to something with the consistency of damp Parmesan, I managed to get some metal gears of Chop (Who is awesome) this however didn't solve the problem although the laser now moved a bit and the the machine made sounds of life, the disc didn't spin up. Thinking (perhaps wrongly) it was the laser, I replaced that with one I could confirm working from a disc-man ( exact same make model as far as i can tell) still nothing.

When connected to the pc engine the display shows PC on the CD-ROM unit and the laser moves a bit, but no disc spin up. Might this also be the spindle motor, or something else? Should i try adjusting the pots? What do the pots actually control? Can I break stuff by turning them? I'm pretty determined to get this thing working again but I don't want to make things worse if i can help it.

Any ideas on my next step would be appreciated.

Thanks.

Snow Crash · 05/17/2012, 02:49 PM

Maybe the caps maybe the motor?

kamiboy · 05/17/2012, 08:48 PM

So far as I've read in the various threads here the laser has to be placed a certain location for the disc to spin up. Try and find that bit of info, slide the laser in place and try again.

Keith Courage · 05/17/2012, 09:36 PM

Check to see if the lens is actually working. Open up the CD lid and hit the play button while using a screw driver to hold in the CD lid switch to make it think the lid is closed. Take a quick look at the lens to see if there is a red light. Don't look too long or you could damage your eyes. This would let you know if the lens is bad or not hooked up correctly.

Snow Crash · 05/18/2012, 01:36 PM

Quote from: Keith Courage on 05/17/2012, 09:36 PMCheck to see if the lens is actually working. Open up the CD lid and hit the play button while using a screw driver to hold in the CD lid switch to make it think the lid is closed. Take a quick look at the lens to see if there is a red light. Don't look too long or you could damage your eyes. This would let you know if the lens is bad or not hooked up correctly.

I can't believe i hadn't done this. Nope, it's not lighting, which is odd because i tested it before install.

turbokon · 05/18/2012, 05:17 PM

Double check the ribbon connection again.

Keith Courage · 05/19/2012, 01:00 AM

Sometimes it can be difficult to get the larger cable for the lens pushed in all the way. You have to get the right angle on it so you can push it in without bending it in the process. Both sets of ribbon cables should be installed with the contacts facing outwards away from the CD drive.

Snow Crash · 05/19/2012, 12:49 PM

Quote from: Keith Courage on 05/19/2012, 01:00 AMSometimes it can be difficult to get the larger cable for the lens pushed in all the way. You have to get the right angle on it so you can push it in without bending it in the process. Both sets of ribbon cables should be installed with the contacts facing outwards away from the CD drive.

Okay, i tried this and it worked! the large ribbon wasn't all the way in! But there was no sound. So then i checked the smaller ribbon and it was the wrong way round, but now nothing happens at all other than the red led display, the lens doesn't light or move.

Why does it toy with me like this!

Snow Crash · 05/20/2012, 12:35 PM

Pretty sure now, seems like the laser's fried. Bollocks.

Bernie · 05/20/2012, 12:36 PM

Quote from: snow Crash on 05/20/2012, 12:35 PMPretty sure now, seems like the laser's fried. Bollocks.

Well, you in luck. BlueBMW has got a ton of them bitches in!!

BlueBMW · 05/20/2012, 01:37 PM

Quote from: Bernie on 05/20/2012, 12:36 PMWell, you in luck. BlueBMW has got a ton of them bitches in!!

True that! About 80 of them to be exact... shoot me a PM if you need one Snow Crash

Snow Crash · 05/20/2012, 02:02 PM

Quote from: BlueBMW on 05/20/2012, 01:37 PM
Quote from: Bernie on 05/20/2012, 12:36 PMWell, you in luck. BlueBMW has got a ton of them bitches in!!
True that! About 80 of them to be exact... shoot me a PM if you need one Snow Crash

Cool, might need to do that, but before i do i need to figure out why this one blew. I've got an untested laser from a properly dead cd-rom unit that i might try first.

Keith Courage · 05/20/2012, 04:36 PM

Well, I just double checked the ribbon cables and I was mistaken before. The lager ribbon cable gets inserted with the contacts facing out away from the system. The smaller cable however goes in with the contacts facing inwards towards the system. Turn the smaller ribbon cable back around. As far as not having any sound goes I bet some of the capacitors have gone bad.

Snow Crash · 05/20/2012, 05:56 PM

Quote from: Keith Courage on 05/20/2012, 04:36 PMWell, I just double checked the ribbon cables and I was mistaken before. The lager ribbon cable gets inserted with the contacts facing out away from the system. The smaller cable however goes in with the contacts facing inwards towards the system. Turn the smaller ribbon cable back around. As far as not having any sound goes I bet some of the capacitors have gone bad.

Yeah, seems that having that smaller ribbon cable the wrong way round is pretty fatal to the laser unit.

Luckily my spare works! It now loads and plays cd-rom games! I didn't know that all the sound is output thru the adapter unit so i probably was getting sound before and didn't know it. ( if only i had...)

The only problem left now is the audio tracks skip like crazy, not sure what to adjust to fix that though, the disc is spotless.

Keith Courage · 05/20/2012, 10:59 PM

Turning that cable around shouldn't have broken it. Basically if it is backwards the contacts don't touch anything meaning no signal is going through it at all.

Keith Courage · 05/20/2012, 11:25 PM

It is is skipping then potentiometer adjustments might be in order.

BlueBMW · 05/21/2012, 12:48 AM

You did remove the solder blob on the new laser ribbon cable yes?

Snow Crash · 05/21/2012, 12:56 PM

Quote from: Keith Courage on 05/20/2012, 11:25 PMIt is is skipping then potentiometer adjustments might be in order.

I fiddled around with them a bit and made it much worse! I really don't know what i'm doing with them so i put them back as they were.

Quote from: BlueBMW on 05/21/2012, 12:48 AMYou did remove the solder blob on the new laser ribbon cable yes?

Wasn't one on there, these are salvaged lasers rather than new ones.

Snow Crash · 05/21/2012, 08:02 PM

Finally success!

I found this post in a forum which gave a hint as to what the potentiometers actually control: http://nfggames.com/forum2/index.php?topic=2890.0

I'll paste it here also:

POT = Function, Test Point
VR101 = E/F balance, pin 13 of U101
VR102 = Focus Offset, pin 18 of U101
VR103 = Track Gain(Track error level), pin 45 of U102
VR104 = Focus Gain, pin 48 of U102
VR105 = VCO, pin 30 of U102

Not sure exactly what all these mean to be honest, but it was enough to help me decide which pots to adjust and which to leave be.

I adjusted VR103 slightly until I got consistently good skip-free playback. I think VR103 controls how sensitive the laser is to end of track markers, and my system was previously too sensitive.

Now all I need to do is get some descent cd-rom games!

NightWolve · 05/22/2012, 03:20 PM

Quote from: BlueBMW on 05/20/2012, 01:37 PM
Quote from: Bernie on 05/20/2012, 12:36 PMWell, you in luck. BlueBMW has got a ton of them bitches in!!
True that! About 80 of them to be exact... shoot me a PM if you need one Snow Crash

I have an old bud that's possibly interested in buying one, Blue, lemme get your email and I'll put you guys in touch.

Because he didn't have the special screwdriver, he used "special" methods/techniques to open it up which didn't quite lend themselves to putting it back together the way that it was. ;) He calls it "FrakenDuo" and somehow it still works, of course, that's also because he changed a few of the important capacitors...