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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: jeffg on May 10, 2009, 03:16:33 PM
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I got a Turbo CD unit today, it will spin continuously really fast but never seems to access it or anything. Also pressing stop doesn't do anything, you have to either open the flip cover or turn off the power to get it to stop?
Is this thing repairable?
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My TG-CD just starting having the same problem. As soon as the power is turned on the spindle starts spinning like nuts, before the run button is even pressed and even without a CD or system card. I've done some work on my Duo but I've never tinkered with the TG-CD, any suggestions?
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This is interesting, I've never seen nor heard of this problem before. Anyone else had this happen?
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I've seen it on a Duo. It's laser related I believe. Focus being lost or something along those lines.
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I got a PCE CDrom2 unit that has the same symptoms. Never fixed it, but my guess would be laser related too.
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=; *arise thread*
Still having the problem - the second the CD drive gets power it starts spinning its brains out. Doesn't matter if it's running stand-alone or connected to the TGCD interface. Doesn't matter if it has a CD in it or if it's open or closed.
My usual fix-all of taking the unity apart, cleaning the board with electronics cleaner and q-tips, and reassembling actually didn't work for once. #-o
So, assuming it's "laser related," do I buy a new laser or adjust my pots? I've seen posts describing what each of those five pots do, but I'm intimidated. Can anyone give me specific advice on which one to start with?
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If the disc starts spinning as soon as power is applied it is NOT the lens.
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Both the sled motor and the spindle motor are controlled by IC104. It has most likely burnt out, probably caused by the traditional jammed sled/gear. If you have a VOM, and want to check this out, monitor IC104 pin 8 (sled motor control). It should be about 5.5v if the system has told the motor to shut off. I suspect this will be correct. So, why then is the motor still on? Check IC104 pins 9 and 10. You will probably find one pin above 5.5v by about 1.5v (= 7v), and the other pin below 5.5v by about the same amount (= 3.5v). This puts the voltage across the motor at about 7v-3.5v = ~ 3.5v, which of course turns it on. If this is the case, then IC104 is almost certainly bad.
FYI, substitute pin 5 for control, pins 2 and 3 for motor voltage, when testing the spindle motor.
Charlie
Edit: It is clear, isn't it, that the same operation applies to the spindle motor as I have described for the sled motor?
That is, this is a generic description that is applicable to BOTH motors.
Edit #2: I should make clear that the difference between the OFF signal voltage and the ON signal voltage is only a few tenths of a volt.
Something like 5.5 vs 5.2. But this is the steady state; if you can watch the voltmeter when you press the PLAY button, you will see the voltage momentarily drop to something like 4.5v for less that 1 second.
If all this looks good, you will probably be better off checking with an oscilloscope....but you could also suspect the motor, which is obviously an easier path to take.
Edit #3: Umm, I assume you HAVE replaced the caps....right?
Charlie
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Thanks so much Charlie. I have a VOM, but I don't really know anything about this stuff. What parts do you think I'll have to replace?
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I said:
==>Both the sled motor and the spindle motor are controlled by IC104.<==
You said:
==>What parts do you think I'll have to replace?<==
???????
Not a good start! But, that's the reason for the VOM testing: It may NOT be IC104.
Charlie
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By the way, anybody out there that has done repair on these things, I find them VERY sensitive to vibration...even a slight tap on the case will cause skipping, or even a full fledged track change. I thought maybe I was screwing up the system during the repair, but this occurs even on working units that are touted as "fully functional" (and yes, they do actually work)
Is this typical? Were these things alway like that? Or are all these guys suffering from old age? Anybody got a fix? Or do I have to do some more troubleshooting?
Charlie
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They all do that. I remember back in the day when I had my brand new Turbo grafx CD player that the audio would sometimes skip if I paused the game and walked away to fast or too hard to go use the restroom.
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WOW! Well, thanks for that. I can breathe a little easier knowing that I didn't screw anything up too badly. Of course, now I have to ask myself...can I make it better?
Do you think others would be willing to mod their CD's to fix that, assuming a practical fix could be found? Or just leave it, relying on the fact that the unit is generally used in a rather fixed/static environment where vibration shouldn't generally occur?
Charlie
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By the way, anybody out there that has done repair on these things, I find them VERY sensitive to vibration...even a slight tap on the case will cause skipping, or even a full fledged track change. I thought maybe I was screwing up the system during the repair, but this occurs even on working units that are touted as "fully functional" (and yes, they do actually work)
Is this typical? Were these things alway like that? Or are all these guys suffering from old age? Anybody got a fix? Or do I have to do some more troubleshooting?
Charlie
Yes, in my experience the TG-CD was quite susceptible to skipping if you tapped on the unit (for me, it was always the right-hand side).
This was true back in the day (early 90's), when the TG-CD was a young one.
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ok the issue on vestacoat's drive is solved.
it turned out to be a bad trace from the drive chip to the servo controller.
I consider it a random failure and unlikely to be repeated in another drive (in the specific sense), tho in general bad traces/via's are likely to become more common.