Problems with Turbo Duo system

[Billd420]

Hello everyone,

I'm new the the PCEngine FX message boards. I've found these forums to be an outstanding resource so far. Last week I got my first Turbo system (a Turbo Duo). It had known problems before I got it, but I wanted a new project to tackle. Prior to me attempting any fixes, the CD audio in CD games would randomly cut out. I did some research, and found the post here where it recommends replacing the caps in the audio amp area. I did the mod outlined here:
http://img148.imageshack.us/img148/1302/r9x600copyxo4.jpg

I went ahead and got some new capacitors for the job, however my electronics shop didn't have direct matches. I was able to match the uF's, however the voltage on the caps I bought were all 50v. I desoldered the old caps, and put in the new ones. I tripple checked my work for polarity, bridges, solder splashes and loose connections. When I fire up the system now, the CD audio plays consistently, however it is very quiet and has lots of distortion (scratches).

Any suggestions on what I should check? Is it possible the caps I got were too high in voltage for the amp? Or, is it possible that some of the caps I purchased were bad?

On a side note, since I've owned the system, you have to flip it upside down in order for it to read CD's. Is this a common issue? Does this indicate the laser is on its last legs? Are there any recommended fixes for this?

Thanks for any help!
Bill

[Mobius]

Based on my experience with the same problem (redbook audio cutting out and FMV skipping horribly), I really don't think it's a capacitor problem -- it's a laser problem.  I don't have the hardware expertise to rule out capacitor problems, but it definitely makes sense that it would be the laser instead.  If it was the capacitors, wouldn't all audio cut out, not just redbook?

Anyway, what really seals the deal for me is that redbook audio and FMV are directly streamed from the disc and don't contain the same level of error correction that data portions have (this is true of any CD-ROM based application).  This is why you can load and play a game just fine and only have problems with the audio -- though you may notice long load times.  Couple this with the fact that turning the unit over seems to resolve the issue with some games (I had the same experience with that, too), and all signs point to the laser.

I followed the instructions here: http://www.teamfremont.com/features/TurboDuoRepair.shtml, and that fixed things right up for me.  Redbook audio played fine and loading times were much improved.  I started having the same trouble again a few weeks later, but an adjustment to the potentiometer on the laser cleared that up, and it's been smooth sailing since.

All that said, I honestly didn't even try adjusting the potentiometer on the old laser before replacing it.  I'd fiddle with it first (it's the gray plasic screw on the side of the laser assembly) and if that doesn't work, replace the whole pickup.

[SNKNostalgia]

There are some more capacitors you might want to replace. In the picuture post just under the 22uf 16v there is a 47uf that you want to replace. Also, 2 caps to the left of the M5205 chip (says it right on it). They are in the upper right side of the board. You will see a 47uf and a 10uf capacitor. Replace those two plus the 47uf under the 22 uf in the picture.

The 50v capacitors are fine, I used 25v on mine. You definately want to replace the lens with a hop-m3 like that link that Mobius gave you. It only costs like $20 plus shipping. Still, do the capacitor replacement on the other 3.

[Billd420]

Thanks for the input guys!

The funny thing is the CD Audio worked fine volume and clarity wise (only cut out at random). Only after I replaced a handful of the caps did I get the low volume and scratchy audio. I'll go ahead and replace the other caps that were suggested, and try to adjust the later.

Now when doing the laser adjustment, I want there to be less resistance then there currently is? Correct?

I'm going to go ahead and order a new laser for the unit... I'm sure the current one is soon to kick the bucket.

-Bill

[Mobius]

After reading about Turbo Duo audio problems, the conclusion I ended up coming to is that scratchy and fading audio is a capacitor problem, but CD audio cutting out is a laser problem.  So I get the feeling you introduced a capictor problem that wasn't there originally.  But I know my way around a CD drive better than a circuit board, so maybe you know something I don't.

Anyway, I had to give my potentiometer a pretty good counter-clockwise turn -- about 90 degrees -- before it started working better.

[Billd420]

Mobius: That makes sense about the laser problem being there, and me introducing the capacitor problem when I installed new ones. Looking back, I wonder if I accidently cooked some of the caps that I was replacing. I realized after I finished soldering I had my iron on 30w. I should just order some direct replacement caps and try again.

-Bill

[FM-77]

Hmm, PC Engine consoles... are these the systems with the most problems up until the Xbox 360? I think so.

[Keranu]

Hmm, PC Engine consoles... are these the systems with the most problems up until the Xbox 360? I think so.

Maybe up until the Playstation.

[nat]

Hmm, PC Engine consoles... are these the systems with the most problems up until the Xbox 360? I think so.

Maybe up until the Playstation.

I don't think I know a single person who still has an original-model PS (or PS2 for that matter) that didn't crap out on them some years ago.

[FM-77]

I have both.

[termis]

Between a couple of my friends, I must've replaced about 4 laser assemblies on the goddamn PS1 (And I bought the 9000 series model, which was *supposedly* more reliable).

[SNKNostalgia]

It seems that the 5501s are more realiable for the PS1's. My original first run of the 1001 model of course crapped out on me in a year. I sent it off to get the lens replaced by sony for like $80. Then it started to crap out again a year later.

Well this is funny, all my friends didn't buy a PS1 until the time I got mine fixed, which was December 96 (hmmm christmas). Their systems crapped out the first time exactly when mine did the second time. I said to hell with it getting repaired. After some simple research, I figured you should buy a PS1 where the lens is to the right instead of slanted to the upper left above the power supply (Genius Sony, just shear genius.). So, I buy the 5501 model that Christmas of 96. All my friends did the same and got the same exact model. We all had no problems at all for all the years the systems were owned. They didn't buy a PS2 until like 2002. I like to think that is a reliable model, atleast if treated right.

As for my PS2 I got lucky maybe, or I just took way good care of it. Maybe it was both since I did a little repair. It is a first run system from 2000. It did have CD-Rom disc errors when booting and it also took a while to start DVD games. Then, I fixed it by just regreasing the lens track and cleaning dust out of the lens and the mirror inside it. Works like new.

Dust seems to be a big issue with the PS2 system and heat affects a few. While the PS1 it was mostly just heat warping the lens. Well, the X-box 360 problem seems to have overheating issues in two affecting ways. The main processors are not soldered with lead. What happens when the system overheats is that you get cold solder joints and they detach from the mother board. On the Elite model 360 systems they use Epoxy to hold the chips down better, pretty funny ehhh. The other problem is overheating of the DVD rom since the GPU chips are not heat synced that well and they are right under the drive. That is how you can tell the difference with the problem you have with the system with the red rings of error around the power button.

My suggestion is to dust often, and keep your system as cool as possible. Buy external fans, but not a cooling module that connects to the system. Also, keep the AC cranked and put the system on a flat wood surface with open space. Ever noticed how the top of the line PCs nowdays use liquid cooling systems? It would be nice if they used better cooling techniques with todays consoles. Did the 360 really have to be compacted in the little encasing like that?

[MrFulci]

SNK maskes some good points.

Design flaws, nothign much easy you can do to prevent problems due to that, however where you place your system can make a difference.

Newer systems, and even systems such as the Sega Genesis, should be kept on a flat surface. Tile, Wood, Glass, etc. Don't place a system on a carpet. It traps the heat. You want air to circulate aroudnt he system. if your system is missing "feet" (common with some older systems), buy some and place them on the bottom fo the system.

Airflow and the air temperature around the system is important. Don't place systems on top of a cable box or some other component that puts out heat. If the system has a fan, don't block the in or out ports.

Buy a dust cover, even if you use the system daily. You don't have to buy one specific for your system (though, they are out there), finding one similarly sized at an electronics store (Printer cover, etc) can help. It may not fit snugly, though it will do the job. Many dust covers are also water resistant, so you have some protection against spills. I use a Turntable dust cover on one system, and a printer dustcover for my Duo-R and Genesis.

[nodtveidt]

Hmm, PC Engine consoles... are these the systems with the most problems up until the Xbox 360? I think so.

No, they're just very old now. Can't expect 20 year old technology to stay stable for...well, 20 years.

[Necromancer]

Did the 360 really have to be compacted in the little encasing like that?

Yes, otherwise everybody will bitch about it being a big ugly box (see original Xbox for more information).  Many people seem to be more interested in style than content, as the recent success of Apple products will attest.