REPAIR GUIDE - TurboDuo/PC Engine Duo: Total capacitor replacement chart

Platinumfungi · 06/16/2007, 03:35 PM

Here's a complete chart of all the SMD electrolytic capacitors in the Turbo Duo and PC Engine Duo for reference purposes. Hopefully this will help individuals involved in Duo repair and troubleshooting.

The SMD electrolytic capacitor layout is identical on both the Turbo Duo and PC Engine Duo, so this chart can be used for either system.

I hope to eventually add individual voltage ratings, but for now - if you use all 16V except for the 50V by the cd-rom you'll be fine.

Questions and comments welcome.

Cap Replacement Chart for the Turbo Duo and PC Engine Duo:

Mobius · 06/16/2007, 04:03 PM

That's cool. Just going off of memory, I think that's exactly the same as the US Duo, too. But I'd have to open mine up to confirm it.

Turbo D · 06/16/2007, 07:49 PM

Thanks man, thats awesome! Ya, its the same as the US duo except the US duo has a big metal plate covering some stuff.

grahf · 06/16/2007, 08:30 PM

Great job. This is useful info to have around. I havn't checked one personally, but ive heard that the Duo-R and RX are identicle inside. Supposedly the only real difference is the inclusion of the arcade pad with the RX. Maybe somebody can verify.

Air_Zonk · 06/21/2007, 02:05 AM

Wow! This site has really stripped away much of the intimidation that goes along with the idea of repairing Turbo items. If anyone decides to do a Turbo Express/ PCE GT chart, that would be much appreciated.

Anyone have a good/inexpensive Multi Meter suggestion?

Platinumfungi · 06/21/2007, 07:48 PM

I'm willing to do a chart on any system, but I don't have a PCE or portable at my disposal.... If I did I'd happily map out the caps for you. Any others you'd like to see?

SignOfZeta · 06/21/2007, 09:46 PM

Quote from: Air_ZonkAnyone have a good/inexpensive Multi Meter suggestion?

Sears makes a pretty decent Craftsman branded one for $40 that I'd recommend. The ones cheaper than that you generally want to avoid since they don't have the same 10MΩ impedance the $40 one has, and long story short that's a good thing to have to avoid frying things like computer chips, and the meter itself.

Air_Zonk · 06/23/2007, 01:15 AM

There are a bunch of different $40 meters HERE on the SEARS site. I am pretty lost when it comes to purchasing one of these, I don't even know what "10MΩ impedance" means. There's 9 different meters ranging from $30-$50. Can someone recommend one on the page? I'm ready to dive into my defective PCE GT and replace the faulty capacitor(s)!!! Some guidance would be much appreciated, thanks!

nat · 06/23/2007, 01:53 AM

I hope you have small and steady fingers.

I had an absolute NIGHTMARE with my GT. I gave up after only replacing 1 cap. I blew the fuse in the process.

At least I got the audio working through headphones.

Air_Zonk · 06/23/2007, 11:51 AM

I wouldn't be asking questions if I didn't think I could do it. I'm obviously new to these kind of repairs, but I'm not a stranger to a soldering iron. Any real help would be great!

nat · 06/23/2007, 04:35 PM

There's not much to say other than what I mentioned in my last message.

The TE/GT repair is one of the hardest soldering jobs I've ever attempted due to the extreme proximity of ICs and caps on the PCB. This was compounded, for me, by large and unsteady fingers. The TE/GT is incredibly cramped inside. The PCB is small and everything is extremely close together. When you first get the screws out and are seperating the two "halves" be careful in disconnecting the ribbon cables. They tear easily. After you're done with the repairs, make sure nothing will short out when you power back on before you put it back together. Otherwise you will blow the fuse.

There's another thread in this very forum that has pictures and step-by-step instructions on what exactly needs to be replaced so I won't rehash that here.

Beyond that, all I can say is "Good luck" and your mileage may vary.

Air_Zonk · 06/24/2007, 03:53 AM

But here's the thing, nothing you posted answered any of my concerns... This thread involves capacitor replacement and I'm not trying to derail the importance of that. You obviously must have misunderstood my posts, because all I am simply asking for is a recommendation on a Multi Meter and to hopefully get some clarification on what the reference "10MΩ impedance" meant...

nat · 06/24/2007, 04:52 AM

I read the following statement:

Quote from: Air_Zonk on 06/23/2007, 01:15 AMI'm ready to dive into my defective PCE GT and replace the faulty capacitor(s)!!! Some guidance would be much appreciated, thanks!

And assumed you were asking for guidance regarding replacing the caps.

SignOfZeta · 06/24/2007, 09:33 AM

Quote from: Air_Zonk on 06/24/2007, 03:53 AMBut here's the thing, nothing you posted answered any of my concerns... This thread involves capacitor replacement and I'm not trying to derail the importance of that. You obviously must have misunderstood my posts, because all I am simply asking for is a recommendation on a Multi Meter and to hopefully get some clarification on what the reference "10MΩ impedance" meant...

When you use the voltmeter mode of a DMM (or any mode other than ammeter mode, since the other modes are just variations on voltmeter mode) you are measuring the difference in voltage between two points. In doing so you are making a complete circuit with the meter. Because of this its important that the meter have a high internal resistance to avoid creating a near short condition and allowing too much current to flow through the meter, and the two points on the circuit you are testing. If a meter says it has an impedence of 10MΩ (10,000 ohms) then it's far too thick to make any meaningful/dangerous short circuit using household, or automotive levels of power. IN this situation the DMM is basically tranparent to the circuit, and has zero effect on it. Now, this doesn't apply to ammeter mode. Incorrect use of a DMM in ammeter mode will blow the meter's fuse, or something worse.

The meter I bought from Sears years ago seems to be no longer made, but this one is kind of close.

http://www.sears.com/sr/javasr/product.do?cat=Electrical+Shop&pid=03482139000&vertical=TOOL&subcat=Multi-Meters%2C+Testers+%26+Accessories&BV_UseBVCookie=Yes

It claims 7.5MΩ impedance, which is certainly enough security for things like a TG-16. The impedance ratings aren't mentioned in the "stats" section on Sears' website, but if you look at the owners manual PDF they provide, its usually listed there. If it isn't mentioned on a cheap meter, assume its a terrible rating.

BTW, replacing these capacitors is going to suck. Not because of the tiny work spaces, but you are going to have to be really really careful not to pull any tracing off the board when you remove the old components.

Platinumfungi · 06/27/2007, 05:15 PM

I found some updates that I need to make to the chart. I'll be adding them as soon as I can.

OldRover · 06/27/2007, 07:28 PM

What's with the hideous watermark?

Got a clean version?

Platinumfungi · 06/27/2007, 09:56 PM

I hate watermarks too, but I feel that the time I have invested is worth one. It's just so people don't try to pass it off as their own work. I don't think it hinders the chart but I'm open to constructive criticism.

OldRover · 06/27/2007, 10:38 PM

Do you think you could email or PM me a clean version? I'd like to have a printout of it for my binder, but the watermark just bugs me, heh.

If not, then well...I'll do something else.

Platinumfungi · 06/28/2007, 07:31 AM

Well I could try and lighten it a bit more if that would help you out? Don't print one off yet though as I have just added an edit yesterday that I found some more info I missed on my chart and will more then likely have separate charts for the US and the PC Duos very soon.

Edit - Chart updated and the water mark has been slightly lightened.

Platinumfungi · 07/23/2007, 07:50 PM

Just added some more info. Let me know if you need anything else or have questions.

SNKNostalgia · 07/23/2007, 08:25 PM

Here is one thing though. Would it be a better idea to replace the caps that function for the CD-Rom drive first and then buy a Hop M3 laser if there still is a problem with the disks reading?

Also, what caps function for the CD-Drive? I find it funny how Duo-Rs use the same exact drive but different board layout with less functioning issues. It must be a cap issue, or just how the controller part works for the CD drive.

Turbo D · 07/23/2007, 08:30 PM

My U.S. duo pcb has both those insulated wire holding legs and is missing the ceramic disk capacitor. Also, it has that one part on the bottom with the pad, like the pc engine. Do you think my U.S. duo is earlier or later model?

Platinumfungi · 07/23/2007, 10:00 PM

SNK - Unfortunately I don't know which caps regulate which areas of the system. I'm new to working on NEC systems so I had been following D-Lite's suggestions on the audio replacement. I still had issues so I decided to randomly replace two at a time and then test. I eventually replaced two that got my cd audio going only to find it gone again later. I continued to have problems until I replaced one other specific cap and then it seemed fine. I can point out the three caps that most effected my PC Engine's audio but it could just be that those caps were going bad on my system and might not be of any use to anyone else. I was going nice and slow and charting my results but unfortunately I'm fixing this system for someone else and so my deadline came up and I had to hurry along. I'd love to have a chart that shows which caps relate to which part of the system if anyone/everyone could figure it out....

Turbo D - So....perhaps it's not the difference between US and PCE but an earlier or later model eh? Sounds like we should both check the model numbers and compare.

I edited my post slightly to try to figure out what the real reason is for the differences on the pcbs.

Turbo D · 07/24/2007, 04:18 AM

The model number on my U.S. Turbo duo pcb is "L61-I-280IY." The serial number on the plastic case is "28011731A." It says under the serial number that it was manufactured August 1992.

SNKNostalgia · 07/27/2007, 02:28 AM

My Duo is a March 93 model and resembles the typical US model. Serial 33000254A. Will look at the PCB later on, playing my system right now and really far into Legendary Axe.

Platinumfungi · 07/28/2007, 03:17 PM

The PC Engine Duo from the pics:

PCB # - L31-4-2804B
Serial # - 28008251B
CD-ROM # -02920618
No sticker on the bottom for manufactured date.

The US Duo from the pics:

PCB # - L61-2-3107AV
Serial # - 31024101A
CD-ROM # -02921107
Manufactured - January 1993

agt_dale_cooper · 12/08/2008, 01:12 AM

Holy Bananas, Nat quoted this original posting.

Yes, Red Ghost, this is the one I wanted to see the volts updated on...[and, as long as I've got everyone's attention by necroposting this, both this chart AND the Express charts are WORKS OF ART according to us folk who like to repair stuff and both deserve to be stickied...how does one access this functionality? I see the buttons at the bottom of the main page, but.........?]

[Special Agent Dale Cooper (http://en.wikipedia.org/wiki/Dale_Cooper) adds his name to the list of folks who have appreciated your efforts....]

Platinumfungi · 12/09/2008, 11:01 PM

Quote from: agt_dale_cooper on 12/08/2008, 01:12 AMHoly Bananas, Nat quoted this original posting.

Yes, Red Ghost, this is the one I wanted to see the volts updated on...[and, as long as I've got everyone's attention by necroposting this, both this chart AND the Express charts are WORKS OF ART according to us folk who like to repair stuff and both deserve to be stickied...how does one access this functionality? I see the buttons at the bottom of the main page, but.........?]

[Special Agent Dale Cooper (http://en.wikipedia.org/wiki/Dale_Cooper) adds his name to the list of folks who have appreciated your efforts....]

Hey thanks

It's nice to hear someone finds it useful. When I first posted it a few people gave comments, but I didn't know if many people were actually using it/finding it useful.

I'll see if I can update it in the next few days. I'm going out of town till New Years soon, so if you don't see it updated in the next week, I'll get it done early January.

I've also thought about making charts for the other NEC systems, but I think they would be of less use as the Duo and Express (and variants) are the most problematic it seems.

nick3092 · 12/11/2008, 06:48 AM

Quote from: Red Ghost on 12/09/2008, 11:01 PMHey thanks

It's nice to hear someone finds it useful. When I first posted it a few people gave comments, but I didn't know if many people were actually using it/finding it useful.

I used it to do a total cap replacement on my US Duo as well, and it was a lifesaver. Just printed it out, and laid it on the workbench next to me. Only question I have though, unless I'm missing something - the key has a 3.3uf cap listed, but I don't see it marked anywhere on the board. Where is it?

NecroPhile · 12/11/2008, 09:24 AM

Quote from: nick3092 on 12/11/2008, 06:48 AMOnly question I have though, unless I'm missing something - the key has a 3.3uf cap listed, but I don't see it marked anywhere on the board. Where is it?

Right below the laser and above a pair of 22uF caps.

nick3092 · 12/11/2008, 06:19 PM

Quote from: guest on 12/11/2008, 09:24 AMRight below the laser and above a pair of 22uF caps.

Wow, do I feel like an idiot. Between it being under the wires and the plastic holding the wires down, I never physically saw it on the board. And it just blended into the picture. Well, it works as is. But considering I replaced all the other caps, and I have the 3.3 sitting here, I might as well replace it. Eh, this weekend.

Platinumfungi · 12/11/2008, 07:40 PM

Make sure to note the voltage of that cap when you remove the old one. From what I recall (and will update as soon as I can) the voltage on that cap was really high. Like 50V.

nick3092 · 12/11/2008, 09:11 PM

Yeah, it says:

3.3
50
20

on the top. Luckily the 3.3 I ordered was a 50.

Platinumfungi · 12/11/2008, 09:17 PM

Quote from: nick3092 on 12/11/2008, 09:11 PMYeah, it says:

3.3
50
20

on the top. Luckily the 3.3 I ordered was a 50.

Great! You should be all set then.

Duo_R · 12/12/2008, 12:35 AM

is the 3.3 the memory backup "battery" cap?

nat · 12/14/2008, 04:10 AM

Quote from: Duo_R on 12/12/2008, 12:35 AMis the 3.3 the memory backup "battery" cap?

Negative. The backup battery is the component directly to the right of the yellow-circled component in the second pic.

Platinumfungi · 12/14/2008, 06:50 PM

Did a little update. Tried to clean the post up a bit and make the 1st chart a bit nicer. Will add the rest of the voltage ratings and other things after New Years. Enjoy

agt_dale_cooper · 12/15/2008, 12:41 AM

While I'm not one to reengineer 'works of art', isn't the new background rougher on the color cartridge?
Is plain white out of the question?
Color is REQUIRED for this printout, but really only for the board itself where the different color marks are...perhaps this brilliant new blue could take the place of the grey 3.3V that another member already commented he didn't see..perhaps this new hue would be more appropriate there?

For whatever it's worth, I disagree with the watermarking issue...to an extent. Yours was originally rather large, but is now easily cropped out. How about a nice little line along the space/trace lines above the HuCard slot? For more style points, take out the "L31-XX-2804B" and replace with text/watermark of your choice...."All your PC Engine are belong to www.pcengine-fx.com!" HAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!!!!!!!
It'll go with my t-shirt: http://www.thinkgeek.com/tshirts-apparel/unisex/gaming/3777/?cpg=ab

All comments herein intended as non-insulting / constructive... O:)

Enjoy your time away for the holidays, I hope to have more progress on this sound issue by the time you return, I've another JAP unit on it's way here, gonna compare apples and apples....

Platinumfungi · 12/15/2008, 11:08 AM

Quote from: agt_dale_cooper on 12/15/2008, 12:41 AMisn't the new background rougher on the color cartridge?
Is plain white out of the question?
Color is REQUIRED for this printout

Good point. I hadn't thought about printing it out. I usually just reference these off my computer. I've made the change.

Quote from: agt_dale_cooper on 12/15/2008, 12:41 AMthe watermarking issue...

I put the name/website at the bottom so that people who are bothered by it can remove it for printing. However, there are multiple water marks in the image. Only one of which I think is even distinguishable to the eye. I set it up this way so that hopefully most people will be happy with it, including myself.

Quote from: agt_dale_cooper on 12/15/2008, 12:41 AMEnjoy your time away for the holidays, I hope to have more progress on this sound issue by the time you return, I've another JAP unit on it's way here, gonna compare apples and apples....

Thanks, and good luck.

Zeon · 03/21/2009, 08:37 PM

Edit: Nevermind, it's .047 farads, not microfarads, which is 47000 microfarads, which is pretty big for a cap for being in a duo. I'll have to order some.

There is an odd type cap I have circled in red in the picture. I don't know what type it is specifically it looks like it is some special type as NEC is silk screened on it. It might be a high quality cap used to filter the audio. I can tell you it is a 5.5 volt polarized .047 microfarad cap (it says 473 on it, the 3 being the decimal place), but beyond that I don't know anything else about it. Duo says on his duo-r there is a rather large electrolytic cap in it's place.

I only realized this was a cap today as I didn't look at it to closely, dismissing it as something else. When I get back to my apartment tomorrow, I will try replacing it with a electrolytic cap with similar specs and see if it fixes or improves the audio issues on the duo I am repairing.

Duo_R · 03/21/2009, 08:51 PM

yup, I think we have discovered another cap. Is this the one that Nat mentioned a while back? I never assumed this was a cap until I saw my JP Duo with a large cap right in the same spot. Everything parts wise looks identical from JP Duo to US Duo so that part stuck out like a sore thumb. The US Duo has this Monolith rectangle looking thing that I guess IS a cap.

Here is a picture of the cap on the PC Engine Duo (big green cap):

/downsized0321091757m.jpg

I will take another snap of the two Duo's that are side by side. I have been running / testing games with the covers off, I kinda feel like DJ Turbo......

nat · 03/21/2009, 09:07 PM

That's the BRAM battery.

Zeon · 03/21/2009, 09:31 PM

Quote from: nat on 03/21/2009, 09:07 PMThat's the BRAM battery.

Haha makes perfect sense, big cap for longer retention of save data. Don't know why I didn't think of that, well back to the drawing board, my next suspect is the M51131L which is a 2-Channel Electronic Volume Balance ic. Beyond that and the oki chips, and those small amps, i am stumped. My reasoning is suspecting the M51131L is that one of the audio caps that we typically replace in repairing duos, it dangerously close to the M51131L. When the cap leaks it's possible that electrolytic gets around the pins of the M51131L and shorts something out damaging it. Anyone know of a place where I can get a replacement?

pceslayer · 04/05/2009, 02:31 PM

Does anybody know which caps are responsible for the operation of the laser?

I have an odd issue where my Duo won't reliably read tracks past a certain portion of the disc.

I'm not really sure its an issue with the caps at all, but figured i'd start here.

nat · 04/08/2009, 09:57 PM

Your laser needs to be tuned. There are four or five pots on the Duo motherboard that control intensity, sensitivity, focus, etc. Calibration drifts over time.

override · 04/15/2009, 10:56 PM

Was just wondering does it make a difference if the caps are "16 V" or "16VDC" ? Upon making an order on the net I noticed at checkout that some were VDC....

Thanks for the help

Also was wondering anyone that would recommend a site? I checked newark but they charge a $20 handling fee....I dont think I want to pay that...LOL $10 worth of caps turns out being damn near $40...

Hey NAT did you get my message?

nat · 04/15/2009, 10:58 PM

No, they mean the exact same thing.

Zeon · 04/16/2009, 04:08 AM

Quote from: override on 04/15/2009, 10:56 PMAlso was wondering anyone that would recommend a site? I checked newark but they charge a $20 handling fee....I dont think I want to pay that...LOL $10 worth of caps turns out being damn near $40...

Where do you live? I have ordered from newark in the past a few times and I have never been charged a $20 handling fee. If I was I would have ordered elsewhere!

override · 04/16/2009, 09:27 AM

Quote from: Zeon on 04/16/2009, 04:08 AMWhere do you live? I have ordered from newark in the past a few times and I have never been charged a $20 handling fee. If I was I would have ordered elsewhere!

I live in Texas....I was pretty sure that newark was in the states so I dont understand why they want to charge me the handling fee either....Not sure but if I cant get it off I will find elsewhere...I have already looked around but the other sites I have found dont carry everything I need....I was very suprised to see that newark carried the .047 Micro Farad 5.5 V Polarized Cap! Its only $1.47 so not a bad deal for such an important cap (in my mind).

Zeon · 04/16/2009, 03:20 PM

Quote from: override on 04/16/2009, 09:27 AM
Quote from: Zeon on 04/16/2009, 04:08 AMWhere do you live? I have ordered from newark in the past a few times and I have never been charged a $20 handling fee. If I was I would have ordered elsewhere!
I live in Texas....I was pretty sure that newark was in the states so I dont understand why they want to charge me the handling fee either....Not sure but if I cant get it off I will find elsewhere...I have already looked around but the other sites I have found dont carry everything I need....I was very suprised to see that newark carried the .047 Micro Farad 5.5 V Polarized Cap! Its only $1.47 so not a bad deal for such an important cap (in my mind).

Really? So do I! Do you live in the DFW area by any chance? It's always cool to find out when a fellow member lives at least somewhat nearby.

Newark is in the states, and my last order (made last month) which consisted of mainly caps, some ics, a plastic enclosure, and other electronic miscellany did not have the $20 fee tacked on. How much does your order total to? They might only put it on really small orders as my last one was something like $47 before shipping and whatnot.

EDIT: Nevermind, I know why. You must be ordering one or more items that are labeled: "Farnell UK Direct Ship" which means that they don't have the item(s) available stateside, so they have to put in a special order direct from the UK. I generally avoid those items. See if they don't offer an equivalent that is in stock stateside. They should as they have a crap ton of caps in general.