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

[Platinumfungi]

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]

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]

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]

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]

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]

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]

Anyone 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]

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]

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]

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]

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]

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]

I read the following statement:

I'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]

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…

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]

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