Turbo Express not working. No power. please help!

[turboexpress]

Hi guys! New to the forum. Glad to be here!

I been trying to fix my Turbo Express and joined this forum so I can get some professional advice from you guys. Ok, my TE gets no power at all with new batteries or with AC adapter. I did a ton of research so I went ahead and did a few things.

...replaced the 1 AMP fuse and the continuity checks out ok

...replaced the only leaking capacitor I was able to find (the large sound capacitor)

...cleaned all the solder joints with 99% isopropryl alcohol and cleaned all the soldering pads

...cleaned the switch terminals

I watched countless videos on youtube and read many articles on how to repair these things. Many of these places lead me to the 1A fuse which I already replaced. I have prior soldering experience and a minor knowledge in electronics.

Can anyone tell me what did I miss? The system doesn't power on at all. Screen is black as if there are no batteries in it. Please any help would be appreciated.

[ApolloBoy]

I would replace all the caps, not just the one. Even if they haven't leaked, assume they've gone bad.

[turboexpress]

Thanks! I was thinking of doing that, but why would some other bad cap cause no power and no backlight?

Some people have leaked video and audio capacitors and their TE still powers on, and they get backlight. Makes no sense.

Anyways I guess this is my only option, I will go ahead and replace all the caps and see what happens.

btw what is 7508 reg? where is it? I can't find it

[BlueBMW]

Thanks! I was thinking of doing that, but why would some other bad cap cause no power and no backlight?

Some people have leaked video and audio capacitors and their TE still powers on, and they get backlight. Makes no sense.

Anyways I guess this is my only option, I will go ahead and replace all the caps and see what happens.

btw what is 7508 reg? where is it? I can't find it

Start with replacing all the capacitors, it needs to be done anyways (you'll probably be surprised by how much leakage there is underneath the caps that you cant see until you pull them off) If it still doesnt work after all that, let me know and I'll direct you to someone who knows a ton about these things.

[turboexpress]

Start with replacing all the capacitors, it needs to be done anyways (you'll probably be surprised by how much leakage there is underneath the caps that you cant see until you pull them off) If it still doesnt work after all that, let me know and I'll direct you to someone who knows a ton about these things.

thank you sir. will try that definitely.

How do I get to the capacitors that are under the metal plate in the center? I can't see how to remove the shield.

[FABombjoy]

It's soldered in place. Examine the edge of the shield and you'll see where the tabs stick through.

[turboexpress]

awsome!! got the shields off!! thanks for yer help. Just waiting on a few capacitors to arrive. Gonna replace one by one and then assemble, test, reassemble etc.
I hope this pays off because I read in some threads on other forums that I might have a burnt out backlight or a bad transformer etc. I really hope I can fix this by just doing a capacitor swap. we will see.

[BlueBMW]

If that ends up being the case, dont worry about it, I know someone who either will have original screens or can do a screen swap with a larger, better screen.


awsome!! got the shields off!! thanks for yer help. Just waiting on a few capacitors to arrive. Gonna replace one by one and then assemble, test, reassemble etc.
I hope this pays off because I read in some threads on other forums that I might have a burnt out backlight or a bad transformer etc. I really hope I can fix this by just doing a capacitor swap. we will see.

[turboexpress]

If that ends up being the case, dont worry about it, I know someone who either will have original screens or can do a screen swap with a larger, better screen.

that will be epic!!! I think I saw somewhere bigger screen mod. That's crazy!!
yeah I will definitely contact you if it should come down to this. I really hope I can just fix it with capacitors. Thanks man!

[BlueBMW]

This guy "thesteve" has figured out some awesome stuff on the express. He and I came up with the switchless region mod chip for the express / gt, and now he's gone on to figure out an effective screen swap and a/v out.

Look in this thread for some shots of the screen mod:

http://www.pcenginefx.com/forums/index.php?topic=9334.msg210849#msg210849

[turboexpress]

wow!!! that is insane!!!

hey, whats a switchess region mod?

[BlueBMW]

By switchless we mean that it doesnt require an external physical switch. Region locking on the express (And other NEC consoles) is done by swapping the 8 hucard data line positions. 1 to 8, 2 to 7, 3 to 6, 4 to 5... So you need a way to phsyically change the circuit paths. Normally this is done with some sort of large multipole switch (an 8PDT to be exact) or with some sort of IC switcher. Thesteve and I designed a chip using a single 10 channel bus switcher IC, but it is still switched by sending either a high or low signal to a certain pin on it. Usually this is done with a physical switch to send either 5v or ground to said pin. For the portable systems like the express though, an external switch isnt easy to mount and usually isnt very aesthetically pleasing. thesteve came up with a circuit / ic setup that basically monitors the status of the "select" button on system boot. If the "select" button is presses, the switch flips to the alternate region mode. If the "select" button isn't pressed, then the system stays in its native region.

Long story short, the switchless method basically means that if you want to play a Japanese game on your US Express, you just put in the hucard, hold the select button and while holding the button turn the system on. Very clean and simple.

More info etc here:
http://www.pcenginefx.com/forums/index.php?topic=10112.0


wow!!! that is insane!!!

hey, whats a switchess region mod?

[turboexpress]

truly amazing what you guys were able to come up with. Now I don't have to buy an overpriced overgouged converter. yaya!!

but first thing is first. I need to fix the express. Still waiting on some capacitors. They are shipped from Hong Kong, so it could take a while to arrive.

[BlueBMW]

That guy thesteve is fantastic with electronics. He came up with the design basically, I just drew up the boards and had them manufactured.


truly amazing what you guys were able to come up with. Now I don't have to buy an overpriced overgouged converter. yaya!!

but first thing is first. I need to fix the express. Still waiting on some capacitors. They are shipped from Hong Kong, so it could take a while to arrive.

[turboexpress]

still waiting on a few capacitors. They are being shipped from Hong Kong so the seller says it might take a while. It's been a few weeks already, so 1 more week I'm guessing. Can't wait to start working on the TE.

[turboexpress]

progress!! all the capacitors came in. I replaced the whole sound section caps, I cleaned the switch and resoldered some points. Resoldered the adapter jack.

Boom!!!! the system turns on, the sound is very loud and thecontrols work as I can hear that when I press the buttons.

Here is the bad news...The screen is still black. There is no life at all in the screen. It looks straight up black, just as if it would when the system is off.

So while I am definitely making some progress here, I need to figure out what needs to be done to fix the screen issue.

Will replacing all the capacitors in the video section fix this? Anything else? Thanks in advance guys. I can really use some help here.

[FABombjoy]

You need to change them all before troubleshooting further. All the surface mount caps will be bad. I've even seen that little non-surface mount cap on the controller PCB leak, too.

[APE992]

You need to change them all before troubleshooting further. All the surface mount caps will be bad. I've even seen that little non-surface mount cap on the controller PCB leak, too.

This. I've had the same thing happen with GameGears and replacing them all usually fixes it, stopping half way is only introducing a variable into the equation that is not necessary and will render the whole thing unsolvable.

Finish replacing them and get back to us, I think you'll find it works fine now.

[turboexpress]

You need to change them all before troubleshooting further. All the surface mount caps will be bad. I've even seen that little non-surface mount cap on the controller PCB leak, too.


This. I've had the same thing happen with GameGears and replacing them all usually fixes it, stopping half way is only introducing a variable into the equation that is not necessary and will render the whole thing unsolvable.

Finish replacing them and get back to us, I think you'll find it works fine now.


but what do the rest of the capacitors have to do with the screen being black like this? I will do what you guys say, but I just don't understand why do I need to replace capacitors that have nothing to do with the screen. I'm not gonna argue with you guys and I will continue to replace all the caps. I am just curious to know why do all the caps afffect my black screen issue.

I'm glad I got the sound and the power back. So the only thing that's left to fix is the black screen.

Thanks so much guys! I will keep updated.

[APE992]

Mainly because it eliminates one variable from the equation. If you know the capacitors are all good you can start looking at other possible causes.

The other? Because they may have something to do with it even if it doesn't appear they do.

[FABombjoy]

For example, the backlight is driven by T500 and/or T900, which have 4 neighboring caps, of which two are 100uf parts that leak profoundly (http://console5.com/techwiki/images/7/71/BADCAP_Wetted_Underside.jpg). There are also a few more related to the chopper that drives it.

It is possible that the backlight tube is burned out or a transformer has failed, but there's no point in troubleshooting until the caps are ruled out. They are a 100% failure point and should be replaced wholesale.

[turboexpress]

For example, the backlight is driven by T500 and/or T900, which have 4 neighboring caps, of which two are 100uf parts that leak profoundly (http://console5.com/techwiki/images/7/71/BADCAP_Wetted_Underside.jpg). There are also a few more related to the chopper that drives it.

It is possible that the backlight tube is burned out or a transformer has failed, but there's no point in troubleshooting until the caps are ruled out. They are a 100% failure point and should be replaced wholesale.

awsome man! I found the T500 and T900 box looking things, the capacitors around them are surrounded by some silicone stuff. How do I remove that white silicone? It has to be removed to get to the capacitors and to clean the board.

[FABombjoy]

What I end up doing is:

1: Rotate the caps back and forth until the legs break off. I hold on to the cap body with pliers and make them do the twist, just a little at first, and then rotating further and further each time. Once they're off, you can remove the wafers, any remaining leg, and clean / prep the solder pads.

-- As an aside, I've changed thousands and thousands of damaged surface mount caps. This twisting & leg breaking method, for me, has the lowest rate of pulled or damaged solder pads.


2: With the cap bodies out of the way, more of the silicone is exposed, and you can gently peel it away with your finger, or break off chunks using needle noise pliers or a hemostat. That silicone is covering several surface-mount coils and other parts, so don't go crazy trying to peel it off of the PCB. You shouldn't need to remove much, just enough to clean the pads and install the new parts.

[turboexpress]

^ thanks so much man!! gonna go do this right now