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[Console Repair/Mod Center / Re: Turbo Duo Shorted Out - Trying To Fix]

dead systems is the only option as its a custom chip
seen several go bad

Thanks my friend.  I will have to put it in a bin until I find one.   Sucks to get this far and hit a wall.

[Console Repair/Mod Center / Re: Turbo Duo Shorted Out - Trying To Fix]

Where do you guys source out the parts?  You can't seem to find dead systems on Ebay anymore without paying an absolute arm and a leg for them.  Does this system BECOME a donor system now?  So sad.

[Console Repair/Mod Center / Re: Turbo Duo Shorted Out - Trying To Fix]

Yeah, that is the scary part.  Lots of pins on that guy but I am thinking it has to be the problem.  I have a new torch element coming in next week so I will have to wait till then to pull the chip.  How does one go about finding a replacement?  I have tried to search for the part number online but haven't found anything yet.

Have you ever seen one go bad before?

Lastly, is there any schematics for the Turbo Duo kicking around?  I can't seem to find any online.

[Console Repair/Mod Center / Re: Turbo Duo Shorted Out - Trying To Fix]

The resolution of my crappy automotive multimeter sucks so it is very hard to pinpoint but it looks like I was able to isolate it to around C501.  Just for shits and giggles I removed L501 to try and isolate the short.  Well, everything before L501 is no longer shorted out.  It is also IC501 which is the only component, besides the regulator, that gets hot enough to cook an egg on.  Everything else on the system is running cool. 

FYI, I have ordered up a nice Fluke multimeter with a lot better resolution.

[Console Repair/Mod Center / Re: Turbo Duo Shorted Out - Trying To Fix]

thesteve, I have read a lot of your posts on here and I know you are kinda the master when it comes to these systems.   I am trying to understand your post but I am a bit lost.  Am I to understand that if the power is going through the chokes then the short is obviously after those points?  I had pulled all the 22uf SMD caps thinking that I may have bridged one of them and it make no difference to the short.  I was still getting continuity between the 5v and ground even at the 7805 which is the beginning of the circuit.

I am getting very close to sending this board out to one of you guys for checking it out but since I am in Canada, I would still prefer to find it myself.

[Console Repair/Mod Center / Re: Turbo Duo Shorted Out - Trying To Fix]

Ok, I have taken a look at the board with my trusted multimeter.  The CDROM side of the board has a short when looking at the OHM resistance between 5v and ground.  In most places it gives a reading of about 1.2.  As mentioned, the C519 chip is REALLY hot when running for a while.  I am sure if I kept it running for longer then you could probably cook an egg on it.  After about 3 mins or so it is uncomfortable to touch.  Everything else runs nice and cool. 

Just for the sake of testing, I pulled all the SMD ceramic caps I put in thinking that perhaps I bridges one but the short is still there with all them gone.  All traces on the board look fine and the only lifted pads I had were on the TG16 side which functions fine. 

Seriously looking at investing in something like a Leakseeker 89 to help identify where the short is in the system.  Might come in handy for the future too. 

I am sure if I sent this to one of the senior guys on here then they would be able to figure it out without much effort but there is no sense of satisfaction if I don't find it myself.

[Console Repair/Mod Center / Re: PC Engine DUO-RX That Reads some discs but not others]

Thanks!  Looking forward to being able to play EVERYTHING with it.  Hoping that a new laser will get it working properly.  Should be here by next week!

[Console Repair/Mod Center / Re: PC Engine DUO-RX That Reads some discs but not others]

Its been a while since I could sit down and work on this system but here is some more information.  Without any adjustments, it will try and read the disc for about 2 mins and give a "load error" message.  During that time the LED light will flash every 15 seconds or so and the laser makes a resetting noise each time. 

I have attempted to adjust the VR102 little increments at a time and still nothing.  Once I get so far one way it gives me a "set disc" error.  The other way it just keeps giving me a "load error".  One thing I will mention is that sometimes it doesn't give me a "load error" until a LONG time has passed. 

As mentioned, it will read a lot of different discs except for these two friggen discs that I have and one of them is brand new.  EXILE is the one that is annoying me. 

I have a new laser on order and will give that a shot when it comes in.  I have reset VR102 back to the original position.

[Console Repair/Mod Center / Turbo Duo Shorted Out - Trying To Fix]

I picked up a Turbo Duo off ebay and trying to get it to work.  I noticed that there was a short on it and a few bad caps.  I started by replacing all the caps initially to get that out of the way and now I am tackling the short.  The short is in the CD-ROM side of the system but I have been unable to track it down.  All the traces visually seem to be fine but one thing I did notice is that the 7805 closest to the CD-ROM runs hot as expected because of the short but also IC501 runs hot.  System will run TG16 cards but will not boot up to the CD menu.  Any idea where to start to track down the short? 

First question, how do I know there is a short?  If I check any cap on that side such as C519 then + and - have continuity.  This was present prior to the recap.

[Console Repair/Mod Center / PC Engine DUO-RX That Reads some discs but not others]

This system has been region unlocked for card based media but that really doesn't matter as the issue I am having is with CD based media.  I picked up a bunch of mint condition discs and there are a bunch that just won't read while a bunch of others with scratches will read.  I know the RX systems are more immune from capacitor problems and I would assume that the scratched media would be the first ones to suffer from a weak laser.  One of the games in question is Exile which was sealed when I purchased it.  Works fine on my Duo but not on this Duo RX. 

What do the PC Engine gods recommend I try first to get this system up-to snuff?

[Console Repair/Mod Center / Re: Old Turbo Duo Repair Not Going Right]

Nope.. Swapped in a new 7805 from Digikey.  I get all my electronics from them.
https://www.digikey.ca/product-search/en?keywords=NCP7805TGOS-ND

[Console Repair/Mod Center / Re: pce duo not working after recap only card side works]

Just check the output voltage on the 7805 regulator facing away from the card slot.  I just had one bad which was giving me card operation but no CD operation.  This regulator was also running really, really hot.

[Console Repair/Mod Center / Re: Old Turbo Duo Repair Not Going Right]

As mentioned ALL caps had been replaced on this board prior to me posting here.  AND, the problem has been FIXED!  Thanks for the help guys.  The issue was exactly what I thought it was to start with and I should have gone with my gut feeling.  The Turbo Duo has two 7805 regulators.  It appears one of the regulators is for the CD portion of the system and the other one is for the card based portion of the board. 

The 7805 for the card portion of the card had the proper input of power and would output a steady 5V output BUT the 7805 on the CD portion was pulling a TON more power trying to output to 5V but only really putting out about 1.8v while drawing a ton of amps.  This was causing the heat sync to get really hot on top of that. Because of this increased amp draw, it was causing the power supplies to short out and die in the case of the original power supply and the Genesis 2.  The aftermarket Genesis 2 that I used lastly just didn't have the juice to output the amps the system was drawing while maintaining the voltage to get the board portion of the system to display anything other then a white screen. 

In the end, it took me hooking up my old desktop power supply unit to the board and providing it the power it needed to actually get good readings on the regulators.  And yep, confirmed, bad 7805.
This 1.8v low output was what was causing the cd drive to spin slightly and become somewhat responsive but not totally responsive as it should with 5v.

[Console Repair/Mod Center / Re: Old Turbo Duo Repair Not Going Right]

Well, that is an interesting situation.  I must have read the power supply picture incorrectly on one of them.  I will post back tomorrow with an outcome.

[Console Repair/Mod Center / Re: Old Turbo Duo Repair Not Going Right]

I will get a chance to mess around a bit more with it on Monday.  For shits and giggles, I am going to wire up another Genesis 2 power supply and flick it on to see if I can get it to come back to life again to check for warm components.  I have done a lot of recaps before but not on a DUO so I am pretty confident on my workmanship there but there is always a first.  Today I even did a full express recap which went really well and fired up right away.  2 pads were damaged beyond repair with acid on that guy.

[Console Repair/Mod Center / Old Turbo Duo Repair Not Going Right]

I have an old Turbo Duo that I am repairing.  I got it from someone who had it as a childhood system and it hasn't worked in like 20 years.  It was sent off to Radio Shack way back in the day and they sent it back non-repairable so now I am attempting it.

First off, a few caps were blown so I started with a few cap replacement.  A few pads were damaged but I ran jumper wires to the proper places and all is good.  I tried the original power supply and found out after a bit of testing that it was completely dead.

I then modified a Genesis 2 power supply to work with the DUO and made sure that the polarity was reversed when I did up the cable.  I plugged in a TG16 game, hooked it to the TV and turned it on.  First thing I noticed is that the CD motor was spinning and the laser was in a bit of a focus spasm.  I disconnected the laser assembly and turned it back on.  Next, Kid Courage came on the screen in perfect picture and I played it for a few minutes to make sure that the system accepted input.  Cool, best progress in over 20 years!

20 Mins later the Genesis 2 power supply died on me.  Very interesting since it is rated at 9V and 1Amp which is more then enough to power this system and there is no reason it should blow so I chocked it up to a bad power supply.  I then switched to my desktop  power supply and provided it the 10V 1A power requirements and got no kid courage on-screen at all, just a white screen. 

Next, I made up another Genesis 2 power supply.  I have an abudance of them and it worked the first time.  This time I interrupted the power line with my multi-meter and checked for ampage drain thinking that perhaps it was trying to draw to much power.   Yep, over 3 AMPS were being drained by the system!  3 AMPS! 

So, something in the system is trying to REALLY drain power and I am not sure what to look at now.  I did notice that the voltage regulator on the right side was running very hot but would a faulty voltage regulator draw more power or perhaps it was running hot because of the power drain?  I am not an electronics engineer but I do know enough to be dangerous. 

Where would you start from here to diagnose and fix this system?  I *REALLY* want to get it working and feel like I am close!