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NEC PC Engine/TurboGrafx-16 Games/Consoles => Console Repair/Mod Center => Topic started by: KeithCourage89 on 09/20/2018, 11:36 PM

Title: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: KeithCourage89 on 09/20/2018, 11:36 PM
To all that can help: I bought a Turbo Express on ebay, no video, little sound. I replaced the capacitors, and still nothing. sometimes the brightness would work, and sometimes it will be barely lit. But now there was no sound and no video. After another test, Transistor Q506 started activating some solder flux around it, due to overheating. I will need a new transistor, but don't know the part number, so if anyone does, please tell me. After turning it off and back on, nothing was powering, probably meaning a blown fuse. After further inspection, I noticed there was no Resistor on R706, but I didn't do work on that side and the pads seem to be untouched, so I don't know if there is supposed to be anything there or not. I can't find any schematics, documentation or reference designators on the TE and am hoping someone with more knowledge can help me out. There may be more problems, but I'll tackle these first while I wait for a new fuse to arrive.

Thank you for looking into my problem, Austin

Images of PCB- https://docs.google.com/document/d/1o6wab3VkYzI9xW82Klrc-VGnAuQRnav8eWwsYd38QDw/edit?usp=sharing

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Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: NightWolve on 09/21/2018, 12:05 AM
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Uh, yikes, you beat up those new capacitors pretty bad there...  And, were they scribbled on top with a red marker for some reason ?? ;)
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: KeithCourage89 on 09/21/2018, 12:11 AM
Yeah, I ripped the trace pad and had to expose the traces a bit. Not my best job as surface mount is not particularly my forte, and the red is just for my sake when replacing Caps when I check for continuity.
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: Keith Courage on 09/21/2018, 02:30 AM
You are in luck. That resistor that is missing is actually just a jumper/filler fake resistor. Meaning you can just solder a wire to each connection. Resistor says 000 on it so that means no value. 

(https://web.archive.org/web/20190509195303im_/https://i.postimg.cc/L6Cjx0bm/IMG-20180921-012725.png) (https://postimg.cc/3dGyR9hq)
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: KeithCourage89 on 09/21/2018, 05:37 AM
Thanks, That solves one of the problems. Luckily that's simple. Don't know why there was nothing there though.
The other thing is finding what part number transformer Q506 is. I know that Q900 and Q901 are 2sd189 transformers from other threads, but no info on Q506 yet.  Don't know if its the same, as those are labeled DFØT but 506 is a BCØT.
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: NightWolve on 09/21/2018, 01:27 PM
Ah, I see what's going on, so a 0 Ohm resistor just fell off which obviously can be replaced with a jumper wire/metal.

Some sort of last minute change happened in the PCB design that no longer necessitated resistance so they slapped a 000 resistor component on it which is wasteful over just a trace or wire - must've been a testing area for whatever reason ? Who knows.

But anyway, if you got transistors overheating like that, you got worse problems and given your recap job...well, I'm just gonna skip ahead and tell ya to message thesteve (https://www.pcengine-fx.com/forums/index.php?action=pm;sa=send;u=3863) to send it off to him for repair. Good luck! ;)
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: KeithCourage89 on 09/21/2018, 04:17 PM
Thanks,
I wanted to avoid sending it off, as I'm broke right now with college going on. Do you know how much this will cost me, cause if its around $75 then that's fine. I just don't want to drop another $150 to get it repaired as I might as well get a PCE GT for that with the LCD and region mods off ebay for around $300.
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: NightWolve on 09/22/2018, 03:42 PM
Our Turbo Repair/Mod Titans (TheSteve, Chris/Keith Courage, turbokon, chop5) don't usually have set rates for these sorts of things/random jobs and typically make deals privately, so you'll have to message them if you're ready. People could still help you here to troubleshoot it yourself further, but I think you're gonna need more sophisticated diagnosis with probe tools to identify the problem (best guy for that is Steve) and maybe another recap job (with a full cleaning/wash of flux/leaked electrolytic fluid)...

I recall there are some schematics floating around BTW, I know they're online for the TG-16 at least (Since the TurboExpress portable is almost a carbon copy of the console version, plays the same HuCards, that can still be useful for the motherboard/PCB.).
Title: Re: Turbo Express Transistor/resistor Q506 and R706 failures
Post by: KeithCourage89 on 09/22/2018, 11:47 PM
Okay, So I replaced the fuse and bridged that resistor space, and it still gets hot and trips the fuse. It looks like that transistor went, so I'll message Steve tonight for rates.
Thanks for all your help on the subject. Wish me luck