Pi 3b+ not working a few weeks after I added the iuniker dual fan

I posted this on raspberrypi.org on July 8,2018 and got 62 views but no replies. I was hoping someone would have some ideas why the pi is dead and maybe how to remove the heatsink/fan module.
I set up a Pi 3B+ as a router back in March 2018. I had same setup on a Pi3B that was running fine for 2 plus years with no issues and only heatsinks. Well I decided to switch the micro card to the 3B+ but of course it did not boot since the OS was not compatible.
So I flashed the newest of Raspbian , installed the code and changes for the router config and the new 3B+ was working fine. I didn't have any overheating issues but decided to put on the new dual fan system from Iuniker made for the 3B+.
This worked for I guess about 2 weeks and I went to upgrade my Pi's last week. (I have many small projects on Pi Zero, pi Zero W, Pi3B and this new Pi3B+) and could not SSH or VNC into the 3B+. So I checked on it and the only light that was on was the Red led and the fan was still running. No green activity light and the ethernet lights were not flashing.
 I found it strange the Pi was not running but the fan was. I unplugged the pi. Waited a minute and plugged the power back in. Only the Red led came on and the fan.
The green light didn't even flash once. So I tried everything. Unplugged the fan. A power supply (I uses 5V with 2.5 or 3 amps) I know is working from another Pi3B. I replaced the card with a fresh image of the OS. Still nothing. I have another Pi3B+. I took the card and power supply from the bad one and put it in the new one and all is ok and working on the 2nd 3B+.

So is my 3B+ fried? Why does the fan come on and nothing else? How do I check? Also do I return the unit to Microcenter where I purchased it? How do I remove the fan/heatsink? Could that have caused issues? If It shorted I would think it would not take over 2 weeks to stop working.
I'm also worried if I put the dual/fan on my newest 3B+ it may cause the same issues.
I also saw someone on youtube who said to pull and reseat the connector above the sdcard as that has cause him issues in the past. But it didn't fix the problem.

 Any help would be appretiated.
Chuck LoweAsked:
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Dr. KlahnPrincipal Software EngineerCommented:
Sounds like the Pi ate itself.  The heat dissipation possibilities for Pis are not very impressive.

Since you are starting over ...

For this application I would recommend using a "real" PC such as an HP T5740 thin client instead.  It can run real linux, any release, supports 4 GB of memory, has USB slots out the wazoo, and costs about $25 on the fleabay.  With an Intel Atom it is considerably more capable than a Pi and there are no heat issues -- I've been running mine for over a year 24/7/365.
Chuck LoweAuthor Commented:
@Dr. Klahn
 Thank you for your response. That model sparked a memory in me. I goggled it and it looked exactly like one I had 3 years ago for my Kodi box. A friend had got me a ST5742. All the same specs except no Wi-Fi. I even put 4GB of DDR3 in it, we found a connector (bought 2 cause he said bending it may break one which it did) and put in a 120GB SSD. I abandoned it as I got into the Pi. Since I see on eBay they are very cheap , cheaper as the Pi sometimes, BUT my issue is the size. I like the small form factor.
Plus the power consumption is lower. 5v 2Amp ver 19V 5 Amp. Plus the Pi was as strong as my old Linksys Wi-Fi signal. (I have a new Netgear but too lazy to install it). But I may fool around with one just to see so I can say I did it.

This is the first I had a Pi die on me. Don't know if the insulating tape that came with the fan melted and caused it to short. But all the youtubers swear by it. How it keeps the pi below 47 Centigrade even during stress test. I'm going to remove the fan and tape with a exacto and some alcohol and see if the tape melted.

Maybe the Pi 3b+ has a bad batch run. Anyone else have issues with it?

Thanks for the reply
Dr. KlahnPrincipal Software EngineerCommented:
Plus the power consumption is lower. 5v 2Amp ver 19V 5 Amp

Side note:  Power supply rating generally is well over what a system actually pulls -- it has to be.  In my experience, an inline power supply running at its rated power will overheat and eventually burn up due to poor cooling.

A Kill-a-Watt reports that the T5740 pulls 13 watts, running or idling.  I would expect the Pi to pull 5 to 8 watts plus the fans.  (If the fans pull any significant amount of power, this may be pushing the power supply toward its limit.)
Chuck LoweAuthor Commented:
@Dr. Klahn
 I used a 5v, 3A on all the Pi 3's. Plus I measure the amount of power being drawn with a volt meter and USB inline volt meter.
I also use dietpi as OS to keep it minimun footprint and resourse. Shutdown the USB hubs (except the one that draws on the ethnernet).
Shutdown the HDMI. Basically shutdown what ever I don't need so I uses as little power as needed. Plus I switched this power supply and
the sdcard to another Pi3B+ and all works. Just didn't add the heatsinks and fan. After I take the fan and insulated tape off the bad Pi I'll report back and let all know if it's working. I'm hesitant to put another fan on the Pi that is working. Luckily I live near a MicroCenter and get the Pi3B+ and (PiZero W $5) cheaply. I actually have like 5 each. But I don't want to fry them all. Also I posted this on a few other sites including raspberrypi.org and had like 62 views but no replies.
Wish me luck.

The one issue I'd really like to know is why the fans (connected to the GPIO pins) still run when the pi is essentially dead!!
Dr. KlahnPrincipal Software EngineerCommented:
The fans are connected to the GPIO pins?  As control, or as primary power?

If the fans are connected to the GPIO pins as primary power, that would burn up the Pi's GPIO drivers pretty darn quick.  Even a small fan pulls at least 50 mA.

"After a reset, the RPi comes up with the GPIO outputs set to 8 mA drive capability. "
Chuck LoweAuthor Commented:
@Dr.Klahn
I'm not sure what you mean. I followed the instructions with the paper that came with the fan which was the same in 2 YouTube videos.
Pin 4 (5v) was the Red wire and pin 6 (ground) was the Black wire.
Chuck LoweAuthor Commented:
Just for kicks, I used alcohol and a exacto (razor) to remove the fan and the other heat-sinks. Yes I let it dry for 24 hours before adding power to it. First I used a magnifying glass to make sure nothing was shorting out metal to metal. Also there was no melting of the adhesive tape
that could be shorted. Waited a day and the Pi still wouldn't start.
I have my other 3B+ running for over 4 weeks with no fan or heat-sink. I hesitate to add another iuniker dual fan to this one.
If I do and it dies I would assume there is an issue with the iuniker unit.Or I may start with just the dual fan and wait a month and
add each heat-sink and wait a few weeks in between. It could tell me the 3B+ was defective. I will have to check which manufacturer (the Pi) came from. Even though someone said they use the same site and assembly line.

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Chuck LoweAuthor Commented:
No solution found. The Pi is dead.
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