Mechadoll charred foam, broken thermocouple, help!!!

dildoll · Post by **dildoll** » Sat Sep 09, 2017 10:04 pm

Hi Folks,

I have a Mechadoll heated Sophie. She's been great for 2 years, no major issues.

Until last week.

Heating is broken and dangerous.

The thermal controller read "LLL". Given that it is a MH1210F controller it was easy to find the instructions. "LLL" means it is reading a below -58 degF. So....broken. I hold the room at about 75 deg F. Sure enough, I bought a new MH1210F controller and it came with a new thermocouple. Testing it with my Fluke 73 meter the resistance did vary with temperature.
I replaced the controller in the Mechadoll control box and instead of plugging it into the doll plugged the new thermocouple into it. Functioned perfectly. Controller was probably OK.
Then I replaced the wires exactly from the doll head cable that runs into the controller unit.
SO: now control unit is new, plugging into doll that likely has a broken thermocouple.
Sure enough, "LLL" again.

Now I need to find and replace the doll's thermocouple. NOT FUN.

I have not had information passed on my the manufacturer, so I carefully did the surgery myself (not pretty):

: sasha_dangerous_1.jpg (691.27 KiB) Viewed 3216 times

Note the charred, discolored foam and silicone right above the elements:

: sasha_dangerous_2.jpg (654.2 KiB) Viewed 3216 times

Anyways, does anybody know where the HE** the FU**ING thermocouple is???

My guess is below the belly button, but I hate to do cosmetic damage to the front of her.

TIA, and beware...

dildoll · Post by **dildoll** » Sun Sep 10, 2017 9:52 pm

Quick update: no response at all from the MD folks.

Flying solo here, so here's what I'm going to do...

Somebody slap me if this logic doesn't flow:

The controller they are using is a simple single input single output closed loop feedback system.
The doll has 3 main 10 amp fuses. They need to be replaced about every week or so depending on the temp settings....and...(read below)...

There are times when one section of the body doesn't heat up.

This means there are 3 heating elements / sub circuits all in parallel with the main power source...(slap me if I'm wrong here). Those resistances in the 3 branches have to all be really close to the same value or the system goes out of balance (hence 3 fuses).

One input (still do not know where that little sh** is) is all that is coming back to control the current pumping into those output parallel branches.

The controller is programmed manually to tweak the PID loop, based on MD's recommended values. They must have a fairly repeatable situation (thermocouple location, thickness of silicone, foam thickness, etc) to give those values.

The location of the thermocouple (input) is not that critical in this case, though....as long as it is close to the vagina. The controller will have different PID values that will have to be found in a bit of trial and error, but this seems logical to me.

SLAP? Punch? Throw it at me!

TIA

LovesBlackWomen · Post by **LovesBlackWomen** » Sun Sep 10, 2017 10:00 pm

Looks like you need an engineer to fix that.

dildoll · Post by **dildoll** » Sun Sep 10, 2017 10:03 pm

naaaaah....I gots me a roll'a duck tape and some pliers...

dildoll · Post by **dildoll** » Sun Sep 10, 2017 10:07 pm

I have to say I am impressed there were no major problems like this for 2 years. Things break, you just have to be able to fix them. For serviceability I give MD an F-. But then again, they don't make a lot of these dolls, they are not ReadDoll. When you break it down it's a simple system, I just need to know where the fu**ing thermocouple is. But I'm holding to the logic above as I'm not going to cut the front of her belly...done enough digging in the back.

dildoll · Post by **dildoll** » Sun Sep 10, 2017 10:10 pm

...and engineers are overrated and generally full of BS (I am one, I'm allowed to say that). Somebody that knows how to actually fix things is much more valuable IMHO. Now give me a minute while I shove my foot in my mouth and look at the mess I have to repair...

samara78 · Post by **samara78** » Mon Sep 11, 2017 5:30 am

I would just remove it altogether if it were me and snuggle under a heating blanket with her. That looks difficult to find, much less to repair. When you get on to closing her up, i would be delighted to help you out.

dildoll · Post by **dildoll** » Sun Sep 17, 2017 8:31 pm

OK Folks, quick update:

Still nothing from our buddies at MD. Complete silence.

So since the warranty is void (haha) I'm going all in.

You've seen me open up the back and try to pull the plug out of her so I could find the broken thermocouple (repair of the skin is going to be a bitch):

: sasha_dangerous_1.jpg (691.27 KiB) Viewed 3030 times

Since then I have done a bit more digging. Again, new controller and new thermocouple work fine (thermocouple was the issue inside doll). NOW, have to find the correct leads and understand the system better.

ALL INFO BELOW IS NOT MEANT TO BE INSTRUCTIONAL, USE AT OWN RISK!

Here's what I learned:

: sophie4.jpg (259.84 KiB) Viewed 3030 times

A breakdown of the voltages from the step-down transformer:

: sophie8.jpg (234.51 KiB) Viewed 3030 times

The pin out of the connector:

: sophie6.jpg (125.06 KiB) Viewed 3030 times

Some details of the heating elements I found on her aluminum heat-spreading chest plate:

: sophie2.jpg (171.31 KiB) Viewed 3030 times

Turns out I should have dug a bit deeper into the foam when I did my first life cast of her boob-less chest in the mission to fix their defective breasts:

: sophie1.jpg (300.32 KiB) Viewed 3030 times

Her left pelvis and knee heat up now, her right pelvis and knee don't. That fuse blows quickly, probably because somewhere inside her there is a broken wire or burned-out element causing that parallel heating circuit to be imbalanced, also lowering the total resistance letting more current through the 10 amp fuse that pops within 10 minutes or so now.

The upper heating system is fairly stable...but not sure about the overall resistance being what was initially there when she left Yves shop. I accidentally cut the heating element around her torso, remember, and that is screwing up the system again due to lower resistance. It's not as obvious, though, because the 12 ohm ARCOL knock-off elements are OK and symmetric inside the body.

SO: what to do???

System is at least working again and I can place the new thermocouple somewhere in there.

System is broken and imbalanced. Not going to do any more digging as it is stupid (even for me!) to think you could repair a heating strip inside the right leg and have some chance of it being correct and cosmetically repairable.

Thoughts?

Again, all above information is not intended to be instructional, use at own risk. ALSO given the shifty nature of MD's doll's inconsistencies that seem to vary depending on year made and location made I have no idea if your system is like what I have found.

GGGGGGRrrrrrrrrr.....

dildoll · Post by **dildoll** » Mon Sep 18, 2017 5:03 pm

SLAP!

If there are any EE's reading this post I just punched myself for a basic error:

Pull a resistor out of a parallel circuit -> total resistance goes UP, not down, idiot!

OK, so apply that logic.

E=IR

I=E/R

Hold 18V constant, raise resistance, current drops linearly.

There are two 18V taps on that transformer. One for upper body, one for lower body.

Controller is simply turning entire transformer on/off (not single taps)

Measured resistance:
Lower body: 12 ohms (this is the one popping fuses)
Upper body: 3 ohms (current draw under 10A)

WTF is going on? The opposite should be happening! EE's: try to explain the behavior of a transformer that has dual secondary windings when exposed to 2 parallel loops that have different resistances. Internal coil resistance in the PT is very low, imbalance will throw you off, you cannot count on voltage to remain constant. SO: higher resistance = more current? Still not able to sink in to this idea...stupid mechanical engineer here...

This transformer they are using is a dual primary winding and dual secondary winding toroidal PT. (Triad's VPT36-4440)
Primary windings are wired in parallel, so good for 115 VAC.
Secondary windings MUST be wired in parallel (2 10 amp fuses, 2 parallel loops of thermal resistors), so they get 18VAC.
Outputs are rated for 160 VA.
"VA ratings are also often used for transformers; maximum output current is then VA rating divided by nominal output voltage."
So the transformer will let out smoke if you exceed 8.8 amps????

I pulled the tech spec sheet for that transformer, this is a kind of important thing in there:
Output Voltage:
Series:
36VAC CT@ 4.44A
Parallel:18.0VAC@ 8.88A

I also called the Triad techs and they said it could probably handle more but it will eventually saturate the core and overheat.

YUP. There is a very, very good reason Yves stuck to his guns in making MD buy very pricey aluminum enclosures for the thermal control unit! It does get warm on the surface, maybe 40 deg C or so. The transformer has a good internal 1/4" clearance from the top of the control box. For anybody that has done some CFD / thermal work or has some sense of electronics and temps that means our little buddy in there is COOKING! Triad makes a very good product, apparently, because that transformer is being tortured. If 10 A fuses are being popped regularly on a component that should not see more than 8.8 A...not good.

EE's: please call me out on any errors in the above.

It looks like a bigger power transformer should have been spec'd in the first place.

Each loop should get its own transformer, but this would cut into sales margins (each transformer they are using is about $50).

TIA and be careful!!!

dildoll · Post by **dildoll** » Mon Sep 18, 2017 5:17 pm

...technically those are not "taps", I know...sounds cool though...

carlys_guy · Post by **carlys_guy** » Mon Sep 18, 2017 6:10 pm

personally i would do like samara said and forget the internal heater before you burn up the doll or your house.

carlys_guy

dildoll · Post by **dildoll** » Mon Sep 18, 2017 6:31 pm

yeah, I hear ya. It's in my monkey-brained nature to take things apart and figure out what is broken.

BOTTOM LINE: dangerous to send a product out that will overheat at 8.8 amps and give it to a customer with 10 amp fuses.

CrazyCajun · Post by **CrazyCajun** » Mon Sep 18, 2017 7:19 pm

dildoll; Sounds like the heating element is shorting. When current is applied if there is any damage to the heating element the nichrome wire inside can shift and contact the outer housing which is a short! Once power is removed the heating element cools, pretty quickly, this allows the wire to shift back to the correct position inside the element and the short is now not readable on your meter because it no longer exists. I see this all the time with strip type heating elements! Drives a lot of people nuts! And yes Higher Resistance will = Lower amp Draw! Assuming all voltages are equal!

dildoll · Post by **dildoll** » Mon Sep 18, 2017 7:27 pm

Aaaaahhhh....good to know! I had no idea that heating elements failed that way. It turns into a car turn signal relay!!!

Well, shit. If that is the case then pop goes any idea on futzing with the power supply and control system. I'm not digging in blind to remove a strip heater. Our buddies never gave me info on location of wires, otherwise I might try something like that...maybe not.

Well folks, anybody see any way to fix the situation if CrazyCajun is right? And NO, not talking about getting a heating blanket!

dildoll · Post by **dildoll** » Mon Sep 18, 2017 7:31 pm

HANG ON...the thermocouple issue was real and I was able to find and fix that issue. CrazyCajun, if that blew out and caused the system to keep pumping in current (although elements were protected by 10 amp fuses), how likely is it that the elements are toasted? The only way I know to test this is an obvious outer temp measurement on where heating elements should be getting hot...or could something else cause those elements to not get power? Like an imbalance parallel resistance in the loop? Hmmmm....