SRT CH6012 HV CL Servo Review for GT Style 1/10 Touring

I picked up this servo as an upgrade to go in my ancient Tamiya TA03 Porsche 911 GT1, which I’ve been renovating from box stock to something resembling race spec and a speedy street basher over the last couple of months. (See the actual build log for that one in another post!)

The original steering servo was an old Acoms AS-12, which was ok for it’s time, but a bit low on torque and a little sluggish. I “upgraded” to a servo that came with a GoolRC motor/ESC combo but that, while strong, was actually somehow slower and made it practically undriveable. 

The SRT CH6012 has certainly solved those problems. This is a very fast steering servo. It's fast and quick to react but also somehow smooth in it's response. Compared to my other fast servo, an AGFRC A81, it's maybe very slightly slower, but defenitely smoother and possibly a little more linear in feel. The SRT also works great on standard 6V power, with a little bump in performance if your ESC can go up to 7.2V. I also got rid of the old Tamiya servo saver and replaced it with the hi-torque version, which instantly improved a lot of the play in the steering system.

Here are the tech specs:

Torque @ 6V: 9KG
Torque @ 7.4V: 12KG

Speed @ 6V: 0.07Sec
Speed @ 7.4V: 0.06Sec

Operating frequency 330Hz

Metal gears: Copper and Aluminium 

I also tried this servo in my Tamiya M03 Mini Cooper, and that was a great fit for that car. Brilliant direct control of the steering, and plenty strong enough for the smaller scale M-Chassis model. I think this might become a really solid go-to servo for racing M-Chassis stuff and other models that sort of size and weight.

The servo feels really well made, with the external plastics feeling really solid, with the whole unit feeling really solid all round.

If you’re looking for a reasonably priced reasonably high performance servo, this gets a strong recommend from me. 

Here’s a completely non-sponsored retail link for the store I bought mine from in the UK:

https://www.modelsport.co.uk/product/srt-ch6012-hv-cl-servo-90kg-007-sec-at-6v-semi-m-case-433882

I believe they’re being carried by quite a few shops. I also saw them on the MB Models website when I was browsing for pricing and stock levels.

Tamiya M03 Rover Mini Cooper Racing

My first project that brought me back to the hobby is to completely renovate my old RC car that has been sitting broken in its box for 20+ years.

What happened to it 20 years ago you ask?

Well, basically I built it stock around my early teens with plastic bushings and at some point in the first test run (I hadn’t even painted the shell), one of the bushings fused to a shaft in the gearbox and melted part of the gearbox casing (which is also the chassis). The holes where the shafts sit had melted and actually moved around while they were still hot. What I believe to have happened was that I didn’t grease anything when I built it and that caused the heat to build up. 

Anyway fast forward 20 or so years and the M03 is no longer in production and chassis replacement parts are hard to come by. eBay turned up  several complete chassis though and a couple of overpriced limited edition parts so I ordered a few bits.

First to arrive was this lovely blue plated plastic chassis. This was expensive and shipped from Australia... It looked awesome and on initial inspection seemed to be in great condition. So I started the rebuild in this chassis armed with a reprinted manual, as my original copy had gone missing. 

What a satisfying process the rebuild was. The M03 is a super easy kit to build “and a great starting point for someone starting in the hobby” (is what I would say if it was still 1997). The main hop up I stuck in there was a set of bearings to replace all those terrible plastic bushings. Pretty much everything else is stock, except for some lovely blue aluminium C hubs. Even the original motor was still working fine and I even made use of the old Acoms servo (which is a bit slow but will do for now). The main replacements from the original parts came in the electronics. I got a new receiver for a modern 2.4GHz controller and a Hobbywing 1060 ESC to get reliable motor control. 

Anything else broken?

The body mount posts were bent at funny angles from years of sitting upside down in a box under a load of other boxes… making it very hard to get the body fitted straight to the chassis. I tried a few things out to straighten them out with little success, but then remembered something from my A-Level Design and Technology… that most plastics like these are mouldable with heat and could even return to an original shape with just the heat. So I boiled the kettle, popped the plastic parts into a pan (so they could lie flat) full of boiling water and like some sort of witchcraft they began to straighten out. Couple more runs with the boiling water and we got to 99% straight which was enough to find the body holes without too much faffing about.

First rebuild looked great. First drive... not so much! I clipped a slightly raised curb on the edge of my drive and the entire suspension assembly on the front right snapped completely off at the chassis. Turns out vintage plastics can go brittle quite quickly… not only that but the shock tower part of the chassis had also cracked through. So I went about gluing it together with ABS plastic cement, which melts the two sides of plastic to together to form a bond "99% good as the he original moulding". Upon even closer inspection there were cracks all over the chassis shell. At that point I decided to finish patching it all up with the plastic cement, and setting it aside for a shelf only blue build. Thankfully more chassis parts had just arrived.

Onto rebuild number two then! This was the same silver style chassis that I’d had on my original. I inspected it closely and, with my new knowledge of what to look for, found nothing wrong with it. The plastic felt a little more supple with a little bit more give to it than the blue plated one.

This build also went great and the test run also went well. I might fill and seal the diff at some point to make it a bit more grippy as it's quite loose with just the grease inside it. Generally pleased with how it turned out though, and super pleased to have my old RC car working again. Even the old 90's standard 540 motor runs great! 

Original Model
- Tamiya M03 Rover Mini Cooper Racing

Retained Parts
- Acoms AS12 Servo
- Tamiya 540 Silver Can motor

Current Upgrade List
- Full Sealed Bearings

- Aluminium Front and Rear Hubs (Jazrider/RCJaz)

- Hobbywing Quickrun 1060 ESC

- Tamiya Torque Tuned Motor

- SRT Servo

- JK RC Oil Filled Shocks

- Absima Radio Rx/Tx kit

- Absima 4000mAh NiMH

Final Form

One thing I’ve skipped over is that in my desperation for new chassis parts I’d also done some late night bidding on a couple of complete rolling chassis with wheels and motors. So now I have three complete M03 chassis… I’ll talk about them in another post!

Welcome to Revive RC!

Hi, welcome to the blog!

I'm a dude approaching 40 getting back into my childhood RC hobby. I'll be fixing up old cars, maybe building some new ones and possibly even doing a bit of racing, and trying to get some of my mates into it too.

My main aim is to have fun while I fiddle with old RC cars and see how well I can get them running. Hopefully some of what I do and document as I'm doing them can be helpful to you or someone else too!

Here's a little about my history of RC cars and the toys that preceded them.

As a child of the late 80's and through the 90's I had a number of RC toys from the likes of Tomy, Nikko, Tyco and so on. It was a golden era for cheap exciting toys you could bash around the house or in the garden. Stuff like the Tomy Char-G, Tyco Triple Wheel, Tyco Rebound and a great Nikko speedboat among quite a few other bits and bobs. We had some other cars too, there was a small tracked car, and I think a Tyco buggy of some kind, along with some Lego Technics motorized cars.

After the toys my dad got a Mardave Cobra for us to build together. I think was an attempt to get us off the video games quite so much, and he was also desperate for us to get into building stuff with him, but we never really liked Meccano he tried us on before.

The Cobra was a lot of fun. We bashed that car around our garden all the time. The real flaw was that the old 90’s NiCad battery packs were pretty low capacity and lacked the punch of even NiMH packs. Much later I did buy a couple of decent NiMH packs for the Cobra, but by that stage the Cobra was already in a bad way reliability wise. 

Eventually it broke and it was deemed beyond repair so it was binned(!) between a couple of house moves. An action I now regret, as now I want to get a new buggy!

Around the same time my brother wanted a car too, so he got a Mardave Mini. That was a fast car! But it wasn’t as fun bashing around the paved bit of our garden or the dirt paths near our house. We didn’t really understand that it was a racing car designed for use on a properly prepared surface, like carpet. That car also got smashed to bits and was eventually thrown out too. Which is a shame too, but that was also heavily damaged. 

Sometime around 1999/2000 I picked up a Tamiya Mini kit on the M03 platform. I wanted a new Mini, but with a bit more in the way of suspension for bombing around our uneven paved drive and the unmade dirt road down the side of our house. Unfortunately in running it for the first time, as an excitable teenager, something seized in the gearbox for some reason. I put it down to the lack of lubrication in the plastic bushings, but it could have been any number of things even down to just bad luck and bad driving. When that bushing seized it caused the axle to heat to such a level that it melted the part of the chassis that it sits in and all of the gears ended up way off axis meaning the gears didn’t mesh so it stopped. I hadn’t even painted the shell…

There ended my engagement with RC cars, until 2023, when I decided to get the Tamiya mini out of my parents basement and get it running, which is where we begin with my next article.