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This is an interesting one, and I have been looking for one of these for quite some time... even without knowing what they actually looked like.

About a month a good friend of mine was looking to buy an Optima, and in the background of one of the eBay pictures I spotted a mystery ESC, looking very much like one of the 'heatshrink era' British offerings of the time. I offered a little advice to the guy considering the purchase and casually mentioned my interest in that ESC when it arrived. He said i was most welcome to it as he had no interest in old electronics. Cool freebie.

BINGO!

This was all i had to go on in the auction pictures:-
When it arrived there on the back of the PCB was the answer i was hoping to see.... the letters MFT.
I immediately sent some photographs to Nick Marson of Nosram fame, who having had a good look over the pictures sent me one back of the same speedo he still had in his collection, confirming it as one of his. I had seen the name Marfet in some magazine tech sheets from the 1986 Radio Race Car Series so knew they were top-notch for the period, and had always wondered what they were.
Nick got back to me and gave me plenty of details about this unit. He built 6 of them as a hobby in 1985 when he was a competitive racer himself; one for himself, which he still has, and a handful for a few other local racers. One of those was Mark Mainey whom you will notice using the Marfet in the above tech sheets. I spoke to him and this is what he said:-

'Previous to that I was using a Lazer speedo with a great big relay on it which kept blowing. Nick turned up at the Gloucester track on Friday night and said to try this, a Marfet, in my car. Well the difference was amazing. Felt like I had put a modified motor in. That weekend I raced at GEC in Stafford and for the first time managed to keep up with the big boys, even though I never had the matched cells or works motors they were using.'

I can see then why he stuck with it for the 1986 season.

The story goes that Nick Marson did not want to be producing speed controllers which would lead to him spoiling his racing hobby, so when he was approached by RRC magazine to potentially sell the Marfet design, he went for it. In fact, he traded it for an RC10 and the freshly-unveiled Pb Mini Mustang. This would have been very early 1986. (He then tells me he got asked a couple of months later to write a review on said Mini Mustang which was used in RRC, and he then found out the kit had been sent to the mag for free for review!!! Some clever wheeler-dealing went on there to basically get a free esc design!)

The Marfet design was then made available in kit form and you could build it up yourself via the magazine, marketed via a company known as Century Systems. I am still looking for any relevant adverts.

Ironically not long after Nick Marson set up Nosram (Marson backwards) and developed the esc line up we are more familiar with. The Marfet though, was his 1985 original.

Nick said that he was looking out for the flux having been removed on mine, and the MFT lettering, so that suggested this one was one of the ones he made before selling the design. He also sent me a shot of the side of his PCB which showed the exact same component layout as mine.
I sent mine off to electronics whizz Ian Mullaney in the UK who tested it and confirmed the reason why it was piled in a heap of spares in the sale; a blown FET. He replaced that and rewired it and it is now all up and running again. All it needs is fresh heatshrink and popping into a suitable car.

Nice story about old ESC.
What is really interesting to me is the relais found at the PCB. It is fully watertight and is what I used also at my own ESC around 1982/1983.

Thought that looked familiar , there's just a smudge where you have MFT but the circuit design is the same , we already talked about this one , it came with the PB Mini Mustang I have . I've removed a burnt out FET and two of the heat sink plates were removed to do it but it looks right to me .

Yeah, now that is interesting, and a great addition to my thead I just sent you a quick PM about it mate.

I can see now what Nick meant regarding the flux removal on the underside, and the MFT lettering on mine being able to determine mine as one he made.

It looks like yours had some sort of case too at one stage?

It's kind of a mica frame , think it was used as a means of mounting it , if this was a kit then the builder could solder pretty well . Looks messy where I removed the smoked fet , it's been sealed with resin underneath .

I just sent the pictures to Nick.... he replied straight away:-

'Wow, of course people were free to do what ever they wanted to... Also to cheapen it regular electrolytic caps have been used rather than tantalum.'

I guess he can see some differences in the components used compared to his.

Quite interesting to compare the two.

I had a Marfet back in the day.
Got it second hand and it's long gone but I think it may have come from Andy Langdon who ran some of Nick's equipment (and raced the same areas as Mark Mainey) so there's a chance it was an original.
Was in black electrical tape though, not heatshrink so maybe not
Didn't know the back story of 'selling' the design - that's really interesting.

Hi mate - great info. I have just asked Nick whether Andy was another of the original recipients. So far i know Mark Mainey and Nick Elliot had them off him, plus Nick retained his own. So there are another three unaccounted for....

Bit of feedback below for Keith regarding Andy Langdon. It also sounds like other built-up versions were available later according to Nick. I presume they were not allowed to use the MFT lettering though.

Nick said 'No Andy joined team MGN later when the Nosrams were out. Rory and Andy would have bought kits. Actually I recall that Century Systems also offered an assembly for people who didn't want to try and make their own.'

Thanks Martin - even more interesting.
Didn't realise MG and Nosram combined for a team, assuming that's the MGN you mention as I've not heard that term before.
Andy's rise to real top level was maybe a bit late for those prototypes. Strong chance he had a kit version as his dad was handy with stuff like that, rather than prebuilt - which would also explain the slightly hap-hazard insulation tape

Yes, it is a little known fact... MG and Nosram joined forces to make Team MGN for a while.... some names in that team too.

Another cool bit of Marfet technical info.

I don't suppose you have a circuit diagram ? After replacing all the FETs it's still dead but now the relay clicks and the break FETs warm up , I found a short across the main drive FETs and assumed one of the new ones was a dud so removed them again only to find the short is on the board still . The original owner applied a waterproofing resin to both sides of the board and I can't remove it without removing the part numbers of the smaller transistors so a circuit diagram would be a good send .

All I have is what is shown in the above article. I will pass your comments on to Nick Marson who might have some suggestions also.