The steering diodes should be testable if you can borrow/buy a continuity/resistance/diode test meter. CPC and Lidl's sell adequate meters for under £10 if you don't have one.

Re: VSS. I have tested the VSS circuit a few minutes ago while I still have Ian's 12-pin TSM ( it is a bit drizzly here so I am delaying a walk up to the PO for a while).
Yes, you are completely correct in that the VSS is used to cancel indicators after 7 seconds above a certain speed. That speed is a tad slower than with the 18-pin TSM, which could be due to manufacturing tolerances in the CPU's RC oscillator.

Ian's problem is solved, you will be pleased to hear.

It was not a duff relay or diode ;-)

But Fuzz!

I cannot remember the correct term for this. Corrosion of the copper will generate copper sulphate (and other salts) which conduct electricity.
It may be worth spraying with something to prevent it reforming, e.g. 'conformal coating' or even WD40, but keep the spray to the area only as some relays do not like silicone. Many years ago, I heard of a telephone exchange getting a sudden increase in relay contact failures when the cleaners went from using bees-wax to silicone floor polish!

Radio Control modellers see something similar: it's called 'Blue Death' (or is it Green Death?, can't remember), in which the cable from a NiCd battery pack to the receiver corrodes.

A lot of my R/C equipment has suffered black wire corrosion. As Alister says, the most frequent occurrences are in Receiver (and Transmitter) battery packs, and seems to happen in storage even if the battery concerned is disconnected. It can also occur in servo wires. Wherever you spot it, cut it out and replace it, or it can have bad consequences.

To avoid any oxidation problems with the negative cables of the electric harness on the frame, I solder all the negative electrical terminals with lead and strip the frame of its paint and protect it with aluminum grease when removing the body for the first time. .

I have not heard as to how the test is going, so I am assuming that all is well and the first TSM-2 is driving all over the country as we speak!
Therefore a batch of 20 will be made as soon as I get a shipment of capacitors in - there is a world shortage of all sorts of components at the moment, and that's not helping

If people wish to buy one of the new 18-pin TSM-2 modules then please email me at work. Once the batch is ready I can let you know the price.

Use my name (without the trailing 'W') followed by @qbi-c.co.uk

The first batch has had the conformal coating applied this afternoon and half the batch are now in their enclosures, labelled and tested. Here are some snaps taken today...[img]https://www.dropbox.com/s/tpo7qihzsisxqd8/DSC02747.JPG?dl=0[/img]
[img]https://www.dropbox.com/s/2nfp0d2n3g9xnvu/DSC02752.JPG?dl=0[/img]
[img]https://www.dropbox.com/s/mr3hazh4nfgm3j7/DSC02755.JPG?dl=0[/img]
[img]https://www.dropbox.com/s/fcqp3ccb1m1v5lm/DSC02758.JPG?dl=0[/img]
[img]https://www.dropbox.com/s/v1l2z9jdgz7ndhs/DSC02759.JPG?dl=0[/img]
We should post some out tomorrow morning, but it won't be first thing due to an early Zoom meeting.

They look splendid. Most professional! Here are the photos without having to access dropbox:

Thanks very much for sorting that out ;-)