GTS OWNERS CLUB

MikeHolland

warning - technical article!

On sunny days I find it very difficult to see whether my indicators are flashing - those lights on the instrument panel are too faint.

On my GT200 I solved this problem by replacing the tiny bulbs with 5000mcd LEDs. Worked like a charm!

So I decided to try the same mod on the GTS. Pulled the handlebars apart and extracted the speedo/instrument box, opened it up and found the whole assembly (except the speedo itself) was a single PC board.

The indicator lights were tiny flush-mounted LEDs, about 3mm square, as were all the other lights on the panel. The PC board circuit was fairly clear on the left side - 100 ohm dropping resistor, then another component looking like a resistor in parallel with the LED, but infinite resistance, which I assume to be a zener diode, setting the voltage to 3.6 volts.

The right-hand side is probable the same, but the layout is much more complicated, and the LED is the other way up.

I couldn't just replace the LEDs while the diode and resistor were controlling the voltage and current, as brighter LEDs would obviously need a higher current. So I would have had to modify the whole circuit.

Anyway, the long and the short of it is that I gave up on that project.

Reassembling the speedo was a bit tricky. I had removed the needle to open the box, and would have to position it correctly on the shaft. But the stop pin just pulled out, so I set the needle where I estimated zero to be (not the zero on the dial!) and then moved it out of the way and replaced the pin. I don't have a GPS to check it, but +- 1-2kph is fine with me.

Otherwise all went together with no problems. I only dropped one screw down the steering column. Hope it doesn't rattle!

Wish that indicator switch was more positive.

Mike

Sorry, didn't take any pics.
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Vespa GTS250 Vintage Red

Bunter · Posted: Sat Dec 27, 2008 3:23 am Post subject:

Did you use the opportunity to hard wire the cutout switch while you were in there, saves problems in the future. Idea

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GTS 250+PX 200+Dragster & Runner 180+ Hexagon 125+Hexaphoon project.
Darkside and Norwich Broadsmen SC member.

nicey · Inspector Joined: 08 Dec 2007 Posts: 302

lot of hassle just 4 that just press button again sorted Cool

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NORWICH BROADSMEN SC

CheekyThomas · Guvernor Joined: 18 May 2007 Posts: 1374

Grease the kill switch so its terminals cant corrode and its never a problem anyway... Wink