Temp gauge mod

[Alamo]

Hi All

I'm thinking of doing the temp gauge mod as described in the link below, but having trouble finding the correct resistors.

http://www.toyotasurf.asn.au/techsite/tempgauge.htm

I've already tried places such as Maplin, RS and one or two on-line suppliers to no avail. Can anyone here suggest a possible source of 56ohm 5W and 120ohm 5W please?

Thanks in advance.

AL

[MattF]

CPC/Farnell, Wizard, SEME.

[Alamo]

Thanks Matt, but unless I'm missing something, they don't seem to be available at those places either.....

AL

[MattF]

No idea then. The larger wattage can be dogs to source for certain values. I'd try ringing SEME though. Remember you can always pop a couple in parallel or series too to alter values and or wattage, if space will permit.

[MattF]

Plus, just had a look at that link you posted. I can't see why you would need 5W resistors. 2W or 3W metal film would likely do perfectly fine. (Although I accept sod all responsibility if they don't).

[Alamo]

Yes I'd already considered using lower rated ones like 3 Watt but it looks like they are just as hard to come by at the correct value. No doubt I'll find something useful at the next local radio rally, even if it means stringing a few together.....space permitting! In the meantime I'll give SEME a try as you suggest.

Thanks again.

AL

[Haydn Callow]

A guy called Dave Mason already produces this mod for Bongos and Hiace.
They cost around £25 for the kit and incorperate a "over" temp audible alarm which you can set up/ajust yourself.
It makes the standard gauge much more responsive.
Info is on Bongo Fury web site...search...Mason Alarm.
Might be worth contacting him !!

[Apache]

I'd be very very surprised if RS didn't stock them. Granted, their website can be an ar5e to navigate though.

I'm guessing (as there's no circuit diagram shown) that the zener is used as a voltage reference so the temperature gauge is correct over a range of voltages. (Dunno how accurate charge regulators are on Surfs) and replacing it with a resistor will remove that failsafe. Making the span of the meter shorter so it is more sensitive will exacerbate that.

If you do the mod, it would be worth seeing if there is a difference in temperature reading between cold idle (before you have lots of charge into the battery) and revving. If you do, then you aint gonna see accurate temperature readings.