voltage stabiliser

Post by **sidsmith** » Tue Jul 29, 2008 12:53 pm

hi all, i've been through most of the threads about temp' gauges and senders as mine always reads hot after about five minutes running even on tickover.
I don't think it's the rad' or the gauge or the sender, as i have read that you can mix gauges and senders. There are no wires connected to the back of the speedo stabiliser to wire the gauge to , so I bought a stabilser from Maplins, Prod' No / n38ca. I have read that it needs to be a certain voltage IE. neg or posi' and that the stabiliser has to be set at 10 volt or something like that. Therefore can anybody enlighten me as to the solution of what to do to set the maplins stabiliser to the correct voltage / amp' My car is a '56 splitscreen that I have converted to neg' earth
help.

Post by **alex_holden** » Tue Jul 29, 2008 12:56 pm

What voltage are you getting at the stabiliser output?

Post by **Rob_Jennings** » Tue Jul 29, 2008 1:45 pm

how to add a solid state regulator.... such as the one you have just bought:

http://www.robjennings.plus.com/morris/ ... e_reg.html

the regulator you have is fixed 10v nothing to set, just wire as in the page link above. then wire the gauge to light green wire output (colour used to match what would be original wiring) and the sender output to the other side of the gauge and it should all work fine.

you are right you don't have to worry too much about matching sender and gauge, although I have found out there there is a sender designed to run at 12v but these are rare so you are unlikely to have one of those and even if you mixed and matched with that it would just result in a low offset on the gauge.

Post by **sidsmith** » Wed Jul 30, 2008 11:35 am

hi rob, I have wired the stabiliser exactly as shown on your link IE .
L/H conn' to a spare fuse box I installed
centre conn' to earth via stabiliser screw that screws to bulk head.
R/H conn' to gauge
from other side of gauge to the sender

the stabiliser is screwed to the Bulk Head WITH the wire from the centre conn' for earth,

As I have said I can't use the stabiliser body on the back of the speedo as there are no wires there, the only wires are for the petrol gauge which are not connected to the stabiliser. Could it be that the centre earth wire should be connected to earth on it's own and not with the stabiliser body ?

Or perhaps I am looking at the wrong cause as to why the temp' gauge is giving a reading of hot/red after a few minutes running or could there be another reason.
your help is much appreciated.

Post by **alex_holden** » Wed Jul 30, 2008 11:39 am

It sounds like you're talking about a solid state linear voltage regulator rather than a traditional stabiliser. What is the part number and what voltage are you getting at the output?

Ah, I see it's a 7810. On those the middle pin (ground) is connected to the tab.

Post by **Rob_Jennings** » Wed Jul 30, 2008 4:00 pm

the tab and centre pin are connected together

if you have access to a meter measure the output (light green wire) and you should see 10v there. If that is ok then its a problem with the gauge or sender or you are actually overheating!

earthing the sender wire should give you full scale hot reading, and if you have only just put the sender in the block you may need to remove airlocks from the system.

silly question, it is a temperature sender? not a thermo switch or pressure switch? (that would simply turn on and cause instant full scale hot reading when it operates)

Post by **sidsmith** » Wed Jul 30, 2008 5:32 pm

I haven't access to a meter, couldn't use one anyway, not being electrically
educated. It is a sender unit and I tried earthing the connector from it with the ignition on and the gauge just stayed the same without any movement. I don't think there is an air lock as the heater belts out warm air when turned on. So what I intend to do now is buy a new rad' cap, drain the water and flush some descaler through to make sure there is not any blockages, If that doesn't do any good I will try and run it without the thermostat and see how I get on. I will keep you posted. Thanks for your input
sid
what an enigma
even sherlock holmes would have problems solving this one

Post by **bmcecosse** » Wed Jul 30, 2008 8:07 pm

Buy a wee cheap multimeter in Maplins - it's easy to use - we will tell you how ! Does sound like the sender unit is knackered - do you have another you can fit ? Otherwise - take it out and clean the exposed end - the one in my TR 7 suddenly went 'hot' and it was simply a collection of conductive particles on the exposed end causing it to short out.

Post by **sidsmith** » Fri Aug 01, 2008 12:56 pm

I was wondering, as I have said, I haven't got any wires on the stabiliser on the back of the black speedo, just wires to/from the petrol gauge. So would it be possible to attach some to the stabilser if so where to/ from/ how ?
or should I just buy a new one from mm shop and fit that, but I suppose I would still have the same problem.

Also with the engine running at normal speed / and temp' should the top and bottom hoses get hot as well as the rad' top, or should the bottom hose stay cool.
mungo '56 splitty