Kalvinder Dhillon Posted November 26, 2021 Report Share Posted November 26, 2021 Hi, I've recently started my winter project, replacing the old dash for a nice new the burr walnut, as part of this I've fitted a Smith's clock and sent my original gauges away to be reconditioned. All went well just started to put it all back together and noticed that the fuel and temp gauge are not working !. I took photos of the wiring so I know it's all gone back together properly and know the gauges are connected to the voltage stabiliser on the back of the speedo, can any tell if there are any steps to help me diagnosed the fault ? Quote Link to post Share on other sites
stuart Posted November 26, 2021 Report Share Posted November 26, 2021 1 minute ago, Kalvinder Dhillon said: Hi, I've recently started my winter project, replacing the old dash for a nice new the burr walnut, as part of this I've fitted a Smith's clock and sent my original gauges away to be reconditioned. All went well just started to put it all back together and noticed that the fuel and temp gauge are not working !. I took photos of the wiring so I know it's all gone back together properly and know the gauges are connected to the voltage stabiliser on the back of the speedo, can any tell if there are any steps to help me diagnosed the fault ? If its both fuel and temperature gauge then its more than likely a fault in the voltage stabiliser circuit, do you have power in to it (12v) and power out (10v) Stuart. Quote Link to post Share on other sites
RogerH Posted November 26, 2021 Report Share Posted November 26, 2021 9 minutes ago, Kalvinder Dhillon said: Hi, I've recently started my winter project, replacing the old dash for a nice new the burr walnut, as part of this I've fitted a Smith's clock and sent my original gauges away to be reconditioned. All went well just started to put it all back together and noticed that the fuel and temp gauge are not working !. I took photos of the wiring so I know it's all gone back together properly and know the gauges are connected to the voltage stabiliser on the back of the speedo, can any tell if there are any steps to help me diagnosed the fault ? HiKalvinder, welcome to the forum. As Stuart states check the 12V in and 10V out on the stabiliser. If you need to replace it use the later solid state version Stabiliser Roger Quote Link to post Share on other sites
Kalvinder Dhillon Posted November 26, 2021 Author Report Share Posted November 26, 2021 I'm not sure how to test for that ? I did notice that the body of the speedo was getting warm ? Quote Link to post Share on other sites
stuart Posted November 26, 2021 Report Share Posted November 26, 2021 Could be indicative of a missing earth, there should be a black fly lead with a ring terminal that goes on one of the speedo fixing studs. You will need a meter or at the very least a bulb with two wires to check voltage, with a bulb its should be bright with 12 volts and not very with 10v. Stuart. Quote Link to post Share on other sites
RogerH Posted November 26, 2021 Report Share Posted November 26, 2021 (edited) The stabiliser may well get warm but not hot. Have you got a Multimeter for testing voltages etc If so place the black(common) lead on the car body (earth) and place the red lead on the (Green) input wire. This should show the battery volts >12v The place the red lead on the output - this should read 10v Roger Edited November 26, 2021 by RogerH Quote Link to post Share on other sites
RobH Posted November 26, 2021 Report Share Posted November 26, 2021 2 hours ago, RogerH said: The place the red lead on the output - this should read 10v Depends on the meter. If it is digital and the stabiliser is the bi-metallic type you might just see a blur of numbers as the output switches frequently between zero and 12v. Really you need a moving-coil analogue meter to make any sense of it as the inertia of the needle will integrate the waveform and give an 'average' reading. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted November 26, 2021 Report Share Posted November 26, 2021 (edited) Should the voltage stabiliser be earthed to make it work? If the gauges are just hung in then perhaps no earth exists Edited November 26, 2021 by BlueTR3A-5EKT Quote Link to post Share on other sites
RobH Posted November 26, 2021 Report Share Posted November 26, 2021 The heating coil of the bimetallic type needs an earth - without it the output will be stuck at 12V because the switch will never open. The regulator chip in a semiconductor type needs an earth - without it there will be 0v out because the regulator has no control current. Neither type will work without an earth. Quote Link to post Share on other sites
stuart Posted November 26, 2021 Report Share Posted November 26, 2021 21 minutes ago, RobH said: The heating coil of the bimetallic type needs an earth - without it the output will be stuck at 12V because the switch will never open. The regulator chip in a semiconductor type needs an earth - without it there will be 0v out because the regulator has no control current. Neither type will work without an earth. Which was what I said earlier,did he have the earth link that loops across all the gauges fitted? Stuart. Quote Link to post Share on other sites
stillp Posted November 26, 2021 Report Share Posted November 26, 2021 What car is it? The voltage stabiliser on the TR4A is earthed by it's fixing screw in the driver's footwell. Pete Quote Link to post Share on other sites
stuart Posted November 26, 2021 Report Share Posted November 26, 2021 6 minutes ago, stillp said: What car is it? The voltage stabiliser on the TR4A is earthed by it's fixing screw in the driver's footwell. Pete Judging by the voltage stabiliser being bolted to the back of the speedo it would be a 5 or a 6. Stuart. Quote Link to post Share on other sites
stillp Posted November 26, 2021 Report Share Posted November 26, 2021 Yes, I missed that! Pete Quote Link to post Share on other sites
Lebro Posted November 26, 2021 Report Share Posted November 26, 2021 Call me Mr picky, but if the gauges are the type which need a voltage stabiliser, the gauges themselves do not need earthing other than to make any internal panel lights work. Bob Quote Link to post Share on other sites
stuart Posted November 27, 2021 Report Share Posted November 27, 2021 13 hours ago, Lebro said: Call me Mr picky, but if the gauges are the type which need a voltage stabiliser, the gauges themselves do not need earthing other than to make any internal panel lights work. Bob True but with the voltage stabiliser needing an earth and it being bolted to the back of the speedo then ergo its going to need an earth to the instrument as well as for the illumination bulbs. Stuart. Quote Link to post Share on other sites
Kalvinder Dhillon Posted November 27, 2021 Author Report Share Posted November 27, 2021 Hi guys, thanks for all your help especially Stuart, I tested the voltage stabiliser on the back of the speedo and it's showing no volts on the output end !. So new solid state one on order, thanks again everyone Quote Link to post Share on other sites
Steves_TR6 Posted November 27, 2021 Report Share Posted November 27, 2021 25 minutes ago, Kalvinder Dhillon said: Hi guys, thanks for all your help especially Stuart, I tested the voltage stabiliser on the back of the speedo and it's showing no volts on the output end !. So new solid state one on order, thanks again everyone The oe voltage stabiliser works but turning its output on and off to achieve an average voltage over time of 10v, so it’s possible that it is working correctly …. however a new solid state version will actually give 10v all of the time :-) steve Quote Link to post Share on other sites
Kalvinder Dhillon Posted November 27, 2021 Author Report Share Posted November 27, 2021 Nope it's as dead as it can be holding 0.10 volts !. With no fluctuations Quote Link to post Share on other sites
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