Hi,
Years ago on another forum whilst spending time repairing vintage valve radios I used to get involved with unusual projects helping members out as favours; if it looked interesting and something totally out of my comfort zone I'd do my very best however long it took or difficult it became; I did all these favours without charging a penny my satisfaction was in succeeding and learning something new.
I was known for my transformer and coil winding; one day a member posted regarding his hugely expensive very rare open top antique Lagonda car asking for help or advice regarding his petrol tank sender unit/petrol gauge. The original gauge had been replaced with a non standard gauge the original gauge impossible to obtain; this replacement gauge was reading only half full whilst the tank was full and the sender unit was faulty to say the least.
What followed involved many weeks of time consuming work; research and experimentation. It's an awfully long story but for members who have never seen inside an antique petrol tank sender unit I'm happy to share a bit of the story.
The tank sender unit as received through the post.
This is the sender unit potentiometer track in very sorry condition; it was a challenge and as it was giving a wrong reading it meant starting from scratch so a bit of frustration was in order.
Here the resistance wire is being coated with special varnish where I set up to run it through an heater to dry the varnish as seen.
Whale Tufnol was chosen for the new track former; I was familiar with this Tufnol having used it on other radio projects. I wondered if I could heat form it around a steel bar here seen experimenting as a first stage.
The new potentiometer track completed ready for installation into the sender unit.
Having experimented and discovered the Whale Tufnol could indeed be formed into a track profile by heating I designed and made a forming tool seen in action; heat was directly applied using a cartridge blow torch taking care not to burn the Tufnol; once formed the new track was left in the forming tool until everything was cold.
The new track fully installed and working. The replacement petrol gauge was reading 50 Ohms on full scale but only reading half full; this new bespoke track was now 50 Ohms on full scale which was perfect. I matched the track to the float travel between empty and full.
After heat forming I checked to ensure the new track actually fitted and it did much to my delight.
Rather than spending forever researching I thought up this very simple method of obtaining the float sweep from empty to full noting the potentiometer reading in degrees and used the finding to work out the resistance wire details. Once the solution is known then it looks so easy.
I posted the story on the forum at the time whilst experimenting so even had I failed I wouldn't have minded because I was learning so much; the project however was a total success with the car owner absolutely delighted. I used to do lots of such unusual favours just for the fun and interest of doing something unique. I've had to give up doing such favours due to the length of time involved where I really needed to be doing jobs around home.
I hope this is of interest.
Kind regards, Colin.
Years ago on another forum whilst spending time repairing vintage valve radios I used to get involved with unusual projects helping members out as favours; if it looked interesting and something totally out of my comfort zone I'd do my very best however long it took or difficult it became; I did all these favours without charging a penny my satisfaction was in succeeding and learning something new.
I was known for my transformer and coil winding; one day a member posted regarding his hugely expensive very rare open top antique Lagonda car asking for help or advice regarding his petrol tank sender unit/petrol gauge. The original gauge had been replaced with a non standard gauge the original gauge impossible to obtain; this replacement gauge was reading only half full whilst the tank was full and the sender unit was faulty to say the least.
What followed involved many weeks of time consuming work; research and experimentation. It's an awfully long story but for members who have never seen inside an antique petrol tank sender unit I'm happy to share a bit of the story.
The tank sender unit as received through the post.
This is the sender unit potentiometer track in very sorry condition; it was a challenge and as it was giving a wrong reading it meant starting from scratch so a bit of frustration was in order.
Here the resistance wire is being coated with special varnish where I set up to run it through an heater to dry the varnish as seen.
Whale Tufnol was chosen for the new track former; I was familiar with this Tufnol having used it on other radio projects. I wondered if I could heat form it around a steel bar here seen experimenting as a first stage.
The new potentiometer track completed ready for installation into the sender unit.
Having experimented and discovered the Whale Tufnol could indeed be formed into a track profile by heating I designed and made a forming tool seen in action; heat was directly applied using a cartridge blow torch taking care not to burn the Tufnol; once formed the new track was left in the forming tool until everything was cold.
The new track fully installed and working. The replacement petrol gauge was reading 50 Ohms on full scale but only reading half full; this new bespoke track was now 50 Ohms on full scale which was perfect. I matched the track to the float travel between empty and full.
After heat forming I checked to ensure the new track actually fitted and it did much to my delight.
Rather than spending forever researching I thought up this very simple method of obtaining the float sweep from empty to full noting the potentiometer reading in degrees and used the finding to work out the resistance wire details. Once the solution is known then it looks so easy.
I posted the story on the forum at the time whilst experimenting so even had I failed I wouldn't have minded because I was learning so much; the project however was a total success with the car owner absolutely delighted. I used to do lots of such unusual favours just for the fun and interest of doing something unique. I've had to give up doing such favours due to the length of time involved where I really needed to be doing jobs around home.
I hope this is of interest.
Kind regards, Colin.
