How to / DIY > Engines

Lister LT1

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Welderherup:
Hello to all. Iím new here. I bought an LT1 on gumtree for £300. I had been looking for a diesel genny to be my primary genny should power go out. Iím in Ulster so there is seldom a lister for sale and normally they are very expensive so I was happy to get one for £300.

The genny was working fine when I bought it. I only give it a wee run a few times. Iíve had it for about 3 months. Today when I went to it to service it I noticed it was down on voltage. 70v when it should have been over 220 or whatever. I took the back cover off and noticed two little capacitor looking boyos were damaged. I also noticed a damaged clip and the races the brushes run on on the rotor were filthy and one of the little arms that holds the brush wasnít springing nicely back to its position. So I fixed that and changed filters. Fuel was a horror show. Iím amazed it was even running. So fired her up and she was making 130v now. I noticed when I moved the throttle control it increased the voltage so I screwed it up until it showed me 230v. I tried my drill and it was spinning at a good speed but still seems low on power.

Look at the photo, what is that little board? Are those capacitors that are damaged? The machine looks tired in general. Do you think I can rely on this machine? Are there tests I can do to verify the power side of things? The engine is grand. Starts first crank, not smoking. Sounds like is should in the respect that it makes the most shocking racket imaginable but is nice in its dieseling way.

Thanks in advance.

mobile_bob:
if i were you, i would be taking the board out, and carefully cleaning it up!
scrub it down and see if i could identify from the circuit board what the components are or rather were.

be very careful as you clean, so that any printing on components doesn't get wiped out, or scrubbed off.  use a small soft brissel pain brush to start, take a picture, blow it up and then mark on the picture any identification numbers on components you can find, and any marking on the circuit board that might help identify the part(s).

my bet is this is the voltage regulator and that is why you are down on voltage.

you also want to carefully clean the brushes, the brush holders, and using very fine wet or dry paper the slip rings on the rotor, make them bright and shiny again.

i don't have any schematics, for your genny, or that pc board, but with some cleaning, some better pictures and as much info from the parts and the board, we ought to determine what parts are and what is needed to get it functioning again.

the genny is not dead, it produces power, so in my opinion, the parts that are burnt are likely going to be fairly easy to determine what they are and their values.

good look

bob g

Welderherup:
Great thanks. I will get the board cleaned and hopefully have some details tomorrow. The outer cover of the little components that show damage is pretty much gone but it looks fresh to me. I did have a problem the first time I used it, I was charging my batteries and tried to turn on a hover at the same time to test the power. This seemed to spike the power as my charger died. I reckon this is what damaged those components. Hopefully I can identify them and simply replace them on the board

mike90045:
Be careful when changing engine speed to adjust voltage - engine speed sets the frequency of the output 50hz or 60hz

cobbadog:
Welcome to the Forum.
As suggested take the circuit board out and gently clean it up using the least damaging solvents possible. Try it on an area that wont matter if damage occurs. Clean dry soft brush first even using compressed air to aid the cleaning. Electronic stores sell aerosol cans of solvents suitable for cleaning circuit boards but still be careful using them.
The last thing to do is give up on these well made old generators nothing new stand up against them on build and quality. I know very little or less on electronics but I have been coached into attempting a fix on a circuit board on a MIG welder. I now, almost know how to identify a transistor, capacitor and diode by reading the board. I still have a long way to go to work out what the values are or mean but with time and patience I am going forward.
Freeing up the brushes in the brush holders is very important and I mean 'clean' not just so they can move in and out. Also the contact surface on the armature must also be cleaned up using some fine wet n dry paper and I dont use any water when I have done these in the past. New brushes should be readily available and if not easy to get a hold of I have bought some that were a little bit bigger than the originals and filed them down to size. Like anything the cleaner every thing is the better it works and also runs cooler.
Look forward to seeing more pics of the generator and the board.

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