Author Topic: Lister LT1  (Read 481 times)

Welderherup

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Lister LT1
« on: October 24, 2021, 07:03:48 PM »
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

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Re: Lister LT1
« Reply #1 on: October 24, 2021, 07:15:29 PM »
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
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Welderherup

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Re: Lister LT1
« Reply #2 on: October 24, 2021, 07:36:00 PM »
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

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Re: Lister LT1
« Reply #3 on: October 25, 2021, 02:55:56 AM »
Be careful when changing engine speed to adjust voltage - engine speed sets the frequency of the output 50hz or 60hz

cobbadog

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Re: Lister LT1
« Reply #4 on: October 25, 2021, 04:14:28 AM »
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.
Coopernook - the centre of our Universe.

Welderherup

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Re: Lister LT1
« Reply #5 on: October 25, 2021, 11:27:52 AM »
So I pulled her out and cleaned the board. The board was covered with wax to keep it dry and the two offending articles seem to have perished because the wax came off. They have an alloy skin which shows corrosion and so I think itís been like this a while. One is worse than the other. I suspect the alloy skin has actually broken on one but if so itís extremely small hole. I canít see it clearly with my eye.

Any thoughts? What is this board? What are the damaged components? Is this easily replaced? Would it account for my voltage issue? There are two components with adjustable dials in them. What are those?

I would really like to keep this instead of buying a new one but I have to be able to rely on it.
 I canít load the photos at full res so Iíve had to do them on low.
Thanks Iím advance.

mobile_bob

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Re: Lister LT1
« Reply #6 on: October 25, 2021, 02:34:37 PM »
in my opinion it is a voltage regulator board
and while there might be a replacement, i would be surprised.

you need to remove the board from the unit, unplug the wires, noting where they go.

get some pictures of the back side of the board as well as some high resolution pictures of the component side, and send them to me via email

and we might be able to reverse engineer the board and determine the values of those two capacitors. they died of old age.

and yes their death would have an adverse affect on voltage regulation.

meanwhile do a search for a service manual for your unit, or one close to your unit, preferably one that is within the s/n range of yours would be best. often times the service manual will have a schematic for the boards used, and with that life gets much easier.

failing all else one and after reverse engineering the board, drawing up a schematic one might get close with a guess as to the typical values used for a regulator.  if they are simply capacitors used to filter rectified current to provide for the board to regulate, then  we might be able to refer to other similar types of regulators and look to see what they used.

usually capacitors are not critical in value, other than meeting a minimum voltage rating, so you err on the higher side for voltage.

look at this as an adventure

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Welderherup

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Re: Lister LT1
« Reply #7 on: October 25, 2021, 03:18:47 PM »
Thanks Bob. I will take off the board and take better photos of front and reverse. Iíve looked for a manual but didnít find a free one. I didnít want to buy one unless I knew it was the correct one.

Welderherup

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Re: Lister LT1
« Reply #8 on: October 25, 2021, 03:28:37 PM »
I bought this book Ďhome generatorí and hope to learn the basics of generators. Are there any others that you would suggest or any other things that you could suggest so that I may get to a basic level of knowledge? I have no qualifications but Iím An ex sidecar racer and so enjoy engineering in general. Iíve got a lathe and a half decent workshop but of all things electronics are my weak spot. Perhaps I shall remedy that in the fixing my genny. Maybe being able to fix mine when it breaks is more valuable than having one that doesnít break down at all.

cobbadog

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Re: Lister LT1
« Reply #9 on: October 26, 2021, 05:43:31 AM »
I am with you with the electronic department, it is all something very different and tricky to get my head around. At least you are prepared to have a go at the repair with guidance. Bob should be able to help you the most and to have the ability to reverse engineer electronics is something made of nightmares in my book and comes easy to others.
I would do my best to resurrect this generator and board as the new ones are not as well designed and built to last. I look forward to following this repair and outcome, good luck with it.
Coopernook - the centre of our Universe.

BruceM

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Re: Lister LT1
« Reply #10 on: October 28, 2021, 04:46:58 AM »
+1 on Bob's opinion that this may be the regulator board.  It's an easy to repair, fairly modern design.

I can't be certain but the two tubular devices look like (aluminum body with once intact plastic skin) electrolytic capacitors; they are something that is very cheap to replace, and something that does fail with time.  Not having a schematic for this lovely, easy to reverse engineer single sided, through hole component board makes it a bit tougher. 

Worst case, you can get a Chinesium brushed generator regulator to replace it with, but it's well worth trying to fix if you can.

A meter which can measure capacitance is pretty cheap these days, if the labels aren't readable.   A hot air gun or hair dryer might melt the wax to let you read components and resistor color bands to reverse engineer it.  If you can get high quality photos of each side, and get the part numbers off the components I may be able to help.  It may be possible to figure out a suitable value once the circuit diagram is completed.

That said, I also agree that the mechanical brush/slip ring issues should first be addressed.  Checking the excitation coil resistance via ohmeter, with and without brushes can be a useful diagnostic. 

A brushed alternator is as simple as they get, and is a good way to learn.  Once you get it sorted out, you'll be able to keep her running in the future without breaking a sweat.

Best Wishes,
Bruce








Welderherup

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Re: Lister LT1
« Reply #11 on: October 28, 2021, 04:56:53 PM »
So Iíve had another look at this today. When I put it away last time I tuned the throttle until it was making 230v and it ran for half an hour consistently. I turned the rpm up by about 500rpm. So quite a bit. Today when I started it and tried a 1800w hoover it started fine and hoover was working normally with plenty of power. Checked the voltage and it was up to over 300! I turned down the rpm and when I did the load fell off and we are back to making 50v. It was starting and stopping. So going no load showing 50v to loading for a second showing 280 and then cutting the load again and showing 50. Iíve got better photos of the board and the back of it but I canít upload them. Can you pm me your email and I will send it to you? Iím thinking I shouldnít start this again as Iím worried Iím going to damage something with the voltage being so out of control. That little sticker on the back has a number hand written on it. 4529. There is a letter above it and itís either an a or d

Welderherup

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Re: Lister LT1
« Reply #12 on: October 28, 2021, 05:06:22 PM »
So voltage is now gone totally. Flashing up 1 and then 8 and then 0. I am getting nearly 20v from positive to earth on the socket where youíd put the plug. Doesnít that mean there has been a wiring catastrophe?

mobile_bob

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Re: Lister LT1
« Reply #13 on: October 28, 2021, 05:07:42 PM »
clean your brushes and slip rings (or commutator if it has one)
it sounds to me like with added rpm the brushes are bouncing and making enough contact to work, while at the normal rpm they are floating on crap/corrosion/oxidation.

start with that, and then lets get to fixing the board.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
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Welderherup

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Re: Lister LT1
« Reply #14 on: October 28, 2021, 05:21:33 PM »
Hi Bob. I did that already when I serviced it. They are clean and all brushes are making good solid contact with the rings and springs are nice and strong. The two larger capacitors at the very bottom of the power head are making 280v and even when I turn the rpm down it stays a constant 260. So Iím getting a nice steady feed off the generator at that point. Doesnít that mean the windings have to be good? It has to be this board then?