My neighbor owns a dairy farm and uses this loader to carry hay to the cows. About a year ago, it went dead ... just would not move. I found there was no power to the joy stick. Ran a power wire from the connector to the stick ... worked great. Yesterday a similar issue. Found a broken wire in the joystick .... soldered it back ... found a blow fuse ... new fuse ... worked great. Today he calls ... it won't go forward or backward. It runs great .... steers .... loader arm moves (he has a spike on it for the round bales) ... won't go forward or back. Checked the switch in the joystick ... working. Checked the board ... I can see (feel and hear click) the spool relay and the direction relays working. So, now where do I go? It would be great to have a wiring diagram ... then I can check to see if I have voltage at the connector going to the solenoid. If I know what solenoid does what, I could check to see if I have voltage there. I don't even have a block diagram for the hydraulics ... the bucket and steering work ... does the transmission work off the same pump? Maybe the pump died (or relief valve or ...)? I am a machinist by trade but always try to help the neighbors (dairy and horse farms on both sides of me) going. Thanks!
It is not easy to find this model in pdf, but you can access all detailed schematics and service documents for this model from the Volvo prosis program. https://machinecatalogic.com/volvo-prosis-2023/
Thanks ..... not a bad price if I need to go that way but these farmers are just barely hanging on. I try to keep then running and never charge them for the work I do. As I said, I am a machinist by trade ... I weld ... plus I build industrial control panels. I didn't know anything about tractors and farming till I moved out in the country ... learning on the fly. OK ... downloaded a few bits of manual I found online and went over today to take another look. I tried again to get the whole story. Seems it was working fine and just stopped moving. The steering and lift works but it will not move forward or back. The lights on the dash indicating forward or backward that go on when he "clicks" (using the switch on top of the joystick) no longer come on. First, I did take a good look at the relays while he moved the control on the top of the joystick. I can see (hear and feel) relays K8 and K10 alternating. Relay K8 has an indicator light beside it (K10 does not) that also goes on and off. These control the directional spool (solenoid) via connector X105 pin 4. I also confirmed the power on pin 4 is 0 or 12 volts ... so it is working. He said he had three broken wires and "sorted them out" before I got there yesterday. From the pieces of the schematic I found, it looks like relay K7 feeds both the direction relays K5 and K6, the neutral relay K4 ... and the spool relays K8 and K10. So if K8 and K10 are working then K7 should be OK I guess I am down to K4 (neutral), K5 (forward) and K6 (reverse) relays. It also looks like K4 must be off to feed K5 / K6 (which makes sense). Raining now but I will head over tomorrow again ... look to see if K4 is energized or not ... and if it is feeding power to K5/K6 I also need to make sure what ever the three wires in the joy stick he sorted out are correct. Is there anything I am missing or should look at ??? Thanks!
I think you need to review the plumbing. Any short circuit may have damaged some components. Have you checked all the fuses?
Yes ... he found the broke wires last week. He said it still would not move. I went over and did find a blown fuse ... well lots and lots of fuses are blown but I found the one for the drive relays (most blow were for lights and stuff that is long gone from the machine). It worked after that for a day or two ... then just stopped dead while he was using it. Thanks!
A little late to the party here. The first thing to do whenever faced with a HST problem, check the brake pedal. If it's rusty, crusty, has accumulated crap under it that won't let it return all the way. The brake pedal serves 2 purposes. The first part of travel sends a signal to the pumps to destroke, basically putting it in neutral. This is a hydro-mechanical act and doesn't care about electrical inputs. The second part of travel is actual braking. The next thing to look at is the propshaft itself. Is it turning? What about if you apply the diff-loc? This is an option you may or may not have. Let us know what you find. Good luck.
Thanks! I will be running over there again tomorrow (when the rain stops ... wish my new workshop was finished ... just getting ready to roof it ... check out my FB page, I made it large enough to fit equipment like this). I will definitely check those things out! This is used in barns to haul hay .. lots and lots of SH#T .... everything is covered with oil and mud. As I can see on the control board the relays are not pulling in that are marked forward and reverse travel, I am guessing it is an electrical issue but I could be completely wrong. Thanks so much! Mike Log into Facebook Log into Facebook to start sharing and connecting with your friends, family, and people you know. www.facebook.com Vermont Country Workshop | Jericho VT Vermont Country Workshop, Jericho, Vermont. 46 likes. Michael Csele, owner of Vermont Country Workshop, is a self-described jack of all trades whose attention to detail produces quality pieces each... www.facebook.com
I'll see if I can find specific service literature for that model. At least you were good enough to post the serial. That's so critical on the smaller machines.
Thanks so much ..... I have learned no matter what I am working on, the first thing to do is to look for a manufactures plate. Always asked myself why a phone would have a camera (I am not much of a social media guy ... no one cares what I am having for supper) ... now I grab for it all the time .... what's the old saying "a picture is worth 1000 words" Mike
OK ... so just a follow up. I found pieces of a wiring diagram on the web .. some from a L20B and some from an L25B ... enough to get a feel for how the forward and reverse relays should turn on and off. I did a bunch of checking with my meter .... seemed like the problem was on the relay board. Then I got a puff of smoke ....hmmmm ... time to pull the board. The board was in rough shape ... some burn marks, glue and repairs from ???? (the starter is now just a button they added ... said the board had issues years ago). I did find one trace which I may have destroyed during testing (jumping in and out the solenoids trying to see if they were working) but I did find one trace between the two relays which is exactly what I thought was wrong (no getting voltage on the forward / reverse relays ). You can see in the picture ... the trace to the left, I think I did during testing ... the one in the center is the one that I suspect caused the tractor not to work. It goes between the two relays that were not working. I jumped the old traces with wire .... soldered wires where the traces should have been. Put the board back in .... IT WORKS! The farmer called last night to say he had moved his hay and all the cows are happy. Mike