I picked up an old Drexel SLT30 swing mast forklift at auction that recently developed some problems... It uses GE EV-100 electronics and I seem to be having an issue with the oscillator card. I replaced it but I think I need to change some parameters on the new card, but not sure... Back in August or September it went on the fritz. The pump motor and hydraulics all worked fine, the steering worked fine, but the traction motor was dead - no relay pickup, nothing. I turned it into a lawn ornament through the winter but I really need to move some junk so I started poking at the forklift again a few weeks ago. I've got a manual for the EV-100 control card and the service manual for the forklift itself, curtesy of Landoll, and I decided the problem was the oscillator card - the logic board that controls the SCRs and relays for all of the forklift functions. I found a remanufactured card online and the retailer's service department assured me that it was a direct drop in replacement for the card. My card was the first generation and was missing the "Y" plug for a handset or display (p/n IC3645EVS1 to be specific). They shipped me an IC3645LXCD1 SR card, a much newer version that has the Y-plug for a handset / display. I hooked everything up and tried it out. It sort of works but it has very little power. In fact, I got stuck because I couldn't reverse through a *very* slight dip in the driveway. I was able to limp it back to its resting spot by manually closing the 1A and REV relays (i.e. poking them with a screw driver and walking with the forklift - a funny sight indeed). Plenty of power when the relays are bypassing the SCRs, so I don't think there is a problem with the traction motor or super weak battery (although the battery is not great). Here's what I'm noticing with the new card: 1) Slow to pick up: The pedal has to travel quite a bit before the SCRs start to hum. I don't think I'm getting the "full torque" start feature. 2) I don't think I'm getting full 1A bypass, either. Particularly trying to reverse out of the dip, when I go all the way down on the pedal, I hear the microswitch close in the pedal sensor and there is a quick "clip clap" relay sound. For just a moment, I get a big lurch but then it goes back to a stall with SCR hum. I think the "clip clap" is actually the 1A bypass kicking in and immediately kicking out. I just get a momentary torque bump from the bypass. 3) When in stall with the SCR hum and no 1A bypass, quite a bit of heat is generated in the electronics compartment; more than when I manually close 1A to provide full battery power to the traction motor. I'm not sure what the controller is doing, but the panel and the cables get very warm / hot. 4) When driving (assuming I'm not stuck in a dip), the steering feels sort of gritty and weak. It feels fine when stationary - smooth and plenty of power to twist the rear wheel even though it's not rolling. Could be my imagination, though. 5) My forklift is a 36V unit, somewhat less common these days. Based on the manual, it sounds like the card should auto-range for 36V or 48V trucks, but I haven't been able to confirm this. Maybe my current draw - particularly when 1A closes - exceeds the safe threshold for a 48V truck so it goes into some kind of limited power mode...?? I'm guessing I'm going to need to buy ($550 YIKES!) or rent ($50, better) an LX handset to read status codes and change parameters on this card. Reading the manual, I haven't figured out exactly which settings could be causing the symptoms I'm experiencing, and that's what I'm hoping someone here can help me out with. The manuals are not super informative and, in some cases, they provide "helpful" information like "Listen to the SCR hum. If abnormal, do xyz" but I'm not experienced enough to know what it's supposed to sound like!
For the sake of posterity, I wound up buying a used LX handset on eBay after having some issues with MRK Sales (the company that supposedly rents LX handsets). Turns out the problem was due to the current limit and the 1A drop out current limit both being set too low. A few minutes with the programmer to change those settings and the forklift is back up and operational.
That is all pretty interesting. I take it you are working on a battery powered forklift. When you say GE EV=100 electronics, are you talking about a standard package that might be used in other brands of lifts as well?
Yep, that's correct. It's a battery powered forklift and the EV-100 "control panel" includes a logic card, the SCRs and related components necessary to control the traction motor, pump motor, p/s pump (if so equipped), etc. It was used in a bunch of different electric industrial products including forklifts, order pickers, etc. from manufacturers including Yale, Clark, Landoll / Drexel, and a number of others I'm blanking on at the moment.
How can you tell if that is the system being used in the machine?
I suppose it depends on how much access you have. If you just have a model number of the forklift, you'd have to contact the mfg or someone who knows a lot more about forklifts than I do! If you have access to the actual machine, you just need to find where the controls are located. They are usually fairly easy to access. The control panel will be located near the relays and you can generally find it by just tracing the battery cable back into the guts of the machine. Once you find the control panel, it is conveniently labelled (you can't see in the photo below, but in the lower left hand corner on the side of the heatsink for the current sensor you'll find the exact model number and configuration code for that specific EV-100 unit. You'll also see the card model number / configuration on the sticker that is obscured by the gray wires below): Incidentally, this is a picture of one of the older EV-100s that don't have the "Y" plug for a handset. Instead, you see 5 holes between the gray wires and the other plug with all the bright colored wires. Those are potentiometers to set things like current limit, acceleration time, etc. Newer ones have a second plug in that location for connection to the handset, where you set all those parameters digitally.
It sounds like you were able to look that stuff up on line then and find parts and info?
Yeah, so some of it I learned through Landoll (who acquired Drexel a while back) and they were very helpful providing service manuals and information. Flight Systems Industrial Products is also a great resource. They have old manuals from GE and they have remanufactured parts and repair services for a lot of this kind of stuff. Very useful website to poke around. Manuals / tech documents are available here: https://shop.fsip.biz/en/content/technical-documents