I can't believe I read five pages of comments without ever finding out what the problem was.

space,
when you say the panel refurbished what did you send them? The scr panel? or the whole panel including the contactor panel?

I would like to add my two cents worth if its not too late. Firstly ,never over ride any safety (PMT) feature on any system. Secondly this problem sounds like a function of load (current demand) not scr switching. Components like battery,cables even power fuses should be checked for VOLTAGE drops under as much current load as you can apply before drop out. You must track voltage drops@battery and across everything in the power circuit down stream ,resistance measurements under no load conditions are inconclusive.Start at the battery and move down stream UNDER CURRENT LOAD until you measure a suspicious drop across a component or connection. (What are the coildriver signals @ the contactor coils doing before they drop out?)

Well to bring this up from the dead!! I have now had the EV1B panel refurbished by FSIP. I changed the brushes on the motors and no longer have any conductivity to negitive. Still nothing has changed. I am still getting a pmt when trying to creap with a load. It basically jumps and its dead. I have now had the local Clark guru out and he to is scratching his head. Anyone else have any ideas? Or how do I just override the PMT? there has to be a way to just eleminate the 2 PMT drivers from the system?

The tech was a crown forklift tech for 22 years. He spent 4 hours testing the machine. He tested all the recs and contractors. He found a bad rec 2. I replaced it but the rec I replaced tested good for me. He used a handyman tester. I used jumpbox, test light, and some clips. I verified rec1 and the thermal sensor. As well as rec 5.

mrfixit you are fairly close to him compared to the rest of us, maybe a roadtrip is in the making?

Alot of good suggestions have been made here about this problem and from the sounds of the replies space brings back to us and results he is definatly in need of some professional help.
Its been many years since i've even seen an EV1 panel in a truck but from what i can remember generally they are easy to diagnose and fix but this one sounds like its in need of someone more experienced.
yes alot of time and 'some' money has been used up to try and diagnose this problem. Maybe its time to get someone experienced in this system involved. ;o)

if the insulation is the least bit not perfect, then it is worth it to change them.
if the cables insulation is cracked, soaked in corrosion or oil, or the insulation is soft from the oil in the past, then they need to be changed to prevent this sort of troubleshooting problem in the near future.

2 weeks, 86 posts, service person there once, probably at least $500, still nothing. This is crazy. If you want, e mail me and I'll give you my phone number. You can stand next to your machine and call me. I'll quickly run through some tests. That way we be on the same page understanding the tests. I have attended the week long factory authorized GE EV1 troubleshooting training and have 32 years experience as a road tech.

have you checked the creep speep adjusment on card ? could have someone turned it dowm or off? Sound simple but really this problem souhld have showed its hand by know (come on guys this is old school EV1 stuff).

I tested the power cables with the ohm meter. They where all in the 0.01-.03 ohm range. Basically no resistance. Would they still be relevent then?

to replace the cables running to the traction motors, my guess at the OEM was most likely a #1 gauge wire, I might use 1/0 or 2/0 welding copper cable, that I got at the local welding supply house, but take a sample. they can get you the eye-lugs (ends) that will match, too. use the same size as all the rest of the cables to that same motor.

also, it's worth noting here, that when you see a rec gate on with a test load like a light bulb, you are trying to check something's ability to carry 500AmpsX36Volts=180000watts using something like.03 watts. that does seem to fail more 'under load'.

fix the power cables

I tested rec #1 and the thermal sensor. The rec gated and the thermal sensor responded to heat.

why could'nt be a shorted #1 SCR? ("#1 SCR shoot through")

Any idea what wire size and ends to get?

there are switches on the steering that (on this truck) are underneath the controller, if my memory serves correctly. if the wheel is straight ahead both motors should turn at pretty much the same speed, make sure they both have equal turning (rolling) resistance (no brakes dragging) by turning with your hands while in the air.
These "spongy" cables are part of what I was talking about earlier, as far as cables that MUST be replaced first, as they are oil soaked.
Before further troubleshooting can be done correctly. any that have the insulation cracked (visible when cable is bent) or have been saturated with corrosion must be changed too.

The insulation on the 3 wires going to the right front motor is spongy. I am goning to disconect these and load test them just to make sure. Also is there something that tells the right motor to turn faster then the left motor? maybe a switch on the steering or rear swingarm?

It sounds like one of the SCRs is misfiring under load. In the EV1 manual look up symptoms 1E and 2B. Since the #2 and #5 are new, check the 22 and 25 RECs. Notice that it says the 25 can check good but still cause the #5 to misfire under load so that may be the next part to try. If any of the SCRs misfire it is going to shut down with the pmt, like what is happening.

OK. Here is what its doing. Wheels on the ground. Forward no creep but just past 1.4 pedal it jumps and pmts. Reverse creeps for a second at 1/4 pedal then pmt's it will not move forward or reverse creep or not without PMT.
Wheels in the air. Creeps forward and reverse. High speed works as long as you don't just floor it. If you floor it it PMTs.

It would be much easier to diagnose what's wrong if you explain exactly what's it doing or not doing. Does it creep at all when the petal is pushed 1/4 of the way? Forward and reverse? Does it shut itself off (pmt)? If so, what are you doing exactly when it shuts down? How does it react as you slowly press the petal down? Can you press the petal down all the way and have it click into high speed and run? Does it run differently with the wheels spinning off the ground rather than driving it? It shouldn't be difficult to figure out what's wrong but you have to be crystal clear in explaining how it is reacting while trying to drive it.

Its not the card :( although I was able to get it to move a little in reverse. So maybe just a little the card. Please Tell me what to check next. I would be pulling my hair out by now but I have no hair to pull out :(