Is the time before M speed comes in the same each time? 10-20 minutes? Is there a noticeable difference in the SCR speed and the M speed. Does the truck travel a long distance. There is nothing wrong with running in top SCR range. The SCRs work harder and the heat sinks stay hotter. Speed might be a bit slower.

Sounds as if the encoder (drive motor direction and speed), if there is one, would be the issue. Feed back from the encoder and amp draws across the drive motor are used to determine if hi speed is allowed.

I thought Raymond trucks were using transistor drive by '92. Guess not the 020, which were built in Canada.

hi James, as stated the thermistor was tested at 105Ω, well within the 200Ω spec. thanks

After thinking it over. I belive the temp sensor/sender is located on the Main SCR 1 heat sink. You could pull the (2) wires off it and jumper them together, thereby eliminating the temp sensor, if you feel you are dealing with thermal cut back.

thanks James,
checked motor grounds, did not see any temp sensors on this drive motor. it does seem like a thermal cutback mode because adjusting VR3 does have a small effect on drive speed. but i see no motor temp sensor, only four cables coming out of the motor.

I'd stick with the early suggestion of drive motor. Temp. sensor. Motor grounds (look at voltage from motor to the truck frame). A dirty motor (brush dust) can cause problems.

The only rec. that could cause a slow travel speed is the recirculating (flywheel) rec. if shorted it will blow the power fuse. If open it would cause slow speed in scr range. the other rec. is for plugging. If open the plugging will be very harsh. if shorted I don't think the truck will run at all. If any of the scrs have failed the truck won't run either.

Hi, Yes the problem is persistent. Hi-speed is no longer coming in at all, I have had the truck powered-up with key-on since my last posting and hi-speed is still not functioning. Intellidrive card displays 2-4-5 during acceleration and stays at 30% or so of top pulse speed, M-range does not engage and M contactor does not come in. Again adjusting the VR3 pot does change this speed slightly but not much so it must be into thermal or overcurrent cutback but I cant find the cause.

are you still having problems?..when you say it has no high speed, does the high speed contactor come in? I had one that had a similar problem, someone had installed the wrong vr1 pot, then had all the tcc adjustments changed, trying to make it work. i changed the pot, did a rms 80 and tcc set up, and away it went

Update, I have acquired a brand new Raymond manual for this unit. I performed the nulling procedure for the throttle card per the manual. While performing speed limit adjustments with VR2 and 3 I noticed that altering VR3 (1/4 speed limit) affected the drive speed slightly. This leads me to believe the unit is either in thermal cutback, overload protection, or height cutout mode.
I measured the thermistor resistance (TH1) at 105Ω. I measured shunt resistance (SH1) at 0.3Ω both at its terminals and the ICC card terminals. Voltage at the shunt wires stabilised at 13.3V at both ends of the wires (twisted properly along full length). This truck has no height cutout switches, so I verified that the jumpers on TS3 were still in place. They are. I did not check continuity of the wires back to the card, though.
The truck stays in pulse mode for a much longer period of key-on time now, (was locked in pulse all day today) so I'll recheck measurements of TH1 and SH1 once M-range comes back. TH1 spec is less than 200Ω at ambient, but I could find no spec anywhere in the manual for the shunt. I have been chasing this based on the assumption that since VR3 on the throttle card did successfully affect drive speed that it must be in cutback mode. Should I keep pursuing this or is it possible that there's a bad component elsewhere? 2 and 3 rec test good, have not checked heatsink insulation pad, #2 SCR or main SCR yet.

Please do! my username at hotmail...

thanks!

If that is a Intellidrive, I have a service manual for it. It doesn't list the scr's as numbers. You got the main, charging, turn off scr's and braking, freewheeling diodes. Setting up the card is somewhat involved, I could scan and email that.

Hi, Does anyone have the part number for #2 and #3 Rec? or the specifications for them?

Hi, does anyone have card setup info for this unit? Remember this problem is time-related, M1 comes in after about 15-20mins of key-on and restarting the truck resets the time. Thanks

you said that all of the cards were replaced. your problem makes me think but try to do this hint maybe it can help to solve your problem......
1. try to check the battery. short to frame test.
2. reconfigure the truck first maybe the speed limit is out of range
3. maybe the traction heat sink is short to the frame.
4. bad temperature sensor(drive motor,power panel,)
5. try to replace a good drive motor from the same unit.
6. and also the mast speed limit switches(check for continuity)


best regards and good luck!

Still gathering info for this problem, any info is appreciated.

edit........................

hello friend, you have something bad in their hands: it can be a problem of isolation. if there is any leakage to the chassis the diodes go into saturation and cause fire protection circuits. check the armor of the engine, the pickup and wiring