@Knight007 posted:I've noticed an odd issue with my PS2 upgraded Big Boy in that it seems to run fine except for intermittently jumping in speed for a second at random places around my track. The jump in speed is brief but very abrupt and risks breaking couplers on longer consists or possibly derailing the front wheels. This seems to happen more after first running the locomotive after a few weeks of sitting on the shelf and appears to work itself out after several minutes of running. I've cleaned the pickup rollers and oiled all the rods but it didn't seem to make much of a difference. Any insights would be welcome. Thanks!
Typically, if the lurch is a speed increase, also combined with loss of chuff sound and lack of puffing smoke at that time- then we suspect something, somewhere in the tachometer feedback loop. It does not mean the tach is "bad" or the sensor is bad, it means that the tach in the engine on the motor and the board is in the tender (most likely) connected via wires in the tether.
The fact it happens intermittently could be a problem in the tether wiring (it can and does fail from flexing) but also could be a cracked solder joint on the engine side mounting PCB
or other failure. It could be the tach tape or some other issue with optical sensor mounting.
Thus lies a minor problem- the upgrade PS2 kits as far as I know came with one piece tether/wiring harness in steam kits. In other words, actual PS2 Steam engines delivered from MTH often use a 2 part tether with the portion that goes between the engine and tender being a plug in at both ends (right angle one end, straight on the other- both 10 pin straight through wiring).
Again, the problem is, now, given what is in stock at the moment- you might have to buy the current stocked "universal version" of the 10 pin tether, and splice in all 10 wires to your existing harness at the board end in the tender.
Similar topic and problem.
https://ogrforum.ogaugerr.com/...0#171907990373318750
All that said, if PS3 steam upgrade kits (which use the same steam PS2 harness) are supposed to be coming in stock, it's unknown if we might see harnesses- specifically the typical steam upgrade harness for PS2 3V (also PS3/2 "steam upgrade harness) come in.
