Hey everyone! Been getting more advanced in train repairs and really enjoying it thanks to you guys. I've come across an engine i cant fix. New to me from a forum member, but cant get the smoke unit to work.
Lionel Lionmaster SD90mac Canadian Pacific (tmcc)
Number: 6-28211
Heres my issue:
No smoke, but fan spins. Assumed AC regulator. Ordered and replaced- no change
Upon digging around the smoke unit, the Lm78L05ACZ 5v regulator was super hot to the touch when smoke unit turned on. Ordered and replaced- still no change and replacement gets very hot too.
---Then replaced the diode- no change
---Then, replaced the input filter cap(100uf 35v)- still no change.
I probably should have changed them all at once, but did them as they arrived. (Do have multiples of each)
Only part i didnt change/forgot to order was the output filter cap (skinny cap labeled 50V on side)
ANOTHER wrench in the mix, the engine always had a humming/buzzing sound once powered up. I discovered unplugging the 3pin plug to the smoke unit, OR turning the smoke switch off, stops the buzzing sound. Is this a SEPERATE problem, or related to the smoke unit issue you think? (I feel like the smoke unit components the culprit?) Did check for loose/broken wires.
Random tidbits:
-Does have 8ohm resistor and checks out
-on the 3pin harness going to the smoke unit: pin2+3= approx 10V
-regulator: pins 3+2=16V dc & pins 2+1=5V dc
Diode: 6-10V constantly fluctuating
Input cap: 16v
Output (skinny) cap: 10-14V constantly fluctuating
Resistor: 0 volts when powered, (8ohms)
- Thank you in advance for all the help, ive spent hours reading/learning about the AC regs and board components but still stumped! Maybe thinking the output cap the culprit?
-Brandon
***There is a red "line" under the blue cap and 3pin harness, I accidentally "drew" that when labeling the PIN numbers on my phone!***
