Need a wiring diagram for armstrong air model mb14aa-1a

the service manual covers all this, get one.
or read the side if the cap and it tells you that ,oops gone.
uF and volts AC
no country told and AC power is not the same all over earth a fine dream by MR Tesla, (RIP)
all I can do is guess any of that, 230vac or 250vac or?
model stated is not a heatpump.
not sold now,
scu10b42-1a 10 = seer year 1997 made? seer 10 is mostly banned.
42 = 42000 BTU .
the dual cap for fan and compressor on the out door pad?
that?
I found the install manual SCU (era) and no parts list wiring diagrams yes.

https://inspectapedia.com/aircond/Armstrong-SCU-Series-Air-Conditioner-Manual.pdf


the parts lists are missing at makers site
https://www.armstrongair.com/

ask them for the parts list. your SCU. (by tons/btu and seer) etc.
that PAD units come on as TON ratings, and the cap must match the compressor and the fan there. or fails. and line voltage not told
(my 5ton AC THE CAP FAILS EVERY 3 YEARS) LIKE A CLOCK.
the maker ended support on old SCU10 series.
seems so. 20+ years old. as most are gone now. R22 phased out.
some laws in some countries ban support for that old of AC
even make did as I can see. (gone)

decodes of models then.
The Armstrong SCU-10, a SEER-10 split system AC using R-22 refrigerant, as an AC series was discontinued before 2020. Models included the Armstrong SCU10B12A1012,900 SCU10B24A SCU10B30A SCU10B36A SCU10B42A SCU10B48A SCU10E18A SCU10E24A SCU10E30A SCU10E36A SCU10E42A SCU10E48A SCU10E60A - where the last two numeric digits are a very rough approximation of the SCU's BTUh rating.

no number if front is gen1.
2SCU is gen2, and so on.
gen 4 is now.

no serial told but the decode is here (yy= 97?

• Armstrong 10 Digit Alphanumeric Serial Number Age Decoder:
• PPYYM67890 where PP = Manufacturing Plant No.,
• YY = Year of Manufacture,
• M = encoded Month of Manufacture and
  
  Months are encoded Alphabetically as follows:
  
  A=Jan, B=Feb, C=Mar, D=Apr, E=May, F=Jun, G=Jul, H=Aug, J=Sept, K=Oct, L=Nov, M=Dec.
• 67890 =serial#

First you need to know the function of the capacitor.

Manufacturer's parts service could be a source of valuable information - link below...

https://expertappliance.com/armstrong-ac.html

I never know what size capacitor until I pull it off and read the lavel.
Compressor or motor capacitor, both compressor and motor dual capacitor, there's different kinds.
After testing the capacitor and determining it does not hold charge, replace it and if it is a dual capacitor with one side bad, I end up rewiring for having two individual capacitors, keeping the old dual capacitor for its good side that still works and for future ease of repairs.
You did not specify which capacitor, it could be a 5 or a 25uf, dpending if its for fan or compressor motor and 370 or 440 volts. pull it off and find out. Take pictures before removing and mark the wires and terminals so it can be put back together as original.

without a meter a knowledge on how to test I would replace the $10 capacitor first. keep in mind that just because the fan isn't running doesn't mean the motor is bad.

If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

The armstrong concept 10 comes in 7 different sizes. We need the model number off the outdoor unit.

If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

Pure speculation on my part; I think your thermostat may be at fault.

Remove the cover of the wall unit to see if the wire terminals are marked with their functions.
There are no dangerous voltages present (24 Volts)

See this link below to check if your thermostat wiring resembles the diagrams and tables:

Wire Thermostat

If you have a green lead, disconnect it to see if the fan shuts down.

You didn't state if it is the outside or inside fan that won't turn off so the above may not help at all.

http://www.armstrongair.com/armstrong-links/

from here select the particular furnace that you have this is the only resource the is avail. due to the furnace being a Lennox made furnace

Google Lenox and you will get armstrong also. The have tech site for diagrams and instructions.

Atta way.

There may be pins on the circuit board inside the air handler that you can adjust. First turn off the breaker then look inside at the board. They may say 30-45-60-90 etc. Put the pin on a lower number. Do you have a digital or programmable T-stat? There may be a setting in the T-stat setup program that allows for blower delay also. consult you installation instructions. Last if the blower isn't turning off at all then the relay on the circuit board is stuck closed and should be replaced.