Mooney SBM20-245B Owner's manual

Brand: Mooney

Model: SBM20-245B

Type: Owner's manual

Mooney SBM20-245B is a modification kit for Mooney M20M aircraft electrical systems. It rewires the 24-volt system to enable the overvoltage warning light in the annunciator panel to function, alerting pilots to potential alternator issues. The kit includes detailed instructions and necessary parts like wires, wire caps, and a 2-amp circuit breaker. Installation requires disconnecting voltage regulators, removing the glareshield, and routing wires. Once installed, the modification enhances safety by providing a visual indication of alternator overvoltage conditions.

SERV ICE BUL LE TIN M20- 245B

DATE: 11 - 25 - 91

SUB JECT:MOO NEY 24 VOLT AIR CRAFT ELEC TRI CAL WIR ING MODI FI CA TION,

( Re vi sion A is ap pli ca ble to M20J and M20K air craft only and is still in ef fect for those model air craft .

- - Re vi sion B is ap pli ca ble to M20M only - -).

MODEL/S/N

AF FECTED:MOO NEY MODEL: M20M - S/N 27- 0001 THRU 27- 0052

TIME OF

COM PLI ANCE:AT NEXT SCHED ULED MAIN TE NANCE

IN TRO DUC TION:THE 24 VOLT ELEC TRI CAL SYS TEM IS WIRED IN A MAN NER THAT REN DERS THE

OVER VOLT AGE WARN ING LIGHT IN THE AN NUN CIA TOR PANEL AS SEM BLY IN OP ERA TIVE

SHOULD AN AL TER NA TOR OVER VOLT AGE OC CUR. THIS S. B. PRO VIDES IN STRUC TIONS

TO RE WIRE A POR TION OF THE CIR CUIT TO EN ABLE THIS WARN ING LIGHT.

IN STRUC TIONS:

1. Dis con nect volt age regu la tor (for Al ter na tor #1) lo cated un der the in stru ment panel on the co- pilot’s side.

2. Lo cate ex ist ing wire number M- PA13A18; push wire out of pin 8 of #1 regu la tor main har ness re cep ta cle.

3. Cut pin from wire, M- PA13A18; cap wire end us ing AMP 324485 wire cap (in cluded in kit).

4. Re move Glare shield per in struc tions in the ap pro pri ate S & M man ual, Sec tion 39- 10- 01 .

5. In sert wire number M- PA13B18 (in cluded in -1B kit) into pin 8 of volt age regu la tor re cep ta cle and re con-

nect regu la tor.

6. Route wire number M- PA13B18 along ex ist ing wire bun dle to an nun cia tor panel con nec tor (M- WT103A).

Se cure with lac ing cord or Ty- Raps.

7. Lo cate wire number M- WT02A20 con nected to pin 1of an nun cia tor panel con nec tor, M- WT103A, and cut

M- WT02A20 wire ap proxi mately 6 inches back from con nec tor.

8. Use AMP 320559 wire splice to re- connect wire number M- WT02A20 and the un con nected end of ne w

wire, M- PA13B18. (SEE FIG URE M20- 245- 1B).

9. For No. 2 Al ter na tor: re peat Steps 1 through 5 with #2 regu la tor but on wire num bers M- P A33A18

(Steps 1, 2 & 3) and M- PA33B18 (Step 5). Route un con nected end of wire number M- PA33B18 to vac-

uum switch on back of Ar ti fi cal Ho ri zon and con nect to “white” ter mi nal.

10. Re move the 1 amp An nun cia tor C/B and re place with the 2 amp C/B, in cluded in -1B kit.

11. Func tion ally check op era tion of al ter na tor(s) per POH/AFM, Sec tion IV, Nor mal Pro ce dures, Be fore

Take off.

12. En ter com pli ance note in air craft log book and re turn air craft to serv ice.

WAR RANTY:This kit should be or dered from the Moo ney Serv ice Cen ter in your area. Nor mal war r anty bill ing

poli cies will be in af fect for this kit. Moo ney Air craft Cor po ra tion will al low up to 2.0 h ours la bor to

ac com plish this modi fi ca tion if a com pleted War ranty Claim is re ceived within 180 days from the

date of this Serv ice Bul le tin.

REF ER ENCE DATA:N/A

PARTS LIST:KIT P/N - SB- M20- 245- 1B (M20M only)

ITEM.P/N.....DE SCRIP TION........QTY

1...M- PA13B18....WIRE AS SEM BLY........1

2...M- PA33B18....WIRE AS SEM BLY........1

3...324485.....WIRE CAP (AMP)........2

4...320559.....WIRE SPLICE (AMP).......1

5...7277- 2-2....C/B, AN NUN CIA TOR (2 AMP).....1

FIG URES/

TA BLES:

M- WT02A20 M- WT02A20

SPLICE

M- PA13B18

FIG URE M20- 245- 1B (M20M only)

Mooney SBM20-245B Owner's manual

Mooney SBM20-245B Owner's manual

Mooney SBM20-245B Owner's manual

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