Heathkit IT 21 Manual

Page 2

IMPORTANT NOTES

" Special short'test for tubes with internal connections. A good tube will not show short when the levers shown In parenthesis { ) are moved 5?:
simultaneously. it moved individually it will show short. .

g ' Be sure to set filament selector switch to .63 volts when checklng for continuity or short tests.

Tubes followed by suffixes such as G, GT. Y. W, A, 8, etc., in general can be tamed by the same setup listed for the tubes without a suffix.

Tube T he Fit. Plate T . 0 Bottom B Tube- T he Fil. Plate T- . Bottom {B} I Tube Type Fil.,-
00A. 2 5 30 BC D 1AM 4 1.4 60 N HM 1302 4 1.4 86 N BEH
MA 2 5 45 BC D No short test. Good tube reads above 20 Tube damaged if BE or H is moved.
on 4 011 40 . AE BOG Tube damaged if H 01' M is moved. 13x2 4 1A 67 N ADFJ
600 the reads We 1°: 11154 1 1.4 23 ' BCF A: No short reel.
0 4 011 30 E ECG 1AF 1 1 .4 28 BCF IE 13 41 1 4 80 N HM
0M 4 Off 40 (3 BE 5 1' 1: 35: 35F 2G Tube damaged if H or M is moved.
4 0" 44 5 BG 1 A 1 1'4 24 BCF ' G 113 1 1.4 25 BCDEF G
032 4 0" 95 5 BOG ' No open element test on BE & F.
Good tube reads above 10. , "0 0P9" 39mm 5 0" B- 1 cs 2 1 4 37 ODE s
033 4 on 1 30 ~ E BOG 1AU2 4 1.4 100 (AJ) E 1 2 2 42 CD F
Good tube 9 10' 32:: tub 4read's4abovgf25 N BE" 1 2 68 BEN F
mm 4 on 40 AE soc ° ' 11:7 2 2 41 EF 1:
Tube normally shows leakage. "2 _ 4 . 1-4 53 , N G 1 2 56 CDN . 6
Good tube reads above 10. Insert Into pins 2 81 7 of 9 pm mln. ' 1021 4 Off 45 E 36
003 4 2 0H 30 E BOG . 133 1 1 .4 . 93 N ACDEFGH 1 05 2 2 39 CDN G
Good tube reads above 10. U89 6 3' N Or? 0 9'9 "m I 105G? 2 2 33 cm»: s
, Good tube reads above 28. 1D? 1 2 31 SF G
5 003 , 4 Off 30 E BOG . :
. 134 1 2 27 BCN D 1 2 95 CDN G
1 Good tube reads above 10. 13", 2 2 35 BCN D ;
é. 033 4 0 32 1 M35" 396 135125901 2 31 BE F 108 2 "4 43 F a 3
3' Good tube reads above 10. 1 2 40 D F $ 1: 37 305 S '
on 4 011 22 E CGH ' 1 2 40 c F 1 013* 1 1'4 3: (BF) ca
024 4 01f 22 E CH ' 1
4 011 22 0 EH 37 1 1-: 3: SEN g was 4 1.4 so N 'CE
I 1A3 1 14 75 BF CG 138 2 1'4 32 CDE G Good tube reads above 30. No short test.
1 1 2 28 BCN D 2 1 :4 60 m G le1 1 14 70 N B .
I MS 2 1.4 50 ODE G 1 1_4 95 H G Insert 2 base leMs into pins 1 & 2 of 9 pin min. skt.
MB 2 2 50 CD F 1302 4 1.4 70 N BEH Use plate cap on single lead.
I 1A? 1 2 95 BEN F Tube damaged if BE or H is moved. Good tube reads above 20.
1 :1 3; SEN g 1862 1 1.4 32 N s , WK 1 1-4 _ 32 _ N _B _
' Insert 2 base leads into pins 1 & 2 01 9 pin min. skt. Insert 2 base leads Into pins 1 81 2 of 9 pm mln. skt.
1ABS 1 1.4 25 BCF GH 1 Good tube reads above 20. Good tube reeds above 20.
1A 1 1. 25 BCDEF G L 1W5 1 1 4 52 D G
No open element test on B, E 8. F. BKZ 4 1'4 52 N BE . 1 1'4 BCF
No short test. Good tube reads above so. - 27 G
1

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