IBM G74, CKB5237, CKB5237L, CKB7227L Schematic

11 Schematic Diagrams

11-1 Cautions

1.The areas marked with a ! , or on the schematic diagram designate components which have special characteristics important for safety. Replace these parts only with parts identical to those in the original circuit and those specified in the parts list.

Before replacing any of these components, carefully read the “Product Safety Notice.”

2.Areas marked with a on the schematic diagram designate controls which have been sealed for safety during manufacturing. If these controls need adjustment, they must be replaced with new controls and then sealed after their adjustment.

3.When taking measurements, pay special attention to the following:

1)Do not use your instrument between primary ground (symbol ) and secondary circuit.

2)Do not use your instrument between secondary ground (symbol ) and primary circuit.

11-2 Notes

1.Resistance is shown in OHM. K = 1,000, M = 1,000,000 and the rated power of resistors not noted in the schematic diagram is 1/4W.

2.Capacitance is shown in µF. Capacitances not otherwise noted are shown in pF (1µF = 1,000,000 pF). Rated voltage of condensers not otherwise noted in the schematic diagram is 50 V.

11-3 Abbreviations and Symbols

MO			R-Metal Oxide	WW			R-Wire Wound
FU			Fusible	C			R-Composition
CM			R-Cement	MPP			Metal Polypropylene
MP			C-Metalized Polyester	T			C-Tantalum
P			C-Polyester				Can emit X-radiation
			Hot Ground				Cold Ground
			Electrostatically Sensitive Device	!			Provides special safety
			(ESD)				considerations

1.The secondary voltage is read with an SSVM from the indicated point to a cold ground ( ). The primary voltage is read with an SSVM from the indicated point to a hot ground ( ).

2.This schematic diagram is subject to change without notice.

CKB5237L/7227L

11-1

11 Schematic Diagrams

11-4 Main Schematic Diagram

				27
		R503_7	R500_7 R502_7					R535
			Q500_7			25
			C543_7	R501
		R504_7	C537_7
			C540_7
			R505_7
			26	C538
		17" ONLY
		15" ONLY
						24
		R506				D524_7
						C522_7
			28
R201_7
						23		L501
			R302			22
								21
29			R310				20
						19
								R517
	5	7
		6				C456	16
		R444_7 R441_7
			10
							C422	L406
								15
		8						L402
						C432
						C434	C458	L401
			Q417_7
		C455_5	R443
		R425		R467_7
		9	C465_7	R417		C419
		R451
1		R450		R409
			R414			14
					11	12
2
	R613
	3
		R315
						13
4

11-2	CKB5237L/7227L

11 Schematic Diagrams

	1	14 V (T601, #1), 110V		2	DC V (IC602, #3)		3	292 V (T601 #5), 110V		4	3.68 V (C612, –), 110V		1	DC V (T601, #2), 220V		2	DC V (IC602, #3), 220V		3	444 V (T601, #5), 220V		4	3.80 V (C612, –), 220V

CH1 P-P = 14 V

CH1 RMS = 142.6 V

CH1 P-P = DC V CH1 RMS = DC V

CH1 P-P = 292 V CH1 RMS = 181.6 V

CH1 P-P = 3.68 V CH1 RMS = 840 mV

CH1 P-P = DC V CH1 RMS = DC V

CH1 P-P = DC V CH1 RMS = DC V

CH1 P-P = 444 V CH1 RMS = 354.2 V

CH1 P-P = 3.80V CH1 RMS = 902 mV

5

12.0 V (IC302, #28)

6

8.80 V (IC302, #26)

7

640 mV (IC302, #24)

8

3.12 V (IC302, #23)

9

928 mV (IC302, #16)

10

2.56 V (IC302, #12)

11

124.8 V (T401, #1)

12

10.0 V (Q406, Base)

CH1 P-P = 12.0 V CH1 RMS = 6.912 V

CH1 P-P = 8.80 V CH1 RMS = 6.176 V

CH1 P-P = 640 mV CH1 RMS = 2.908 V

CH1 P-P = 3.12 V CH1 RMS = 3.620 V

CH1 P-P = 928 mV CH1 RMS = 320.8 mV

CH1 P-P = 2.56 V CH1 RMS = 820 mV

CH1 P-P = 124.8 V CH1 RMS = 66.16 V

CH1 P-P = 10.0 V CH1 RMS = 1.672 V

13

128 V (Q411, Drain)

14

1.016 kV (Q406, Collector)

15

64 V (L402_7, S)

16

76 V (L402_7, F)

17

26.0 V (IC300, #6)

18

46.0 V (IC300 #5)

19

1.16 V (IC501 #5)

20

12.48 V (IC501, #9, 10)

CH1 P-P = 128 V CH1 RMS = 63.3 V

CH1 P-P = 1.016 kV CH1 RMS = 316.0 V

CH1 P-P = 64 V

CH1 RMS = 126.0 V

CH1 P-P = 76 V

CH1 RMS = 127.2 V

CH1 P-P = 26.0 V CH1 RMS = 13.30 V

CH1 P-P = 46.0 V CH1 RMS = 6.38 V

CH1 P-P = 1.16 V CH1 RMS = 823 mV

CH1 P-P = 12.48 V CH1 RMS = 6.672 V

21

148 V (Q504, Drain)

22

5.28 V (Q503, Base)

23

848 V (Q503, Collector)

24

1.00 V (Q301, Base)

25

22.4 V (G1)

26

260 mV (Q500_7, Emitter)

27

332 V (R502_7)

28

88 V (T502_7, #6)

CH1 P-P = 148 V CH1 RMS = 68.4 V

CH1 P-P = 5.28 V CH1 RMS = 1.290 V

CH1 P-P = 848 V CH1 RMS = 305.2 V

CH1 P-P = 1.00 V CH1 RMS = 163 mV

CH1 P-P = 22.4 V CH1 RMS = 54.24 V

CH1 P-P = 260 mV CH1 RMS = 2.286 V

CH1 P-P = 332 V

CH1 RMS = 138.0 V

CH1 P-P = 88 V

CH1 RMS = 288.2 V

29 5.20 V (IC202, #16)

CH1 P-P = 5.20 V CH1 RMS = 4.912 V

CKB5237L/7227L

11-3