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Philips P2000M Capacitor Replacement Guide

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Philips P2000M monitor cabinet power supply schematic (fig 4.16)
The monitor cabinet power supply (Field Support manual, figure 4.16). C13 smooths the +5 V input to IC2, and C14 to C16 the +12 V input to IC1 (723) and IC3 (7812).

The Philips P2000M has two power supplies: the basic cabinet supply it shares with the Philips P2000T, and a second supply in the monitor cabinet for the floppy drives and the monitor. Philips's Field Support manual gives the circuit diagram of each, with capacitor values, and the parts lists for the supply boards, the Business CPU board, the video board and the extension board.[1][2][3][4] The basic cabinet supply is covered in full on Philips P2000T Capacitor Replacement Guide. The monitor cabinet supply and the boards fitted only to the P2000M are below. For the general signs of a failed capacitor see Capacitor Failure Symptoms.

Before replacing anything

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Both cabinets have their own mains lead, transformer and fuses. Unplug both before opening either cabinet, and discharge the CRT before handling the monitor assembly (CRT Discharge Procedure).[5][6] Measure before unsoldering: the monitor cabinet supply gives +5 V and +12 V to each floppy drive connector and +12 V to the monitor connector.[1]

Monitor cabinet power supply

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Monitor cabinet power supply electrolytics (PCB power supply monitor, 5103 108 50350)
Ref Schematic value Parts list part Circuit
C13 4700 µF 16 V 4700 µF 16 V (2222 033 45472) Reservoir after the BY164 bridge D1, feeding IC2 (7805), +5 V for the floppy drives and power LED
C14, C15, C16 No value printed 3300 µF 40 V (2222 033 47332) is the only other large capacitor in the list Reservoir after the 1N5401 bridge D2 to D5, feeding IC1 (723) with TS1, and IC3 (7812)
C12 10 µF 35 V 10 µF 35 V (printed as 2012 017 01015) Output of IC2, +5 V
C11 10 µF 35 V As C12 Floppy +12 V output, at connector CD4
C10 10 µF 35 V As C12 Monitor +12 V, at connector CD5

[1][2]

Two notes on the schematic:

  • C14 to C16 have no value on the drawing. The parts list for the board has one 3300 µF 40 V capacitor and gives no quantities, so it is the likely part for all three, but read the values printed on your capacitors before ordering.[1][2]
  • C1 to C4 are drawn as unpolarised capacitors across the four 1N5401 diodes and labelled "10µF (4x)". The parts list has no unpolarised 10 µF part; its only small unpolarised capacitors are 10 nF 63 V (the value of C5 to C8 across the BY164) and 2.7 nF 100 V (C9 is marked 2 nF on the drawing). Check the parts on your board.[1][2]

The fuses on the drawing are F1 and F2, both 2 A slow-blow; the parts list has a 4 A fuse and a T2A fuse.[1][2]

Board capacitors

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Capacitors of 0.47 µF and above in the P2000M board parts lists (Field Support manual, chapter 6)
Board Values in the parts list Philips 12NC
Business CPU board (M-version), 5103 108 00500 4.7 µF 35 V; 15 µF 35 V; 33 µF 16 V 2013 017 01012; 2013 017 01107; 2013 017 01031
Video board (M-version), 5103 108 01220 33 µF 16 V; 1 µF 35 V 2013 017 01031; 2013 017 01007
Extension board, 5103 108 00523 0.47 µF 35 V; 47 µF 10 V; 33 µF 16 V 2013 017 01005; 2013 017 01157; 2013 017 01030

[4][3][7]

The parts lists number the parts by position on the board layout, not by circuit designator, give no quantities and do not say whether these small capacitors are aluminium or tantalum types.[4] Record each part's position, value, rating and type from your own board before removing anything.

Monitor assembly

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Philips supplied the 12-inch monitor as a complete assembly (5103 107 53010). Its main board, video board, deflection unit and picture tube are listed as spare parts only as complete items, and the Field Support manual gives no component list or capacitor values for them.[8] Work from the values printed on the boards, or from a service manual for the monitor chassis if you can find one.

Procedure

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  1. Unplug both mains leads. Remove the monitor cabinet cover: Philips's procedure lays the cabinet upside down on a soft cloth, loosens the four screws, then stands the cabinet up again to lift the cover off. Discharge the CRT.[9][5]
  2. Disconnect the wiring from the power supply board (transformer, LED, the two floppy drive leads and the monitor lead), unclip the regulators from the frame plate and heat sink, and lift the board out.[10][11]
  3. Note the polarity of every electrolytic and replace one at a time, with the same capacitance at the same or a higher voltage rating. Clip the regulators back to the heat sink when refitting the board.[10]
  4. Before refitting the drives and monitor, check +5 V on pin 5 and +12 V on pin 1 of CD3 and CD4, and +12 V on pin 1 of CD5. Set the floppy +12 V with R4 if needed.[1][12]

Post-recap checks

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Supply checks after recapping
Point Expected Source
CD3 and CD4 pin 5, to ground on pin 2 or 3 +5 V Figure 4.16
CD3 and CD4 pin 1 +12 V, adjustable with R4 Figure 4.16 and section 3.4.2
CD5 pin 1, to ground on pin 2 +12 V Figure 4.16
Basic cabinet: CPU, video and extension board sockets, right-hand pin to second pin from the left +5 V Field Service Manual, step 7
Basic cabinet: CPU board socket, left-hand pin to second pin from the left +12 V Field Service Manual, step 8

[1][12][13]

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 4-35, figure 4.16: power supply monitor cabinet, drawing 5103 108 5035 dated 27.8.80. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-49: parts list for the PCB power supply monitor, 5103 108 50350. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  3. ↑ 3.0 3.1 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-17: parts list for the video board, 5103 108 01220. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  4. ↑ 4.0 4.1 4.2 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-23: parts list for the Business CPU board, 5103 108 00500. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  5. ↑ 5.0 5.1 Philips Data Systems, Field Service Manual P2000, publication 5122 991 30703, October 1982, p. 1-19, section 1.2.3: safety procedures, including discharging the CRT before handling the monitor assembly. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  6. ↑ Philips Data Systems, Field Service Manual P2000, October 1982, p. 1-14: power requirements and fuses of the basic and monitor cabinets. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  7. ↑ Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-13: parts list for the extension board, 5103 108 00523. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  8. ↑ Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-53: service code list, including the 12-inch monitor complete (5103 107 53010), its main and video printed boards, deflection unit and picture tube. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  9. ↑ Philips Data Systems, Field Service Manual P2000, October 1982, p. 1-36, section 1.2.5.6: monitor assembly replacement, including removing the monitor cabinet cover. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  10. ↑ 10.0 10.1 Philips Data Systems, Field Service Manual P2000, October 1982, p. 1-36, section 1.2.5.8: power supply monitor replacement. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  11. ↑ Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-51: monitor cabinet cables, transformer to PCB, PCB to LED, PCB to the floppy drives and PCB to the monitor. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  12. ↑ 12.0 12.1 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 3-23, section 3.4.2: the monitor cabinet supply, with the floppy +12 V regulated by IC1 and TS1, sensed through R2, R3 and R4 and adjustable with R4. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  13. ↑ Philips Data Systems, Field Service Manual P2000, October 1982, p. 1-24: M-version troubleshooting steps 7 and 8, the 5 V and 12 V checks at the board sockets. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.


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