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Philips P2000T Capacitor Replacement Guide

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Philips P2000 basic cabinet power supply schematic (fig 4.14)
The basic cabinet power supply (Field Support manual, figure 4.14). C1, C2 and C8 smooth the +5 V input to the three 7805 regulators, C3 the +12 V input to the 7812, and C4 the unregulated negative supply.

The electrolytic capacitors of the Philips P2000T that matter most are in its power supply, which the P2000T shares with the basic cabinet of the Philips P2000M. Philips's Field Support manual gives the supply's circuit diagram with capacitor values and its parts list with values and voltage ratings; the parts lists for the CPU board, extension board and modulators give values and ratings but no circuit designators or quantities.[1][2][3] For the general signs of a failed capacitor see Capacitor Failure Symptoms.

Before replacing anything

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The power supply board is mains powered through the transformer in the same cabinet. Unplug the lead before opening the cover, and measure before unsoldering: Philips's own supply check is +5 V at each board's power socket and +12 V at the CPU board socket.[4][5] Because TS1 and TS2 short the +12 V line while +5 V is missing, a +5 V fault also kills +12 V.[6]

Power supply capacitors

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Basic cabinet power supply electrolytics (PCB PSU 5103 108 00470)
Ref Schematic value Parts list part Circuit
C1, C2 4700 µF each See note: the list has 6800 µF 16 V (2222 033 45682) and no 4700 µF part Reservoir after D1 and D2 (1N5401) and fuse F3, feeding the three 7805 regulators
C8 10 µF 10 µF 35 V (2013 017 0105) Across the same +5 V input
C3 3300 µF 3300 µF 25 V (2222 033 46332) Positive output of the bridge D3 (BY164), feeding the 7812
C4 470 µF 470 µF 25 V (2222 032 16471) Negative output of D3, the unregulated -20 V supply to the logic boards
C5, C6, C7 10 µF each 10 µF 35 V (2013 017 0105) Outputs of regulators 1, 2 and 3 (CPU, video and extension boards)

[1][2][6]

The schematic and the parts list disagree about the main reservoir capacitors. Figure 4.14 marks C1 and C2 as 4700 µF; the parts list for the same board has a 6800 µF 16 V capacitor and no 4700 µF part. Neither gives a quantity. Read the values printed on the capacitors fitted to your board before ordering, and use at least 16 V, the rating in the parts list.[1][2]

The parts list also has a 10 nF 63 V capacitor, which is not an electrolytic.[2]

Board capacitors

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Capacitors of 0.47 µF and above in the board parts lists (Field Support manual, chapter 6)
Board Values in the parts list Philips 12NC
CPU board, Economy (T-version), 5103 108 01210 4.7 µF 35 V; 15 µF 35 V; 33 µF 16 V 2013 017 01012; 2013 017 01107; 2013 017 01031
Extension board (optional), 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
VHF modulator, 5103 108 00540 3.3 µF 16 V 8203 235 09000
UHF modulator, 5103 108 01380 10 µF 35 V 2013 017 0105

[3][7][8][9]

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.[3] Record each part's position, value, rating and type from your own board, using the component layouts in chapter 6, before removing anything.

Procedure

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  1. Unplug the mains lead and remove the cover, held by seven screws from underneath.[10]
  2. The power supply board is fixed to the aluminium backplate, which is the heat sink for its regulators, and the other end sits in a groove in the frame. Disconnect its connectors to the boards; Philips fits them with the red wire down.[10][11]
  3. Note the polarity of every capacitor. C4 is on the negative supply, so its positive lead goes to ground.[1][6]
  4. Replace one capacitor at a time with the same capacitance at the same or a higher voltage rating, and refit the regulators to the heat sink with their insulation if any is fitted.
  5. Before refitting the boards, check +5 V at each power socket and +12 V at the CPU board socket.[5]

Post-recap checks

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Supply checks (Field Service Manual and Field Support manual)
Point Expected
CPU, video and extension board sockets, right-hand pin to second pin from the left +5 V
CPU board socket, left-hand pin to second pin from the left +12 V
Across C4 About -20 V, unregulated

[5][6]

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References

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  1. ↑ 1.0 1.1 1.2 1.3 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 4-33, figure 4.14: power supply basic cabinet, drawing 5103 108 0047 dated 26.06.79 (C1 and C2 4700 µF, C8 10 µF, C3 3300 µF, C4 470 µF, C5 to C7 10 µF). Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  2. ↑ 2.0 2.1 2.2 2.3 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-27: PCB PSU (5103 108 00470) parts list: capacitors 6800 µF 16 V (2222 033 45682), 3300 µF 25 V (2222 033 46332), 470 µF 25 V (2222 032 16471), 10 µF 35 V (2013 017 0105), 10 nF 63 V (2222 629 01103). Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  3. ↑ 3.0 3.1 3.2 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-19: PCB Economy CPU (5103 108 01210) parts list, by position number. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  4. ↑ Philips Data Systems, Field Service Manual P2000, publication 5122 991 30703, October 1982, p. 1-19, section 1.2.3: never remove a module without first removing the plug from the power source. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  5. ↑ 5.0 5.1 5.2 Philips Data Systems, Field Service Manual P2000, October 1982, p. 1-24: steps 7 and 8, the 5 V checks at the CPU, video and extension board sockets and the 12 V check at the CPU board socket. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  6. ↑ 6.0 6.1 6.2 6.3 Philips, Documentatie P 2000 (Field Support manual, 8111), p. 3-23, section 3.4.1: the transformer voltage rectified by D1 and D2 and smoothed by C1 and C2; the second winding rectified by the bridge D3, giving a positive voltage over C3 and a negative voltage over C4; the unregulated -20 V to all logic boards; regulator 4 for +12 V; the TS1 and TS2 protection. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  7. ↑ Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-13: PCB extension board (5103 108 00523) parts list. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  8. ↑ Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-29: PCB modulator board VHF (5103 108 00540) parts list. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  9. ↑ Philips, Documentatie P 2000 (Field Support manual, 8111), p. 6-31: PCB modulator UHF (5103 108 01380) parts list. Hosted as File:Philips P2000 Field Support Manual 8111.pdf.
  10. ↑ 10.0 10.1 Philips Data Systems, Field Service Manual P2000, October 1982, p. 1-9, section 1.1.3.1: cover held by seven screws from underneath; the aluminium backplate as heat sink for the power supply regulators, with the power supply board connected to it and supported by a groove in the frame. Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.
  11. ↑ Philips Data Systems, Field Service Manual P2000, October 1982, pp. 1-30 to 1-35, section 1.2.5: board power connections disconnected "red wire down". Hosted as File:Philips P2000 Field Service Manual 5122 991 30703.pdf.


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