Warning: this listing was originally generated for 4QD internal use only, so is not as fully detailed as it should be if it were intended for general circulation. Also 4QD's policy is one of continual improvement, so changes tend to be small and frequent. Also changes usually first appear as a board modification on an the earlier board issue! This makes change history difficult to document fully, but it does improve the product! The history is however included here as it may be useful! No liability is accepted for the accuracy of the information in it!
The NCC series consists of two different circuit boards: one for the NCC-35 and a different one for the NCC-60 and NCC-70. These two boards are handled internally on a common computer file, consisting of three sections:
There have been no fewer than five different models in the NCC family.
NCC-35 and NCC-50 used one board, the -60, -70 and -100 use the other board.
The smallest board in the family, uses two MOSFETS.
Now discontinued, the NCC-50 used the same board as the NCC-35 but had four MOSFETs in place of two, so giving twice the current. It was an uprated NCC-35, but somewhat 'overstretched' the relays handing capacity. In the early days we used a relay manufactured by Schrack and MOSFETs were not as good as they now are. As MOSFETs improved, the available current increased and we started to get relay contact failure. Then Siemens bought Schrack and this particular relay was discontinued. Its replacement was of lower current carrying ability so the NCC-50 was dropped in late 1998, issue 14.
This is essentially the same as the NCC-70 but without the thermal sensor and parking brake driver. Discontinued in Autumn of 2001 (Issue 24 board) for no better reason than our range was getting too large!
The modern commonest member of the family. 4 MOSFETs, two drive, two regeneration.
In the early days (when MOSFETs were not so good) one customer tried an NCC-70, liked it but said, could we make one with slightly more current. The -100 was the result. It uses 6 MOSFETs (same as the Pro-120). However, it stretched the circuit board and main capacitors rather too much. It was discontinued soon after the Pro-120 was released, around NCC issue 08.
The board numbering system was implemented slowly: early boards did not have numbers or used a different identification, so it can be difficult to identify some early issue numbers. Key features are italicised.
| Click on the Issue number you want | |||||||
| 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 |
| 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
| 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
| Issues above are too old for repair. | |||||||
| 25 | 26 | ||||||
After issue 3, the shape of the circuit board was changed: subsequent boards were shorter and fatter.
Early boards had been pre-select reversing. Later boards were 'Dual ramp'.
Early boards also sensed pot fault at the bottom end of the pot. Later boards sensed at the top end of the pot, allowing the bottom end to be a direct battery negative connection to simplify external wiring.
This resistor is behind the expansion connector, just below the main capacitor.
Boards earlier than issue 25 are generally too old for economical repair.
In early 2003, the NCC was redesigned as the Mark 2 NCC. In mid 2005 this was redesigned as the VTX.
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