Otari MX-5050
MX-5050B›Service

Generation

FirstMark IIBB-IIMARK IIIB-IIIMARK IV

MX-5050B

OverviewIdentifySpecsHistoryDocumentsService

Machines

B-2B-4B-F

Servicing the MX-5050B

The factory manual↑ TOP

The maintenance manual OS2-004 (digital edition) covers the whole B line — the synchronous 2H, 2L and 4L and the DC-servo 2HD, 2LD, 4LD, FHD and FLD (parts and schematics, p.83). Its Section 4 is the performance tests and electronic alignment. OS2-004 calls itself a supplement to the B's instruction manual, OS1-011 (front matter), which is not on this site.

Alignment↑ TOP

The factory procedure is OS2-004's 4-6 Electronic Alignment, after the performance tests in 4-4. The shared method, with modern test gear, is at Calibrating the MX-5050; its pot numbers are the first generation's, not the B's.

How it differs from the shared method↑ TOP

  • Voltages are for the B-2H. The levels in Section 4 are "for the MX-5050B-2H (D) model"; the B-F and B-4 align "in essentially the same manner", but their head sensitivities and bias and record currents differ — the manual sends you to their block diagrams for the values (4-1).
  • A reference-level switch. A RECORD LEVEL switch on the back panel sets the reference: 250 nWb/m at M, and 320 nWb/m at H for IEC equalisation (4-1; 2-3, Table 2-1).
  • NAB or IEC from a switch. The EQUALIZER switch (SW505) on the back panel selects NAB or IEC, followed by a fine equaliser adjustment (2-3).
  • Reproduce EQ per speed only on L models. On the high-speed version one set of reproduce EQ controls serves both 15 and 7½ ips, so 15 ips is set first; the low-speed version has controls for each speed (4-6-(3)).
  • Speed pairs and conversion. The 2H runs 15 and 7½ ips, the 2L and 4L 7½ and 3¾ (Table 2-2). A D model changes pair with switch SW701; a synchronous model also needs a new drive pulley and belt. Either way the equaliser needs fine adjustment afterwards (2-6).

Sources↑ TOP