FIELD SERVICE BULLETIN NO. 6
SBE 9plus CTD Retrofit for Use with
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All SBE 9plus CTDs that meet both of the following criteria are affected:
In September 1997, a modification to the 9plus CTD changed how the negative supply is generated for the card file and telemetry. The original design used a Computer Products DC/DC converter with a clamped input for over-voltage protection. This change removed the DC/DC converter circuitry and placed a charge pump circuit on the CSAD board that could supply the -13.2 volts necessary for the CTD. This circuit used an LT1054, which is only rated for 16 volt operation.
Alkaline batteries in the Searam (1.5 volts/battery * 12 batteries = 18 volts) produce a voltage greater than the acceptable operation range of the LT1054 and will damage the 9plus. A 9plus built between September 1997 and April 2004 should not be used with a 17plus Searam that is powered by alkaline batteries, without first modifying the 9plus.
The use of Ni-Cad or NiMH batteries in the Searam is still acceptable, as the
maximum voltage of these battery packs is only 14.4 volts (= 1.2 volts/battery *
NOTE: All Searams sold during the period in question were shipped with Ni-Cad batteries installed. Damage to the 9plus will occur only if the Ni-Cad batteries are replaced with alkaline batteries.
In April 2004, the LT1054 on the 9plus CSAD board was replaced with an LTC1144, which has an operational voltage of 18 volts with 20 volt transient suppression. These CTDs are not affected by the problem described above.
Before proceeding, contact Sea-Bird, providing your 9plus’ serial number, to determine if your 9plus requires a retrofit.
For customers using a 9plus with CSAD board PN 801042 (Rev. 40904 or 40904A) with a Searam:
For customers using a 9plus with CSAD board PN 801042 (Rev. 40904
or 40904A) with the 11plus Deck Unit:
The 9plus used in this system configuration is not affected by the over-voltage problem, and does not need the modified CSAD board. However, when your 9plus is returned to Sea-Bird for calibration and/or repair, we will modify the 9plus to the current CSAD assembly at no charge to make the 9plus compatible with an alkaline-powered Searam in the future.
Last modified: 26 Dec 2012
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