Operator's Manual
DS7A - Constant Current Stimulator
Appendix 1 .. DS7A Modification Record Status
The DS7A has a "MOD RECORD" label fixed to its rear panel.
This indicates which modifications have been performed to that unit and all numbers may NOT be struck
through.
New Instruments
Currently, all new units (at time of first delivery) have had all numbers struck through and this implies a
'Mod. State' that is the highest number that has been struck through.
i.e. If all number 1 through 22 have been struck through - the MOD STATUS is "22".
Units that have been modified after first delivery
Units may have had some modifications done subsequent to manufacture and all numbers may NOT be
struck through.
The Modifications made
The recent changes that have occurred indicating a rise in 'Mod. State' are:-
Mod.
State
Change from previous 'Mod. State'
10
a) The FAULT indicator (and output inhibit circuit) is now latched. The OFF position of the
Output Enable Switch is used to 'reset' this latch.
b) The 100 µs Trigger Out and 10 kHz repetition rate has been removed. (Trigger Out is
1 ms, max. Rep. is 1000 Hz)
11
Front & Rear panels labelling changed to include more symbols and conformance with the
MDD requirements. Trigger LED now amber not Green.
12
Internal modifications including larger Output Capacitor.
13
Output Current dial changed from 4 to 3 digit due to failures of 4-digit dial mechanisms.
14
Internal changes to reduce errors due to leakage on PCB due to contamination.
15
PCB up-issued to incorporate numerous, previous, changes (CN.1749)
16
Front Panel Pulse Duration switch now has keyed component and knob. (CN.1819)
17
Internal changes to add diode to discharge capacitor. (CN.1879)
18
More ESD material added to enable full compliance the 60601-1-2:2001. (CN.1964)
19
Minor internal electronic changes for increased ESD and EMC (CN.1987)
Digitimer Ltd.
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Copyright © 2014
File Ref: N:\Docs\Company\Manuals\DS7A\Issue-14\DS7A-iss14.odt
Last Revised: February 1, 2017
Digitimer Ltd
WELWYN GARDEN CITY
HERTFORDSHIRE, ENGLAND
SERIAL No.
MOD.
RECORD
STATUS
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24
MADE
IN
ENGLAND
Digitimer Ltd
WELWYN GARDEN CITY
HERTFORDSHIRE, ENGLAND
SERIAL No.
MOD.
RECORD
STATUS
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24
MADE
IN
ENGLAND
