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Good  luck with your project’...  Enjoy your classic motoring...
Fixed price repairs are based on the assumption that unit/s received
 are
‘original & complete’... a surcharge may be applied to cover
missing  parts etc...  If in doubt send in the unit for inspection
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Mileage correction
Clocks
Other services
Post & packing
Contact details
Speedos
Rev counters
Jaguar XK 120 ( 1948 / 54 )
117.1 M
Parts Order E-Mail Link
Payment options
Payment options
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Payment options
JDO Instruments
Classic Car Instrument Repairs ( Est 1963 )
Fixed price repairs for most British & European Classic Car Instruments
48hr service  
available... Why pay more & wait longer ! No UK vat
Tele: (UK)  01535 672125    Mobile / SMS:  07831 886545
Please check the  FAQ’s page  BEFORE ringing / emailing... thank you
Connecting diagrams... Smiths & UK Jaeger Rev-Counters
Type RVI v1
Current loop
( 1 full turn )
A
B
C
Positive  OR  Negative Earth*
A= Ignition feed  - ve.. (+ ve)*
B= Coil - ve. (+ ve)*
C= Ignition feed - ve  (+ ve)*
Case to be earthed + ve  ( - ve)*
If unit fails to work  REVERSE
A & B connections
These units will not work
with Electronic ignition

upgrade available
(See picture @ top R/H side
For ‘current loop’ info)
A
B
Type RVI v2
Normally Negative Earth*
A= Male bullet  Ign +ve
B= Female bullet  coil +ve
C= Ignition feed + ve
Case to be earthed -ve
* A few early units were
Positive Earth
These units will not work with Electronic ignition
upgrade available
C
Type RVC
A
B
Negative Earth only
A= Male bullet  Coil - ve
B= Ignition feed  +ve
( positions may  vary )
Case to be earthed -ve
These units will  work
with Points OR
Electronic ignition

Some Jaguar units may be fitted with a lead
& a 3 or 4 pin plug
A= Camshaft generator
B= Camshaft generator
( either way round )
Case to be earthed
( for illumination only )
These units can be
Upgraded to work with
Points OR Electronic

ignition
A
B
Type RV
Current loop
( 1 full turn )
Positive  OR  Negative Earth*
A= Ignition feed -ve  (+ ve)*
B= to coil -ve  (+ ve)*
Case to be earthed +ve ( -ve)*
( for illumination only )
If unit fails to work  REVERSE
A & B connections
These units will not work
with Electronic ignition
upgrade available
(See picture @ top R/H side
For ‘current loop’ info)
A
B
12v -ve
6v -ve
+ve
Type RVI v1 ‘Universal 80mm unit’

RVI version 1... It is important to retain the nylon block correctly  with  the metal clip
&  loop the ‘pulse lead’  as shown  otherwise the unit will not work