Support - Fusible Mains Input Resistor Replacement

There have been recent issues around the (three) fusible input resistors used on all Electrocorder models (Plug & IP65) delivered prior to 10 June 2002 - models affected - EC132/xxx & EC164/xxx.

The problem concerns these resistors (R1A, R1B & R1C) fusing (blowing) and therefore cutting mains supply to the Electrocorder, this problem can be diagnosed by the fact that the Electrocorder will not and does not record any data. Also, when connected to mains supply, neither of the LED's (red or green) light!

EC132/Plug & EC164/Plug

Before working on an Electrocorder you must ensure that it is disconnected and isolated from the mains voltage supply. Work must be carried out by a qualified person.

One or more of the 3 input resistors (R1A, R1B & R1C) may have fused, you may check the resistance with an omhmeter. In the past various resistances were used 50R, 100R, 470R and 1K for each.

The solution is to leave all 3 resistors in circuit and bridge them with a SINGLE 1K (1000 Ohm), 2 Watt, MAINS RATED resistor, see the diagrams below. On plug models, remove the 3 case screws, disconnect the battery. On the New 1K resistor, clip 5mm off each leg, and bend them to fit the position shown on the top side of the PCB. Insert a new battery and replace the cover. The original (3 or 6) resistors R1A, R1B & R1C are now redundant. They do not need replaced or removed; all 3 have been bridged with the 1K (1000R), 2W resistor! To test simply apply mains, both LED's light!

EC132/IP65 & EC164/IP65

Before working on an Electrocorder you must ensure that it is disconnected and isolated from the mains voltage supply. Work must be carried out by a qualified person.

On IP65 Models, remove the 4 cover screws and open the case, remove the battery, loosen the cable gland and pull the cable back through it, allowing easy access to the three input resistors (R1A, R1B & R1C). There is no need to remove the PCB, as this will break the waterproof sealing. Clip and bend the legs to ensure that the main body of the resistor is as far from the cable glad as possible and as low to the PCB as possible. Solder the resistor in the position shown. When cool, feed the mains cable through the cable gland ensure the cable does not touch the resistor body and tighten the gland. Insert a new battery and replace its securing cable-tie (tie-wrap), replace the cover. The original (3 or 6) resistors R1A, R1B & R1C are now redundant. They do not need replaced or removed; all 3 have been bridged with the 1K (1000R), 2W resistor! To test simply apply mains, both LED's light!

The resistor to install is a suitable mains-rated 1K (1000 Ohm), 2 Watt type, for example the PR02 series available from Farnell Electronic Components (FEC) www.farnell.com or http://rswww.com

Suitable resistors are available from FEC (Farnell) and RS Components.

FEC Part No. TBA
RS Part No. 214-1951