Isotherm Fridge Control Unit spares/diagnostics advice please

[andyp]

Hi,

My Isotherm ASU 3701 fridge will not power up.

Last time this was corrosion on the thin RJ11 socket contacts which link to the ASU control panel. This time it seems more fundamental.

There is +12.7V at the main connections from the supply breaker to the control unit (terminal strip at bottom of the picture) but no sign of life on the three coloured LEDs on the control panel.

The Control Unit mounted on the side of the compressor does not have the T, C, P connections mentioned elsewhere, it just has a three pin connector direct to the compressor, a fan connection and remote RJ11/RJ9 socket connections to control panel and thermostat.

The Control Unit is mostly a heatsink for a number of power transistors (picture attached).

Any ideas on what to check first or where to get a spare?

 

[andyp]

Had a closer look at the fridge control unit circuit board and it is likely to be one of the off-board connectors which is at fault.

About a year ago I replaced the RJ9 socket which connected to the thermostat. That had corroded in the salty atmosphere next to the through hull log probe.

There is also an RJ12 socket (6p6c) which connects to the control panel. One of the internal connections (right hand side looking in) looks to have corroded clean away in the attached picture.

I have ordered some replacement sockets from RS and will fit and test. Then some anti-corrosion treatment once it is all working again!

 

[mapu]

Hi Andy,
My isotherm 3701 will not power up as well although voltage present on control unit. Same as in your picture. Did you manage to fix problem just by changing sockets? Or it's something deeper ?
Thanks
Marty
Rival36