old mitsubishi 12 rv a2

[savoc]

having some problems with this unit, i have been told the voltage across terminal 1 and neutral should be around 9>12 volts d/c. when i checked i found had 20>22d/c. was told by tech support to replace faulty indoor board. Installed new board still the same. i get 240 volts on terminal 2 (supply to outdoor) for a few seconds then unit faults. the green lights just flash.

[install monkey]

is the transformer external from the board? if so check outputs- as you say its a 12v dc signal on 1,2 for cooling,and 3 energises reversing valve

[install monkey]

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=20&cad=rja&ved=0CE8QFjAJOAo&url=http%3A%2F%2Fes.mehvac.com%2FUploadedFiles%2FResource%2Frad4AD33320059122819.PDF&ei=w6inUfiYKMr30gWL_YHwCw&usg=AFQjCNGn-kOYSc7r51WISjoqxsMDy62Law
service manual

[savoc]

the transformer is built into the board, cant see the voltage on the transformer. the compressor relay on the board (indoor) has 12volts d/c coil. could there been something causing the higher voltage?

[install monkey]

is the 12v transmission cable run parallel with any mains cable