robin kmp3075dl problem

[Superspark23]

I was using my robin kmp3075dl today, tested 7 circuits with it worked perfectly as normal, then when to test next circuit, tried nulling the leads which they did as usual then went to ohms setting put the test leads together and -90 comes up, never seen this before, went back on the auto null setting meter said it nulled 0.00 as it should, then when back to ohm setting and still at -90. thought id try testing with it continuity for a circuit id expected to be around 0.35 came up as - 89. Changed the batteries, checked the fuses and used different leads and still same problem any ideas?

 

[MarkieSparkie]

Robin yellow bricks are usually very reliable, auto-null problems are often the first signs of a repair required. However, before condemning your tester, check the continuity of your leads with another tester, flex the stress points while doing so. Clean the inside of 4mm test sockets with isopropyl alcohol on a cotton bud and the end caps of the fuse in the battery box with a glass fibre brush. Whilst in the battery box test the batteries to ensure that each is in good condition and clean the battery contacts with a glass fibre brush. Reset the manufacturers initial settings by unplugging the battery pack for longer than 30 seconds. These areas are all known issues with Robin yellow bricks that won't null properly.