De-5000 LCR issues with larger capacitors

[chromguy]

I have a DER EE DE-5000 and has been working great for years except with high capacity caps basically larger than 1uF. At first, 1kHz was cranky and would not lock on to a value and keep switching back from Cp to Cs like it was hunting. After a while it would only work at 100/120 HZ, Now it will not work at all. I did take it apart and cleaned the board with IPA but it did not help.
At this point it will not calibrate and get stuck at 00 on the short circuit stage. I have tried multiple probes and even bare wire. Funny a bare wire between +/ - the unit switches back and forth between Cp and Cs.
I did notice that all solder joint look very crystalline but perhaps that is the lead free solder they used. I was thinking of reflowing as my last attempt.
I did check google for repair information but not luck with anything useful.
I am thinking "I need another Timmy"
Suggestions welcome
 

[usadave]

I have had similar problems.  It seems to read everything in capacitance quite low.  It won't lock on to series and some of the button's don't work at times.  I went to Amazon to read some of the current reviews and it seems the thing works great for 6 months to a year and then falls apart.... so disappointed as it got many good reviews on Youtube from many reliable people...  trying to find a schematic here on eevblog but no luck so far...  thx,  Dave T

[coromonadalix]

For the calibration  you have an english manual floating on the web, you have the open and short calibration mode, they have a 30 second timer  when you do it,  you have to do it all the way to get a good calibration, if you move or open or short the "wires"  you'll have to redo it again ..

I did get a new de-5000 and wanted to push it against my sencore lc102  for the large caps ex: 12000 uf and up, but with the covid-19 thing, i did not had the chance to do so



Maybe the rubber key pad is not good enough for the mode(s) ??

They are based on 2 chips design, and i did not saw any leaked schematics.