K6002 help

Good morning:
I am new to the forum, just bought and set up a k6002 (with k6001 included) and when I went to feed 9VAC I find that the menu is blocked and appeared constantly FAIL.
The funny thing is that with 9VDC if I could navigate the menu but, of course, had no measurement of temperature and clock …
and finally consulting this forum before registering, I discovered that the problem could come from the 4N27 optocoupler included, I changed the til111 having the same problem of blocking.
raise the resistance R3 of the optocoupler and became operational seemingly perfect.
I checked all welds several times without finding anything unusual …
Why 9VAC crashes with the k6002 and k6001 12vdc as instructed with r3 r3 connected and disconnected works?
many thanks for the help.
Diusculpen English is through a translator.

Hi,

Doesn’t the 6002 require 9 volts AC and the K6001 require 9 volts DC.

Or am I not understanding your post?

sorry if I do not explain properly.
The manual clearly states that the k6002 must be supplied with 9v ac and 12V dc with k6001.
The problem is that these tensions and everything seems correct, it only works with the r3 off.
I read in some forum that this only affects the speed of response of the optocoupler, is this true?
Many thanks in advance