Hakko fx-888D temperature fluctuation
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Hakko fx-888D temperature fluctuation

by bilsch on Sun Nov 05, 2017 8:11 pm

I'm curious if anyone has seen an issue I've been having with my hakko 888d soldering iron.

Once heated and I start soldering things the temperature readout goes all over the place very rapidly. The unit must then be power cycled before it will heat to the set temperature ( 750F ).

I've had this iron for a while - 3 or so years I think ( just about the time they retired the 888 analog ). It started doing this maybe a few weeks ago. I tried switching nozzles. Checked and cleaned the ceramic heater ( was a little black char on it but not much ). I also looked over the wire contacts for the pen holder ( pcb inside ) and it looked just fine. I have not checked the power box yet.

Any ideas what could be going on? This has been a great soldering iron and I would prefer to keep it ;)

Posts: 17
Joined: Thu Oct 25, 2012 5:16 pm

Re: Hakko fx-888D temperature fluctuation

by adafruit_support_mike on Mon Nov 06, 2017 3:14 am

It sounds like the feedback path from the temperature sensor to the power control circuit has developed an intermittent connection.

Hakko irons change temperature in a few seconds, but the actual temperature of the iron can't swing high and low faster than that. If the readout on base station is showing changes faster than that, it's probably a sign of the feedback loop being broken.

The fact that the system behaves once the iron has had some power flowing through it suggests a small gap or broken solder joint that expands enough to make contact after the power cycle.

Posts: 48489
Joined: Thu Feb 11, 2010 2:51 pm

Please be positive and constructive with your questions and comments.