JBC AD2700 not heating - Page 1
Forum section: electronics / repair

author: fredboivin
author_rank: Regular Contributor
timestamp: January 23, 2016, 03:55:57 am
content: Hi,I have a JBC AD2700 soldering station that I'm using with new tips, but I can't get the tip temperature higher than 120-150C and moving the dial doesn't do much. The "in-use" led is lit permanently when the tool is out of the stand, so it is not fixed temperature. The cartridge open and short detection, and sleep are working. I opened it and there were no evidence of blue smoke having escaped.Do you have an idea what might be wrong with it?Thanks!

author: wblock
author_rank: Regular Contributor
timestamp: January 23, 2016, 04:24:26 am
content: On my AD2200, the same or a similar problem was due to the handpiece, probably broken wires from flexing:https://www.eevblog.com/forum/repair/jbc-ad2200-soldering-station/It's hard to test without a second handpiece.

author: rich
author_rank: Frequent Contributor
timestamp: January 23, 2016, 05:00:02 am
content: just read your AD2200 thread - would measuring the tip resistances as you did, then put the tip back in the handle and remeasure at the connector have show up the eventual handle fault do you think. Could be something for the OP to try out?As an aside: I also had an older 2900 which had similar weird behaviour to yours although less extreme. Replacing tip and handle fixed it. My theory (unproven) was the tips really don't like bending force being applied during soldering and this created an internal intermittent fault.

author: wblock
author_rank: Regular Contributor
timestamp: January 23, 2016, 06:07:11 am
content: The wires do get flexed right past the end of the strain relief, so I think they become intermittent or at least higher resistance. Maybe they use pairs of wires for better current capacity, and this type of failure happens when one wire breaks.Measuring the tip resistance through the wires could work. A meter with a fast continuity test would help. Wiggle the cable to try to find intermittents.The AD2200 and my DI3000 were both bought used, so I can't really say how long a handpiece ought to last. The well-used 2245 that came with the DI3000 is fine.

author: fredboivin
author_rank: Regular Contributor
timestamp: January 23, 2016, 04:15:58 pm
content: Thanks for the link, wblock. My handle seems to have been repaired at the strain reliefs, but the seller confirmed me it was working before shipping. I'm willing to believe him, but he was selling more than one so tests might have been done with another iron.I took resistance measurements of the tip (results match spec) and at the connector and only found 3 pairs of pins out of 15 possibilities that where in the 3R range.Both of my tips are new and exhibit the same behaviour, so I think I can rule them out. Taking temperature measurements with or without pressure or wiggling don't change the results.Looking at your experiences, I think I'll buy a new handle and see from there.

author: fredboivin
author_rank: Regular Contributor
timestamp: February 09, 2016, 09:41:36 pm
content: Ok, I got some update on my problem.I went to the store and my handpiece works on another station! But my station also works with a new handpiece, however with settings higher than usual... The salesman also noted that my connector is unusually loose.This all points out to a dicky connection between the station and the handpiece.I went back home all happy that I avoided forking up 130$ and played with the spring contacts inside the connector. It now fits snuggily and I can now melt solder when setting above 700F but not lower! HAHA!I will continue playing the the contacts and may end up replacing the connector all together.

author: wblock
author_rank: Regular Contributor
timestamp: February 09, 2016, 11:03:01 pm
content: Nice that you have narrowed down the problem! 700F (370F) seems pretty high. Does the tip actually get that hot?Digikey sells a panel mount version of that connector. I have not found an exact replacement yet.

author: fredboivin
author_rank: Regular Contributor
timestamp: February 10, 2016, 02:56:18 pm
content: I measured the tip temperature and it barely gets to 180C at max power. Yet, it's melting solder. On any setting, the temperature is half or lower the set point. Wiggling the connector doesn't change the temperature.The connectors are Hirose RPC1-12RB-6P(71) for the base and Hirose RPC1-12P-6S(72) for the handpiece. Inside the station, the connector board is connected to the main PCB by what seems to be a Molex Premo-Flex round flat cable.I will try replacing the flat cable with new wires and resoldering and cleaning the connectors with contact cleaner and see from there. I don't really want to get into changing the handpiece connector...Thanks for the support! I hope it will be working soon!