Hakko fx888d connected to the wrong outlet - Page 1
Forum section: electronics / repair

author: Mmad0
author_rank: Newbie
timestamp: March 08, 2018, 12:18:16 pm
content: Hello this is my first postAnd I need your helpA friend of mine asked if he can take my hakko fx888d for a day or twoI agreed but told to connect it to 110v acBut he forgot and connected it to 220v ac the fuse has blown upSince I no longer have a working iron I bought fuses and gave it to a technician to fix it but after a couple of minutes he called me saying I can't fix it and he broke 2 fusesWhat I want is to check if the transformer had burned out so can anyone give me the resistance of the primary and the secondary.My primary measures 6.6 ohms and the second is .6 ohms if the transformer is good I'll just buy the fuse board with the black thingAnd thanks for your help.

author: Mmad0
author_rank: Newbie
timestamp: March 08, 2018, 06:30:49 pm
content: Can any owner of hakko fx888d helpThanks

author: helius
author_rank: Super Contributor
timestamp: March 08, 2018, 07:02:52 pm
content: Are you in Brazil?From what I've read, Brazil is one of the few places in the world that uses identical sockets for 120V and 220V.

author: Samogon
author_rank: Frequent Contributor
timestamp: March 08, 2018, 08:45:20 pm
content: I dont want to open unit, but measuring resistance in the input i getting 7.27 Ohm. Check if you have close to zero, then you have shorted primary winding. and you can buy new iron.

author: KL27x
author_rank: Super Contributor
timestamp: March 08, 2018, 09:01:29 pm
content: If you have 5V power supply, you should be able to check at least if the board does anything. It's a little tricky to suss out the power rails on this board, though. IIRC, it is set up so that the power to the micro is 0V, and the ground is -5V rail. And I think there's also a -12V rail and linear regulator, or maybe I'm remembering wrong. At any rate, the board runs on just the half wave rectified -13ishV DC, so you could also just feed it 12V at the right spot, with a lab PSU with current limiting. If you can figure it out, you can test the micro/display before buying stuff. There are some polar electrolytics on there to guide you around. And there's also a large power resistor dropping some watts on the -13V rail, for reference. Aside from the Renasas micro controller, everything else on the board is easily replaceable. Triac, transistors, diodes, linear regulators, caps, a dual opamp. That's about it.I'll open mine up and give you some readings in a bit.*Ok, yeah, the fuse board has an MOV maybe on it? If that burned out, it could be causing the fuses to blow, maybe? I'm not great with AC.On the secondary, I'm reading 0.54R. (0.5R with an occasional blip to 0.6R).If the transformer is good but the main board is toasted, I wouldn't throw out it out. The regulation on this transformer is excellent. 88.8V peak to peak output on the secondary, after it's warmed up. Like clockwork. Even under full load of the iron heater, you don't see any significant change to the output. There are a variety of 936 controller pcb you could adapt to this and possibly fit into the enclosure, if not make your own opamp and comparator circuit with analog control.

author: Mmad0
author_rank: Newbie
timestamp: March 09, 2018, 07:34:57 am
content: Thank you so much for your help

author: ciccio
author_rank: Frequent Contributor
timestamp: March 09, 2018, 03:27:24 pm
content: I don't have a FX888d on hand, but searching for teardown videos I've seen the "black thing" that the OP refers to, soldered on the primary mains PCB.It seems avaristorin that is placed after the fuse, in parallel with the transformer primary.Maybe it has shorted, or simply has been damaged, and I think it is a simple and inexpensive test tocut it offand see what will happen. In my humble opinion the station will power on, and there is no need to replace the varistor (but you must never connect it to 230 V again).Good luck

author: Cyberdragon
author_rank: Super Contributor
timestamp: March 09, 2018, 03:48:05 pm
content: Removing the varistor means it could also get zapped by any power surges.QuoteQuote?

author: ciccio
author_rank: Frequent Contributor
timestamp: March 09, 2018, 08:15:51 pm
content: Quote from: Cyberdragon on March 09, 2018, 03:48:05 pmI do not think so... Obviously, if available, the varistor should be replaced, (if it is the cause of the problem, and I cannot be sure of this) but I think that, if I'm right it was seriosly underspecified. It should carry enough current to break the fuse, but it should survive.Best regards

author: Samogon
author_rank: Frequent Contributor
timestamp: March 10, 2018, 04:37:31 am
content: Quote from: Cyberdragon on March 09, 2018, 03:48:05 pmNothing wrong,I measured via AC plug, he did it directly on transformer.

author: Armadillo
author_rank: Super Contributor
timestamp: March 10, 2018, 05:02:40 am
content: I didn't even remember I have a Hakko FX888D. hahahaha LOLI measure at the plug, live and neutral is 36 ohms. [230VAC system]