yihua 8508D SMD rework station - Page 1
Forum section: electronics / general

author: ptricks
author_rank: Frequent Contributor
timestamp: November 27, 2012, 02:50:27 am
content: At a recent ebay discount sale I bought a yihua 8508D rework station .Mine quit working after about the 4th time I used it. The station was working fine up to the point it started to get intermittent and then quit with a puff of smoke coming out the case. I opened it up, and found more than I expected. Pic belowOne of the connectors on the power switch was no longer attached, the wire didn't come loose, the whole connector and internals of the switch had pulled out of the casing. I removed the heat shrink on the switch connector expecting to find a wire and connector , instead it was a wire soldered directly to the switch connector, just tacked in place. Normally that isn't a terrible practice but what they did compounded the problem. They used the switch terminal to join several wires together, so you have the end of 2 wires coming off a solder point on a switch, wires not even twisted together just a blob of solder with wires stuck to it and heat shrink over the top.When they soldered the connections like they did they heated the switch connections up to the point that the switches plastic deformed allowing the internals to pull out.I had to re-wire the whole thing with a new switch, new connectors on the wires and wires joined before the end connector. Wires should never use the connection point as a junction, it is prohibited in residential wiring for the same reasons , it is dangerous. Put a bunch of wires together and solder them to a single point and you are almost guaranteed to have one that has a poor connection.Other issues are they bring in the AC wiring using 12AWG wires then heat shrink that to a single wire that is 18AWG and just bundle all that together along with the low voltage wiring and send that out to the part you hold. For a 5A current at least AWG15 is required and yet they wired the unit with lots of the 18-20AWG stuff.The air pump is another issue. All the air lines were cut too short and have kinks in them that block air flow. It will take me a few hours of work to fix all the issues I found. I'm still debating if the purchase price was worth it or not, was about $65 shipped. If you have one of these you may want to remove the cover and take a look inside.

author: T4P
author_rank: Super Contributor
timestamp: November 27, 2012, 05:35:58 am
content: Hold on, you do not need AWG15 for 5A. "power transmission" and chassis wiring ampacity is a different thing, if what you said was true mains wiring in equipment at least in my country would have required AWG 7 in everything!What really matters is the length, it's only a several cm from the inlet of the station to the board NOT 50meters! Chassis wiring ampacity is what you're after and AWG18 will do 16amps not a issue, they're not in trunking which leaves no cooling ability for the wires unlike cables mounted in equipment with natural convectionAnd in the end it's only 700W. or probably less, more like 500W or so so it only carries 2.4amps because the heaters if it's the right one is about 90 ohmsBut in the end these stations are made only for less than 40USD so it's not a surprise if quality is non-existent

author: ptricks
author_rank: Frequent Contributor
timestamp: November 27, 2012, 12:20:41 pm
content: Quote from: T4P on November 27, 2012, 05:35:58 amI am aware of the difference, I have done home wiring in the past and know the NEC codes very well .It isn't several cm, it is about 2 meters. Inside the unit itself the wiring is proper size but from the unit to the heater is where the size is changed. I didn't really measure the wire size but the conductor itself is really small.The unit itself uses about 4A . After the repair I replaced the 6A fuse with a 5A and the unit worked for about 5 minutes till the fuse blew, so I assume there are peaks up to 5A, maybe slightly over. 6A fuse worked fine.If they had a better engineer they could have had a quality product, instead they spent money on things that could have been lower quality instead of the right things.

author: T4P
author_rank: Super Contributor
timestamp: November 27, 2012, 05:18:07 pm
content: It's OHL chinese stuff, what do you expect?