T890 BGA IR rework station - users experiences? - Page 1
Forum section: electronics / general

author: Fraser
author_rank: Super Contributor
timestamp: November 06, 2019, 06:47:01 pm
content: Hi,I am considering buying a Puhui T890 BGA IR rework station as it appears a little bit more ‘advanced’ than my T862++I am not using this technology in a professional capacity and I am aware that all such sub £1K machines are in the ‘toy’ category of BGA rework. They do work in many hobby scenarios however.The T890 appeals to me because of its large preheated plate, 6 tube quartz upper heater head (not the common square ceramic heater plate) and temperature profile capability. It has the important closed loop temperature control of the upper IR heater head as well.HOWEVER ...... I am aware that many Chinese sourced rework solutions look the part, whilst not actually delivering on their promises. The T862++ is bordering on this and is not a great design due to its lack of profiles and no closed loop temperature control of the lampThe Puhui T890 can be purchased in the UK for £360 which, whilst not pocket change, is relatively affordable for a BGA rework station.What will I be working on ? Well my patients include thermal cameras with BGA Chios of around 1” x 1” and also the odd laptop and similar tech. The BGA chips on those will be North and South Bridge types so quite large. I thought such work required a far more powerful IR rework station but I have witnessed a T862++ reworking a North bridge with surprisingly good performance. The operator knew the tricks needed for even heating and hoe not to incinerate the Chip and PCB !When it comes down to the task, this is physics..... you pre-heat the PCB gradually to avoid warping and to aid the solder melt. You apply additional heat to the target IC from above and do so in a manner that is recommended in soldering and desoldering profiles. Provided the heating is done under reasonably accurate control and is of adequate power output for the task, the rework process should go smoothly. The caveats are many however. The IC has to be treated with care to avoid burning it, the IC can popcorn due to fluid uptake in its life and the PCB contact points need to be scrupulously clean to avoid poor solder joints. All of these caveats can be managed, provide the BGA rework station is of adequate performance.I would welcome any comments in the T890 and it’s built in profile and Quartz heater capabilities.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 06, 2019, 11:24:08 pm
content: The Quartz top heater used in the T890. This is supposed to give better performance than the Flat ‘Dark IR” ceramic types. It also has a longer life and better coverage than the Halogen IR reflector lamp used in the likes of the T862.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 07, 2019, 10:59:34 pm
content: I have been doing some research on BGA rework stations and it is now clear to me that most lower priced stations are intended for light duty simp,e takes like mobile phone rework. I thought the Jovy RE7500 was decent, but it is really only powerful enough for mobile phone workFor serious work on larger PCB’s and involving larger BGA chips like the Northbridge and Southbridge, plenty of pre-heater power and top heater output are needed and this us where the cheaper rework stations can fail.This forum thread sheds excellent light on the matter.....http://advancedreworks.com/forum/archive/index.php/t-238.htmlOne dealer is honest enough to decline sales of the Jovy RE7500 and Scottle 6500 if they intend to work on larger PCB’s. He asks when receiving such orders !I have decided that I will safe my money and live with my current very limited IR rework capability. Buying a T890 would be a waste of money for what I was considering.The lack of comment on this thread also suggests that the T890 is not in common usage which is surprising considering it was released in 2013. One chap on a forum was about to receive a T890 and comment on its performance. He went silent soon after ..... maybe the T890 was very disappointing ?It has been an interesting little investigation into BGA rework stations. They are not ‘rocket science’ but good ones remain expensive due to their specialist nature. DIY is definitely possible and more affordable if your time is free.To anyone wondering, the bottom end of the market at the sub £1K or maybe £2K point is really a mix of lower power mobile phone rework kit and dodgy kit claiming greater capabilities than it can reliably deliver ! Be careful when buying BGA rework stationsFraser

author: wraper
author_rank: Unknown
timestamp: November 07, 2019, 11:09:28 pm
content: Quote from: Fraser on November 07, 2019, 10:59:34 pmNonsense. It can be used replace any chip unless it's something of ridiculous size used in non consumer equipment. And it's certainly not for mobile phones as main use. Without special top heater shield it will melt all of the board. But it has downside, small bottom heater, so some, especially thin and large boards may warp when heated. RE-8500 is supposed to fix that.But I suggest looking at Russian Termopro if you can get it.http://termopro.ru/en/

author: Fraser
author_rank: Super Contributor
timestamp: November 07, 2019, 11:46:49 pm
content: Wrapper,It is the bottom heater that has been highlighted as too small for the likes of gaming and PC PCB’s. Hence the 8500 having a very powerful and larger bottom heater. From what I have read the preheater is a very important part of the reflow process. North and South Bridge Chips are not huge so I had hoped that the T890 would be capable of dealing with them. After reading the comments of those who have first hand experience of working on multilayer laptop and PC motherboards, I think the T890 would struggle. I was surprised, and disappointed to read that the Jovy 7500 could be similarly challenged on the pre heater front.So if the bottom preheater is inadequate for larger PCB’s such as those of PC’s and gaming consoles, does that not make it a unit more suited to mobile phone type tasks ? I was considering buying a used Jovy 7500 unit but comment in the referenced thread appears to suggest that the 8500 is the better option, but sadly my financial justification precludes the purchase of such.I am happy to be totally wrong about BGA rework as I can only rely upon the sources of information I found in my research. There does seem to be a lot of equipment in the budget end of the market that looks the part, but fails to deliver however. At Least you have provided comment in this thread. No one appears to have experience of the T890 here but you clearly have knowledge of the Jovy 7500 and I thank you for the input.Fraser

author: wraper
author_rank: Unknown
timestamp: November 07, 2019, 11:52:12 pm
content: I had replaced large GTX 980 and GTX 10x0 GPUs with RE-7500 just fine. But i had problems with much smaller ICs on feeble boards which warp.QuoteIt's not about power. Bottom heater has more than enough of it. Only size is a problem. If it had 3x size with the same power, it would work just fine.

author: Fraser
author_rank: Super Contributor
timestamp: November 08, 2019, 12:10:52 am
content: Thanks Wrapper,Your insight is much appreciatedFraser

author: Fraser
author_rank: Super Contributor
timestamp: November 09, 2019, 01:48:25 pm
content: Well I just had an interesting morning of experimentationI decided to do a Northbridge Chip removal, re-balling, and re-install on a sacrificial laptop motherboard..... wait for it..... using my humble T862++I did cheat a bit as I used a large Aoyue quartz tube equipped IR pre-heater in place of the sorry little Ceramic thing fitted in the 862. The Pre heater was placed behind the 862 and the top heater repositioned to suit.I controlled the profile manually so concentration was needed as I monitored the PCB upper and lower temperatures. The pulsing Halogen IR lamp for the top heater was not as nightmarish as I had imagined.Removal of the Northbridge went without incident. It was then the more laborious task of cleaning remaining solder away from the PCB and Chip pads. The rebelling was also done under the Halogen lamp but I could have used my Pace flat plate preheater instead.Re-installation of the Northbridge was not too difficult but alignment took some time to be certain it was spot on the correct position. Pre-heater set up and a PCB raised gently to temperature, then profiling the soldering operation using two thermocouples feeding a digital thermometer and some careful adjustment of the upper heater controller. The top heater controller is a disaster..... no feedback, just preset on/off cycle periodsAnyway, after the completion of the soldering cycle the flux had activated and the Northbridge looked well soldered at the visible edges, with nice donut shaped balls.The PCB was allowed to cool and then tested in the laptop. I was surprised that it actually still workedTime will tell how good the soldering of the IC truly is but I proved to myself that some common sense, understanding of the soldering process and careful manual control over the upper and lower heaters can lead to success even without professional grade IR rework kit. This was a hobby experiment and would not make sense in a commercial operation.I still fancy a play with the T890 with its self contained profiles thoughMaybe if I sell some more kit and have some spare cash to risk on it ?Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 10, 2019, 11:21:47 am
content: Thanks to the excellent comments by Wrapper, I did some investigation into the Jovy RE7500 and its capabilities.I then went in search of a used unit and fate has been kind to me. I found a good condition RE7500 on eBay. It was well above my budget at £600 but I negotiated with the very friendly seller and I got it for £340That is around the same price as the new T890 but the two machines are very different in terms of quality and capabilities.During my investigations into the Jovy units, I was sad to see that the Jovy Systems web site had disappeared. It looks like Jovy maybe closed their business in mid 2018This almost put me off buying the used RE7500 as I need the software to drive it and I do not think that is included with my purchase. There was also mention of software activation via direct email contact with Jovy which would now not be possibleThe good news is that I found an old copy of the software on line and it does not require ant activation that Incan see after loading it onto my laptop. I think activation came in with the later software that runs the RE7550 and RE8500. From looking at reviews showing the older RE7500 software, it looks very user friendly and well thought outI am very pleased to have found a BGA rework station that is built to last and has a decent reputation. The alternative option was an Archi IR6500 but there are many clones and performance appears to be variable. A new clone from China costs about the same as what I paid for the Jovy unit.If I decide that the bottom preheater is not powerful enough in the RE7500, I can always fit something more powerful later. At least I will be upgrading a solid well built design. The ceramic heaters used in the Jovy unit are high performance types so may well outperform those on cheaper units claiming higher wattage in terms of IR radiation.I was bidding on a Jovy RE8500 which is a beautiful unit, but after talking to the seller, it was clear he wanted T least £800 for the unit and I had to travel to collect it. Whilst a very nice BGA station, I cannot justify such expenditure on it and decided to pull my bid. I was suspicious that I would be subjected to Schill bidding to bump up the price as the unit had no reserve. Also, as previously stated, the software used with the RE8500 required activation that appears to be no longer possible with the disappearance of the Jovy web site.I would be interested in hearing from anyone who owns a Jovy RE7500 and who is willing to share the software with me (no piracy issues as it is free) and any rework profiles that they may have accumulated.Any and all comments are welcomedFraser

author: Fraser
author_rank: Super Contributor
timestamp: December 05, 2019, 04:52:13 pm
content: The Jovy RE7500 BGA workstation arrived from Estonia today.It is very nicely made and perfect for my needs. Thankfully the seller knew how to partially disassemble and pack the unit so it arrived today without damageI am very pleased to have found such a nice unit at a price that I could affordFraser