MOSFET ID and replacement - Page 1
Forum section: electronics / beginners

author: starman999
author_rank: Newbie
timestamp: March 18, 2015, 09:54:15 pm
content: I am trying to repair a hydraulic control. I believe that it has one or more bad MOSFET transistors that are used to switch current on and off to 12v hydraulic solenoids. I have the schematic and it ID's the MOSFET's as MTB3GN06V they were made around 1998 (unknown manufacture)(Unknown values) I believe that the pass through is controlled and switched by 5v but not 100% sure and I have not identified which of the legs are source, drain, or gate (the legs need to match original to work with my board) I have not been able to find a supplier (not even the OEM) who can ID these or cross reference these to supply with compatible replacements to match my board. Any help or suggestions would be appreciated. Schematic attached

author: Falcon69
author_rank: Super Contributor
timestamp: March 18, 2015, 10:16:34 pm
content: http://www.onsemi.com/pub_link/Collateral/MTB36N06V-D.PDFThis might helpThat G is actually a 6Just look at the specs, and find a mosfet that matches those specs that is NOT obsolete, like your current chip is.You may also get lucky and be able to buy the obsolete version as an exact replacement through one of the big online suppliers, or through eBay.

author: wagon
author_rank: Frequent Contributor
timestamp: March 18, 2015, 10:24:37 pm
content: Usually in these type of applications I've found the specifications of the device aren't that critical, provided the current rating, voltage and on resistance are about the same.

author: starman999
author_rank: Newbie
timestamp: March 18, 2015, 11:51:29 pm
content: Thanks very much Falcon69, I honestly thought that I also searched using a "6" but it's possible that had the "B" wrong in that search, I was uncertain if it that was a B or an 8 Appreciate you clearing the ID up for me now I can move forward with this!Wagon, I wondered if inexact matches might work too figuring all I needed was to achieve the 12v pass though at a high enough amperage. I was even considering going low tech on this and just fusing in a manual 12v toggle switch to operate the failed solenoid valve which is only a hydraulic system dump valve.

author: wagon
author_rank: Frequent Contributor
timestamp: March 19, 2015, 01:35:45 am
content: Quote from: starman999 on March 18, 2015, 11:51:29 pmI've done allsorts of 'butchery'at 17.00 on a Friday when it "just has to go NOW!". You have to be versatile when something is busted and 'proper' parts are a week or so away.

author: starman999
author_rank: Newbie
timestamp: March 19, 2015, 04:40:42 am
content: One addition question. Will any MTB36N06V match the pin and mounting configuration pictured in the attached file (picture matches my original configuration) or is there an additional "style" specification for that such as style 2 or style 5 etc that I need to look for?

author: LabSpokane
author_rank: Super Contributor
timestamp: March 19, 2015, 09:04:50 am
content: What you're showing is a TO-220 package. Give this one a look (FQP30N06L):https://www.fairchildsemi.com/datasheets/FQ/FQP30N06L.pdfLooks pretty close to me.About a buck each at Mouser:http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/FQP30N06L/?qs=%2fha2pyFaduji0fg%2flrI0nk1olBaTBVmAwVSKddLwzfQ%3d

author: starman999
author_rank: Newbie
timestamp: March 19, 2015, 01:24:50 pm
content: Looks close but I think that the gate, drain, and supply may be on the wrong pins to work on my board. I am not 100% certain of that though and still have to physically test out mine to confirm the pin locations.

author: wagon
author_rank: Frequent Contributor
timestamp: March 19, 2015, 01:59:03 pm
content: I don't think I've ever seen a Mosfet in a TO220 package that had a different pinout to the 'standard'.

author: LabSpokane
author_rank: Super Contributor
timestamp: March 19, 2015, 02:30:28 pm
content: Quote from: starman999 on March 19, 2015, 01:24:50 pmBoth datasheets look to be in GDS order to me.Testing should be a simple matter of jumping 5v to pin 1 of another MOSFET on the board.

author: starman999
author_rank: Newbie
timestamp: March 19, 2015, 04:52:36 pm
content: agreed, unfortunately I will not be where my test equipment is until next week. and you may be right, the fet you linked may turn out to be a good fit in all aspects. Do you think that the Gate on min 1.0 and max 2.5 will be an issue as it differs from the MTB which is 2.0 and 4.0 respectively?

author: LabSpokane
author_rank: Super Contributor
timestamp: March 19, 2015, 05:35:48 pm
content: I think the gate voltage thresholds should be fine. The FQP is actually a better spec part in that aspect.

author: starman999
author_rank: Newbie
timestamp: March 19, 2015, 05:39:45 pm
content: OK thanks, Looks like I have my fet once I confirm the pins match next week.