BK9130 / Keithley 2231 / Itech IT6302  3 channel power supply - Page 1
Forum section: electronics / testgear

author: Jester
author_rank: Frequent Contributor
timestamp: September 04, 2022, 04:07:03 pm
content: I’m a bit quirky with my workbench, I prefer to have the instruments that I use all of the time within arm’s reach. So given a choice I prefer equipment with the same front facing 1/2 rack dimensions for example 34401A, so they can be stacked efficiently.I just picked up a clean BK9130 that should fit nicely in the stack. The size, simultaneous display of 3x V&I, 1ma resolution and power are all appealing for my needs. My initial quick test (3 channels loaded) indicates *everything is working as expected. The user interface is quite decent. The fan has speed control and is not noisy even when loaded heavily, the fan starts when the heatsink is at about 40 deg. C. Overall I’m impressed, this might be my go to power supply instead of the Agilent E3615 because of the 1ma resolution.* the one quirk I did find is when switching on all three channels simultaneously with the master On/Off switch the outputs do not switch on simultaneously, they power up in sequence with about 40-80ms delay, depending on the load.I’m guessing that these are not that popular because there is surprisingly little information available via a google search, just a couple of videos and not a lot of forum discussion. I’m curious about:1) Common failure modes and repair?2) I’m assuming the schematic is unavailable?3) General comments on this series?4) Differences 9130, 9130B, 9130C?From the IC markings on my unit, it appears to be a 2009 model, so replacing the electrolytic capacitors seems wise, none appear to be leaking or bulging but there are at least 27 of them, all 105C, mostly G-LUXON, the 2x 4700uF@100V are TEAPO brand.Should I replace all of them?I have attached a spreadsheet of the electrolytic caps, upper board should be accurate, lower board needs to be verified, there are ~ 42 5.7x12 mm caps that appear to be mostly 4.7u@50V, looks to be a a few that are 22u@25V and 47u@25V, I can't tell for sure until the bottom board is removed.There are three on the front terminals that I can't see the value, if they fail less of an issue as they will only leak onto the bottom chassis not a PCB.I'm not sure on the pin spacing of the large 4700uF on the bottom board

author: Kean
author_rank: Unknown
timestamp: September 05, 2022, 02:31:43 pm
content: I bought my BK9130 brand new back in 2009 for about AUD $1500. I really found it a great PSU, so I was pretty sad when it started playing up about 2014/2015. It was my primary bench PSU and powered on near 24/7.I believe I replaced all electrolytic caps on the top PCB with whatever I had in-stock just to see if it came good. At least half were leaky, particularly the larger ones near the regulators & heat sinks. Some had noticeably popped their "pressure relief valves", and there was gunk all over the PCB. I don't believe I changed any caps on the lower PCB as they looked fine.I did the original repair back in 2016, so don't have any records of the values, sizes, or original brand. I have photos, but I can't make out the brand. It does look like LUXON based on the fragments of text visible.Unfortunately the unit works but has readout issues that makes it near unusable, almost certainly due to corrosion from the leaky caps. I took another look at it in 2019, and again in 2021 - with no joy. I have many more programmable PSUs these days, so it hasn't been a priority to fix but I was quite fond of it so it is still in the repair queue (along with several other PSUs).I recall that I looked at some photos of the BK9130B/IT6302 internals and it seemed that they improved the design a lot, and made repair a lot easier. I don't know anything about the 9130C.