Fluke 5100B AC voltage issue - Page 1
Forum section: electronics / repair

author: Squarewave
author_rank: Frequent Contributor
timestamp: June 24, 2018, 09:15:49 am
content: Good morning.So I made a thread in the test gear area, before disovering this repair section section.Origional thread herehttps://www.eevblog.com/forum/testgear/fluke-5100b-ac-voltage-issue/Basically to summerise, origional post hereQuote from: Squarewave on June 14, 2018, 09:47:12 amA helpful reply hereQuote from: capt bullshot on June 15, 2018, 05:25:45 amMy last post hereQuote from: Squarewave on June 23, 2018, 11:11:43 pm

author: Squarewave
author_rank: Frequent Contributor
timestamp: June 24, 2018, 09:27:12 am
content: Just had a thought regarding extender cards, which I don't have.If I use some heat shrink, I could connect wires to the test points, mark them and insulate the ends with heat shrink....That way, I've extended the test points and should be able to work my way through the troubleshooting on the Power Amplifier section without the use of extender cards.

author: Squarewave
author_rank: Frequent Contributor
timestamp: June 24, 2018, 10:05:01 am
content: Quote from: capt bullshot on June 24, 2018, 10:01:03 amDon't understand your post. Unless you mean you can't help any further?

author: capt bullshot
author_rank: Super Contributor
timestamp: June 24, 2018, 04:36:54 pm
content: Quote from: Squarewave on June 24, 2018, 10:05:01 amNo, I just left that popcorn here to have that thread on my watch list (show new replies to your posts). So I can follow your progress and maybe answer questions. Otherwise the thread just would vanish from my span of attention. It's common here in this forum to leave such a post if one wants to watch a thread.BTW: Soldering wires to test points to make them available is a simple way to get around not having the extender boards. I did that also before. But I don't think Q106 is bad. I'd check the relays first.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: June 24, 2018, 04:49:19 pm
content: I usually just hit the Notify button, and then I get updates to a thread without posting.Looking forward to hearing the solution, but sadly, I have nothing to contribute either. Sorry.

author: Squarewave
author_rank: Frequent Contributor
timestamp: June 24, 2018, 08:12:52 pm
content: Quote from: capt bullshot on June 24, 2018, 04:36:54 pmThat's fine, I understand now. I'll keep you updated and thanks for the help so far. I hope to maybe take another look sometime this coming week.

author: Squarewave
author_rank: Frequent Contributor
timestamp: July 15, 2020, 05:54:47 pm
content: Never did look back at this issue, however, I wonder if anyone knows whatL. erris?It's not listed in the manual, it occurs when I switch off my variac.

author: capt bullshot
author_rank: Super Contributor
timestamp: July 15, 2020, 08:36:28 pm
content: Looks and sounds somewhat familiar, I vaguely remember having that seen somewhere ...But no, my memory ends here, so no idea.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: July 15, 2020, 08:41:28 pm
content: I repaired three 5100B.One of my cases was unstable AC voltage.The reason occurred to be faulty C30 (see schematic below).It is 390nF 'TRW' brand capacitor which became 60ohm resistor after warming up.That was a surprise for me, however I had previously problems with leaky 'TRW' caps.Edit: First stage of the repair was replacing all 'droplet -shaped' tantalum caps.Best Regards BR

author: Squarewave
author_rank: Frequent Contributor
timestamp: July 16, 2020, 10:11:30 pm
content: I'm wondering if it's some spike into the mains that the variac is causing when it's switched off and the 5100B reporting that as Line error? Or Live error?