Opus BT-C3100 battery charger display garbage - Page 1
Forum section: electronics / repair

author: Cyclops
author_rank: Newbie
timestamp: December 26, 2018, 05:27:18 pm
content: Hey guys!I have a Opus BT-C3100 charger that has worked perfect for years now, but suddenly a few days ago it started displaying garbage on the screen, the garbage was changing in the beginning, but now all the segments is on all the time, even the backlight is on all the time.The charger seems to charge batteries normal, exept i cant see whats on the screen.Opened it up and poked around a bit, The voltage regulator gets REALY hot, could not touch it more than half a sec. On the voltage regulator chip it says. HT7533S1528I looked around ebay and aliexpress, found the HT733-1 but not my exact one.I dont realy know lot about electronics, but im a decent solder(er?)So my TL:DR would be: would it be the voltage regulator thats the problem, if so what would be a good quality replacement?What else could it be?Edit: Made a Video:https://youtu.be/ns-uqROnP9sToc Toc Toc

author: Cyclops
author_rank: Newbie
timestamp: January 06, 2019, 03:02:22 pm
content: Made another video that shows it much better, it starts out fine, but gradualy become bad.https://youtu.be/MZZGgRNP-bYHow do you identify a smaller voltage regulator? i can find only the bigger ones and they are different. i GUESS mine is a 3.3v but what is the second line, S1528?

author: ignilux
author_rank: Unknown
timestamp: January 06, 2019, 04:07:35 pm
content: I'm not sure if it's the cause of your problem, but the HT7533-1 appears to be a 3.3v LDO manufactured by Holtek. Youshouldbe able to replace it with any 3.3v, >100mA LDO in the same package (watch the pinout!), but the exact part is available from the somewhat legitimate LCSC:https://lcsc.com/search?q=ht7533-1. Just make sure to get the right package. As far as the "S1528", it's probably just a batch code or date code of some kind. I wouldn't worry too much about it.Finally, while this is certainly a good place to discuss electronics, Li-Ion battery analyzers are discussed in depth on flashlight enthusiast forums, namelyBudgetlightforum.comandCandlepowerforums.com. Might be worth asking about your specific problem over there.

author: wraper
author_rank: Unknown
timestamp: January 06, 2019, 04:13:27 pm
content: Quote from: Cyclops on December 26, 2018, 05:27:18 pmMeasure voltage on it's output, it's 3.3V LDO. Heating does not necessarily mean that it's faulty. It could be that there is a fault in something that it powers, increasing current flow through it and thus dissipated heat. IMHO chances repairing it are not that good, quite likely main IC failed and it's a COB (black blob).

author: Cyclops
author_rank: Newbie
timestamp: January 11, 2019, 11:43:54 pm
content: Thanks for the info guys. I ordered 10 for a buck. i will get to it as soon as im able. Life is kicking my but ATM

author: Cyclops
author_rank: Newbie
timestamp: February 21, 2019, 10:08:52 am
content: Hello again folks!FINALY got around to do some checking and soldering, it looks like it was the voltage regulator. i measured it as 12.2 in, that is correct, but out it was a whopping 6.4 to 6.9 volt (fluctuating alot) it should have been 3.3.I soldered it out and got the HT7533-1 in and it works fine now.The -1 one is a pure upgrade, decent tolerance increase.Took a quick finger temperature test on the regulator and its barely warm.Thanks for nudging me in the right direction. It is Fixed