MANSON HCS-3304 OUP-Error - Page 1
Forum section: electronics / repair

author: PSR B1257
author_rank: Frequent Contributor
timestamp: March 26, 2025, 03:23:52 pm
content: Hello allRecently I somehow managed to bust my power supply by connecting it to a PV-microinverter thinking it has enough protection features. After a few seconds, the over voltage protection OUP kicked in.After disconnection the load and restart, the supply performs all self-tests as usual but the OUP-Error remains.There is no visible damage on the board, and large parts of the circuitry must apparently work. But there is no output voltage at all.The ATMEGA is putting out a HIGH signal on its SHOUT DOWN line, which makes sense in these circumstances. Do you guys have any suggestions where to look for the failure?

author: Swake
author_rank: Frequent Contributor
timestamp: April 02, 2025, 04:44:23 pm
content: Check for the usual things like blown components and the state of the internal power supply voltages.Measure the output with a DMM. Is it indeed disabled?You might want to check the junctions of all transistors and diodes. Start with the big FET and/or diodes on a heatsink.It is a SMPS power supply, you'll probably find a, optocoupler or similar to feedback to the primary. Is it still doing it's job?Can you share the schematic or eventually high resolution pictures of the boards?Besides the SHOUT pin on the atmega, do you have a view on how the over protection circuit is constructed, maybe you reverse engineered part of the circuit? The ATMega must receive a 'voltage' signal on some other pin.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: April 03, 2025, 02:56:18 pm
content: QuoteOf course I did, as mentioned aboveAll auxiliary supplies (+/-5V and 12V) are fine, no visible damage to bee seen.QuoteThey are not very accessible (would require to disassemble the whole unit), hence I save that for last.QuoteI hope so. Not easy to check (with the DMM), because there is a 120R resistor in parallel to the emitter diode.QuoteI found a schematic for a similar unit here somewhere (can't remember) and will reupload it.Today, after powering the unit up/down already a number of times, the OUP-Error is gone...go figure... You can now at least program the output voltage and current again as usual, but there is still no voltage present. And the SOUTDOWN-line is still HIGH.

author: Swake
author_rank: Frequent Contributor
timestamp: April 03, 2025, 04:27:55 pm
content: You mentioned that the thing stopped working after having connected an external source. So I guess there is some damage in this sector. Schematic, on the right of page 3 is the output of the power supply.1/ Check F2, 8 amp fuse, not because I think it is the cause but more because this is easy to check and you can as well rule it out.2/ Verify HDV is present (careful, this is lethal level...)3/ It shows there are 2 signals V.M and C.M. I guess this is voltage and current measurement somehow transferred to the MCU. Verify the LM358, these are somewhat fragile chips. I would not be surprised if it would be dead. What do you measure on pins 1, 2 and 3 ? Please check for AC and DC component and if it is stable or fluctuating.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: April 03, 2025, 05:41:42 pm
content: QuoteNot a source, a PV-micro-inverter. So as far as the power supply should be concerned still a load.QuoteIt's fine....would be a pain to replace it, because it is as tucked away, as it possibly gets.QuoteAlready checked HDV=~380V. And yes, I am totally aware of the risk of high voltage DC.QuoteDidn't measured anything (signal-level wise) there jet, because there is no output voltage/current in the first place.

author: Swake
author_rank: Frequent Contributor
timestamp: April 05, 2025, 10:58:50 am
content: Quote from: PSR B1257 on April 03, 2025, 05:41:42 pmHa, my bad, somehow I was thinking that the output of the inverter was connected to the Manson power supply output.Well.... then remains the question how would the over voltage protection have triggered . This inverter thing might just be a coincidence, or it is behaving very badly an is somehow pushing something back.Will the power supply show the real output voltage on it's display? If so, could you connect another low voltage source to the output of the manson. Even a AA battery would do. I'm curious if the Manson is still capable of seing this and measuring it correctly. Except for some resistances there is no protection for the analog input ADC0/pin37. Also measure the voltage on that pin with a multimeter.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: April 06, 2025, 06:26:55 pm
content: QuoteThat's what I'm curious about too. Short circuit would not be surprising, as the micro inverter might tries to short out a PV modul as part of its normal operation...QuoteVery good ideaI hooked up a 9V battery thru a 1k resistor and the displayed voltage was slowly rising, as the output capacitor was getting charged. Since the display is "truly" driven by the ATmega and not an independent 7107 (or similar) it must be fine. As already mentioned, you can also program the output parameters and they get correctly displayed.I wonder, if the TL494 is faulty and pulling the SHUTDOWN line high and not the ATmega ...But then, there is D19 which would prevent any voltage feedback to the ATmega, unless it is also faulty, which does not seem likely.It's quite the mystery. Thank you for you're suggestions so far, they are very much appreciated

author: Swake
author_rank: Frequent Contributor
timestamp: April 06, 2025, 07:30:29 pm
content: Please check these things:- The TL494 has a sawtooth oscillator on Pin 5 and 6.- pin 14 has a reference signal of 5 Volt.- because of the shutdown signal it should not be switching, confirm there is nothing on pin8 & 11.If you want to know for sure if the Atmega is responsible for the shutdown signal I suggest this:- Unsolder the anode side of D19 to disconnect the ATmega from the TL494- Just to avoid breaking things, connect 5V to the anode side of D19 so the shutdown signal stays high and the TL494 does not start switching.- power on.- measure pin 23 of the ATmega, if it is high you know that signal indeed comes from the ATmega. If it is low, well...ps: the mode switch in the back is on 'normal', and not in 'remote' control? because that would be an easy fix

author: Swake
author_rank: Frequent Contributor
timestamp: April 06, 2025, 07:31:30 pm
content: Quote from: PSR B1257 on April 06, 2025, 06:26:55 pmI'm too deep in this now, can't stop anymore

author: PSR B1257
author_rank: Frequent Contributor
timestamp: April 08, 2025, 02:55:31 pm
content: QuoteChecked of the list.QuoteThe more I power it on, the more faults disappearNow the SHOUTDOWN-line is low.Also the "drive-signals" to the halb-bridges Q4/5 and Q6/7 look good.The output of TR2 is not accessible. So I guess there is nothing more to check with the main board installed and I have to disassemble the whole unit anyway. Maybe it is "as easy" as blown driver transistors Q10/Q11 (mentioned in your first reply) since there is no output at TR3...d'oh...did not measured this before...QuoteI wish it was

author: Swake
author_rank: Frequent Contributor
timestamp: April 08, 2025, 05:00:57 pm
content: Quote from: PSR B1257 on April 08, 2025, 02:55:31 pmThat sounds a lot like a bad contact or dry solder joint. Which in turn might have caused some trouble down the road.If you find a single dead component on what I'll call the primary stage between TR2 and TR3 then double check all the other components multiple times. For example if one of the zeners D14/15 has failed short then everything else silicium is gone too.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: April 13, 2025, 04:33:27 pm
content: QuoteNothing as such to bee seen (unfortunately).Everything is looking fine. In-circuit measurements off the diodes off the driver to Q10/Q11 are due to the 5k1 resistors R50/54 not possible/meaningless.I guess I try to feed an external voltage over a resistor (with the unit disconnected from the mains) to the MOSFETs and verify they are switching.Then I maybe hook up some modwires to them and check the drive-signal with the oscilloscope (via a differential probe off course) with the unit powered back on again.Other ideas are still welcome.Bare with me, this might take a while, but I'm far from giving up.

author: Swake
author_rank: Frequent Contributor
timestamp: April 13, 2025, 06:23:36 pm
content: Just noticed that, in the picture of your message #4, the 470µF/250V cap in the picture has some substance at its base. Glue? Sometimes these glues become somewhat conductive over time. If it is not glue then it is leaking: definitively unsolder and replace.Using a differential probe is probably the easiest way forward indeed. Else unsolder the mosfets and other stuff in that region. Might look as a pain to do but you'll have certainty afterwards as it is possible to thoroughly measure the components and the PCB tracks.