Help diagnose Vinnfier sub woofer no power

[mikey5791]

Hi,

Got this sub woofer from storage but the blue led power not on. So i suspect something gone bad at the power board. Noticed a dual op amp 4558d jrc 0058t . Upon checking on google, vcc is at pin 8, ground at pin 4.
Also googling on those 3pcs 5 pin audio power amp tda2030al screwed to heat sink.
Pin 5 is power supply and ground at pin 3.
I saw the 230vac transformer output 12v thru the blue wires to the pcb. I wondered if it is safe to use my dmm and probe the above mentioned pins to check on live voltage.
The problem is since i am not able to find any schematic, i don't have any idea what voltage to expect. Can anyone help me on this and kindly suggest or give guidance.
Thank you.

[budm]

Re: Help diagnose Vinnfier sub woofer no power

Your pictures of the board are not focused, I cannot read anything on the top side of the board.
Please provide good clear straight shots of the whole top and bottom side of the boards.

[mikey5791]

Re: Help diagnose Vinnfier sub woofer no power

Hi,

Thanks for the reply.
Budm, sorry for the earlier photo being not focused. I think i did not use the focus feature on the tablet camera. This morning i retake the top and bottom photo. The pcb board was kind of glued dead to the wooden box with some heavy duty rock hard glue and it is the same with the ac power line connector. The wiring seems to block your view of the board.
Hope the photos are better now and able to see clear. Fyi, I checked the glass fuse F1.5AL, it still has continuity and not blown.

[budm]

Re: Help diagnose Vinnfier sub woofer no power

https://www.badcaps.net/forum/attach...1&d=1602637171

1) You need to scrap off the those bad brown glue on the jumpers J? and J5 and make sure the glue did not eat away the jumper wires and the solder joints of those jumpers, the glue used in this unit is bad news, it is corrosive and conductive.

2) Measure the DCV between the two legs of those two large Lytics caps to make sure we do have Voltages to run the amplifiers.

3) BTW, those OP AMP 4558's in this unit run on + and - power supplier, +V on pin 8, -V on pin 4 (pin 4 is -VCC, not GND in this unit).

[mikey5791]

Re: Help diagnose Vinnfier sub woofer no power

Hi budm,

Thanks for reply.
1. Scrapped off those brown glue on jumper 4 and 5, both jumpers had continuity when tested. I tried to scrap off the rest of the glue as much as i can.
2. Dcv on lytic cap c32=18vdc, c31=18vdc
3. Dcv on op amp 4558, using dmm red+ on pin 8 while black -on pin 4=32vdc

Look forward to your next comments and suggestions.

[budm]

Re: Help diagnose Vinnfier sub woofer no power

So the power supplies are fine.
I see three power amplifiers ICs on that power supply/power amplifiers board, so beside sub woofer, does it also have other speakers that go with this system? It looks like it is a 2.1 system, so not likely not all three amplifiers will go dead at the same time.
I also see a connector with multiple wires that should go to other board, can I see that board?
I need to find user manual for this unit.
I have a feeling that the unit may be stuck in standby mode and does not wake up when audio input is present or the problem is on the other board (pre-amp board where the controls are).

[mikey5791]

Re: Help diagnose Vinnfier sub woofer no power

Hi budm,

Thanks for the reply.
As the sub woofer is from storage, i can't seem to find the other 2 speakers which is a complete 2.1 sound system. I suspect the other speakers are either spoilt or missing.
Without the other 2 speakers, can this sub woofer be repaired then?

You are talking about the wires that are connected to the other board which is in front of the speaker. That is the switch control for volume, bass and treble. I am attaching a picture now. Hope this will help in diagnosing further. Appreciate your patience and easy clear instruction in bringing life to this sub woofer.

[mikey5791]

Re: Help diagnose Vinnfier sub woofer no power

More pictures on the other board(3500-3vol) likely an audio multi function usb,sd interface board. I can't find any info on this board.
Hope the pictures are clear and help in diagnosing.

[budm]

Re: Help diagnose Vinnfier sub woofer no power

I see bad solder joints , you should also check all other boards as well for bad solder joints.

[mikey5791]

Re: Help diagnose Vinnfier sub woofer no power

Hi budm,

Bravo! You got sharp eyes pointing me to those bad solder joints and after resolder those 4 bad solder and redo some bad spot on the power board......the power blue led is on and now I can enjoy using this revived sub woofer again.
Sending you a "virtual" beer to celebrate!

Thank you so much.

[budm]

Re: Help diagnose Vinnfier sub woofer no power

Thanks for the follow-up on the repair, without good clear pictures it would have taking longer to troubleshoot the problem.