Strange malfunctioning LED audio peak level meter problem

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

The led's are the size of a grain of salt. I touched a couple and they went out too. I'm going to have to find an old computer running windows 7 so I can use the only usb microscope I have (Veho Discovery VMS004).

[stj]

Re: Strange malfunctioning LED audio peak level meter problem

well you probably need to replace the lot - so the brightness matches

i would be tempted to build a new one possibly using a chinese vu meter module as a base and making a new led board to match the original spacings.

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

well you probably need to replace the lot - so the brightness matches

i would be tempted to build a new one possibly using a chinese vu meter module as a base and making a new led board to match the original spacings.

Thanks. The more I look at it, the micro sized led's would be beyond my capabilities. Still looking for an old windows 7 pc to use my microscope. Lol

From what I can see with limited magnification it appears that there are tiny single strand wires coming off of the leds!!

[stj]

Re: Strange malfunctioning LED audio peak level meter problem

so what computer are you using now?
i cant believe you cam a HID/cam device that wont just work in Linux or other windows versions.

the wires are bond leads made of gold and welded at each end.

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

so what computer are you using now?
i cant believe you cam a HID/cam device that wont just work in Linux or other windows versions.

the wires are bond leads made of gold and welded at each end.

Veho Discovery vms-004 usb microscope

Worked years ago on old laptop I had. Windows 10 doesn't have a driver

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

Veho Discovery vms-004 usb microscope

Worked years ago on old laptop I had. Windows 10 doesn't have a driver

Read a review on amazon ao got it to work with my camera app!

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

So I can see the microscopic wires and pads dislodged from the led's. Thanks! Now...how to reaffix them? Its insanely small.

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

pics

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

Pic

[stj]

Re: Strange malfunctioning LED audio peak level meter problem

you cant fix them, you have to scrape them off the pads and solder tiny smd leds

[budm]

Re: Strange malfunctioning LED audio peak level meter problem

You can test each LED as suggested, and also use high power magnifying glass each bonding wire of the LED.
I also see strange trace layouts.
I am also surprised that exposed bonding and die last this long, but since they cannot put black blob on top like they did for the IC since they are LED, they could have put on clear sealer instead on the LED's.

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

you cant fix them, you have to scrape them off the pads and solder tiny smd leds

Ok. I'm probably going to relocate this board and run jumper wires from it to individual wired-led's mounted into the plastic housing that mounts to the cassette player's face.

My understanding is that 1 signal goes to one side (let's called it "+" side) of the 1st, 4th, 7th, and 10th led's of both top and bottom rows. Now the other side (let's call it "-" side) of the 1st led goes to the + side of 2nd led. The - side of 2nd led goes to + side of 3rd led. The - side of 3rd led goes back to the IC. This same scenario is repeated for all the groups of 3 led's. There are 4 sets of 3 led groups on each row.

Can someone recommend wired-led's? I'll need some green, amber/yellow and red. They should fit into the plastic housing.

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

Plastic housing

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

You can test each LED as suggested, and also use high power magnifying glass each bonding wire of the LED.
I also see strange trace layouts.
I am also surprised that exposed bonding and die last this long, but since they cannot put black blob on top like they did for the IC since they are LED, they could have put on clear sealer instead on the LED's.

Unfortunately I have neither the tools nor skills to both view, manipulate, and solder those microscopic wires in place.
I CAN solder some jumper wires to some of those larger exposed traces and test points to some wired-led's.

Based on how these traces are laid out, I should only have to connect 9 jumper wires to the board. 1 of those 9 wires will break out into 8 wires itself, which will go to one side of the 1st, 4th, 7th, and 10th led's on both rows. The remaining 8 wires connected to the board will connect to the "other" side of the 3rd, 6th, 9th, and 12th led's on both rows. The remaining led wires would connect together depending on where they fall in the arrangement.

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

https://www.amazon.com/EDGELEC-Prewi.../dp/B07FN5HVPR

Would these work?

[stj]

Re: Strange malfunctioning LED audio peak level meter problem

https://www.aliexpress.com/item/32423249665.html
those are great - 5 colours - 20 of each for about $3

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

https://www.aliexpress.com/item/32423249665.html
those are great - 5 colours - 20 of each for about $3

So I've killed most of the LED's by now. Those exposed microscopic wires are ridiculous. Trying to use that crappy usb microscope I was dragging it all across that board. Only a couple of the LED's still work. So I measured one at around 1.5v and the next one beside it in the "3 led group" was measured at 3v. I couldn't get a voltage reading on the third one in that "group". Do u think it would have been 1.5v higher or double the one before it?

[stj]

Re: Strange malfunctioning LED audio peak level meter problem

each led takes about 2v so with 3 in series that WORK - each will show the same voltage.
the microscope is not supposed to be that close to the board btw!

[JimBanville]

Re: Strange malfunctioning LED audio peak level meter problem

each led takes about 2v so with 3 in series that WORK - each will show the same voltage.
the microscope is not supposed to be that close to the board btw!

Unfortunately that microscope has to be "on" whatever you are looking at when it's set to max magnification.

[redwire]

Re: Strange malfunctioning LED audio peak level meter problem

After a good cry, I would do the surgery on the old pc board. Get a bunch of 0805 or 0603 LED's (old style yellow green) and scrape off the old ones and some solder mask with an exacto knife. Then some flux and solder on the new LEDs.

There are 12 LED VU meter displays and/or kits that might fit as well, from fleabay or Ali.

edit: the description is too funny:
Display effect:
1. strip show after peak travel whereabouts
2. strip show after the disappearance of the peak travel
3. The strip display (no peak display)
4. strip show right after the peak flow disappears
5. The strip display (three lights)
6. striped marquee display peak effect
7. Peak strip show right jump lamp lights two bits whereabouts