Music - Sound Board not working - Can I test a CHIP?

[GT250]

Hi all,
Frustrating, to say the least!

So I got a new MIC and the Ω's matched the old ones. Anyway, just to be sure I popped it in and - nope!
I have spent an hour this morning checking every possible continuity track/pad test from the 470cap and MIC - double checking using the spare PCB.

I include a video that shows 'interference' of some kind. I do not know if this is normal though, or the root cause of the problem.

NB: That this interference by me touching the R's on the LM side, also happens when touching the R14 and R15 etc on the other side of the board...



I'm ready to throw it out of the door Honestly. How on earth can something so simple, what, 2IC's, 1 Cap, 1 Mic, 50k pot and some R's not work..?

Well, I guess putting the IC's in backwards might not help, DOH!

Anyway, I have ordered two more kits! I know, I know..!!!
Reason is, is that I might have damaged the STC chips (because I swapped over the new spare when the IC base was in the wrong orientation.
Also, these new kits have a nice plastic case

An interesting thing though is these new kits have an IC where the ones I have here have those R1,2,3,4,5 in place (cost cutting or more than some Ω's going on in there?)...!

Of course I'd love to problem solve/fix the one I have. Just bugging me, that of course something is wrong - or damaged.
Solving the problem...

Anyway guys,
All good.

Cheers,
GT250.

[Reschs]

Time to do a few tests.
First check the DC Voltage on the positive pin of the mic.
Best to do this by directly across the mic pins.

It is obvious from your video the actual amplifier stage is working.

[wotnot]

From the docs...

Sound Control Induction: This feature allows the USB mini electronic display to react to sound without the need for connecting an audio line, providing convenience and ease of use.

...that's probably the trim-pot....

Customizable Display Parameters: You can set the refresh rate, audio response sensitivity, sampling frequency, and more of DIY speaker led music spectrum. This customization allows for optimal performance according to your specific requirements.

....that's software settings....

Instructions for use
1. Plug in the USB, the device powers on and enters working mode
2. Adjust the pickup sensitivity through RP1
3. Long press SW1 to switch settings, short press SW1 to select parameters

Have you set it up?

It may actually be working, just the software settings are wrong.

[GT250]

Hi Guys,

Reschs: I didn't know I could test the V across the MIC. I was concerned by playing around with the MIC I would damage it as I thought it was a very sensitive device.
So you're saying I can test to see if 5V is across the - and + legs...?

Wotnot: Where did you find those instructions/options?

If it's the case of 'programming' the STC by (if it's a EPROM), pressing the SW1 then I have probably screwed it up!

More than likely I would have been pressing the SW1 - even when the IC's were in wrong!
And I know for sure that I was pressing SW1 when the IC's were in correctly...

As I wasn't' sure what SW1 actually did. I thought it would change the Spectrum pattern - as in - Up and Down, or Sideways, I don't know, LOL!
I agree, I think it's ok.

So the question is: If the STC chip is an EPROM, then I have sent it commands - more than likely when it was in wrong and (for sure), when in correctly.
How would one reset it to default...?

I did read that once assembled, just leave it in default (as it will ok). But as you say Wotnot, there are further options through SW1...

I might not have time to look at it today. But thought I'd just pop of a reply to you guys in appreciation that you have suggested other options and I will endeavor to check them out
Can't do anything Sunday as I'm working and today, Sat is gonna be busy..

Thanks,
GT250.

[wotnot]

Wotnot: Where did you find those instructions/options?

I use this thing called 'google search' and feed it the product identifier (HU-052) + the word 'instructions' and check the hits....



They're probably the same for your chinese knockoff kit (but you only have mono, no stereo)

[Reschs]

Hi Guys,

Reschs: I didn't know I could test the V across the MIC. I was concerned by playing around with the MIC I would damage it as I thought it was a very sensitive device.
So you're saying I can test to see if 5V is across the - and + legs...?

Thanks,
GT250.

Ideally I would expect about 2.5V across the mic.

[GT250]

Hi all,
Ok.
Wotnot: Thank you for finding those 'concise' instructions. Why on earth they don't include them...?

Reschs: Yes you are correct, 2.4v across the mic.

There's 5v at the GND of the STC. There's 5v on the LM. 5v at the 470cap.

Still not working - at this stage. However, with Wotnots find I will have a go later. Got to go to work

I've wound down the VR to 25k (original is 50k).

Before I saw Wotnots reply, I started pressing SW1 and lo and behold a figure 1 lit up in the lower right corner (will post pics later in the day after work). And on the left side a rather large 'symbol' of which I assume is a Chinese Character.
A short press, changed the number to 2 - and then just cycled 1,2,1 etc.

A Long press changed the character and another 1,2,1,2 etc.

Another long press and a Human shaped character and (from memory), 1,2,3 and 4...
We had a laugh as we didn't know what the characters meant and commented about using Google Translate - on the LED's, LOL!!

There were other characters - and of course looking at Wotnots, table, I can see them now

Humm,,.. OK. I'll have to put some time away to set those options to somehow, just get the spectrum lighting up in ANYWAY first on sound input.

Then I can start playing with the options.

Well, getting closer

Cheers,
GT250.

[wotnot]

Thank you for finding those 'concise' instructions. Why on earth they don't include them...?

Most of the time, instructions are in chinese, and the seller cannot/can't be bothered translating same into English (particularly so with Ali* online stores) -- I got those instructions from a completely different stand-alone website (selling to an English speaking audience).

Most of the time, the instructions are actually videos, with chinese voice-over....for example ..and.. ...(I got those from a UK seller)

As this sort of thing costs money ie; translating instructions & printing, or finding a place to host the videos...(never gunna happen because of the great chinese internet wall), so they don't bother, to keep their profit margins.

[wotnot]

M'kay.... found one of these kits on ebay.au (I very rarely buy direct from chinese merchants, except for ** ) and bought it ... should be here in a few days. Same as before, I'm just curious ...ie; some of these kits are sold as 'solder welding learning' kits ; others lack this description. There may be a difference, one might be a knockoff (with problems), and the other the 'genuine article' -- obviously there's only one way to find out =) It will be same as before....ie; standard kit protocol ~ check the BOM, check schematic matches PCB, check all LEDs, then standard assembly process. Then power-up and see what happens....

** ...chinese new-year. .the whole of CN goes on holidays, their delivery logistics falls off a cliff. AFAIK (or have tried) this only works on ebay, wherein sellers don't update their listings to reflect delayed delivery times (a lot of sellers, not doing this is against ebay guidelines). Of course you need a target purchase...mine was ...listing has ended, Amazon want $26 for one, AU sellers with local stock are in the $12-$20 range for the same thing...that listing out of shenzhen is at ~$8 ....I've seen them down near $5 for the same thing.. ..just before chinese new-year I order one of these from 3 different sellers ~ as logistics goes to pot, tracking details are not updated ~ ebay EDD comes & goes (estimated delivery date) ~ contact seller to cancel order & get refund ~ seller complies because not even they can determine where the consignment is ~ 4 to 6 weeks later, all three orders arrive in the mail. Not typically my style, but as China's bidness dealings (with the rest of the world) have become more and more unscrupulous, I really don't mind reciprocating in kind to get annual freebies ; it's just bidness played at their level =)

[GT250]

Hi all,
Wotnot: I had to laugh at your last post "solder welding learning' kits". Yep, that's still me after many years of learning... However, I'm very glad the missus's is very happy to build and see her creation (work), go into something that one can hold and see...

Wotnot: Did you actually order this spectrum kit? I hope not, as I have a few on the way! You are more than welcome to have one...

Did a few videos after playing with the SW1 (not so much, just going through the options).


OK: Here are some videos. I hope they come though ok.
Audio Included.


First: Turn On.


Pressing SW1:


After Effects - Whatever I pressed LOL!
Please note that I did set various options on various settings. But I have no idea what is set
I have just got home and thought I'd just show a VERY brief video(s), of what I see.
I will endeavour to set it to default tomorrow, as per Wotnot's instruction sheet.
And also, this 'After effects' does differ after I had played around with SW1.



It's hard I guess for anyone to know if that by putting the IC's in reverse orientation, has effected the STC.

I've put a brand new LM in. A brand new MIC in. The MIC is ok. I've tested a few R's and they are ok. I have a put generic pot in and that reads ok.

Only way for sure I will know, is when I get those other kits in, with 'new' STC's... I should be able to just pop one in and fire up.... LOL!!


Anyway, all good fun
Cheers,
GT250.

[GT250]

Hi all,
Just a quickie.
Nope.. Gone through all the settings.

I'm going to wait until I get the new kits in with the other STC IC's.
I sincerely apricate everyone's help (and patience), in this LED gizmo.

Cheers,
GT250.

[GT250]

Gulp!
The new boards (with cases) have arrived...

I'll be popping in the STC chips later this afternoon.

Feeling of dread no doubt when turning on for the first time,,, LOL!

[GT250]

Right, ok.
Nope! Can't believe it!

So I put together another kit. Took me two hours, and it worked first time, putting the IC's in the correct orientation obviously helped, LOL!

Ok, methinks to oneself... "I now have a fully working board. And a spare blank brand new PCB, and I have a fully populated faulty board".

When I say swapped, I mean put the faulty board stuff, into the working board and test and it worked!
Put the working board IC's over and - not working.
So I swap over the LM chips (Remember I bought two new LM IC's), nope! Even swapped the LM P with the N's on the working board - worked fine!
Swapped over the STC chips nope!
Checked every Resistor in situ on the working and faulty board -all read about the same.
Checked the 50k pot, ok. The POT sensitivity works as it should on the working board.
Checked the 470 cap, ok.
(Had bought two new mics remember), Checked the V's on the Mic - 5v on some pads, 2.5v on other pads (corresponding pads on the working and faulty boards)

Checked as many tracks as I could to the IC's, all beeped (as well as checking on the blank PCB).
Tested the incredible tiny 'test' hole tracks to wherever I could see and they checked out ok...

I'm flabbergasted...!

Only thing I haven't checked are the 104's but surely not...??

Have also done all the settings and options (as Wotnot found), both boards are set the same.

Well, any ideas anyone?
I mean surely, this fault finding - with a working board and a faulty board AND a blank PCB, should be easy peezy, right?

The missus's has said to just let it go LOL!
But where's the fun in that


I include two pictures.

The lower board is the one I put together on my own this afternoon. The upper board is the one that Bev did (95% on her own), but it is my complete fault that the IC's went on the wrong way.






Anyway, as always, all good fun

Cheers,
GT250.

[GT250]

The missus's is going mad - it's tea time, and I can't stop... LOL!

Shes shouting out something about "Bi-Polar".. Ha, what does she know, eh..?

I just placed the working one next to the Google speaker in the kitchen. Note: that the volume is not that loud, just the way the phone has picked it up.

Very bright. I wonder if there is a way to reduce the brightness...?
[In a workplace as a butcher in Tesco's, Sale, Cheshire in England, 18yrs old, my boss (great guy), said to me: "What I tell you now, you will forget". He said "Polar Bear". Never to this day, have I forgotten that!]
So forget this: "How do I reduce the Brightness". It's not to do with this kit. But a RGB board Clock I have bought is known for being too bright and no one, it seems is able to reduce the brightness.

Anyway, here's a small video of it working
It's something any kid would love to have in ones bedroom as music is playing. I'm going to keep the one I did for ourselves LOL!
But both of us will put together the other 2 kits and hand them out accordingly.
It's just this - non working one that's bugging me...!!

Anyway, Tina Turner.. At QPAC, soon...

[Reschs]

Okay, time for a little fault finding.
DC tests first.
Meter negative on power supply negative.
Test voltage on both mic terminals. Pin 1 2.5V, Pin 2 OV.
LM 358 Pin 8 5V, Pin 4 0V. All other Pins 2.5V.
If all good, change meter to AC Range.
Mic pin 1 measure volts with music playing or tap mic.
Move to Pin 1 of LM358 and repeat. Reading should be 20 times previous reading.
Move to Pin 7 and repeat. Reading should be greater and vary with the volume pot setting.

Compare with good board.

[GT250]

Hi Reschs,

Ok. I'll have a look when I get in from work this afternoon.

AC...? So, there's some DC to AC conversion? Wonder why. Crazy this electronics game

I'll set it up so that I can have both powered up at the same time.

Cheers,
GT250.

[GT250]

Right Ok.
Have tested as Reschs has recommended... (and many thanks to him!!).

Right, hopefully this all makes sense. There's obviously a problem with the LM chip operating, either getting no V or to much V.

On DC:
Faulty: Pin1 0V, Pin2 either 1.3V or 3.3V - but touching (with DMM probe), Pin8, would go back to 1.3V
Faulty: Pin 3,5,6,7 reading 2.5V. Pin8 5.0V Pin4 0V

Good: Pin1 2.5v - Pin2 2.5V - PIN 3,5,6,7 2.5V

On the AC side:

On further testing I found that on MIC Neg;
Faulty: Pin3 would read 4.0V - Pin1 0V
Good: Pin3 and Pin1 would read 2.5V

AC: mVAC:
Faulty: MIC1Neg - Pin2 OL - on normal ACV 6.4v and climbs...
Good: MIC1Ned - Pin2 drops down to 80mv and stays...

Jeeze, my head hurts LOL!

As I was probing away, the Faulty board would light up with random patterns, as the the Good board.

A weird thing - like the spooky thing - if I rub my fingernail and I guess some skin makes contact: On the leg of R17 at the end of R20, both the Good and Faulty board lights react to it...? The Good more so, but the Faulty, certainly about 50% less...

Have to go.
Missus is in... LOL!

Cheers,
GT250.

[Reschs]

Okay something wrong around the the first amplifier stage.
On resistance measure between pins ! and 2, should read 200K. The resistor between them.

[GT250]

OMG!
Jeeze, Reschs!

I just quickly sat down and tested that!

EVERYONE, I'm going to have to learn how to read 'properly' these circuit diagrams..

Pin1 and Pin2 - R on the working one is about 130k

Faulty 0.8M

I daren't sit down and find that, afterall, there is a R in the wrong place - the one between Pin1 and Pin2 - as I have to leave for work and I'd stay until it was (hopefully), working.

Problem is that if this R is wrong, where's the other one.... Then again, they give you in these kits a spare R for every value.
I'm elated Reschs! Work is going to be a slooooooww day

I've learnt so much from this! There isn't anyone around me who is interested in this stuff. At work, all they care about is the 'Footy'.

Cheers,
GT250.

[wotnot]

Resistor is in correct location ~ either it's buggered or (more likely) there's a broken track leading to pin1 of lm358