Problem MK 174 kit, speaker doesn`t work

Kits Audio Hi Fi Projects
1

Hey all,

I builted a MK 174 kit and it works normally. The only thing is, that I only get a signal at the line out, and not at the speaker. Does anybody know how I can go on ?

2

Perhaps speaker defective?

3

Please test the speaker separately.
Sorry, this forum does not allow picture uploads
If you can provide LINKS (e.g. by using a free online picture base) to HI-RES and SHARP pics of your assembly (both solder- and component side)
then we can take a look and provide some feedback.

4

I tested the speaker. I mean, I tested the kit with another 8 Ohm Speaker, and there was no result.

I did some pics. Please have a look at.

dl.dropbox.com/u/107435505/IMG_0649.JPG

and backside

dl.dropbox.com/u/107435505/IMG_0650.JPG

Many thanks for your help.

5

As far as we can see, assembly looks OK.
If you provide an address, we can send a spare IC.

6

Thank you very much, I got the new IC, but I am sorry, still the same. It doesn`t work.
Any idea what I can test next. It is very important for me, because I have to finish a job soon, where I need the MK 174

7

Looking at the solder side of the board it looks like you have a broken trace from Pin 8 of the IC.
This is the pin that drives the speaker.
You may want to look at that closely

Hope this helps.

8

Thanks, i will chewck this

9

Checked, but it still does not work.
I am thinking of, to use a external amp. Do you offer a kit ?
Or may I can send the MK 174 back, and you check it ?

10

You can return your kit for inspection/repair to:

Velleman Projects Tech. Dept.
Legen Heirweg 33
9890 Gavere
Belgium

Please keep in mind that returning a low-cost kit can be more expensive than buying a new kit.

11

you are right. I will do it with an extra amp.
Thx for help

12

Just wondering.

Did you meter pin 8 to the negative side of the speaker output or did you repair it?

13

hi to all,
i resume this topic for a similar problem.
I have some mk174 kits for various applications, and the last kit mounted have a problem on ISD. The audio recorded level is very low, and the problem is also present if i use a last isd, on another kit fully functional. I have tested a old ISD on the broken kit, and the problem not exist. I think but a problem is on ISD of the last kit purchased.
It’s possible buy three ISD part spare, for replace my ISD broken and stored two parts for any possible future problem?

Thanks

14

Sorry to read you have a problem with this kit.
You can return the assumed defective IC for testing/exchange.
Please return it to:
Velleman Projects Tech Dept.
Legen Heirweg 33
9890 Gavere
Belgium

Sorry, no direct sales.
Please turn to your Velleman distributor for spare parts.
Order code of the part: ISD1620COBP

15

thanks for reply,
Italian distributor told me kindly send me a single IC to replace the damaged one, but can not sell other parts individually.
Can I buy additional IC parts directly from you?

16

Please see my previous post: no direct sales.
Maybe you can order the part from a part supplier such as DigiKey, Farnell, etc…