Hi, have anyebody had trouble building the ELENCO 108 AM/FM RADIO KIT

[michael1978]

What part of "trim the leads" did you think meant "add more solder"?

oh sorry i misunderstand you, what do you mean with trim?

 

[KJ6EAD]

Besides correct component per location, the most common error in kit assembly is wrong polarity or orientation of components such as diodes, transistors, capacitors and ICs.

 

[(*steve*)]

oh sorry i misunderstand you, what do you mean with trim?

Cut them off shorter

 

[michael1978]

oh sorry i misunderstand you, what do you mean with trim?

no i think lees

 

[michael1978]

Cut them off shorter

Rely the leads of transistor or capacitor resistor, to cut shorter, ah i gonna do it thnx

 

[michael1978]

There is a lot of motion blur in those photos, so they aren't really useful.

What I can see is that you seem to have filled leads over before soldering them, and have failed to trim them properly.

I recommend that you trim the leads, and then take photos where the light is better, or find a way of ensuring the camera doesn't move during the exposure.

Meanwhile, have you checked every component to make sure you put the right ones in the right places?

Yes all components are in rights position

 

[michael1978]

There is a lot of motion blur in those photos, so they aren't really useful.

What I can see is that you seem to have filled leads over before soldering them, and have failed to trim them properly.

I recommend that you trim the leads, and then take photos where the light is better, or find a way of ensuring the camera doesn't move during the exposure.

Meanwhile, have you checked every component to make sure you put the right ones in the right places?

Hi i make it, but nothing changes...…….

 

[(*steve*)]

Aaaah, that's a better image.

It appears that your solder joints are very poor. You need to Google for how to solder and go over each joint and fix them.

 

[michael1978]

Aaaah, that's a better image.

It appears that your solder joints are very poor. You need to Google for how to solder and go over each joint and fix them.

ooh my god, but what do you think, maybe the board is bad? because like i say before, i did the test like they say in book(i mean with dmm) everythink was correct

 

[(*steve*)]

The solder joints look like balls on top of the pads rather than smooth solder joints. They look like the pads were insufficiently heated and the solder did not flow over them.

It only takes one bad joint to stop the circuit working, I suspect you have some.

 

[(*steve*)]

Your soldering iron needs to be placed so that it heats both the pad and the wire. After a second or so, feed a little solder into the joint so that it flows over the pad and the wire. Remove the solder and the iron. The joint should be smooth and be a concave meniscus joining the pad and the wire.

If the solder is mostly a convex surface then either it is a poor joint or there is far too much solder.

In your case, if the entire pad is not covered with solder, then the joint is poor.

That board looks like the exposed copper may not have been tinned. This can make it much harder to make a good solder joint.

 

[michael1978]

The solder joints look like balls on top of the pads rather than smooth solder joints. They look like the pads were insufficiently heated and the solder did not flow over them.

It only takes one bad joint to stop the circuit working, I suspect you have some.

thnx man

 

[73's de Edd]

Sir michael1978 . . . . .

You say:
when I switch to . . . . . .fm, i just hear high noise


Two tests:

Have the unit working and hearing your rush noise from the speaker in the receivers FM mode.

Then power down and lift one lead wire of R25 from making its connection to the board.

If that noise then stops, when you power it up again, the LM386 associated circuitry seems to be working OK.

If that noise remains, it seems like you might be having some type of oscillation within your LM 386 circuitry..

To evaluate if your FM RF portion is working, take DVM in DC voltage mode and at voltage setting level that gets an in circuit reading..
Constantly measure the voltage being read across R20 and slowly tune from one end of the FM band to see if there are rises and declines in the voltage reading, as you tune onto and then off from each FM station,which signifies being responded to..

That should then isolate / relate the basic problem as being an audio output stage / or / FM receiver portion area of problem.

CONFIRMED . . . .those excess lead length stubs are just an accident waiting to happen . . .with 2-3 mm excess being the norm.

73's de Edd
.....

 

[michael1978]

Sir michael1978 . . . . .

You say:
when I switch to . . . . . .fm, i just hear high noise


Two tests:

Have the unit working and hearing your rush noise from the speaker in the receivers FM mode.

Then power down and lift one lead wire of R25 from making its connection to the board.

If that noise then stops, when you power it up again, the LM386 associated circuitry seems to be working OK.

If that noise remains, it seems like you might be having some type of oscillation within your LM 386 circuitry..

To evaluate if your FM RF portion is working, take DVM in DC voltage mode and at voltage setting level that gets an in circuit reading..
Constantly measure the voltage being read across R20 and slowly tune from one end of the FM band to see if there are rises and declines in the voltage reading, as you tune onto and then off from each FM station,which signifies being responded to..

That should then isolate / relate the basic problem as being an audio output stage / or / FM receiver portion area of problem.

CONFIRMED . . . .those excess lead length stubs are just an accident waiting to happen . . .with 2-3 mm excess being the norm.

73's de Edd
.....

Hi Edd, that problem is not anymore, ii hear only low low noise, and i tune and R20 its stal 1.6V and when i toch the pot where is solder it with finger it comes more noise, i dont understand after R20 it stay at 3.16V, maybe something with pot, problem ( i just think) because the same noise for am and fm, because when i dont touch there is low low noise, what do you think

 

[kellys_eye]

Soldering. Entirely down to poor soldering.

Fix the soldering and it will (possibly) just work.

 

[michael1978]

Soldering. Entirely down to poor soldering.

Fix the soldering and it will (possibly) just work.

Hi Kellys, when i cuts a leads shorter, i dubbel check are all components connected, so when i put the hand to pot or capacitor, they change the noise make it more noise, i desoldeer on capacitor and i put new, again the same problem,

 

[kellys_eye]

Resolder ALL the wires, components and connections then post a new picture of the soldered board.

 

[Harald Kapp]

How to make good solder joints.

 

[michael1978]

this a

Resolder ALL the wires, components and connections then post a new picture of the soldered board.

Hi, i desoldeer all the party of AM, and i soldeer it again beter, and i change LM386 and holder and also al capacitors lytics, , and i solder again no result, so i desoldeer also the potenitomer, now when i rotate i hear voice low and high, but but not so high, and i get no signal, what do you think did i connect maybe the vcapacitor bad or the coil(is not correct like in book is with four wire and i measure i dont get the resistance show it in book, what do you think whats the porblem, what to do anymore? This AM first to fix it?

 

[(*steve*)]

You need to follow the instructions for getting the correct windings of the coil in circuit with the correct phasing.

Also, an updated *sharp* image of the big Spring your improved soldering would be great.