I'm a novice to electronics. I have tried and failed to build an amplifier circuit using five new chips. I am trying to build a basic amplifier circuit around the Texas Instruments LM 4862 amplifier chip. It consistently fails to produce any output. Is it possible that each time I am burning out the LM 4862 chip while soldering? The soldering iron temperature is set at 510° Fahrenheit. The circuit schematic is found in my attachment "03_12_2021 Schematic LM4862..." Any reply would be appreciated.

 

Do you have any pics of your soldering attempts? It might help identify any problems.

You can damage an IC with too much heat. The pins and circuit board should be very clean. And your soldering iron should be clean and tinned properly. If your prep is good, then you should only need to apply the iron for 3 seconds or less to make a soldering joint.

You’ll need to clean the iron tip and re-tin it often.

 

It's possible, but you should be ok if you follow the soldering guidelines in most datasheets.

 

Where did you buy the chips?

 

Did you buy five new cheap fake chips from ebay or one of the other websites "over there"?
What product produces the input signal? The circuit does not produce enough gain for a microphone.
What is your battery or power supply voltage?
What are the values of your R2 and C4?

 

How much time the heat has been applied to the joint is going to determine whether you cooked something or not. You should consider using IC sockets to avoid damaging chips. Also, 510F is too low for leaded solder and WAY too low for lead-free solder. The wrong temp will necessitate leaving the iron on the joint longer to melt the solder, which will increase the risk of damage. I use 60/40 solder at 600F and I only need a second or two for a good solder joint.

 

Since the late 1960's it has been very difficult to damage a semiconductor by overheating it while soldering. Having said that, the datasheet may give guidance for the temperature and duration recommended for soldering.

I don't think I have ever damaged a semiconductor by overheating in the 50+ years I have been soldering semiconductors. This includes both Germanium and Silicon semiconductors.

Listen to SamR and Audioguru again. If your chips came from the grey market, you can expect troubles. If these were bought from authorized distributors then a closer look at your soldering technique is warranted. Note: Using an oxy acetylen torch might cause problems. : -)

 

How much time the heat has been applied to the joint is going to determine whether you cooked something or not. You should consider using IC sockets to avoid damaging chips. Also, 510F is too low for leaded solder and WAY too low for lead-free solder. The wrong temp will necessitate leaving the iron on the joint longer to melt the solder, which will increase the risk of damage. I use 60/40 solder at 600F and I only need a second or two for a good solder joint.

This makes a lot of sense. I will find an IC socket which should avoid some problems for me. I use the same solder as you. At this point I'm pretty sure I cooked the IC chip. djsfantasi's practice of keeping the soldering tip clean and tinning everything properly is something I've made a habit of doing. I use extra flux also. Thanks

 

You'd be surprised at what chips can withstand and keep working. At least the modern ones, not the old extremely sensitive to ESD ones. Flux is your friend, so use it on the DIP pins to be soldered generously and keep your iron tip clean. I don't remember ever soldering a chip directly onto the board so I'm a big fan of sockets. I would never solder a chip onto the board without testing the chip first just as a precaution. They go on a whole lot easier than they come off.

 

Soldering is just one of those skillsets that need developed. Developing good work habits and soldering skills comes with time and patience. No magic to it. Eventually things and looks will just feel and look right. I admit that even with todays SMD it's pretty hard to overcook a component. Good equipment and practice and you will get the hang of it. Always remember the bigger the blob the better the job!

Ron

 

3/20/2021 I took great care not to fry the amplifier chip but I still get no sound - not even a crackle when plugging in or withdrawing from the input jack. Can anyone bring their lights to bear on my implementation of what's in the schematic. Being a newbie I probably did something wrong.

 

Sorry.
Your wiring (long red wires all over the place) and soldering are too messy for me to see what connects to what.

 

3/20/2021 I took great care not to fry the amplifier chip but I still get no sound - not even a crackle when plugging in or withdrawing from the input jack. Can anyone bring their lights to bear on my implementation of what's in the schematic. Being a newbie I probably did something wrong.

I looked at the photos and saw lots of reasons why you have problems. All of your solder joints are suspect. It is not good practice to build prototype circuits in 3D in the air.
The holes in the perf-board you are using are for inserting the leads of the components so that they are firmly supported. put the components leads through the holes and wire them up on the other side of the board. That goes for the amplifier chip too. Keep all of the wires as short as possible and only strip about 1/8" of the insulation from the ends of the insulated wires.
I use single or double sided circuit board with solder pads in a 0.1" matrix but I have used perf-board similar to what you have. I usually draw both sides the layout first and then wire it up using the component leads and single strand, 26 AWG bare wire. I only use insulated wires for connecting external devices to the circuit.
This is how I draw it up before I start wiring It looks like a lot of work but it minimises the possibility of wiring errors and it is good to keep for reference:

 

Does anyone remember the original Star Trek pilot, with Capt. Pike instead of Kirk? A human crashed on a planet with advanced aliens, who save the life of one female crew-member. But they did not know what a woman should look like, so she did not look so hot.

The construction techniques in this thread look a lot like what someone who had never seen an actual circuit might come up with.

Bob

 

Did you buy five new cheap fake chips from ebay or one of the other websites "over there"?
What product produces the input signal? The circuit does not produce enough gain for a microphone.
What is your battery or power supply voltage?
What are the values of your R2 and C4?

The chips I bought from Mouser.
The input signal is from the earphone jack of an MP3 player that I built. 8 volt battery which the voltage regulator reduces to 5 volts. R2 is 22K while C4 is optional so I didn't connect it - it's for a gain higher than 5 where a 22pf C4 would be used.

 

The two jacks are in perfect operating condition. Current is coming out of the voltage regulator. In principle I try to connect the negative lead of a capacitor first at the beginning and the positive lead to the next part of the circuit.

 

This is the layout for the circuit that I want to make. I'll clean it up when I have time. Then I will space out the components so that one can easily see in my photos how the connected components are copying what's in the diagram. This schematic needs to be rotated counterclockwise in Adobe. Version 2 soon to follow.

 

Your wiring and soldering are the messiest that I have ever seen.
I usually make a circuit on a perforated stripboard. The parallel copper strips are cut to length and form half of a pcb and the parts and a few short jumper wires form the other half. This circuit would be about the size of a postage stamp. Small size is important to avoid interference.

It seems that you cannot see on the schematic what is supposed to connect to what, therefore important things are not connected together. Your battery does not connect to the 5V regulator and the 5V regulator does not connect to the LM4862 amplifier IC so no wonder it does not work.

 

When you draw your layout, draw the physical shapes of the components, not their schematic symbols. Draw them all to the same scale, with the leads and pins in the correct positions on them. Their labels will define what they are. Make sure that the lines actually join each other where the wires connect. The devices in your circuit do not have to be in the same orientation as in the schematic. You can rotate them 90 degrees if it makes connecting them together simpler. If you don't have a good clear diagram to work from, you are going to make mistakes when you assemble it.
I took a few minutes to roughly sketch what it should look like. I am sure you can do better.

 

This is the right way for me to use the capacitor from the output of the 5 V power regulator to the power input of the LM 4862 (very tiny in the page). I didn't understand the usefulness of throwing on a capacitor to a direct connection between the power supply and the LM 4862. So I thought inline was the way, discovering by way of a battery tester that connecting the negative end to the power and positive towards the chip allowed current to flow and the opposite way allowed no power to flow. I'm sure I'm not revealing anything to you. I'm not saying Eureka just yet because I looked many times to find current going into the chip (even though it was not provided the right way). No one has criticized the way that C1 0.33uF capacitor (inline) was connected from Audio In.