Also, have a look at this transistor. I don't like the way the legs are bent:
If you don't measure zero's (shorts) they are probably OK.
You mean resistor?
Don't take them out, just measure the legs in circuit.
If you don't measure zero's (shorts) they are probably OK.
i just dont know if led thats attached to cap is collector or not for small ones other things i can measure
btw i replaced the diode with similar one values are not exact but orientation is same so i dont think it will make problems
If the legs don't touch each other it's OK
Good call on that diode.
Ones the transistors are measured, make a list of all the bad parts you found.
Let's consider the two resistors with wire around them bad.
Good call on that diode.
Ones the transistors are measured, make a list of all the bad parts you found.
Let's consider the two resistors with wire around them bad.
Alright, if only these two resistors are bad an all transistors are good,
replace both resistors with 0.47 Ohm 1 or 2 Watt.
Carefully check all other connections, don't put the big transistors back in place and start the amp with the lightbulb.
I'm off for today, will look at the video tomorrow.
If you found no shorts on the transistors, consider them good.
Take care.
Hugo
replace both resistors with 0.47 Ohm 1 or 2 Watt.
Carefully check all other connections, don't put the big transistors back in place and start the amp with the lightbulb.
I'm off for today, will look at the video tomorrow.
If you found no shorts on the transistors, consider them good.
Take care.
Hugo
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I had a quick look and I see you measured no shorts. Good.
If something goes wrong with the big transistors in place they might break.
So first we will test without. Follow what I wrote in post #230.
Now I'm really gone.
If something goes wrong with the big transistors in place they might break.
So first we will test without. Follow what I wrote in post #230.
Now I'm really gone.
Judging from these pictures, it’s a mess! Looks like someone did some really bad job of repairing or modifying the circuit!
If it were me, I would remove all the components from the board and reuse the case, power supply and components that are still workable, building a single rail 2N3055 amplifier from scratch using a proven design like the El Cheapo circuit.
Make this a new project and your grandpa will be proud of you building a new amplifier in his honor.
If it were me, I would remove all the components from the board and reuse the case, power supply and components that are still workable, building a single rail 2N3055 amplifier from scratch using a proven design like the El Cheapo circuit.
Make this a new project and your grandpa will be proud of you building a new amplifier in his honor.
While I agree that someone has done really terrible work on this, or it may have been a badly built kit, I'll assume it worked and should again. I wouldn't be so quick to dump and run.
It would be great to figure out what it should look like, and build it neatly. I routinely see things like this, but I can figure them out and build them back the way they should be. When someone else has worked on something, it isn't uncommon to find parts in backwards or completely incorrect parts installed. Using two and three parts to make up the value of one is also (very sadly) common. I even see parts scavenged from other items used in repairs (customer is charged for new parts). Some folks shouldn't be allowed to touch a soldering iron.
It would be great to figure out what it should look like, and build it neatly. I routinely see things like this, but I can figure them out and build them back the way they should be. When someone else has worked on something, it isn't uncommon to find parts in backwards or completely incorrect parts installed. Using two and three parts to make up the value of one is also (very sadly) common. I even see parts scavenged from other items used in repairs (customer is charged for new parts). Some folks shouldn't be allowed to touch a soldering iron.
Let's carry on. We might be almost there.
You definitely need to check all connections are made and address the problems indicated by chrisng.
The legs of the transistor in the second picture should not be bent like this.
The floating leg of the resistor in the third picture should be fixed.
In the second video at 2:00 you talk about a leg that is 'supposed to be here'.
Make sure the legs are soldered correctly.
Replace both resitors with the wires around. 0.47, 0.56, 0.68 ohm all should work. Make sure they are at least 1 Watt.
Don't compromise on all these points. Check, double and triple check every connection.
Only after that we can move on.
You definitely need to check all connections are made and address the problems indicated by chrisng.
The legs of the transistor in the second picture should not be bent like this.
The floating leg of the resistor in the third picture should be fixed.
In the second video at 2:00 you talk about a leg that is 'supposed to be here'.
Make sure the legs are soldered correctly.
Replace both resitors with the wires around. 0.47, 0.56, 0.68 ohm all should work. Make sure they are at least 1 Watt.
Don't compromise on all these points. Check, double and triple check every connection.
Only after that we can move on.
sorry bro but my grandpa is not longer on earth... i am just fixing it in his honor i know he wanted to do it but he did not know. i get what you are saying but i will do it my way
btw yes that leg is bent but it is connected fine. i have t odrill new hole where it should be and then to move it there i will not do that. so it is not touching anything and it shoud be fine. i made video if you guys say it is ok then i can continue with this project.
btw i also did a reflow of solder for most of the connections just to be sure it's all connected properly. btw i till take time for resistors to arrive , i cant find them near me so i have to order from e bay i will wait but i want new resistors not to put 2 or 3 together to make it that not what i want.
btw that bent leg of transistor is not floating it is connected but i guess that guy who built this amp made a misstake and drilled hole in wrong spot and decided to go this way. i mean this worked for like years and years with no issues. my grandpa was not playing this amp quet he did like playing this very loud for 10 and more hrs because he played it on local celebrations. so this amp worked a lot xdd i would never use a amp that way but it is how it is, my theory about how it broke is that he did connect speaker vires incorrectly but i remember that he wanted to drive two speakers on this mono amp xd he maybe connected speakers to make a lot of resistance and that did a damage or he bridged a speaker wire. also i think its louder then 50w maybe its modified on some point but i cleary remember that this amp was really loud i have guitar amp 40w its not even close