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Need help with a Amp Project.
- Thread starter LeaD_FooT_Tn
- Start date
Shadetree Mechanic
Delaware Base Station 808
Have you tested the parts to see if they are good and within spec.? No magic in the box apart is either good or bad. Since you already took them all out might as well test them! Anything that is out of spec replaces and see what you get.
You kids today give up too easily. I have 3 boys and my younger two give up before they have hardly even tried. You wont get any place in life if you give up this easy.
Since someone has already done the hard work and designed this unit, loaded up a schematic and invented the internet at this point you just need to follow a good plan of action. You have a multi-meter, a soldering iron, the schematic and the parts so just start at one end and follow the circuit! Until you do that and give us more specific info none of us can help you.
You are half way there do not give up! Relax the process is the process and trying to rush things or find the easy answer will not help you. If you where my boys I would not tell you anything different!
Just get back on that horse! When you get frustrated stop and go have a beer or watch some tv, lift weights whatever it is you do to let your mind unwind a bit!
You kids today give up too easily. I have 3 boys and my younger two give up before they have hardly even tried. You wont get any place in life if you give up this easy.
Since someone has already done the hard work and designed this unit, loaded up a schematic and invented the internet at this point you just need to follow a good plan of action. You have a multi-meter, a soldering iron, the schematic and the parts so just start at one end and follow the circuit! Until you do that and give us more specific info none of us can help you.
You are half way there do not give up! Relax the process is the process and trying to rush things or find the easy answer will not help you. If you where my boys I would not tell you anything different!
Just get back on that horse! When you get frustrated stop and go have a beer or watch some tv, lift weights whatever it is you do to let your mind unwind a bit!
wow leadfoot you really made your life harder than it had to be!
you had a car that wouldn't start and you decided to take the engine apart without any mechanics training.
RF electronics are a finicky beast and exact placement on the board for some of those components is essential for proper operation. I'm not talking about which trace it gets soldered to, im talking about where on the trace the part sits.
I know you are here hoping that someone will be able to spoon feed you all the answers and walk you through putting the amp back together, but that's not going to happen.
no tech would even take that amp in to fix themselves much less try to talk you through the whole process. the amp isn't worth the money it would take to get it working.
The motorola circuit you found in the datasheet is a guideline for engineers to use when they design an application for that transistor and is by no means a complete amplifier.
if you really love radio, then it's time to hit the books, and not just books dedicated to CB radio. get a copy of the ARRL handbook anywhere from the mid 70's to the mid 80's in order to read up on this type of amplifier design. they are all over ebay for cheap.
there are people here who like to help, but you have to take the ball and run with it.
don't give up on the hobby, just learn from each mistake you make, and never throw your stuff away!
good luck in your future circuits!
LC
you had a car that wouldn't start and you decided to take the engine apart without any mechanics training.
RF electronics are a finicky beast and exact placement on the board for some of those components is essential for proper operation. I'm not talking about which trace it gets soldered to, im talking about where on the trace the part sits.
I know you are here hoping that someone will be able to spoon feed you all the answers and walk you through putting the amp back together, but that's not going to happen.
no tech would even take that amp in to fix themselves much less try to talk you through the whole process. the amp isn't worth the money it would take to get it working.
The motorola circuit you found in the datasheet is a guideline for engineers to use when they design an application for that transistor and is by no means a complete amplifier.
if you really love radio, then it's time to hit the books, and not just books dedicated to CB radio. get a copy of the ARRL handbook anywhere from the mid 70's to the mid 80's in order to read up on this type of amplifier design. they are all over ebay for cheap.
there are people here who like to help, but you have to take the ball and run with it.
don't give up on the hobby, just learn from each mistake you make, and never throw your stuff away!
good luck in your future circuits!
LC
You can take apart the motor in your daily driver, box up the parts and take them to your mechanic.
Odds are he can put them all back together where they belong.
But ask him to show you how? Well, maybe not so much "show" as "tell" you how.
Not so likely.
All you needed to do is remember where everything was before you removed it.
And put each piece back in the same place.
Before you took it apart it was an amplifier. Now it is a DIY amplifier kit with no assembly directions. Well, a partial kit. If it was not working before being disassembled, one or more of those parts is probably no good.
The relay looks as if it has had a hard life. Any time the protective cover is missing you will usually find the contact points are damaged. Can't adjust the contacts on this type relay. Just have to replace it when it fails. Good chance yours is bad. RF Parts sells that relay.
73
Odds are he can put them all back together where they belong.
But ask him to show you how? Well, maybe not so much "show" as "tell" you how.
Not so likely.
All you needed to do is remember where everything was before you removed it.
And put each piece back in the same place.
Before you took it apart it was an amplifier. Now it is a DIY amplifier kit with no assembly directions. Well, a partial kit. If it was not working before being disassembled, one or more of those parts is probably no good.
The relay looks as if it has had a hard life. Any time the protective cover is missing you will usually find the contact points are damaged. Can't adjust the contacts on this type relay. Just have to replace it when it fails. Good chance yours is bad. RF Parts sells that relay.
73
Mechicanicly I am good to go. If you left me a box of parts I could put it back together without having seen the machine before. Not the ideal way to do things though! LOL....With Electronics I would never be that bold because my brain does not see in "electronics, electrons, or schematics".....LOL
Generally, I take things very slow and methodically and test first, read the schematic or service manual, test again then act! I never try to wing it I always start with plan of action and work that plan! Sketching things out on a notepad is a time-tested technique when walking into the unknown. In today's tech though you would just take a photo with your phone.
A good mechanic or electronic tech would troubleshoot before doing anything else. Do not just tear into shit and start taking things apart that is a terrible way to go.
If you have a good working unit to compare too that helps when you do not have a service manual.
You do not just have an option of building a keying circuit without the relay. You missed something in translation. You will have the relay which is a common item and you will have a keying transistor. Normally one of three things goes bad in a keying circuit for a gray market linear the relay, the cap for the relay or the keying transistor. So after you find out which part is bad you replace it in the system.
That said since you have not tested anything you do not know what needs to be replaced to restore function. At this point, you do not have an amp that needs repair you have a box of subject parts and a pcb. So you need to rebuild the amp before you can build the keying circuit.
THink of it like this. If you tear an engine apart and install a new starter it does not do any good if you do not have a functioning engine for the starter to spin. It is not an either or it is an all or nothing situation.
Generally, I take things very slow and methodically and test first, read the schematic or service manual, test again then act! I never try to wing it I always start with plan of action and work that plan! Sketching things out on a notepad is a time-tested technique when walking into the unknown. In today's tech though you would just take a photo with your phone.
A good mechanic or electronic tech would troubleshoot before doing anything else. Do not just tear into shit and start taking things apart that is a terrible way to go.
If you have a good working unit to compare too that helps when you do not have a service manual.
You do not just have an option of building a keying circuit without the relay. You missed something in translation. You will have the relay which is a common item and you will have a keying transistor. Normally one of three things goes bad in a keying circuit for a gray market linear the relay, the cap for the relay or the keying transistor. So after you find out which part is bad you replace it in the system.
That said since you have not tested anything you do not know what needs to be replaced to restore function. At this point, you do not have an amp that needs repair you have a box of subject parts and a pcb. So you need to rebuild the amp before you can build the keying circuit.
THink of it like this. If you tear an engine apart and install a new starter it does not do any good if you do not have a functioning engine for the starter to spin. It is not an either or it is an all or nothing situation.
Wanted a million dollar lesson for free on a $10 broken amplifier! Took me years to understand the audio circuit in a radio. I was about the hobby and it cost me money to learn. Buy broken and fix to working. Didn’t work the first time so kept reading and testing. Nothing free or easy.
Please understand I am not giving you a hard time or trying to discourage you. Having 3 kids that went to public schools I know for a fact they no longer teach critical thinking or logic. So most kids have no idea how to get started on anything not even on how to set a long term and short term goals and how to set up steps that lead in the direction of each in a methodical systematic manner. All things have rules of thumb, best practices, what is said to be common sense and a flow or order to things. Chaos is great for creativity and inspiration but beyond that, it is usually the opposite of what is needed to solve a problem, understand a problem or actually create once the initial idea has been thought up! You have the desire and the interest but you have too much chaos and not enough order at this point. I hope I did not discourage you because that sincerely is not my intent!
Shadetree Mechanic
Delaware Base Station 808
He hasn't been back in 5 weeks. I guess he didn't get the answers he wanted. Hopefully he learned something anyway. Some people think that everyone else is the cause of all their problems but I don't think this is the case. I think that you don't know what you don't know. The more you know, the more you realize what you don't know. Its all a part of learning and growing. Maybe he will be back someday to show us the amp he put back together and fixed. I hope so.
BJ radionut
Supporting Member and 6m addict
Yes unfortunate...Agree he did not get the responses, he wanted or liked and has not been back.
I just wonder why he gutted the ENTIRE PC board just due to what he thought was a bad relay though(?)...
OH well experience is man's best teacher...Hope he learned something from his experience...
We have all done things along the way we regret in the radio biz
...but that one was unusually interesting.
All the Best
Gary
I just wonder why he gutted the ENTIRE PC board just due to what he thought was a bad relay though(?)...
OH well experience is man's best teacher...Hope he learned something from his experience...
We have all done things along the way we regret in the radio biz
...but that one was unusually interesting.All the Best
Gary