5 Pill homebrew linear problems

[crazy_179]

I just finished my 5 pill linear, I followed the instructions to a T, I would be more than willing to upload them or send them to anyone who maybe able to help me. or just donate to them site for anyone interested in the build. Anyway, on to my problem. First of all, I actually finished this build a few days ago and have since gone over my work step by step ensuring I had not made any mistakes. This is the mobile 12 volt linear schematics available for sale on ebay all over the place. My problem is, I hook up the linear and when i key the microphone, the relays don't kick in, nothing happens, swr is still low, sound is good, no distortion, just doesn't do anything. I was hoping someone could enlighten me to what possibly maybe the problem. If more info is needed, feel free to ask, I will answer. This is my first project of this type so I am not sure what I need to add.

Thanks

KC9HNT

 

[mackmobile43]

I just finished my 5 pill linear, I followed the instructions to a T, I would be more than willing to upload them or send them to anyone who maybe able to help me. or just donate to them site for anyone interested in the build. Anyway, on to my problem. First of all, I actually finished this build a few days ago and have since gone over my work step by step ensuring I had not made any mistakes. This is the mobile 12 volt linear schematics available for sale on ebay all over the place. My problem is, I hook up the linear and when i key the microphone, the relays don't kick in, nothing happens, swr is still low, sound is good, no distortion, just doesn't do anything. I was hoping someone could enlighten me to what possibly maybe the problem. If more info is needed, feel free to ask, I will answer. This is my first project of this type so I am not sure what I need to add.

Thanks

KC9HNT

So you do have radio recieve when the amp is turned on?
A picture is worth a thousand words and makes diagnostics mucho easier, lets' see your relay and keying circuit. thanks

 

[Cajun Invader]

Did you turn it on?

 

[crazy_179]

So you do have radio recieve when the amp is turned on?
A picture is worth a thousand words and makes diagnostics mucho easier, lets' see your relay and keying circuit. thanks

Yes receive works perfectly when amp is turned on, the relays don't activate when i key, I till have my 5 watt output from the transceiver and can communicate and receive as well I as can with the amp not in line, Just does not boost output and relays do not kick in, I will take a picture and upload it.

 

[crazy_179]

pictures

Please excuse my ignorance, I am not 100 percent sure where the rf detection circuit is so i took a overview of the linear. Please let me know what sections you need close up of. Also don't mind some of the sub par soldering. I tried to build this with a 40 watt gun, I had to go out and buy a butane solder gun when i finished to reheat the joints and get them to flow properly. My next one will be much better if I ever build another one.

 

[MisterFatty]

I've cut and paste an enlargment of the keying circuit, some larger macro shots of this area would be helpful. Not trying to detract from your build but you will probably need to reflow some of those joints, many appear to have to much solder, as well as questionable integrity.

Also appears you may have gotten a few components pretty hot when assembling. Hopefully just trouble shooting the keying circuit will be enough. Any chance of a local to help you out on the build?

 

[MisterFatty]

Just looking your picture over there are a couple other issues I would take care of before making it permanent.

 

[crazy_179]

Just looking your picture over there are a couple other issues I would take care of before making it permanent.

I know the soldering is not up to snuff misterfatty. I would appreciate any help you can give me, I thought that was the area of the circuit but wasnt positive. I will take that apart and redo it. ONe thing of note, that called for a 10pf capacitor, I didn't have a 10 pf and couldn't find one online at the places i ordered from so i went with a larger capacitor, the label is 18 on it. Could that be the issue? the only other part that is not exactly to snuff is the 4.7 ohm 2 watt resistors, I couldn't get them as well from the places i ordered from so i went with 6.8 ohm 2 watt resistors. Other than that, all parts are build to specs. Man it really looks ugly when you blow it up like that. I will rework that area.

 

[crazy_179]

The only local that would of helped me with this project passed away a couple years ago. More than once during this build I thought about him and wished he was still around. I own his old house and am building the linear in his old shop. Guess him being here in spirit is as close as I will get. I am going to purchase another 2222a tomorrow and reassemble the circuit, any other trouble areas you see fit to comment on misterfatty would be greatly appreciated. I need to purchase a nice 60 watt iron before i even attempt another one of these. My father has made a comment about wanting a smaller version when I get this one done, but he will have to wait till next year.

 

[Bionic Chicken]

Is it just me or is both ends of the diode in the keying circuit tied to ground? It kind of looks that way in the photo Mr Fatty posted.

 

[linearone]

i think the leg left of the capacitor there is laying on the center leg on the transistor...

 

[crazy_179]

Is it just me or is both ends of the diode in the keying circuit tied to ground? It kind of looks that way in the photo Mr Fatty posted.

that was the problem, in the pictures i had it appeared both ends were to ground, I didn't think that was right, i unhooked one end of them and now it works. thanks

 

[seedkey]

ok, how about sharing the plans now.

 

[MisterFatty]

Good to hear you got it working, yes the diode was one thing but difficult to tell from the angle.

I would still try to clean up some of those solder joints when you get time, there are a few other areas that appear to have connections in very close proximity of the the board, If you bump this around or run it mobile both could cause future issues.

 

[crazy_179]

ok, how about sharing the plans now.

I am a man of my word, Here is the link to download the entire set of plans. I uploaded these to share with some friends awhile ago.



1. Paste this address in your web browser hxxp://www.megaupload.com/?d=OEYN38Q7

2. When the page open you will see a combination of letters and numbers in the upper right hand corner, They are a bit hard to decipher.

3. If the code is successfull A orange box that says premium will show up, under it will say "please wait 45 seconds" and it will count down to 0. When it reaches 0, a black box will apear and say regular download. Click that box and choose save file.

4. After download is complete you will have the file called Linear Cookbook.exe in the location where you choose to save it too

5. Double click the Linear Cookbook.exe file. A box will open and you may click on the browse button to direct the files to a folder of your choice. I recommend creating a new folder named "Linear Cookbook" or something similiar, and then extracting inside of that. Otherwise you will have 10 folders extracted to the desired location. One folder for each build plan. I think it is just easier to put them all in one nice folder.