676
New member welcome / Re: hi too All New guy Hear
« on: July 12, 2014, 03:31:34 PM »
Hey snow bird. goos to see you here.
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677
CB Radio Repair Forum / Resting RF output on cobra 29
« on: June 25, 2014, 10:02:27 AM »
This shows various stages of RF output issues.
The blue dots on the schematic indicate in-out of each RF transistor
The screen shots of the scope shope base-collector open
base-colloctor short
proper amplification
The blue dots on the schematic indicate in-out of each RF transistor
The screen shots of the scope shope base-collector open
base-colloctor short
proper amplification
678
Test Equipment / IFR 1200 checksum error fixed
« on: June 21, 2014, 09:22:57 PM »
After quite some time of this issue I finally resolved the checksum issue on this unit.
On boot up the unit would give an error. What I found was a battery on the CPU board was dead, Not having a solder in coin cell battery on hand I simply mounted a coin cell hold to the rear of the CPU board. Was not enough room to mount on component side.
The battery solved the boot up problem.
https://www.youtube.com/watch?v=S7U9EGVQwPM
On boot up the unit would give an error. What I found was a battery on the CPU board was dead, Not having a solder in coin cell battery on hand I simply mounted a coin cell hold to the rear of the CPU board. Was not enough room to mount on component side.
The battery solved the boot up problem.
https://www.youtube.com/watch?v=S7U9EGVQwPM
681
Test Equipment / Astron VS-50M repair thread
« on: June 18, 2014, 04:55:08 PM »
I will be posting the repair of a astron supply I picked up. ATM it has a blown SCR and the meter pegs when powered up. So either a series pass ot LM723 bad.
While checking the transistors they all read about the same.
Also noticed no thermal grease on transistors
While checking the transistors they all read about the same.
Also noticed no thermal grease on transistors
682
Electronic videos / The dead receiver Tech tip
« on: May 31, 2014, 09:38:08 PM »
Here we look at a simple device for testing the "dead receiver" on a cobra 29 radio.
This radio actually has 2 problems that prevent it from receiving.
https://www.youtube.com/watch?v=K0BRiMj7JHg&feature=youtu.be
You can also use this on other types of receivers to test
This radio actually has 2 problems that prevent it from receiving.
https://www.youtube.com/watch?v=K0BRiMj7JHg&feature=youtu.be
You can also use this on other types of receivers to test
683
Electronic videos / Re: My first YouTube video HP 8640B signal Gen
« on: May 26, 2014, 10:32:44 PM »684
Electronic videos / Re: My first YouTube video HP 8640B signal Gen
« on: May 25, 2014, 09:36:16 AM »
more pics
685
Electronic videos / Re: My first YouTube video HP 8640B signal Gen
« on: May 24, 2014, 05:55:09 PM »686
Electronic videos / Re: My first YouTube video HP 8640B signal Gen
« on: May 24, 2014, 12:39:07 PM »
I was able to fix the range selector gear. Maybe it will hold up till I can find a repalcement.
What I did was remove the brass insert. Then put epoxy in the crack and clamped it back together. I then drilled very tiny holes in the back side of the gear. Then rough it up with sand paper. Nylon is hard to glue together!.
I cut a piece of perfboard to fit the rear of the gear. epoxed everything and clamped it together. After 3 hours of trying time it seems to have done the trick. After the epoxy dried I heated up the insert on a flat piece of steel. Then pushed the gear down over it and cooled it with water. Just had to align the 2 set screw holes then clean them out.
BTW, make sure you mark the location od all moving parts. I had the rear contact disk in the wrong location and had to disassemble everything.
On the broken FM switch there was not enough material to hold when glued together. I then cut a piece of very thin steel and formed it to the underside of the switch lever. I then drilled holes in all pieces and epoxed it together. Seems to work fine.
What I did was remove the brass insert. Then put epoxy in the crack and clamped it back together. I then drilled very tiny holes in the back side of the gear. Then rough it up with sand paper. Nylon is hard to glue together!.
I cut a piece of perfboard to fit the rear of the gear. epoxed everything and clamped it together. After 3 hours of trying time it seems to have done the trick. After the epoxy dried I heated up the insert on a flat piece of steel. Then pushed the gear down over it and cooled it with water. Just had to align the 2 set screw holes then clean them out.
BTW, make sure you mark the location od all moving parts. I had the rear contact disk in the wrong location and had to disassemble everything.
On the broken FM switch there was not enough material to hold when glued together. I then cut a piece of very thin steel and formed it to the underside of the switch lever. I then drilled holes in all pieces and epoxed it together. Seems to work fine.
687
Electronic videos / My first YouTube video HP 8640B signal Gen
« on: May 24, 2014, 06:54:52 AM »
https://www.youtube.com/watch?v=ZQrnKrwrBqE&feature=youtu.be
This is my new HP signal generator I purchased from a very nice fellow up in Pikeville. He bought it 2 years ago and was going to fix it but never got around to it. The unit is well used. And would not power up. While checking switched I noticedthe fine tune switch is stuck and I broke the FM mode switch. That can be fixed no worries.
I addressed the no power up issue and found that one side of the power switch did not work. Removed the switch, drilled out the rivits, and found a spring out of posistion on that side. Put it back together and the unit powers up.
Next was to remove the range select unit so I could address the cracked gear issue. It is simple to remove but I nned to take the front panel off also to repair the broken slide switch and do some needed cleaning. While looking at the cracked gear I noticed one of the contact fingers were missing on the front rotory switch. I cut up an old relay to make the fingers out of, took me 2 tries to get it right.
After I get the unit cleaned up I will put everything back together and start testing to see where it is. I do know it put out some signal but with the fingers missing nothing was right.
This is my new HP signal generator I purchased from a very nice fellow up in Pikeville. He bought it 2 years ago and was going to fix it but never got around to it. The unit is well used. And would not power up. While checking switched I noticedthe fine tune switch is stuck and I broke the FM mode switch. That can be fixed no worries.
I addressed the no power up issue and found that one side of the power switch did not work. Removed the switch, drilled out the rivits, and found a spring out of posistion on that side. Put it back together and the unit powers up.
Next was to remove the range select unit so I could address the cracked gear issue. It is simple to remove but I nned to take the front panel off also to repair the broken slide switch and do some needed cleaning. While looking at the cracked gear I noticed one of the contact fingers were missing on the front rotory switch. I cut up an old relay to make the fingers out of, took me 2 tries to get it right.
After I get the unit cleaned up I will put everything back together and start testing to see where it is. I do know it put out some signal but with the fingers missing nothing was right.
689
Home Brew And Tech Forum / Kenwood ts-430s
« on: April 25, 2014, 08:48:30 AM »
Lots of solder problems on this one.