| Author |
Message |
    
Tech808
Moderator
Username: Tech808
Post Number: 6165
Registered: 8-2002
| | Posted on Thursday, June 23, 2005 - 7:37 pm: | 
|
Before making any adjustment's inside a radio it help's to to take a Fine Tip Magic Marker to MARK all pot's / adjustment location's before making any adjustment's.
This will allow you to know approximately where the pot/adjustment was aligned before you make any adjustment's in case you need to return it to the original location.
Hope this help's,
Lon
Tech808
CEF808
N9OSN
|
Carls86fiero
Member
Username: Carls86fiero
Post Number: 61
Registered: 3-2005
| | Posted on Thursday, June 23, 2005 - 8:16 pm: |
|
Just a little late, thank you very much.. |
Hollowpoint445
Intermediate Member
Username: Hollowpoint445
Post Number: 433
Registered: 6-2004
| | Posted on Thursday, June 23, 2005 - 9:12 pm: |
|
You could also use a VOM to take the value of the pot before adjustment and write it down.
I'm not a fan of marking pots/inductors/caps because as you adjust the circuit the needed value may change more than once. It's better to have the right equipment to do the alignemnt properly. |
Chad
Intermediate Member
Username: Chad
Post Number: 342
Registered: 11-2004
| | Posted on Thursday, June 23, 2005 - 9:36 pm: |
|
And I have found that even a Gnat's butt of a move will make drastic changes on some radios. The pen is good to ballpark the area but proper test equipment is always required to get it just right. |
Tech808
Moderator
Username: Tech808
Post Number: 6169
Registered: 8-2002
| | Posted on Thursday, June 23, 2005 - 10:21 pm: |
|
That is very true for someone who has the knowledge and or equipment.
But! if a person cannot afford or has the right equipment to do a complete alignment then marking will be a major help in placing it approximately where it was before they turned /adjusted it.
Example;
For the RCI/Ranger 2950DX, 2970DX, 2990DX
Equipment required for Alignment procedure:
• DC Power Supply ( 13.8 Vdc, 20A )
• Oscilloscope (50 MHz), with X10 probe
• 50 W dummy load
• Frequency Counter - 100 MHz
• Digital Voltmeter or Multimeter
• RF Signal Generator
• Audio Generator
• Automatic Distortion Meter
• SINAD Meter
• RF Wattmetter ( 25~60 MHz, 100W )
• Automatic Modulation Meter
So as a suggestion /tip for the person who does not have this type of equipment MARK IT!
Lon
Tech808
CEF808
N9OSN
|
Chad
Intermediate Member
Username: Chad
Post Number: 346
Registered: 11-2004
| | Posted on Friday, June 24, 2005 - 8:48 am: |
|
Oh yeah. I mark it even If I have a full test rig, RF gear or not! There's too many variables that can go wrong, never hurts to have a ballpark especially after trying to tweak something then finding out you have a bad component, replacing it then firing it up for the first time.
I worked on large audio power amps with MANY (like 16 per rail) output devices. I like to see the bias in the ballpark before that variac hits 120V!!! Can be an expensive mistake.
Chad |
