| Author |
Message |
    
Jyd
Advanced Member
Username: Jyd
Post Number: 574
Registered: 11-2001
| | Posted on Saturday, January 12, 2008 - 5:00 pm: | 
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i have not messed with power supplys much,but in my 2000 the power supply looks fine but i am getting 16 or 17 volts from it.makes the meters glow when it is turned off. everything looks great so i would guess it is the big regulator.any support would be cool? |
Jyd
Advanced Member
Username: Jyd
Post Number: 575
Registered: 11-2001
| | Posted on Sunday, January 13, 2008 - 1:05 pm: |
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i am looking for a regulator for the power supply. d717 |
Tech291
Moderator
Username: Tech291
Post Number: 492
Registered: 11-2004
| | Posted on Sunday, January 13, 2008 - 6:47 pm: |
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Jyd,
the d717 you are looking for is a 2sd717,npn 80 watt to-3 package transistor.lots of different subs you could use.
check the other components on the regulator board especally the zener diode.it would be rare for the pass transistor to go bad without taking other parts with it.
tech291
cef291/cvc6
kc8zpj |
Tech858
Moderator
Username: Tech858
Post Number: 102
Registered: 10-2007
| | Posted on Sunday, January 13, 2008 - 8:41 pm: |
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Jyd
There should be an adjustable pot on the power supply board , if there is disconnect the power supply from the main board and try adjusting to see if the voltage will drop to 13.8v , it is important that you isolate the main board as you will most likely blow some caps if you go any higher in voltage when turning the pot , as Tech291 said it is very rare for the transistor to go and if it did it would take the bridge rectifier and other components with it and also keep blowing fuses , hope this helps 
Tech858/Jim
MM0TXO
CEF#858
HAM#230
CVC#116
Wavin' a hand at ya' fae Scotland 
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Jyd
Advanced Member
Username: Jyd
Post Number: 576
Registered: 11-2001
| | Posted on Tuesday, January 15, 2008 - 4:23 pm: |
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i am getting 16.6 volts out of the power supply, there is no adjustment for a cobra 2000.it does not have a trimmer pot,everything looks great. nothing brown or discolored.the is the first i seen without a pot to adjust???? and i really dont know what to check |
Tech858
Moderator
Username: Tech858
Post Number: 104
Registered: 10-2007
| | Posted on Tuesday, January 15, 2008 - 7:20 pm: |
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Would that be tr401 that is the 2sd717 ?? as if it is I have just checked the schematic for the 2000 psu and tr401 is 2SD188M and also did a cross reference and the 2SD717 is not a match for the 2SD188M has it been worked on at any time ??? also check the zener as Tech291 said .
Tech858/Jim
MM0TXO
CEF#858
HAM#230
CVC#116
Wavin' a hand at ya' fae Scotland
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Jyd
Advanced Member
Username: Jyd
Post Number: 577
Registered: 11-2001
| | Posted on Tuesday, January 15, 2008 - 8:40 pm: |
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the radio has worked perfect,nothing has been replaced on the power supply yet,the 2sd717 is mounted on the chassis and not a board it is twice the size as a final.it has 3 wires going to the board,i checked the voltage on the regulator and it was 16.5 also.the meter lights will glow after it is turned off for as long as it is pluged in.what would cause the voltage to go up like that.got to be way to much voltage to let the meter light glow when off. |
Jyd
Advanced Member
Username: Jyd
Post Number: 578
Registered: 11-2001
| | Posted on Thursday, January 17, 2008 - 6:11 pm: |
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all fixed,thanks for the help guys. |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 330
Registered: 9-2004
| | Posted on Friday, January 18, 2008 - 12:22 am: |
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What did you find JYD ,maybe you could post what you found so if others are having the same problem they can get it fixed.
Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
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