| Author |
Message |
    
Kc0cf
New member
Username: Kc0cf
Post Number: 1
Registered: 1-2005
| | Posted on Sunday, January 16, 2005 - 5:29 pm: | 
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I have a RCI 2950 (old), No mods done, worked perfect for years, untill the other day, electric went out, back on then off then back on again. Now radio will not power up. Fuse is good, Astron 35M is ok, any one know where I should start to look for the bad component? Thanks in advance. |
Bruce
Senior Member
Username: Bruce
Post Number: 2101
Registered: 9-2003
| | Posted on Monday, January 17, 2005 - 4:29 am: |
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regulator solder joints on thoes were known problem |
Kc0cf
New member
Username: Kc0cf
Post Number: 2
Registered: 1-2005
| | Posted on Monday, January 17, 2005 - 3:37 pm: |
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Bruse,
Thanks for your input, the solder joints were the 1st thing I checked, and the problem is deeper than that.
Mike |
Chad
Member
Username: Chad
Post Number: 83
Registered: 11-2004
| | Posted on Tuesday, January 18, 2005 - 10:14 am: |
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Check the tranny, See if you have AC coming off the secondarys. When your power comes back on after brief outages there is a likely chance for voltage overshoot. Some tranny's have an internal pico fuse to protect from meltdown, others just open up.
If you have AC check for DC after the rectifier, follow in line until you do not have voltage. Best luck!
Chad |
Kc0cf
New member
Username: Kc0cf
Post Number: 3
Registered: 1-2005
| | Posted on Tuesday, January 18, 2005 - 9:25 pm: |
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Chad,
Hummm, been around ham radio for 30 years and have never heard the term "tranny", now my Dodge Mini van has tranny, but my RCI 2950? Keep in mind that the 2950 is a mobile radio, therefore there is no primary, or secondary's, as I described the 35 Amp Astron P.S. is working fine, this delivers 13.8 volts to the D.C. input of the 2950. Thanks for you input just the same.
Mike |
Chad
Member
Username: Chad
Post Number: 87
Registered: 11-2004
| | Posted on Tuesday, January 18, 2005 - 9:41 pm: |
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Oops, My bad!!!!!
I have base radios on my brain today, just wasn't thinking 
I guess I could have noted the mention of the PS in the first post, Steeeerike!
Hope at least someone got a laugh from that one!
Chad |
Tech808
Moderator
Username: Tech808
Post Number: 4569
Registered: 8-2002
| | Posted on Tuesday, January 18, 2005 - 11:27 pm: |
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Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 148
Registered: 9-2004
| | Posted on Wednesday, January 19, 2005 - 3:55 pm: |
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if you had the radio hooked up through a properly working astron power supply, i dont see how the power outage could send any over voltage to the radio. the breaker in the astron would have popped before allowing that to happen. my guess is its the volatge regulator in the radio. try hooking the radio back up, turn it on and start tracing the voltage starting at the on off switch.
matt |
Kc0cf
New member
Username: Kc0cf
Post Number: 4
Registered: 1-2005
| | Posted on Wednesday, January 19, 2005 - 5:47 pm: |
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Kid,
Thanks for your input! I only mentioned the electric outage to give a complete series of events leading up to the radio's failure, not to presume that it was over voltage. I got my VOM out and am doing some voltage checks from the P. Switch. I was hoping that a Tech. who worked on 2950s' would stumble on this post and enlighten me with a couple of test points, and or components to check. Again, thanks for the input Kid,
KC0CF |
Tech808
Moderator
Username: Tech808
Post Number: 4574
Registered: 8-2002
| | Posted on Wednesday, January 19, 2005 - 6:15 pm: |
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Kc0cf,
The best thing to do is take it to a good Tech in your area with Good Equipment and have it checked out.
Otherwise it could be a guessing game that could go on for months and you would still not find the problem or have a working radio.
If you have checked all of the simple things then it is time for a Good Tech to look at it.
Power surges can do strange things to radios and effect components that nothing else would if the radio was on at the time.
Your power supply is much better suited / designed for this type of accident than most radios are.
Just my nickels worth.
Lon
Tech808
CEF808
N9OSN
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Kc0cf
New member
Username: Kc0cf
Post Number: 5
Registered: 1-2005
| | Posted on Thursday, January 20, 2005 - 11:00 am: |
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Lon,
Thanks for your input, I am considering finding someone to fix, but living in a remote area, there aren't many people that work on radios in this part of the state. 73's
Mike |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 341
Registered: 7-2004
| | Posted on Sunday, January 23, 2005 - 7:07 pm: |
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have a 148 sitting on rack right now. i NEVER use it except to 'test' things. it's wired w/fuse to 10 amp PS that is also rarely used, then goes to mjf 1700c switchbox to my ice encrusted maco v5/8. after unburying my durango from 4' snowdrift & finding magmount encrusted w/ice & having to pick & chisel for 1+ hour in -10 wind chill/blizzard to get swr's down from 3:1 to where they should be, went inside & fired up all radios, when i got to 148, i turned on knob, heard faint/muffled pop & lite went out. hmmmm
off & on again-lites in radio out. being a mobile guy, 1st thing i checked was reverse polarity protection diode. yup, it was GONE. lots of black wire, but no more glass. changed it & radio is fine. obviously, nothing was hooked up backwards(this time at least) nor did anything short out. fuse was still intact, too. my wife says it's the ghost of the former owner of house....
been following this thread since last week, kc0cf, & today i had an odd problem arise for no earthly, or electrical reason, that i could figure, so-did you check that diode, just in case? |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 164
Registered: 9-2004
| | Posted on Sunday, January 23, 2005 - 8:22 pm: |
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good point pat, the reverse polarity diode is a must check. i guess i didnt consider it because he said that he was running the radio off of an astron power supply and i figured that the power supply fuse would stop the diode from blowing. but after hearing your post i would check it definitely. one other thing. usually if you hook a 2950 up backwards you will get a 40watt dead key with no modulation. i think this is because the power regulator has shorted out. when a radio wont power up the first thing i check, (besides the RP diode) are the power devices. start with the ones used for regulation, and work from there. there are some good tutorials on the net on how to check semiconductors. i dont know one off hand but do a search and you will find some.
matt |
Kc0cf
New member
Username: Kc0cf
Post Number: 6
Registered: 1-2005
| | Posted on Tuesday, January 25, 2005 - 3:52 pm: |
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Patzerozero,&Kid,
Thanks for the pointers, I thank you both for the pointers. I am going to look see what diode that is for reverse polarity, I did not notice anything fried, burnt. I'll post results if and when I locate the problem.
KC0CF |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 366
Registered: 7-2004
| | Posted on Tuesday, January 25, 2005 - 8:13 pm: |
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it's right inside the back of the radio on the power cord socket going from positive input to ground |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 172
Registered: 9-2004
| | Posted on Wednesday, January 26, 2005 - 6:09 pm: |
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and it is already black, so to check if its burnt, scrape a flathead screwdriver across the top. if it looks like soot or charcoal coming off then its burnt. this is just in case you dont have a diode checker.
matt |
