| Author |
Message |
    
Old_man
New member
Username: Old_man
Post Number: 9
Registered: 9-2006
| | Posted on Sunday, November 19, 2006 - 6:47 pm: | 
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I have had this amp for a while, and it recently started blowing the Q2 transister out. I replace it and it will last for a short time, then blows it again. Anyone have any ideas as to what is going on?
I run this on an older Cobra 148gtl, it runs 4 watts am and 12 watts on sideband, swing on am is up to about 12 watts.
Thanks
Mike |
Bridge_man
Junior Member
Username: Bridge_man
Post Number: 38
Registered: 3-2006
| | Posted on Sunday, November 19, 2006 - 8:03 pm: |
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i have a newer model but i only have a 2 watt dead key and swing about 25 into it and have'nt had any problems besides burning out the pre-amp from leaving it on too long.did'nt know it was on, but iv'e had it about 2 years.have you tried a lower DK? i heard 3 watts max. |
Old_man
Junior Member
Username: Old_man
Post Number: 10
Registered: 9-2006
| | Posted on Sunday, November 19, 2006 - 10:20 pm: |
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I also have a newer model HD 350 and have no problems so far out of it. NO, I have not tried a lower dead key, I was looking at the specs for the 350 and it shows 180 output for 4 watts or 350 output for 20 watts in. It seems to me it should be able to take 4 watts without any problems, but maybe not. I am not a tech, so I really do not understand all the ins and outs of it. I have had this problem for a while now and even took the amp in to a tech who checked it out and said he knew some of their amps will blow this transister, but did not know why, nor what to do to correct it. I just wish somebody knew why and what to do about it to fix it.
Thanks
Mike |
Hotwire
Senior Member
Username: Hotwire
Post Number: 2043
Registered: 1-2005
| | Posted on Monday, November 20, 2006 - 1:52 pm: |
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Old man, Not 100% on this but there should be Q-1 and Q-2 transistors. One is the keying transistor and the other is the recieve preamp transistor. I would definatley use a lower deadkey like 2 watts max. Any deadkey higher or lower than 2 watts I did not like on any of my Texas Stars. Investigate and be sure you have a low SWR. Also measure the voltage be sure that you have 13.8 volts max and no less than 12 volts minimum.Hope this helps.
Kenny
cef491 |
Old_man
Junior Member
Username: Old_man
Post Number: 11
Registered: 9-2006
| | Posted on Monday, November 20, 2006 - 7:55 pm: |
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SWR is about 1.3 to 1, voltage check shows 13.5, This thing has stumped me for a long time, and yes Q2 is the keying transistor, recieve and the pre-amp are not affected. I think the longest this thing has worked at one time is about a week, the shortest time, second key up in checking to see if it was fixed.
I think I may just take it to the range and use it for target practice, LOL.
Thanks
Mike |
Bridge_man
Junior Member
Username: Bridge_man
Post Number: 40
Registered: 3-2006
| | Posted on Tuesday, November 21, 2006 - 6:05 am: |
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is that 13.5 volts under a load?as the amp is keyed,while the engine is running? i would try a lower deadkey,no more than 2 watts max.im no expert but with it only running for a week at a time id say that could be the problem. |
