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Message |
    
Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 27
Registered: 2-2004
| | Posted on Wednesday, March 31, 2004 - 12:41 am: | 
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I just got a Cobra 142 into the shop. The guy had gotten a Maco 200 amp from a guy who had painted the case and then relabeled the back. When he did he labeled it backwards. So this guy hooks up his 142 the way the other guy labeled it. Keyed up and now it wont Transmit.
I told him he probably blew his final, and might have weakened his driver. I told him even if he didn't weaken it that it would be a good idea to replace it any ways. So that it doesnt go out later.
Anywho, I was looking at it and thinking that in the offchance he may have hurt the audio amp I may want to order one just in case. That and alot of people in this area talk on 142s. But I noticed that there are no numbers on it.
What audio amp does a cobra 142 use? is it a 7217, a 7222 or is it something else?
The one & only SeMO Rebel
SeMO Rebel Lectronix
Cape Girardeau, MO |
Mrblack
Junior Member
Username: Mrblack
Post Number: 27
Registered: 2-2002
| | Posted on Wednesday, March 31, 2004 - 3:14 pm: |
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TA 7222P
This is what the schematic says it has
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Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 28
Registered: 2-2004
| | Posted on Thursday, April 01, 2004 - 12:30 am: |
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not 7222AP? Just P?
I know the older 29 classics used TA 7222AP I replaced a few, but I wasn't sure bout this one because there is no part number lists on it.
Thanks I was going to order some anyways but I wasnt sure what this one takes. |
Crafter
Senior Member
Username: Crafter
Post Number: 1013
Registered: 12-2002
| | Posted on Thursday, April 01, 2004 - 7:21 pm: |
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The AP will work have you checked the diodes yet? |
Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 30
Registered: 2-2004
| | Posted on Friday, April 02, 2004 - 2:42 am: |
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not yet
I am sure the final is out. I have ran into this before. I will check the diodes though.
I was just curious about the audio ic because so many people in this area have 142s I just wanted to make sure I had parts on hand just in case someone else might have one go out. |
Bulldog369
Member
Username: Bulldog369
Post Number: 98
Registered: 2-2004
| | Posted on Friday, April 02, 2004 - 8:17 am: |
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my 142 has a 7222p in it. just cracked it opened an checked... |
Yankee
Member
Username: Yankee
Post Number: 81
Registered: 7-2003
| | Posted on Saturday, April 03, 2004 - 6:57 am: |
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when something is repainted, I myself would open up an amp. and see which way the circuit was going. This is a hard lesson and costly, hooking an amp. up backwards can cause all kinds of bad news.
But on the other hand a lot of people don't understand the travel of printed circuits. Yankee |
Kc0gxz
Advanced Member
Username: Kc0gxz
Post Number: 705
Registered: 3-2003
| | Posted on Monday, April 05, 2004 - 5:34 pm: |
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Semo_rebel
Once you have that audio IC out of the chassis you will see its part number stamped on the reverse side. Most generally they are a TA 7222P.
And echoing Crafters' above wise suggestion, don't forget to check the diodes.
LOL. As usual, you're on the ball Crafter.
Jeff, kc0gxz. |
Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 41
Registered: 2-2004
| | Posted on Wednesday, April 07, 2004 - 3:26 am: |
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I usually see them visible not on the heat sink side. |
Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 45
Registered: 2-2004
| | Posted on Saturday, April 10, 2004 - 8:34 pm: |
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I replaced the Final today an it still isnt working so I think maybe the driver got shot too. |
Kc0gxz
Advanced Member
Username: Kc0gxz
Post Number: 726
Registered: 3-2003
| | Posted on Saturday, April 10, 2004 - 11:29 pm: |
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Semo_rebel
In all my rears in the repair business, I have never seen both driver and final go at the same time. But, I suppose it could happen.
Instead of replacing them, why don't you just do voltage checks on them first? That would certainly save you a lot of time and effort.
Jeff, kc0gxz. |
Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 46
Registered: 2-2004
| | Posted on Wednesday, April 21, 2004 - 1:13 am: |
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Well I replaced both of them and POW! it worked the same as it did before it went out.
However it doesnt do what it should so the guy wants me to put it back in the shop to see if something else was messed up when he had gotten it, originally.
The one & only SeMO Rebel
SeMO Rebel Lectronix
Cape Girardeau, MO |
Semo_rebel
Junior Member
Username: Semo_rebel
Post Number: 48
Registered: 2-2004
| | Posted on Saturday, May 01, 2004 - 1:25 am: |
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I got it back into the shop.
The mod limiter resistor had been cut, as well as another resistor. I fixed them. It appears that a diode in the front left corner by J36 has been cut out, because I see part of a leg sticking out of the board.
Someone has also cut out TP3. I am not sure what it is, I think it might be a transistor, but I have never seen TP on a board before.
I know it is not Toilet Paper, so could someone tell me exactly what it is? If it is a transistor, what kind? If it is something else then what? |
Big_mike
New member
Username: Big_mike
Post Number: 1
Registered: 3-2005
| | Posted on Saturday, December 03, 2005 - 4:32 am: |
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T.P. stands for test point. That is wear you would check the defrent circut voltages at, and compair with the voltage refrence chart for that radio. |
