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Message |
    
Rob5mike
Intermediate Member
Username: Rob5mike
Post Number: 150
Registered: 7-2002
| | Posted on Tuesday, April 05, 2005 - 1:44 pm: | 
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I have a PC66a that has the resistor cap mod near the final and is wired to the ch9 switch for HI & Lo power.The radio does not RX (even from radio right next to it)but noise level comes up when antenna is hooked up.It also does not TX at all(cant hear it on same radio next to it)The mic is fine and the PA still works and the light changes from green to red when its keyed up.hope its something simple but might have to send it to the shop.
Mike |
Rob5mike
Intermediate Member
Username: Rob5mike
Post Number: 152
Registered: 7-2002
| | Posted on Wednesday, April 06, 2005 - 9:48 pm: |
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Have it narrowed down to the Pll chip.Does anyone know where a fella can get one? |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 364
Registered: 9-2004
| | Posted on Wednesday, April 06, 2005 - 10:54 pm: |
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i was going to guess PLL chip. you can get almost any PLL chip from RF parts Co.
when putting in the new one i find it a good idea to use a chip socket. that way you dont take the chance of shorting any pins together or blowing the new chip with static. after soldering in the socket, just plug in the new chip!
see if you can trace down why the orig. chip went. this will help you determine if you need to replace any other parts.
matt |
Rob5mike
Intermediate Member
Username: Rob5mike
Post Number: 153
Registered: 7-2002
| | Posted on Friday, April 08, 2005 - 12:42 pm: |
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Thanks Kid vicious.Need a few other things too!So I geuss I'll make the order from RF parts.The socket deal sounds like a good idea also.
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2600
Advanced Member
Username: 2600
Post Number: 536
Registered: 7-2002
| | Posted on Saturday, April 09, 2005 - 3:22 am: |
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The TC9106 chip is a pretty reliable part. Nothing is failure-proof, but that chip comes close. If somebody tried to put extra frequencies in it, the chip could have been damaged in the attempt. It's a "lockout" chip that can't be modified for channels by changing pin connections.
There is a 7.5-Volt zener diode that leads to pin 1 on the PLL chip and regulates the supply to the chip. If that zener dies, you won't have any juice on pin 1. Check that before pulling the chip. Zener diodes fail a lot more often than PLL chips. Don't have a diagram for that model, so I don't know the callout number for the zener.
73
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Rob5mike
Intermediate Member
Username: Rob5mike
Post Number: 154
Registered: 7-2002
| | Posted on Sunday, April 10, 2005 - 4:02 pm: |
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Sounds good 2600.And you hit it right on the money!extra channels were tried,thats why I got it for free. The chip is a SM5126BP not the TC9106 |
2600
Advanced Member
Username: 2600
Post Number: 539
Registered: 7-2002
| | Posted on Monday, April 11, 2005 - 2:27 am: |
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Hmm, if you got it for free, sounds like maybe the previous owner "tried" a channel mod?
The TC9106 is the part that Uniden used to buy from Toshiba, before that chip was discontinued. The SM5126B is the same chip, supplied by NPC, a competing chip maker.
Either number should work equally well in that radio.
73
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Rob5mike
Intermediate Member
Username: Rob5mike
Post Number: 158
Registered: 7-2002
| | Posted on Monday, April 18, 2005 - 5:11 pm: |
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2600,thats right,a failed attempt at getting some extra channels. Finally found a replacement PLL chip for it and it works real well.I really like the looks of it and it is a stout little radio.Thanks for the help.
Mike |
Rob5mike
Intermediate Member
Username: Rob5mike
Post Number: 159
Registered: 7-2002
| | Posted on Friday, May 06, 2005 - 2:55 pm: |
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more problems with this radio.No matter what channel I turn it to it will stay on ch1.The numbers will change on the channel display but no matter what channel it is showing its TXing and RXing on ch1.Any help would be apreciated. |
2600
Advanced Member
Username: 2600
Post Number: 564
Registered: 7-2002
| | Posted on Saturday, May 07, 2005 - 1:25 pm: |
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Sure sounds like you may have lost the connection from the channel 9 switch to the channel selector. The "CB" side of the channel 9 switch turns ON the channel selector.
Don't have any diagrams for that one.
73
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