Picked up a 2980WX with the (EPT-690010C board). The radio was functional BEFORE a main board recap was performed. After the recap, the radio would go into tx as soon as you powered it up. The frequency counter reads correctly but no channel display and no meter lamps. What I found was C112 has a backward silk screening on the board as well as C157. I found this out by looking at the picture (CB TRICKS) of the top side main board layout...going over the polarity of each electrolytic capacitor. Can someone assist to getting this thing back working? Both C112 and C157 have been replaced as per the picture Not the silk screening on the board.
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RCI-2980WX PROBLEM
- Thread starter Alabama Trainman
- Start date
If it was correctly done radio should work, isn't it?
Someone
that radio with recapping.
First of it all I would check tx/rx keying transistor area. Something is messed here.
Mike
Someone
(fucked up)
First of it all I would check tx/rx keying transistor area. Something is messed here.
Mike
You should recheck the polarity of the caps you suspected of being in backwards. C157 is part of the ALC and is backwards compared to the parts layout. Here I took that section of the board layout and overlayed it with the foil so you can see how that capacitor connects underneath. If you notice on the parts image, it looks as though the negative goes to R186 and the positive goes to D64, but if you look at the schematic (which is the correct way), it is the other way around. ALC circuits often have caps in the other way because they deal in negative voltages.
In fact, you may want to just throw C157 away (probably toast now) and start with a fresh one in the other way around.
Edit:
Not sure what the foil looks like on the other capacitor as I cannot find it (I used the DX2547 foil for C157 as that part of the board is the same), but it would be worth replacing C112 with a fresh cap in the way the silk screen says as well. I called the silkscreen a liar before too and I was wrong lol. But don't reuse those backwards ones, they're junk now.
In fact, you may want to just throw C157 away (probably toast now) and start with a fresh one in the other way around.
Edit:
Not sure what the foil looks like on the other capacitor as I cannot find it (I used the DX2547 foil for C157 as that part of the board is the same), but it would be worth replacing C112 with a fresh cap in the way the silk screen says as well. I called the silkscreen a liar before too and I was wrong lol. But don't reuse those backwards ones, they're junk now.
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Guys..I guess you didn't read my last paragraph where I said I replaced C112 and C157 with new ones. Those 2 caps have been reversed to what is silk screened on the main board. I rechecked every electrolytic on the main board with the overlay component side picture. C112 and C157 were the only two caps that didn't match the picture. So I put new ones in and reversed them to match the picture. Now all electrolytic polarities are matching the picture..not the silk screening. So with all that done, I have no channel display readout or meter lamps, yet the frequency counter reads correctly for what channel your on. Also, as soon as you push the power button on, it goes into tx mode.
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Glad you found it! IC7 is one of the most-reliable parts in the radio, in terms of how often we see one fail. Less than one per year, maybe more like one every two or three years checks bad.
Rock on!
73
Rock on!
73
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