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Antenna amplifier removal & replacement

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Old 06-19-2014, 04:08 AM
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JB 911
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Default Antenna amplifier removal & replacement

As the title suggests I recently removed and replaced my antenna amplifier (perhaps needlessly - but now my radio works so I am a happy camper - more on that in a minute) and since I couldn't find much on the site thought I'd share how it went anyway. I'm not an EE or professional radio installer so if some terminology is incorrect please bare with me and feel free to add if you see something I'm missing or an improvement.

Background
I recently installed a CDR 220 and had bad radio reception upon installation. Noticeably worse than my CDR210 it replaced but it wasn't great either. One test to run is simply to turn the tuning **** to the right or left to search for a station. If you have a good antenna signal the radio will stop at the next strong station it finds until you turn it again. If you have a weak or no antenna signal, it won't recognize any station (or hardly any stations) and just keep scrolling past all of them. You can manually tune them but they will have static. I called Stefan at SW stereo (who I bought the radio from) and he said that is most likely no power to the antenna amplifier or a bad antenna amplifier.

(Another test I failed was AM. Nothing was coming in)

I should point out if you have a weak signal or no signal, it may also be from other reasons too and not necessarily the antenna amplifier - among other causes may be:

Bad head unit (something internal)
No power to antenna amplifier
Connection from amplifier to windshield is bad
mashed wiring from forced head unit installation

I put my CDR210 back in temporarily to eliminate the head unit. It also failed the scan test. My windshield is original (no one hopefully ever messing with the connector) so I am really thinking it is either no power to the amplifier or the amplifier itself.

Next I tested power to the antenna amplifier by disconnecting the clear connector to the white wire coming from the back of the radio:



Note it doesn't just pull apart. You need to insert a small screwdriver, twist gently and then it will pull apart. Stick your multimeter in the end coming from the radio and ground the other to something bare metal you should get a tad over 12v, whatever your battery has in it basically. I got about 12.3v

Next I measured voltage coming back from the amplifier. I wasn't really sure what to look for or expect but I chose volts:



I got nothing. So I decided to go ahead and order one from Sunset PN $158.30

Before installing the new amplifier I was able to power it up and measure voltage coming back from the amplifier with it all just sitting in my lap while plugged into a partially installed radio rather than behind the dash. Basically just connect the power and measure what comes back. I got a very low voltage that fluctuated between .08v and .20v. I presumed this to be since someone was talking on the radio the signal would change (random guess).

OK to install the amplifier you have to find it and I couldn't find a diy on it which motivated me to post up some pictures. It's really not a bad job at all.

Basically top dash cover comes off and radio comes out, that's it. Its 9 screws and one hidden 10mm nut behind the clock for the dash. Just search removing dash and there are many helpful posts. THe tricky part is to remove your clock without scratching it, the potential is high. I used a 1gal paint can opener like they give you for free at HD and some painters tape to protect under where I applied pressure. I took my time and it worked well. I also cleaned the rubber gasket and put some 303 on it prior to installation and the clock slid back in easily.

Ok so now you are looking at this fuzzy pic (sorry) :



The antenna amplifier lives behind the large oval. The 3 smaller ovals are plastic ties that hold the antenna cable in place. The top two are pretty accessible and by twisting the plastic tie I was able to open them with out breaking them and resuse them for the new cable. The third one, lower down is a little trickier. The good news was mine was loose enough to leave as is and just pull the cable thru it. Except the 90 connector that plugs into the radio wouldn't fit thru it. I was about to cut it off but gave it one more gentle tug/twist and then came my humble moment. That 90 degree connector isn't one fixed unit. It's two pieces and they popped apart and the cable came thru and the 90 part fell to the passenger floor. I just kind of looked at it for a second then I was like. Hmmm. Loose connection? No signal? Couldn't help myself but to power up the old antenna amplifier and re-measure. Yep it worked just fine. Put back .08 to .20v just like the new one. Lesson here is before you try anything make sure that cable is pushed all the way into the 90 on the back of the radio. It wouldn't hurt pull it out of the 90 to open up the contact springs a little with a screw driver (and perhaps give them a light clean with some emory cloth or similar) like I'm doing in this picture because mine slid in and out pretty easily compared with the new cable which was a much tighter secure fit



So now that I fixed that connection I went back and forth listening to stations with both amplifiers and they both sounded great am or fm. They both passed the scan test too, stopping at all the stations. I decided to install the new one since I had it. Interesting it has less metal on it than the old one. No metal screws holding it together even the mounting point is plastic compared with the metal original one. I'm telling myself this one is really a whole lot better than the old one so I didn't actually just blow $165 after all This is the only pic I have of the new one, (installed ) all the other pics in this post are the original one recognized with the 4 screws holding it together.




Basically, the amplifer is held on by one 10mm nut. It's a bit of a challenge to get to but if you got the one by the clock out, you are in good shape this one is about the same. I would put a shop rag or two under that nut as you are removing it since there is an abyss below.

It is tricky to disconnect the connector from the windshield to the amplifier with the amplifier installed. Ok not to be confusing, but the amplifier has three cables/wires running to it. The antenna to the radio, the power from the radio and then the wire to the windshield. I'm talking about the wire to the windshield it is the wire visible in the pic above going over the amplifier and above to the windshield. Maybe if you had smaller hands you could do it, but I ended up removing the 10mm nut then there was enough wiggle room to actually get the amplifier out through an access hole where you have full access to the windshield wire connector. Again a small screw driver like this twisting while gently pulling and the connector comes right off. Note in this pic below is the old amplifier after the fact so the windshield wire connector is not present so you'll have to use your imagination but you can see the connection on the new one in the previous picture.




That's pretty much it. Install reverse of the removal. My lesson was that 90 connector at the radio. I would check that first if you have bad radio reception. If you have the radio removal keys, you could literally check that one by itself in just 5 minutes. Admit, reseating the radio might take another 5 or 10. But that's a good free start and you can check your voltages with it out too.
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Old 06-19-2014, 09:15 PM
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Thanks. Would be great to post this on Robin's DIY (p-car.com)
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Old 03-31-2015, 05:57 AM
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What's the white wire in the first post?

Is it 12V ?
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