receive on president madison

[awisconsin]

new to the madison world here. i had heard about the amazing receive these radios have so i picked one up to check it out. i have been a cobra 2000 user and had high hopes the receive would be as good based on everything i had read. maybe i got a bad one. i had it tuned locally but heres my issue. distant stations sound great but the closer you get the more bassy it gets. if someone is close and loud forget it. i cant even understand them. better receive on my little cobra 25ltd. now this is a first edition 858. stock from what i can tell. i turn the tone all the way to the right and it helps but not enough. i can mess with the clarifier a bit but it makes the good stations sound bad. being an old radio im thinking electrolytic caps may be bad or getting bad. this radio sat in its box for a long time. im looking for the amazing receive its so well known for..what im looking to find out is if theres anything i can do to improve this at all. great looking radio and everything on it works. gets great reports otherwise but i must say the receive is for lack of a better term terrible..i know i can turn it around for a profit but id like to keep it if i can make the receive right...i really look forward to any assistance from my fellow 11 meter junkies..thanks in advance

 

[9C1Driver]

With an older radio like that a receive alignment by a good tech with the proper equipment is in order. I have an 8719 Madison and I love it.

 

[awisconsin]

as i made mention of in the thread i had it tuned/alligned locally after i bought it..i sure dont love mine..maybe its just old...

 

[awisconsin]

also does anyone know if there is an adjustment for the noise blanker and i know vr7 is the audio pot but is there anything that might be clipped? i heard d38 but not sure. i want to replace it if it is..havent looked yet

 

[9C1Driver]

I would ask the local tech that worked on it. If he can't tell you if it was clipped or not I would have to call into question his ability to properly align a radio. If that is the case then you might not have gotten a true receive alignment. Maybe the 858 chip versions are not as good but I don't see how that could be. Hope you get her straight all the same.

 

[awisconsin]

your probably right on that one. unfortunately not a whole lot of tech options here. in process now of re capping the radio. couple of the caps i pulled so far are not looking to good. gonna be a process but ill get it done and see what it does once its done. of course ill have it alligned again once its done. searching for another tech but not alot of cb techs around these days...

 

[unit_399]

When you turn down the rf gain control on close-in signals, does it sound better ?? If it does, then the rf gain circuit is probably misadjusted. You can use the Realistic TRC449 Service manual on CBTricks. It's basically the same as your Madison. 73s.

- 399

 

[AdvancedCommunicationWest]

After you re-cap it, you are going to need to realign it again. Also the type of capacitors in the audio chain make a big difference. So if you are going to re-cap it, why not use tantalum capacitors in the audio section, and also change a few values to tailor the RX audio?

 

[awisconsin]

last question. anyone know what diodes get replaced when doing the receive mod.? schottky diodes. i have some here and the noise blanker isnt working correctly figuring a bad diode as i cant find anything else wrong in the circuit. figured maybe diodes or just a bad switch...when i hit the noise blanker it cuts the receive way way down. have to crank up the volume to here it. plus i want to replace the diodes anyway..