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Car Forum / Saab Cars / March 20041993 900 Clarion radio AM band is very weak
Hi - I have the OEM Clarion radio in my 93 Saab 900 turbo. On this radio, the FM band works fine, and that's what I've used all these years. However, since the car was new, the AM band never worked well (very poor sensitivity), but I never cared. Suddenly there are two new AM stations in the area that I would like to listen to, but I can barely get them. Many AM car radios have a small hole hidden somewhere on the case. You insert a small screwdriver through the hole to make an adjustment (trimmer capacitor) for the AM band. I can't find such an adjustment on this radio. As near as I can tell, the power antenna is in good shape - it would have to be for the FM band to work so well, right? Anyone got any ideas on how to return the AM sensitivity to something like a normal level? Thanks Bill > Hi - > [quoted text clipped - 18 lines] > > Bill Maybe because they know njoone uese AM here in europe we stopped use AM at least 30 years ago for that sort of of transmissions. You knoe the AM reception on yor radio doesnt have a extarnal antenna its inbuilt in the radio itself...if you eant better reception i think you have to align the car in righr direction for best receiveing or better buy a multiband radio with possibility to connevrt external antennas Pelle > > Hi - > > [quoted text clipped - 28 lines] > > Pelle I don't think that is quite true. What we call AM in the US, I believe is called MW in Europe (based on my experience in Germany). All car radios use external antennas; none have an internal antenna - even in the old days of AM only car radios. The direction that the car is facing should have no noticeable effect on reception. My recommendation to the OP is that it may be the antenna, even if it looks like it is in good shape. I had a similar problem where the antenna was good enough for adequate reception for FM, but AM barely worked. I found a Saab Technical Service Bulletin that outlined a test procedure that identified the antenna as being "worn out" on my car. It is actually the connections between the segments of the antenna that break or wear out. I replaced the antenna mast, and reception improved drastically. I went the cheap route and ordered the replacement mast from Radio Shack through their spare parts service. It cost about $5 plus shipping. It is actually for the power antenna that they once sold. It is available in chrome only, and is a bit shorter than the correct part. I can't find the TSB that outlines how to test for a malfunctioning antenna, but it involved using an ohmmeter to measure the resistance between adjacent segments of the antenna mast. I think the resistance was supposed to be less than 10 ohms. Aha! What you say makes some sense, Walt. The FM would still work, because at the higher frequencies, the segments would capacitive-couple even across a high-resistance joint. I will try the test you describe - and I may even open up the antenna assembly in the trunk (boot) and connect a temporary wire antenna. If anything spectacular happens, I'll post, but in the meantime, thanks for taking the time to answer. And yes, after I posted, it occurred to me that I should have clarified "AM" band as being equivalent to European "MW". I know that, but ... So thanks to Pelle as well. Bill ============================= >>>Hi - >>> [quoted text clipped - 18 lines] >>> >>>Bill > My recommendation to the OP is that it may be the antenna, even if it looks > like it is in good shape. I had a similar problem where the antenna was [quoted text clipped - 12 lines] > segments of the antenna mast. I think the resistance was supposed to be less > than 10 ohms. I have two 9k t's, an '88, and a '94 CSE - both have Clarion receivers, and both are weak on AM reception. As for the notion that the antenna might be worn out: I purchased my '88 new, and presumably it was sold with a new antenna - now a month shy of 16 years old, and AM reception is just as bad today as it was off the show room floor. >> Hi - >> [quoted text clipped - 26 lines] >to align the car in righr direction for best receiveing or better buy a >multiband radio with possibility to connevrt external antennas That's true for a plastic bodied portable radio, but not for the average automotive radio. The metal case shields the internal antenna from external radio waves. In the 9-5, there is an amplifier between the antenna and the radio, it's located near the back of the car, iirc. Not sure if any of this is there in the earlier models. However, because of the frequencies (and type of modulation) involved, an FM radio can tolerate a worse connection to it than an AM radio. Assuming that your car has a wire whip antenna, and no amplifier, I'd do a continuity check between the antenna and the connector to the radio. I'd check the schematics before I did that, though. Another check would be to plug in a wire directly into the radio and see if that helps. If not, then the radio may be at fault. Harvey >Pelle A schematic would give me the answer at a glance. Anybody got one? Plugging a wire directly into the radio would be a very good check, but will be tricky because the radio makes connection to all wires (including the antenna) at the time it slides into the DIN sleeve. If I put a wire in the antenna connector, the radio won't slide in. Bill > Assuming that your car has a wire whip antenna, and no amplifier, I'd > do a continuity check between the antenna and the connector to the [quoted text clipped - 3 lines] > > Harvey You can take (pry) out the DIN sleeve and then be able to find the standard antenna connector - and the connectors for all the other wiring too. To do this, take the radio out of the DIN sleeve and find the tabs where the sleeve engages with the dashboard. Gently pry them up so you don't bend the sleeve. When you have enough of them disengaged from the dashboard, the entire sleeve (or cage) can be slid out the front. If you take out the ashtray, you can grab it from the back to help push it out. I would expect that your '93 900 has a radio setup that is nearly identical to that of my '91 9000 Clarion system. If so, there isn't any antenna signal amplifier or any other hidden external amplifier or device. Walt > A schematic would give me the answer at a glance. Anybody got one? > [quoted text clipped - 12 lines] > > > > Harvey Simple fix, pull out the whole DIN sleeve to test it. It is easy to pull out after the radio is out, just pry it up at the top and bottom. Don't worry about bending it, it will bend back into shape as long as you don't kink or crack it and you would have to bend it pretty far to do that. Jim I am curous, with the low cost of after market radios, why not just replace the old Clarion with a new one? That goes for a lot of people in this newsgroup. If you do this, give up on using the existing rear ampliflier, I never did figure out how to utilize it with its weird 6 pin dim connector > A schematic would give me the answer at a glance. Anybody got one? > [quoted text clipped - 12 lines] > > > > Harvey Good idea about pulling out the entire DIN sleeve. Why didn't I think of that???? WRT replacing the entire radio, it is an interesting idea. Actually, my son did exactly that in his 900S. But I also have the CD player/graphic equalizer in the lower section. I think I would lose the use of that, n'est-ce pas? Of course, I could probably sell it for more than the car is worth - when I tried to buy one for my son, I couldn't find one with cables for love or money. And I tried both! Bill Jeffrey ========================== > Simple fix, pull out the whole DIN sleeve to test it. It is easy to pull > out after the radio is out, just pry it up at the top and bottom. Don't [quoted text clipped - 6 lines] > the old Clarion with a new one? That goes for a lot of people in this > newsgroup. |
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