[200q20v] Rear Pillar AM/FM Antenna Amplifier

Bernie Benz b.m.benz at prodigy.net
Wed Nov 15 18:33:25 EST 2000


Thanks for the tip.  I've had the same problem with my 90Q-20V for a year+.
Previously I had inspected the pc board with a magnifing glass and found
nothing worth touching up.  I was about to throw a rock through the rear
window and have it replaced by insurance, but that seamed dishonest and I
couldn't find the rock.

So, following your experience, I resoldered the apparently perfectly good
solder joint and WHALA!  AM is back.


'87 5KTQ     240K
'90 90Q-20V  130K
'91 200Q-20V 110K 
> From: Martin Kuetzing <martinkuetzing at worldnet.att.net>
> Date: Tue, 14 Nov 2000 22:51:30 -0800
> To: "'200q20v at audifans.com'" <200q20v at audifans.com>
> Cc: "'martinkuetzing at att.net'" <martinkuetzing at att.net>
> Subject: [200q20v] Rear Pillar AM/FM Antenna Amplifier
> About a year ago, I purchased a 1991 200Q 20V sedan.  One flaw that I had
> to fix was no AM radio reception.  I spent a fair amount of time combing
> the audifans archives for solutions to this problem.  One solution
> suggested was - horrors - drilling a hole to install a standard
> fender-mount antenna.  Another was an expensive antenna amp replacement
> from the dealer.
> I thought I would relate how I came about to fix the problem.  Perhaps this
> will be useful to others.  Once again, there was no AM reception.  FM
> reception appeared to work fine.  The previous owner had replaced the
> orginial radio with a newer Blaupunkt with only a single antenna jack.  So,
> before trying anything else, I tried connecting one antenna lead, then the
> other, then both - through a wye-connector.  Still no AM.  Since, it was
> pointed out on the list (somewhere) that the front windshield contained
> only an FM antenna and amp, the problem appeared to be focused on the rear
> amp.  Someone, somewhere on the list gave rather explicit information about
> using a DMM to measure voltage and current at the amp - in my testing,
> everything seemed normal, but inconclusive as there was still no AM.
> So, I went to a local high-end shop and agreed to pay them $15 to check the
> Blaupunkt on the bench to see if it worked for AM.  It did, so they wanted
> $150 - and the car for an entire day - to repair the amp - and $100 more to
> repair the wiring/cabling to it if necessary.  This appeared suspicious to
> me, as I figured that the amp had some specialized components in it that
> one couldn't just obtain - at say, Radio Shack, for instance.  So, I paid
> them my $15 and went home.
> In removing the amp, and opening it up, I noticed a rigid, solid wire lead
> connecting the antenna power connector (on the amp's housing) to the
> circuit board.  In fact, the wire - more or less - broke off at the circuit
> board as I pryed open the amp's enclosure.  This seemed like a faulty
> design to me, in that the rigid wire was constantly subject to the stresses
> of heating and cooling - rear pillar, rear deck, sunshine, etc. - and that
> it easily could fatigue and break over time.  That is, maybe I did not
> break the connection by merely opening the enclosure.  Maybe the amp was OK
> afterall.  Maybe some of the folks in the audifans archives had experienced
> a similar failure, but didn't realize it.
> So, I unsoldered the rigid lead and replaced it with a longer, stranded and
> insulated 22 ga wire & snapped the enclosure together again.  After putting
> the amp back into the car, I had - and still have - great AM radio
> reception.  I noticed no improvement in FM reception - which was fine
> beforehand anyway - so I assume that the rear amp is designed to boost only
> AM frequencies.  Further, the FM reception was not helped in any noticable
> way with a wye-connector tying both windsheild antennas to the single
> antenna jack on the radio.  And as the AM was somewhat noisier with the
> wye-connector arranagement, I settled on using just the antenna in the rear
> window.
> I took a few photos of the amp - opened up - and of those remarkable clips
> that hold the rear head-rests in, as well as hold the rear seat-back in, if
> there is any interest.
> Regards,
> Martin Kuetzing
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