re. bobbing speedo - Speedometer Fix - 5000 CSQT

["Swann, Benjamin R. (BSWANN)" <BSWANN@arinc.com>]

Britt,

I am re-posting a followup I made about a week ago for my speedo with a
commentary by Alan Cordieros.  I'm sure it applies to the problem with your
speedo, as mine exhibited similar behavior before failing entirely.

Followup Speedometer/Instrument Guage Repair:

I fixed my speedometer on the '86 5000 CSQT ('87 was the same) following
some great advice from (thanks!) Alan Cordieros: "The problem is almost
certainly in the solder joints that hold the pins which make the connection
from the guage into the green flex circuit board on the IC(instrument
Cluster).

Pull the speedo guage out from the cluster, this takes a lot of disassembly,
but just careful work, no big deal. On the back you will see three or four
pins that stick out and make the connection into the green flexible circuit
board on the main cluster assembly. Resolder these pins' solder joints...."

I did this, and it fixed the problem.

I noticed that these connections were used to connect most/all of the guages
in the instrument cluster, and so the  fix would be applicable to tach,
temp, etc.

I was surpised at the cold solder appearance of these connections and ALL
WERE BROKEN!

BTW it was not very difficult, just take care with dissasembly/reassembly,
especially when removing the gauge at the pins where they are connected.

Use a solder iron and wick to remove the old crusty solder and resolder with
proper rosin core and flux as necessary - good as new.

Ben Swann
'85 4KSQ - put to pasture.  Considering Parting or selling Whole - has great
running - '89 I5 engine - contact me if interested.  Car needs some things,
but not driving mainly due to additional cost of insuring a third car.
'86 5KCSQT - inpected and on the road.
'86 5KCSQTW - installing trailor hitch ( note: double check hitch diminsions
before installation -  actually recieve hitch that was 1/2' to narrow.)
___________________________________________
Follow-on comments from Alan Cordieros...
Hi Ben,

I am glad you got the problem solved. The instructions were somewhat
cryptic, but I was getting ready for a long (eight day ) trip to Italy. I
just got back yesterday evening...

The speedometer is the worst culprit since it is the heaviest unit, and
tends to put the most stress on the pins due to sustained vibration from the
vehicle.

Many of the relays hidden under the steering wheel and instrument clustercan
be repaired the same way. The "usual suspects" are the solder joints holding
the heaviest components onto the tiny circuit boards. Good engineering
design practices entail fastening such components mechanically rather than
using solder joints to provide this function in addition to the electrical
continuity.

The WOT/idle switch can usually be repaired too in the newer 200q20v if you
know the solder joints that go bad. 
_______________Original Message_______________________

Date: Thu, 2 Sep 1999 09:04:05 -0500
From: "Britt Crowell" <britt@fortcollins.com>
Subject: bobbing speedo

hey Guys I have a 88' 5KTQ and the speedo interminetly will not work
correctly. It doesn't stop working completely it just bobs. It only does it
when you first start driving. It last for about 10-15 min and them starts
working correctly. I have check and cleaned the contacts on the sender.
Anyone have any ideas about this.
___________________________________________
Britt Crowell
the 88 122K mi