PeachParts Mercedes-Benz Forum - View Single Post - Cruise control amplifier on 124 (1990 300E).

dpetryk · #12 08-23-2006, 04:45 PM

Those vacuum valve blocks are fixable - sometimes. I have had them "suck" dirt into the valve orfice which is very small. A good blow job in the appropriate areas sometimes will recover them.

As for the cruise control amps. I own 4 of these cars and all of the CCA's have failed and I was able to re-solder them and they all went to working. I dont have a way to bench test them. That would be ideal, but in every case for me it turned out to be the weak brittle solder joints that failed as a result of vibration over a long time.

I spend about an hour messing with them as there are several hundred joints. I have an electronics shop and a stereo microscope and you can see the problem joints. I resolder all of them regardless of how they look. The joints in question are always on the larger components which are more affected by vibration than the smaller parts since the parts are suspended by their leads soldered to the board.

I should rethink my offer to repair these. I could see a flood of these things ariving at my door and then I would never be able to retire. Also I cannot guarentee results since I cannot test them without putting them into a car. So in some cases the amp may not fix the problem

Lets try this. I'll charge $35 for reworking the module plus actual shipping. No guarentees on outcome. I will guarentee that the work is first class. These things are not very big or heavy so the return shipping should no be too much - probably $5-9 depending on distance UPS ground. I'm guessing on that rate.

Let me know what you think. Open to other suggestions.

BTW I have repaired just about all the various modules in these vintage cars except the EZL ignition module because the EZL is potted in epoxy and I cant get into the thing.