Author Topic: Stromberg Carlson console restoration  (Read 813 times)

childof60

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Stromberg Carlson console restoration
« on: November 11, 2017, 05:03:37 PM »
Moving this discussion from the introduction section.

I completed the disassembly - for the most part no exceptional challenge with the exception of a few hidden staples that were a surprise when preparing to remove the amplifier.  This thing has a lot of small gauge wiring related to the speakers I may replace.  With disassembly completed I starting clearing and testing the components.  Fifty years of dust and a light layer of nicotine with compressed air and alcohol swabs removing most of the gunk.  The tuner and amp work while the pre-amp does not power up.  The amplifier connected to my shop pre-amp and the cleaned up (and recapped) original speakers sounds very good.  I am actually quite impressed with the amp and speakers combination.  The speakers seem to sound "better" with the matched amp than with my NAD test amp.

Fortunately a tiny schematic was under the cover of the pre-amp  The two can electrolytic capacitors seem to be deformed and will require replacement.  Not going to be an easy fix given the space limitations.  I have not decided if I will open the amp and tuner and replace the electrolytic capacitors. 

So far this has been a fun project with more work ahead.  I hope to start reassembly in a couple of weeks.

childof60

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Re: Stromberg Carlson console restoration
« Reply #1 on: November 26, 2017, 09:23:44 PM »
So, the restoration continues.

After disassembly and inspection of the pre-amp and control unit I found a broken coil on one channel of the scratch filter - with of course no direct replacement.  After some consultation with a friend over on the Audiokarma board the most likely solution is to try one side of a matching transformer as a replacement.  The parts are on order and we will see.  I also found the selector switch very heavily oxidized (and coated in nicotine) as well as one contact completely separated from the wafer.  Looks like the only solution will be complete disassembly of the switch.  Not exactly a fun job but at least a direct replacement seems available.  The replacement of the capacitors has not been difficult just different than my experience with 70's SS equipment.  The technique required for desoldering particularly when the lead is looped around connection points takes practice.  My solder sucker is sort of useless for this work.  A few of the resistors have drifted out of spec and will require replacement.

I am building a FM multiplex decoder for the receiver.  The units on eBay just seem more trouble than constructing one of the many designs I found with Google.  I will be testing it this week.

I continue to be impressed with the build quality of the unit. While this is taking more time than I anticipated it is fun on the tube side of things.  I picked up a radio repair man's case of tubes this weekend at an estate sale with a tube tester.  I can see more projects in my future.  The switch is the only real issue at the moment.

TC Chris

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Re: Stromberg Carlson console restoration
« Reply #2 on: November 26, 2017, 10:40:58 PM »
As to unsoldering, I've developed some tolerance for the idea of cutting the leads and soldering the new component to the stub of the old lead.  It protects things like tube socket terminals or any place were there are multiple wires and components soldered to one terminal.  It might not be appropriate for the kind of perfect restoration where you re-stuff old capacitor tubes with new innards, but otherwise it seems to offer advantages in time, frustration, and avoiding more damage.

Chris Campbell

childof60

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Re: Stromberg Carlson console restoration
« Reply #3 on: November 27, 2017, 04:57:22 AM »
Thanks Cris.  I have come to the same conclusion.

Incidentally I have come across a Magnavox Imperial for $50 locally - supposedly in working condition.  I might bring it home as the next project.

Tim

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Re: Stromberg Carlson console restoration
« Reply #4 on: November 27, 2017, 08:33:34 PM »
$50 for an Imperial is an EXCELLENT price...  please do bring it home!
-- Aloha, Ken

No Console Left Behind!