MCS Series, Model 8209, Serial No. TL3K09A677 and TL3K09A678

[Steven Reed]

I bought a pair of speakers on January 26, 2019, and I searched the web for information about them, and I didn't find much. This thread will serve as documentation for the two speakers. I'll share what I know about them along with any repairs or modifications I make to them. Hopefully the next person who owns these speakers will find this information useful, and perhaps other users on this forum will share their thoughts.

Here are the general details:

Brand: MCS (These were manufactured in Japan by Technics)
Model: 8209
Serial No: TL3K09A677 and TL3K09A678
Date Code: C311 (I believe that means November, 1983)

How these speakers came into my possession:
I had seen this pair of speakers at a Goodwill in Greensboro, NC, USA, on or around Wednesday, January 16, 2019. The pair was $30, which was more than I wanted to spend. On Saturday, January 27, 2019, my wife saw an advertisement that the Goodwill was having a moving sale -- Everything for $1. I was shocked to see the speakers still standing in the corner. So I purchased the pair of speakers for $1.00.

 

[Steven Reed]

TL3K09A677 Details and Initial Condition

General condition:
The mid-range driver cone is clearly damaged, though it is functional and sounds fine to me. The cabinet is in decent condition. There are some scratches and dings, but not terribly disfiguring. The grill is in good shape.The crossover seems to be in good condition.

Frequencies:
With my own 42-year-old ears, I can easily hear frequencies 40Hz to 16kHz.

 

[Steven Reed]

TL3K09A678 Details and Initial Condition

General condition:
All the drivers seem to be in good condition. The cabinet is in decent condition. There are some scratches and dings, but not terribly disfiguring. The grill is in good shape.The crossover seems to be in good condition.

Frequencies:
With my own 42-year-old ears, I can easily hear frequencies 40Hz to 16kHz.

 

[Steven Reed]

TL3K09A677 Woofer

Markings: SASS25PL06-F, JAPAN, polarity markings.

Condition: The dome is smashed in, but it looks good otherwise. Tested individually, it sounds good to me.

 

[Steven Reed]

TL3K09A677 Mid-Range Driver

Markings: Technics, EAS-65PH60SE, 8ohm, JPN, 3N161, polarity markings.

Condition: The cone is badly torn. Tested individually, it seems to function ok. To my ears, it sounds identical to the better condition mid-range driver in the other speaker.

 

[Steven Reed]

TL3K09A677 Tweeter

Markings: Technics, 14KH039, JPN, 30 3 encircled B, polarity markings.

Condition: Tested individually and seems to function well.

 

[Steven Reed]

TL3K09A677 Crossover

Circuit board markings: Technics, SUPS 43-1

Back plate markings:
Hi-Fi Speaker System
Ret. No.: 683-8209 Cat.: 853-5577
Product Service No.: 683-8209-00
Power Input: 100W Music Power
Impedance: 8ohms
Country of Origin: Japan
Dist. by: J.C. Penney Co., Inc
N.Y.N.Y. 10019
SGTS 176

Cap values: 33uF, 5.6uF, 0.68uF

Condition: Good

 

[Steven Reed]

TL3K09A677 Cabinet and Sound Material

Color: At first glance, I thought it was black. Instead, it's a very nice, very dark red-brown stain veneer (vinyl, I guess)

Condition: Scratches and dents, but good overall

Markings: SIMULATED WOOD CABINET, PRINTED IN JAPAN

 

[Steven Reed]

TL3K09A678 Woofer

Markings: SASS25PL06-F, JAPAN, polarity markings.

Condition: Seems to be in good condition all around. Tested individually, it sounds good to me.

 

[Steven Reed]

TL3K09A678 Mid-range Driver

Markings: Technics, EAS-65PH60SE, 8ohm, JPN, 3N161, polarity markings.

Condition: Good. Tested individually and seems to function well.

 

[Steven Reed]

TL3K09A678 Tweeter

Markings: Technics, 14KH039, JPN, 30 3 encircled B, polarity markings.

Condition: Tested individually and seems to function well.

 

[Steven Reed]

TL3K09A678 Crossover

Circuit board markings: Technics, SUPS 43-1

Back plate markings:
Hi-Fi Speaker System
Ret. No.: 683-8209 Cat.: 853-5577
Product Service No.: 683-8209-00
Power Input: 100W Music Power
Impedance: 8ohms
Country of Origin: Japan
Dist. by: J.C. Penney Co., Inc
N.Y.N.Y. 10019
SGTS 176

Cap values: 33uF, 5.6uF, 0.68uF

Condition: Good

 

[Steven Reed]

TL3K09A678 Cabinet and Sound Material

Color: Very dark red-brown stain veneer (vinyl, I guess)

Condition: Scratches and dents, but good overall

Markings: SIMULATED WOOD CABINET, PRINTED IN JAPAN

 

[Steven Reed]

Proposed To-Do List

1. Basic cleaning
2. Thorough cleaning
3. Pop up crushed woofer dome
4. Replace mid-range driver (TL3K09A677 only)
5. Recap crossover
6. Rewire the speaker? - Consider the complications that could arise versus the benefits
7. Cabinet sound proofing? - Research proper cabinet insulation and packing
8. Cabinet bracing? - Would more bracing improve the sound?
9. Touch up the dents and dings in the cabinet

 

[Steven Reed]

Repair #1: Popping out the caved-in dome on the woofer (both speakers)

I had watched a guy do such a thing with a vacuum cleaner on YouTube, but that seemed risky to me, so I followed the advice that people left in the comments in that video. Specifically, I used masking tape to pull out the major dent in the dome. I tried Scotch tape first, but it wouldn't stick well enough (though it did pull off some of the animal hair on there). But masking tape had just the right amount of stickiness to get the big dent out, leaving me with a few very small dents.

Following the YouTube comments further, I pointed a hair dryer at the dome, and sure enough, it popped out almost all the small dents. There are some tiny dents remaining upon close inspection, but not really noticeable. I'm hoping it will take care of itself in time.

 

[Steven Reed]

Repair #2: Repair the mid-range driver on the TL3K09A677

I wasn't able to quickly find a replacement for the driver with the torn cone, and it really does sound fine to me, so I researched cone repair, and I took a chance at it.

I diluted Elmer's school glue with water. I don't know the ratio I used, but it was certainly more glue than water. Maybe 70/30, if I had to guess. I used tweezers to pull the pieces of the cone into position, and then I painted the glue over the seams. It dried overnight and seems to be holding strong with no noticeable sound change.

 

[Steven Reed]

Repair #3: Really a modification - Recap the crossover (both speakers)

Advice from the folks on this forum was to replace the two smaller caps with Dayton poly film caps, as those are the caps that do the work of sending the appropriate frequencies to the tweeter and mid-range driver. They are generally considered most important for sound quality. As for the large cap, which is a bypass cap for the woofer, people have suggested that it is acceptable to use a non-polarized electrolytic (NPE). The NPE is physically smaller and much less expensive than the Dayton of the same size. Specifically, I went with these three caps:

https://www.parts-express.com/dayton-audio-dmpc-068-068uf-250v-polypropylene-capacitor--027-408
https://www.parts-express.com/dayton-audio-dmpc-56-56uf-250v-polypropylene-capacitor--027-425
https://www.parts-express.com/33uf-100v-electrolytic-non-polarized-crossover-capacitor--027-350

As you can see, I decided to hang the 33um electrolytic capacity off the side. If it ever starts leaking fluids, it should drip down into the cabinet instead of on the PC board.

As for the two poly caps, I used electrical tape to bind them together to prevent them from moving around.

I did this modification one speaker at a time. I wanted to end up with one speaker done and the other undone, so I could compare them side-by-side. When I tested them, I heard a distinct difference in sound quality. To my ears, the recapped speaker sounded significantly crisper, while the unmodified speaker sounded muddy in comparison. Once I confirmed that, I went ahead and did the same modification on the second speaker. If nothing else, I'm happy knowing that I've pulled those old electrolytic caps out before they leaked or burst.

Thanks to everyone on this forum for their advice when I was gearing up to recap these crossovers.

 

[Steven Reed]

Cleaning (both speakers)

Nothing fancy here. I used Goo-Gone to get rid of anything sticky. And I used a mild dish soap and water for everything else (not the speaker cones or labels). I used a couple old t-shirts (one for soapy water, one for rinsing with clean water). And for the nooks and crannies, I used a toothbrush to get the gunk and dust out. There was some paint or something on top of one of the speakers. I soaked the paint spots in dish soap, and then it scratched off pretty easily with my fingernail.

 

[Steven Reed]

Updated To-Do List

1. Basic cleaning - Done
2. Thorough cleaning - Done
3. Pop up crushed woofer dome - Done
4. Replace mid-range driver (TL3K09A677 only) - Done
5. Recap crossover - Done
6. Rewire the speaker? - Consider the complications that could arise versus the benefits
7. Cabinet sound proofing? - Research proper cabinet insulation and packing
8. Cabinet bracing? - Would more bracing improve the sound?
9. Touch up the dents and dings in the cabinet

 

[LordAragorn]

Thank you for sharing the great work you’ve done on these. Surprised no one has responded in over 17 years!