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Realistic STA-2100 and Mach One together again

L

LairdMcDuff

Don't Panic!
Hi, all - I'm a Seattle-area newbie, and with the kind help of this great group realized the system I added today was worth purchasing.

I bought these speakers last night - Realistic Mach Ones (the original 4024's), and I picked up the Realistic STA-2100 (also the original) today at GW. Sadly, the left channel of the -2100 doesn't work - I just hear bleedover. And the 'AUX' light doesn't light up, either. All else seems okay, except one slightly broken speaker connector. At first I though some of the meter lights were out, but they come on and off with the selector - signal strength only for AM and it adds the fine tuning meter for FM.

The Mach One speakers are amazing. They are beautiful, and sound truly amazing. I listened briefly with Moody Blues' 'Every Good Boy Deserves Favour'. They have the rubber surrounds and look and sound pristine. The previous owner had them for 12 years.

I looked for the fuses in the receiver but couldn't locate them. I think this beauty is worth a trip to the repair shop, though - it is one of the items from my 'youth', and came out a year after my wife (we are still married!) and I were married.

I found the speakers on CL and the -2100 on shop-gw's auction site.

Some of my vintage stuff includes a Pioneer SX-434, Pioneer SX-650, Pioneer SX-750, Akai AA-R32/L, Fisher RS-1052, Technics SA-320, Kenwood KA-405, Sansui SP-1000, Realistic Optimus T-110, Minimus-7 x4, AR-28b, Baby Advent II, Yamaha NS-670, and Technics SL-D202 turntable.
 

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Hey L-Mac (I think that would be your rap name),

I have a pair of those speakers that I fell into accidently a year or so back. They need to be refoamed, but here's some idea of the durability factor. The surrounds are almost completely gone in places, and they still sound pretty darn nice!

I remember seeing them in the radio shack catalogue as a kid and thinking "Man those are big - I need them."

Congrats on your finds!
Matt
 
I have a pair of Mach ONES that do sound good with most music. A little heavy on the midrange for my taste but the ear adjusts. They remind me of speakers like my Dynaco A-25s where the highest octave in the treble just isn't there. Turning up the tweeter level does increase the output from the tweeter but does nothing to add airyness.

Is this a problem with my MACHs or is this normal. I did recap them with Solen caps - not much difference.
 
Oh, ye with no hearing loss! I need all of the midrange/treble I can get, it seems. Too many years, too many loud concerts. ROFL. In college, the first time, I went to a Moody Blues concert when they retired for the first time! They are still touring. Anyway, the speakers sounded wonderful to my decrepit ears, I only hope they sound good to better ears. I must get the -2100 repaired. Both relays 'click' in, so I am hoping it is a minor fix. It's truly a work of art, as are the speakers. I really am excited to have the original versions of the Mach One's and the -2100, toroidal transformers and all. Now I want to hear them in all of their glory.
 
Great score, I think you'll enjoy it! Looks a bit dusty inside.

One thing to look for is too much resistance across the speaker relay. I believe the magic number is 50 ohms, at least that is what I was looking for. I was ok on one side and over 200 ohms on the other side. Cleaned up the contacts and things worked as intended after that.

The relay is not too far behind that great looking toridal transformer. I had to pull the little board that the relay is mounted on and pulled the relay off the board to work on it. Also, the protection relay can have the same effect so you might consider checking the resistance on that one too. With the cover off, just power it up and listen for the clicks. First one is the speaker relay, second one is the protection relay.

Here is a pic of the speaker relay . . .

Have fun!
Smorgy
 

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LairdMcDuff, really hope you can get the 2100 in working order with little or no out-of-pocket expense. It's unfortunate you got it in that condition. That unit was advertised working on the site. And I didn't believe the note taped to the receiver about refurbishing costs. It didn't sound right. But, I was bidding on it too; although cautiously low.
I have the 2000 and enjoy it.
Regards.
 
Smorgy, it is quite dusty inside. I'm not the kind of techy that can repair these beauties, so I fear I must rely on the pros. Thanks for the advice - if I try, do I pull the relay and clean the contacts, or is it permanently attached?

ybaolywa, I was fearful I was bidding against another AK'er. I am somewhat embarrassed at the price I paid, but I am not getting any younger, and I don't have anything like this beauty. My first receiver was a Realistic, and I guess I have had fond memories of old RS. It's nothing like the current mobile phone retailer. I also was a bit dubious of the note, though I looked up the phone number - it's real - and thought about calling the donor. The pix at GW looked as dusty as it really is, too. But it's such a big, handsome receiver! No one makes equipment like this anymore.

I am happy that both relays click in, though, and there's bleedover, so it hopefully will be something simple. I really want get some sound out of those Mach Ones, and it drove them really easily on the working channel.
 
What-No Deoxit?

Howdy, Laird McDuff! I am happy to see you get your "heritage" rig together. You know, one you've always wanted-and the 2100 seems to be a right beastie, indeed!

I can't believe no one has brought up the Deoxit treatment on all switches and connectors. AK is full of success stories of how a Deoxit job brought life to many dead channels, weak signal pass-thru, etc. Even if you're not very techie, surely someone in your area could help you thru this simple,but time consuming procedure. Bellevue and the general area has a few AK'ers, I believe. How about it, folks?

My tuppence.......willhowl :thmbsp:
 
LairdMcDuff said:
Smorgy, it is quite dusty inside. I'm not the kind of techy that can repair these beauties, so I fear I must rely on the pros. Thanks for the advice - if I try, do I pull the relay and clean the contacts, or is it permanently attached? ...
I am happy that both relays click in, though, and there's bleedover, so it hopefully will be something simple. I really want get some sound out of those Mach Ones, and it drove them really easily on the working channel.
Click to expand...

LairdMcDuff,

If you are not comfortable doing the job, its best to leave it to the pros. The advice to clean the switches and contacts with De-Oxit is a good suggestion and not so difficult to do.

If possible, check some of the palces that sell schematics and get one for your unit. Even if you don't use it, the tech who repairs it will appreciate having all of the details.

A simple check you can do is to reverse the Pre-Amp Out to Main In connectors and see if the problem changes sides. Also - does the unit work on both channels when you put it in Mono mode?

Take your time and enjoy, its all a learning experience. You'll be cranking up those Mach 1's before you know it!

//Smorgy
 
Resurrection!

I had time today to re-explore the -2100. I activated more switches, and included a headphone in the test. I discovered the problem stems from the Low Filter button. After a few careful volume-at-zero cycles, IT WORKS! :banana: Both channels, all functions except the Aux Lamp, in full glory, blasting away through the Mach Ones. Oh, the joy. :music: Now I am ready to purchase some Deoxit and make a careful application to the noisy switches, but I truly appreciate the encouragement from all of you - I was in fear of doing damage to this beasty. Wow, does it make LOUD beautiful music.
 
You have an excellent receiver and speakers. They are certainly well worth restoring. :music:

Here is a little Welcome Wagon gift for you that may help to get you started:

http://www.sendspace.com/file/4jaguw


http://www.sendspace.com/file/5nngr6 <--- EDIT - This is a link to a new file. It works now. (Sorry about the adds that pay for the use of the file sharing service. They are something new on that site.)

(be aware that the files are huge. I hope that you are not on dial-up. If you are, don't down load them - send me a Private Message instead.)

And welcome to AK! :D
 
You are truly a saint and a scholar, although your avatar looks more like Maynard G. Krebs than my favorite Little Buddy! lol. I am most grateful for the gift you have bestowed upon me and my receiver. Thank you! This is a wonderful group of folks preserving the best of audio equipment.
 
Congratulations on your STA-2100 reciever. I came across one last year in Near mint shape that had a little on-off switch trouble. I got it working and these are one FINE sounding reciever! You'll like it!

Best,

Paul :thmbsp:
 
Absolutely, my all-time favorite stero combo to sell as a radio shack manager "back in the day!" Also the one I ran all day long during store hours....except during demos of lesser systems for the less fortunate. I remember unloading a truck of 50 mach ones for a blockbuster special shipment one day...yes over a ton of mach ones! A beautiful site stacked in the boxes in a pyramid (stupid display idea BTW...easy up with help, not so easy down when selling a system with no help...commisioned sales, you know). Sold every single one at 149.95 each as I recall. Great punchy sound from that combo... Well done!

God bless!

-Ron
 
Just got back my loaned Mach Ones (the original 4024's). My STA-2100 resides in a box in my garage waiting for the day to get it repaired.
Then try the combo together as I first remember my cousin having (listed in the ad below). He bought the $1329.00 package setup in 1979. I bought the 2100 from him in 1983. A great underrated receiver IMHO. Has a great tone section not to mention lots a power!


STA-210020Systems777.jpg
 
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