Technics SA-290: common problems

I’m just leaving this post here as search engine bait for people in the same boat as I was a few weeks ago, namely having purchased a partially-working Technics SA-290 stereo receiver / amplifier from Goodwill.

After a lot of digging around online, I found that there are a couple common problems with units that are being sold as junk or are kinda messed up.  In most cases, these systems age well and will stay in good condition except for a couple common issues.  A good, honest stereo repair shop (or geek) should be able to diagnose and fix these easily.

Problem: AM/FM LCD status display is wonky, partially working, dark, or unstable (works, doesn’t work, responds oddly to jiggling, etc)

Cause and solution: Cracked solder joints to LCD module, and/or burned-out lamps behind it – it’s a very primitive LCD display which relies on an incandescent lamp for backlighting.  Easy to fix.

Problem: The receiver will only output audio for a short time, or until it gets hot, or may stop giving a signal if touched by hands or unshielded cables, etc.  The shutoff of audio is accompanied by one or more clicks.  The unit may not resume working for a couple minutes after being turned off, or may resume right away when power cycled.

Cause and solution: Cracked or bad solder joints on the relay protection circuit.  This appears to be a very common issue with these Technics receivers as they age, and is easily fixable.

As of May 2013, Technics SA-290 units in good working order were going for $80-90, as best I could tell.  I got mine for $20 at Goodwill and spent $70 having it repaired at Audio Specialties Ltd in Portland, plus buying an FM antenna – I listen to KZME (shout outs, woo!), and I need an antenna in my Portland neighborhood to pick up their signal.  So I got a fair deal in the end.  My SA-290 had both problems – cracked relay solder joints, and a wonky LCD due to cracked solder joints.  The nice dude at Audio Specialties replaced the lamp while he was in there – it’s an incandescent, why take chances when it’s already 25 years old?

As for the quality of the Technics SA-290: it’s a really nice little receiver/amplifier!  If you can deal with 80s-style Back To The Future blinkenlighten, you’ll be happy with it.  I recommend picking up an equalizer, though, even an inexpensive (but half decent) one.  This is true in most cases, but a half-decent EQ can turn a good-sounding receiver into a great-sounding one, and enable you to fine tune the sound when you do something like move your couch and suddenly your stereo sounds weird.

I came across an EQ at a thrift store by dumb luck the day after repairs on my Technics SA-290 were done, did a quick search, and found that the EQ was worth just about the $20 they were asking for it, crazy 80s spectrum LED light show and all (it was a stylistic match, haha).  Totally worth the $20.  Just be aware that with the SA-290, an EQ will work only on external signals, not the radio – so you might want to leave the bass and treble controls flat on the Technics, and just push the loudness button when the radio’s on if you like that boomy DJ voice when you’re listening to AM/FM radio.

I’m very happy with the sound quality, even with cheap EQ.  As for loudness, at the rated 50 watts – well, this is a bedroom system, and the power output blinkenlighten are actually scaled as “watts into 8Ω,” and I can crank the harder music I listen to and you’ll barely ever see it flicker past 5 watts, even though the bass sounds “authoritative,” in my words.  The Technics with some good speakers will speak the bass, nice and simple, not boom it or muddy it up.  It’s a good amp.  Don’t be deceived by the wattage wars – as a coworker told me, an older (1980s and earlier) amplifier, made before marketers got their paws on the wattage definition, will lift the friggin’ roof off your bedroom if it’s rated at 50 watts and it’s any good.  I have not turned the volume on the Technics past about 3 of 10 yet.  30-35 watts would actually be more than sufficient for a large bedroom with good speakers, but, this is what was $20 at Goodwill (poppin’ tags!) and I’m happy with it.  :)

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2 Comments

  1. Posted 31 August 2016 at 08:18 | Permalink | Reply

    I have an SA-290 and 4 power meter lights did not work (the first 2 for each channel). Seems like this happens to many of these receivers based on pictures all over the Internet and on eBay – I discovered that ONLY two LED’s actually need to be replaced – the 1st LED on the left and 1st LED for the right channel. The second LED’s will start to function normally after the repair. I suspect that the first two LED’s actually burn out as they are always on and perhaps the voltage is a little high for them (an engineering fault by Technics?).
    Here is the fix, which is straightforward but tricky if you know how to solder and are handy. I would only attempt if you are confident and detailed. This worked for me.
    Open the receiver up, remove both the meter and signal strength circuit boards. There are plastic clips that simply hold these boards in place. Both come out (connected by a 2 wire ribbon cable) – be careful not to damage the cabling. Push down on the white ribbon connector on the main board and pull up on the larger ribbon cable to remove the wiring altogether and you now can work on the meter lights separately from the unit. Set stereo aside and carefully remove the rectangular plastic film off of the meter panel to expose the LED’s (the LED’s are behind a thin plastic translucent film and are all encased in a single white plastic enclosure). I carefully used a razor blade and started from one side and the entire rectangular piece of film came out with no tears or rips. Set aside carefully when removed (keep the sticky side clean). Get a drill and drill out the 1st LED to the left and to the right of the middle. These are the first LED’s that light when the volume is lit up. You will need to carefully drill them as they are attached to the white enclosure and you don’t want to damage the circuit board. Once drilled out, unsolder the leads from the back and then remove all old leads and pieces of the old LED.
    Purchase (2) green LED lights that are 5v (make sure they are minimum 5v – but not 12v – as I measured and the voltage being applied is 5.3v). You can get these from Radio Shack, Fry’s Electronics, or online.
    Here is the tricky part: Situate the 2 new LED’s in the drilled out sockets to see if they fit (LED needs to be below the surface of where the film cover is placed). I had to re-drill the holes in the white plastic slightly larger to make the LED’s fit so it took a few attempts. Once they fit, then remove the LED’s – don’t solder them yet. Reattach the ribbon cable and insulate the boards from anything metal in the receiver – like a towel. Power the unit on, apply audio (perhaps a radio station), and turn up the volume partially. Hold your new LED CAREFULLY to the solder points on the back where you removed the old ones to determine polarity. If the new LED does not light up, then reverse the leads. Once you get the polarity correct, your new LED will light up as you hold it against the solder holes. You will also notice that the second burned out LED will now light correctly as well. Make a note of the polarity and positioning and repeat for the other channel. Turn receiver off, and solder the LED’s in the sockets and ensure that the LED is behind where the rectangular film is placed.
    Reapply the rectangular film (stickiness should still be good enough to hold fine if it stayed clean). Replace the power meter and LED boards back into the unit and then enjoy your functional power meter!
    I am an electronics hobbyist and determined this by measuring voltages, resistances, and other parts after comparing to the schematic. That is how I determined that only two of the 4 LED’s needed to be replaced. davismvatgmail-dot-com.

    • Posted 31 August 2016 at 09:56 | Permalink | Reply

      Thanks so much for the comprehensive comment, Mark!

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