Realistic STA 77

This video outlines a repair to a defective channel, which affected the other channel, and also clearing issue with no FM stereo operation
#amplifierrepair #electronic #audio #electronicrepair #vintageaudio

[@roroseppel2077]

Hey Ray, there is always something interesting to discover and to learn on your bench ! Great Job !

[@raygianelli3612]

Thanks Roro. Believe me, I'm learning along the way!

[@thomasburns1846]

A nice low power receiver. I have one that my father purchased new. I had it serviced 1.5 years ago. One channel was out. A bad capacitor in the power amp. A few others were replaced as well. I enjoyed your video.

[@raygianelli3612]

While their audio gear didn't have the reputation that the big names did, their gear always sounded good. This little receiver WA no exception. Brought back fond memories. Remember their Good, Better, Best ads? You always wanted the "best, option. 😁

[@willievivanco1]

sunday morning turn on my cell phone and another great video by ray,excellent day bravo my friend

[@raygianelli3612]

Thanks so much, Wilfredo! What nice things to say.

[@loginregional]

Had one of these as well as the 65D. That's the black case with the volume sliders

[@raygianelli3612]

They're nice little receivers. They didn't have the name recognition (or the price tag) of the big Japanese manufacturers, but they sounded good. At the end of the day, isn't that what matters?

[@loginregional]

the 65D had a tendency to require Blue-stuff every couple of months to clean up those sliders@@raygianelli3612

[@bussypaul7326]

Really enjoyed it! Thanks!

[@raygianelli3612]

Appreciated, Paul. Gotta share this knowledge before I shuffle off this mortal coil. It's the only way technicians can reproduce!

[@Trucam2020]

Thanks Ray, I learned a lot from this great video.

[@michaelbyrne8860]

I subscribed but I really have very little idea of what you speak of? But I enjoyed your video and learned some? I have vintage stereo equipment that I still think they sound better than the 5.1, 7.2 systems when it comes old vinyl records, tapes & cassettes and 8 tracks? Very professional nice job! Need to open a shop here in Houston! CMTFU!

[@quiksr20]

Great video, I recently had to change the cord on a Pioneer 626 and had no luck finding a sacrificial extension cord that looked correct. Ive had good luck going to a local Goodwill and buying an old vintage lamp just for its cord. This way the cord looked period correct:) Fun video!

[@raygianelli3612]

Thank you! Yeah, I have a policy of cutting the cord off of anything I'm throwing out. Problem is, I don't throw anything out. 😁

[@josephlalock8378]

😂@@raygianelli3612

[@tihzho]

Memories! I was a RadioShack store manager in the 70's.

[@raygianelli3612]

It was a great place back then, and electronics was more of a hands on thing. Times changed, and they lost that market, and with it their focus. Not surprised they went down.

[@tihzho]

@@raygianelli3612 Yes I agree they lost their focus. Like vinyl records DIY is back. When I was a store manager the money was in the "back wall" as we called it which was all the parts, cables and so on. I moved overseas in 1983 and on a visit in 2004 I wanted to get some parts and batteries for an Archer cordless telephone only to find RadioShack moved the back wall into some bins. They did not have what I was looking for and were trying to sell mobile phones. Gone was the Realistic brand for sound systems and so many other RadioShack staples. I said to my wife RadioShack lost its way and will crash and burn - which is exactly what it did!

[@EdgarsLS]

a good source for red incandescent bulbs is some old christmas lights! while most are the big replaceable bulb type, there are some with miniature incandescent bulbs.

[@chaber6419]

Virtue signaling my issues with Amazon aside; that cheap strain relief plier is a worthwhile purchase. They also sell a $10 blue wire wrap tool that does the job. Both good enough for occasional hobby work.

[@raross6119]

radio shack breadboard's and everything else sure do miss them.

[@kevintubbs4648]

I recently repaired an STA-77 with the same stereo beacon problem. I wanted to use an LED replacement, so to get the current high enough through the MPX chip I paralleled the LED with a resistor (sorry, I don't remember the value). When I got the receiver all back together and turned it on for a final test, the WHITE lamp in the pointer died! So, take it all apart AGAIN. I should have just replaced the white lamp while I was doing the red, but I figured the red would be on most of the time and the white would last forever. WRONG!

[@raygianelli3612]

Oh man, now I'm afraid to turn it back on! Smart to parallel the LED with a resistor like you did.

[@frankgeeraerts6243]

HI Ray , always happy when you reappear on the web................and for once something realy REALISTIC to view on KZbin ! hahaha....................kind regards !

[@raygianelli3612]

Thanks Frank. Just keeping it real! 😝

[@joe1569]

You are a very good tech

[@raygianelli3612]

Thanks Joe! Still learning every day.

[@TheVintageNewbie]

Looks super cool! You mentioned you may sell it…is it for sale?

[@phansternthephreake]

Great video. I haven't seen anyone else get this detailed with amplifier repair. I have a 70's era Yamaha CR-820 that used to have incredible sound quality, but now it's not putting out much power and the balance is way off. I've been looking for someone to repair it, are you interested? If not, that's fine. I'll keep watching and hopefully gain a better understanding of amps in general. Just subscribed and thanks for the content.

[@raygianelli3612]

Thanks! I try to share as much detail as possible, without making excessively long videos. Check out Duality Repair; Nick packs more useful information per minute than anyone I've ever seen. I'd love to help you out with your Yamaha, but with a full time job and other responsibilities I can't take on any other repairs.

[@scrappy7571]

Interesting that the stereo bulb effects the circuit. I've read where folks have installed an LED instead of incandescent, and then have problems receiving stereo.

[@raygianelli3612]

I've heard the same thing. Admittedly, I don't know why they work like this. But if the light's out, the unit won't demodulate the left and right signals.

[@whatcher8151]

A FREQUENCY I HEARD IS COMING OUT OF THE LED'S.

[@raygianelli3612]

@@whatcher8151 ?

[@Douglas_Blake_579]

Gotta say that's a weird input circuit. I don't think I've seen that before. I would be really interested in the troubleshooting sequence that led you to that capacitor.

[@raygianelli3612]

Douglas, due to the voltages in the circuit all being correct, I started wondering why the gain was so much higher in the right channel than the left. Which led me to the capacitor. I'm still unsure why it affected the left channel the way it did though.

[@Douglas_Blake_579]

@@raygianelli3612 Very good. I think I might have struggled with that one a bit. You're probably right about leakage across the balance control. I've seen the old swing-ground balance pots do some pretty strange stuff. Had one receiver that was always "just mono"... that one took a while to figure out. The balance pot's wiper was not making contact.

[@raygianelli3612]

@@Douglas_Blake_579 Wow, that must have been a bear to find all right! Can't say I've ever seen that.

[@Douglas_Blake_579]

@@raygianelli3612 Well, a fair bit of head scratching was involved... But once I figured it out the repair was a little Pssst with Contact Cleaner and away it went. I figure it was just an accumulation of dust. Don't know how long it lasted, though. Since then I've always designed with a stereo linear pot, with one section connected backwards, so that you were turning one channel up as you turned the other down... Balance control with no apparent loss of volume.

[@EdgarsLS]

Using software EQ sounds much worse than an actual EQ. So it's not a fair test for the phono preamp performance using reverse software RIAA

[@raygianelli3612]

Purely subjective.