Realistic STA2700 STA2380 Overload, Shutdown Problem Fix

[@jackderrenberger3733]

Can you give me direction as to where I can find a service manual and schematic for the STA-2700. I don't have the shutdown problem but I have no output and as far as I can tell the speaker relay does not actuate. Thanks ahead of time.

[@b.snoodleman5864]

Yes sir, when I was 14 years old when the radio shack by my house was selling their floor model STA2380 for 225.00. I had a paper route at the time and all it took was a $20.00 down payment and it was put in the back with my name on it until I paid it off, which took forever. after almost a year my Dad paid the last $80.00 I owed as my 15th birthday present. After distorting every crap bookshelf speaker I could find I remember when I finally got some real speakers (3 way's 12"woofer) and the first time I cranked it up and the bass would come in a loud pop and it would go into overload way before any distortion. I loved that thing, but the cutting out was really annoying and it would cut out with 4 ohm speakers almost instantly with out registering and of the out put lights. Yup that was a problem with those.

[@inputmig6625]

i have an sta2700 and it takes a while to warm up or it will go into protection, tho i am running larger speakers than i should through it, awesome machine tho 😎

[@davismv]

I have a question please, my 2700 will not power on most of the time unless I unplug and plug it in repeatedly. I recapped the power board but there’s something that’s not engaging when you hit the power button. Can you let me know if prior to your fix, did the unit have issues powering on? When it went into protection, does it shut itself off completely? Thanks so much!

[@williamstaten8102]

The protection only cuts connection to speakers. You probably have a bad transistor on the power supply board. Look for one that has a direct connection to power relay. Or could need to clean contacts on relay.

[@davismv]

@@williamstaten8102 thank you so much for the response, the funny thing is once it powers on after repeated unplugs and plugs in, it works flawless and will stay on and I can power it on and off as normal. Even after sitting overnight and extended periods. And it performs excellent. It’s almost like when it’s plugged in cold the circuit or function that controls the momentary power button does not engage. I am highly technical and a hobbyist I will review what you suggested. No issues with it cutting out at loud volumes or anything. Unit is flawless except for the first time you plug it in and getting it “working”. Also I have jumpered / bypassed the power relay, The VFD turns on but no other functions or activity - Main board and buttons unresponsive in this scenario.

[@makowskid8]

About to attack this with 8 more months of knowledge under my belt along with my 3rd scope in so many months and scrapping precious metals from electronics along with other various screwing around with all sorts of pcbs etc. an adrino board i picked up, not to mention drawers full of parts ive acquired! Wish me luck, please! 🙏 😂

[@makowskid8]

I did this and it was the worst possible thing that could've happened to my 2380! Was probably my fault as it worked great the night of but next day i found the main fuse blown with the power not even on. So of course replaced fuse, turned unit on and that's when it blew sparks, smoke, and quit, and now nothing! That was awhile ago now and probably more related to an error I may have made while soldering. Just received new ic's from china and going to go for broke yet again!

[@williamstaten8102]

Check the ohm on speakers. If one is bad the stereo is unable to shut down. The sorted speaker will over heat the stereo. Wish I could of came up with a way to make it less sensitive. Mine set up like this jams at my cousins house daily. But never had a low ohm speaker on it.

[@makowskid8]

@william staten Good thought I've definitely thought the same, I actually have 2 sets that are 8 ohm apiece. Unfortunately even with the new ic every time I try to power it on it fries atleast a couple resistors! Not sure where to go from here with it. I'm thinking need to pick up a scope if im going to have a chance with it! Thanks again!