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Realistic STA-2500 Receiver


New member to Hi Fi Engine. I recently acquired a Realistic STA-2500 Receiver that someone put out to the curb. Given to understand these are vintage 1985.

Problem with the unit: it powers on, the led power output meters go to the max and stay there and there is a click noise. There is no output, and none of the input selector functions (i.e., AM/FM, tape monitor, phono input) work.

Welcome any suggestions for troubleshooting this problem. Thanks!

Re: Realistic STA-2500

The power supply board in this unit is very complicated, comprised of three bridge rectifiers, four low-voltage regulators (three using discrete implementations) and three thyristors. Troubleshooting the failure symptom could be rather time consuming. Unless you have substantial experience with troubleshooting and servicing of discrete power supplies, this unit may be better repaired by a vintage audio electronics specialist. Also worth noting, handling the display - FL401 - (mounted on Synthesizer PCB) requires a very delicate touch. The fragile, irreplaceable assembly is vacuum fluorescent (VFD) type, its glass envelope is easily broken. Once restored, op amps on Tone Control PCB could be upgraded for enhanced performance. Power amplifier design is above average for the era, keep this section stock, unmodified.

Re: Realistic STA-2500

This receiver is well worth repairing or getting repaired. From the description you described it sounds like there may be a problem with the output section causing the protection relay to activate (thus protecting the speakers from high DC supply voltage).

And as analogcd said it also sounds like there is power supply issues. Which could also cause some or all of the problems you described. analogch is also correct that the VFD is VERY VERY fragile & IF broken is unreplaceable except from a parts unit.

The receiver is starting to get of the age that it may benefit from a full recap of all the electrolytic caps.

You are VERY VERY VERY lucky that this Realistic receiver model has the Schematics & Service Manual uploaded for it here https://www.hifiengine.com/manual_library/realistic/sta-2500.shtml. I say this because once RS/Tandy went bankrupt I highly suspect that ALL their equipment documents (Owners Manuals, Schematics, Service Manuals, etc., everything) was tossed & is now lost forever.

I suggest you download ALL the Manuals & Schematics for it & start measuring voltages in the power supply section to confirm IF they are correct or IF something is off/out of wack/low.