Realistic STA-85 Slider Volume

[Corod]

All,

Picked up a realistic STA-85...was filthy, been sitting. Don't need it, but like a stray animal i took it in. My wife says I just like cleaning stuff up and that I need to stop buying equipment and just offer to clean up other peoples stuff, a lot cheaper..LOL
I do end up spending half the night and getting a sore back being hunched over.
So I cleaned it up inside and out, deoxit switches and sliders. My issue is the volume on the sliders get very loud immediately, is there a fix for this? possible issue?

Also noticed when i power it on, it takes a minute to warm up.

Thanks,

Richard

 

[Ylli]

My issue is the volume on the sliders get very loud immediately, is there a fix for this? possible issue?

Might try Caig FaderLube on the control instead of DeoxIt. Check to be sure the grounded end of the volume control is truly grounded. Finally, the volume pot may not have as much of a logarithmic response as you like - you can improve that a bit by adding a resistor from the control wiper to ground. Might want to try a 20K on each wiper to ground.

Also noticed when i power it on, it takes a minute to warm up.

What do you mean by this? Is there no output for the first minute, or is the sound quality poor for the first minute? Or what?

 

[quaddriver]

One of these?


nice machines, this came alive fairly quickly and I took the time to sand, restain and oil the case.

The slider are real similar to the ones in the -84 and I really wish they didnt use them but since the early 70's until the mid 80s RS insisted on a midrange unit with sliders - just to be different. I guess its ok, volume = balance also, but they get dirtier easier and the heavy end of the taper (low volume) does seem to lose substrate with agressive cleaning...dont know of ANY replacements. if you want to quiet them down a bit, since its not log volume, you can add safely 1/20th of the total pot with an inline on each channel, it will require more movement to get sound, but once you get sound it will then follow the taper left in the control.

takes time to warm up? hmmm, with magic tune in or out or both? I do find on the 70's auto magic units I generally have to recap everything - however caveat on the -85 above I replaced a diode that was part of the IF and the new Vf cause it to go out of alignment, I had to spend time to bring that one back.

 

[Corod]

Might try Caig FaderLube on the control instead of DeoxIt. Check to be sure the grounded end of the volume control is truly grounded. Finally, the volume pot may not have as much of a logarithmic response as you like - you can improve that a bit by adding a resistor from the control wiper to ground. Might want to try a 20K on each wiper to ground.


What do you mean by this? Is there no output for the first minute, or is the sound quality poor for the first minute? Or what?

Yes, there is output but when the selector is on FM for example, the meter light flickers and sound not as clear until warm (30 sec-1 minute). The 3 faceplate bulbs are out so the meter was my only indicator, well and the sound/signal strength.

 

[quaddriver]

yep, redo the auto tune and every cap around the HA115x chips. Just dont change any diodes.....

 

[Corod]

few pics attached, before/after 4 hr cleaning( where does the time go)...was worse overall but didnt snap a pic until after I gave it a quick wipe down. Cleaned the face and faceplate inside n out. Need to oil the cabinet still.
I know there is no $ in this unit but like to keep things going for the next generation. Unless this volume issue gets too involved. Lol
Hopefully someone appreciates it.

 

[quaddriver]

i just sold the -84 for 165..... there are groups what want RS units....and they dont suck

 

[quiet]

I also suspect the slider issue is the result of the "wrong" aggressive cleaner wiping it out.

 

[Corod]

i read somewhere after a google search and someone else had the same issue and stated it just sat on a shelf until they could get around to adressing it. The seller stated he didnt have this issue, find that hard to believe. The sliders were kinda stiff and i used deoxit fader lube...and it loosened up and dripped out blackish. I assume the fader lube is safe for it, or can too much be bad?

 

[quiet]

So, can fader lube wipe out the control? And ruin it? And just what was the black that got washed out of the control? The control surface? I don't think to much of the right cleaner would do it. But a little of the wrong one can produce failure. And full volume at zero setting can be had.
It don't look good for the home team.

 

[Corod]

So, can fader lube wipe out the control? And ruin it? And just what was the black that got washed out of the control? The control surface? I don't think to much of the right cleaner would do it. But a little of the wrong one can produce failure. And full volume at zero setting can be had.
It don't look good for the home team.

Not sure if you are asking questions, but I only used Deoxit Fader lube so don't think its considered the wrong cleaner. As for the black that dripped out, dirt, graphite grease mixing with the Deoxit is my guess.
I appreciate all the input, was hoping someone else had the model and addressed the issue. I might try the resistor fix or let it go as is. Don't need it. Definitely don't need a project. QuadDriver I do like RS units, I have a few .

Thanks.

 

[quiet]

Some of that black that came out of the control might have been the control.

 

[Jettyrat]

Just found this thread because I was gifted one of these a while back and just got around to cleaning it up and testing it. Fired right up (variac, dim bulb) with no problems save for one channel has no volume until the fader is up almost halfway; the bottom half of its range is evidently toast. I've pulled it for cleaning (DeOxit F5 Fader Cleaner) and inspection but no love upon reinstallation. I might not be so bummed if this unit hadn't cleaned up so nicely. I won't say it's dead mint but close to 9/10, really in great shape. Already searched all the standard vendors and can't find this type of slider anywhere.

 

[Gknokers]

Just found this thread because I was gifted one of these a while back and just got around to cleaning it up and testing it. Fired right up (variac, dim bulb) with no problems save for one channel has no volume until the fader is up almost halfway; the bottom half of its range is evidently toast. I've pulled it for cleaning (DeOxit F5 Fader Cleaner) and inspection but no love upon reinstallation. I might not be so bummed if this unit hadn't cleaned up so nicely. I won't say it's dead mint but close to 9/10, really in great shape. Already searched all the standard vendors and can't find this type of slider anywhere.

I’m about to go through one as well

 

[Jettyrat]

Update, I did find a slider that worked from Parts Express, not exactly the same as the 200k OEM pot but 250k and same basic dimensions with screw holes that lined up. The terminal layout was completely different though so my first attempt to wire it on intuition was a failure. These sliders don't behave anything like standard rotary pots so I had to get out the schematic and really sleuth it out but I finally got it wire correctly and it works great. The biggest bummer was the shaft out the front panel is also different so the original knobs didn't fit, Parts Express couldn't provide anything, and I couldn't come up with anything that would work on them as is, so I ended up snipping and trimming the new pots' shafts until I could get the old knobs on them, but then it was a sloppy fit so had to use glue. This is a great receiver with a lot of really solid design features but slider volume pots on consumer grade components is just a stupid idea.