What does it take to put a decent vintage receiver back in service?

Discussion in 'General Audio Discussion' started by Blue Shadow, May 16, 2018.

  1. Blue Shadow

    Blue Shadow I gotta get me a new title

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    Without doing a recap, just addressing problems and cleaning a long neglected unit, what do you think is needed to make the unit worthy of a shelf?

    Phil has Free written across a tag on a Pioneer SX-828 top-of-the-line receiver from 71-73 with about 50 watts per channel. He meant for it to go with the Marantz tuner, inner box, outer box, cabinet, box and such but as the day got late I asked if it was free and I'd get it out of his way. That is, it seems, what he wanted. I asked him if it worked and he said it was intermittent in one channel and low in volume in the other. Good enough for me. Brought it home and recorded the serial number and put it on a stack of gear needing to see the workbench.

    Then I talked to Doug (@dlucy) and asked if he would be interested in dropping by and looking at a Sansui AU-719 I have been having trouble with and he said sure. This was all at ehoove's excellent get together. Conversations later, I lured Doug in with the 828 and the three extra switches installed on the back of the unit and he dropped by the other day.

    We got the switches determined, one is a preamp/power amp switch, used instead of needing jumpers. Nice.
    The second one turned the power off to the big PS caps (they are for the amp only it seems) and the third switches the power to the relay board. I'm guessing when the unit was used as a preamp the amp section could be turned off. Odd, but the switches were properly installed and I'll leave the preamp/power amp switch. While Doug was digging around with those I was looking into other issues. The access to the control board to shot it with deoxit, the removal of the foam and the stereo lamp which wasn't working, but was it doing FM in stereo.

    We got the switches cleaned, found a burned out Stereo lamp and we replaced it and after proper wait time, fired up the unit for the first time. We had sound...both channels...nearly equal in volume. But it was getting late and Doug needed to get back home. I'm stuck with an 828 spread all over the workbench with dirty parts everywhere. There are four covers inside the unit, the bottom panel, the faceplate, knobs, switch covers, speaker plugs (you know the Pioneer speaker plugs, this one came with three) and various other bits and pieces that were just filthy. Just as if I have company for dinner, I'm stuck clearing the table and washing the dishes. Thanks for your help on this one, Doug. Maybe we can get to the Sansui at a later date.

    After getting all the parts cleaned, I went about looking over the operation of the unit. A pop when using the low filter, asked AK and a couple folks came back with the possible issue. Replaced those caps and that switch, now bent back into place is working quietly as it should. Some internal cleaning, Bias and Offset adjusted to spec and more cleaning.

    Then the washed walnut cabinet cabinet got a light sanding, some 330 grit, did the walnut end caps on the faceplate, too, then a drink of Watco Danish Oil Finish (Dark Walnut). Buffed this off at the proper time, painted the grille satin black and left the parts in the garage to dry. More work on the unit.

    This unit, using two tuning capacitors, common on earlier units has only one tuning string. Not quite enough friction on the tuning wheel to move both caps so I cleaned the grease on the shafts and the pivot points inside of the AM cap (the FM cap is covered and less accessible). This got the tuning indicator to move more in line with the tuning knob. Things are getting better all the time.

    Finally, installed the covers, faceplate, bottom panel and cover and cleaned the back panel. I'm calling the unit ready to go, just service, not rebuilt or recapped and looking nice. Now Dave might want it. He had asked earlier about its availability and he would have brought it to me or another of his contacts who recaps Pioneer for him.

    I'll be hooking this up to some real speakers soon and see how it sounds. Just finished a CR-820, similar power and fully rebuilt. Be a good comparison.

    Anyway, what did you guess as to the hours needed to knock the dirt and wear off this unit and make it look good enough to be allowed to stay around?

    I'm figuring that the 5 hours Doug was here we did about 7 hours of work since some was talking, listening and watching. Doug seemed to enjoy figuring out the switches while I watched and put something else on the main rig. Then a couple days, few hours each attending to the details. Here is why we buy the best condition you can find, those 18 hours of refurb were not something folks can charge for as a service shop. Without a recap and a nominal fee for the clean up hours one is already above what these usually sell for in fair shape. A recap would take a long time with may of the small caps glued down as the ones I changed didn't want to come out.

    Here are some before pictures:
    Back.jpg Cabinet wear.jpg

    I don't think I have a before on the front panel but it was filthy. Fortunately it was not a damaged unit. You can see some of the clean up needed on the front in one of these pics. I'll get some after pics when there is some light out.
     
    Last edited: May 17, 2018
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  2. quiet

    quiet AK Subscriber Subscriber

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    Interesting you used that one as an example. I've been trying to get a clean 828 at reasonable cost for a while. It's like trying to get a Fisher 700 for a nice price. Not so easy to do as one might think. I've got it in my head the 828 would be an excellent example of early 70s Pioneer.
    My plan is to hold out for a top unit as you suggest. And pay more than I was planning to while hoping for the best.
    Thanks for the write up. A fine reminder that the false economy of buying a needy unit might be just that. False economy.
     
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  3. savatage1973

    savatage1973 Addicted Member

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    "Free to a good home" is rarely that--free. Whether it be actual money, or just 2-3 hours of your time every night for a month, it "costs" something to restore/resurrect a "needy" unit. I have done it both ways--spent more time and money that what the unit was worth in restoration, and overpaid for a "prime" example of something that I really wanted, but intended on keeping. It it what it is.
     
    Last edited: May 17, 2018
  4. quiet

    quiet AK Subscriber Subscriber

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    Yep, over paying is just no fun. When that happens I'm going to try to look at it all collectively and leave the Kleenex in the box. And a dirty dead unit that never makes it out of the closet is no good for me, no matter how I came by it. Yes, it is what it is.
     
  5. blhagstrom

    blhagstrom Mad Scientist, fixer. Subscriber

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    I brought two of those SX-828 back to service.
    Both were nearly free or perhaps were.
    A flipper was cleaning out dead wood.

    That series of Pioneer gear is fantastic when working.
    That series of Pioneer always needs work.
    Every 4, 5, 6, 7, 8 and 10 from the 2 and 3 series I ever got needed some love.

    Most I flipped once working but I kept a couple to do a recap on and get them tuned up as good as possible. I would like to see what a total rebuilt one is like.
     
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  6. Blue Shadow

    Blue Shadow I gotta get me a new title

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    Here are some pics of the unit after a bit of work.
    The wood came out great, nice that it is wood but one expects that on TOTL units
    The lamps are on high brightness with the pic taken outside
    The side view shows the door to open to install the unobtanium PP-402 SUT for LOMC. Input sensitivity with the PP-402 is 115┬ÁV or 0.115mV so lots of tunrs ratio in that SUT.
    Back panel has a couple fewer switches and I'll cover the holes from the two removed
    And finally the dial blacks out nicely when the unit is off.

    Sweet unit. Now to hook it up and give it a listen.
     

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  7. BMWCCA

    BMWCCA AK Subscriber Subscriber

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    Like I've said before, "a one-owner car that would have been better off with two!"

    Seems like it found the right home. As I said, I got it for free thrown in with some free speakers off Craig's List. Just sitting in a guy's garage. Speakers were advertised as probably JBL, which they weren't. Mostly low-level PA stuff with sloppy crossover mods. Passed those along to a neighbor, delivered, for free, and just kept the Pioneer doing nothing to it until the opportunity to pass it along, too, arrived. Happy to provide the service.

    My reward will come when someone passes some free Crown stuff to me!
     
  8. Blue Shadow

    Blue Shadow I gotta get me a new title

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    Have this unit in the main rig. CD works great, Phono, using Chip's PS-X5 with Shure M91ED (original stylus, the good one, slight wear, 80% remaining) and this unit has a bass heavy sound, nice. Looks good sitting there on the table, too. I need to compare it to a newly recapped x2x or x3x to see if there is anything missing. The speakers will show it, it is driving MG-IIIa speakers right now. Sure we are not headbangingrockandroll but listening even at nice volumes is something this top unit will do. Maybe Dave can bring over a redone Pioneer for comparison. Right now this is a great original condition survivor except for the few caps replaced to eliminate the low filter switching pop and a light bulb.
     
  9. quiet

    quiet AK Subscriber Subscriber

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    Come on now. We all know your gonna cut it loose on some rock from time to time. Just because.
     
  10. gadget73

    gadget73 junk junkie Subscriber

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    Next time you have a hankering to do so, I can drag over a fully rehabbed Pioneer SX-1500TD. Might be interesting to listen to a few different generations of receivers. You'll just have to excuse the Allied badge on the front of it. I think that one is from their last generation of cap-coupled units too, so it should have a rather different signature compared to a later direct coupled unit.
     
  11. tarior

    tarior Dirty pool, old man? Subscriber

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    It's been a while since I've worked on a SX-x2x, but IIRC there are a few small signal transistors in the amp that will go crackly. Then of course there are the usual dirty switches/pots, and probably a few cracked solder joints and dried out caps in the regulated P/S, burned out lamps, stuff like that.
     

     

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  12. tubed

    tubed Lunatic Member

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    The Pioneer SX-828 was my first HiFi receiver I bought while in high shcool.
    I played it for a year or two before I purchased a Yamaha CA-1000.
    Decades later I recently pulled the 828 out for a listen.
    Very nice sound.
    DC offset measures 28 and 35 mV.
     
  13. Blue Shadow

    Blue Shadow I gotta get me a new title

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    Well Dave came by and brought an LEDed, recapped 737. Wow it was a nice radioactive Blue, a bit bright for my taste but not the more greenish-blue of the original bulbs in the 828.

    Sound was similar, but before Dave got here I was testing all inputs and the phono amp is a bit noisy, just a background hiss, more in one channel than the other. I have the caps and 1845s in stock to replace the 2SA458 transistors that should make it right. I'll put a coat of feed 'n' wax on the cabinet, too. More after the parts are changed.
     
  14. ConradH

    ConradH Addicted Member

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    "Free" is a funny word. What it says in the dictionary is never what it turns out to be in real life. IMO, you have to enjoy working on this stuff and hours be damned. I don't believe in doing blanket recaps on everything in sight, but for that philosophy to be successful you have to be able to measure and you have to be paranoid enough to replace certain parts just because your gut tells you to. After so many years, most units seem to have developed some iffy connections, maybe a noisy transistor and certainly noisy switches and pots. IMO, Pioneer made some of the most reliable receivers and their production volumes were probably higher than most because their prices were lower than most.
     
  15. Blue Shadow

    Blue Shadow I gotta get me a new title

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    But wait, my unit has 1344s not 458s. No problem, those are gone now.
     
  16. bluesky

    bluesky Addicted Member

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  17. Rybeam

    Rybeam Super Member

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    Recently did a detox clean up, loosen up on a SX-750 I got for free. Just an outstanding sounding amplifier, sound stage and space equal to my "high" end stuff, a bit tiring at moderate sound levels after some time, but nothing you would notice unless you are spoiled.
    Tuner picks up the low power college station 50 miles west of me. That is something my higher end digital will not do because it does not stop at weak signals. Overall a real joy to play with. Have it in bedroom now on a small pair of B&Ws sweet set-up.
     
  18. gadget73

    gadget73 junk junkie Subscriber

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    My only real experience with vintage Pioneer is the Allied 495 / SX-1500TD I've mentioned a bunch of times. It ran from 1970 - 2017 with no real issues beyond a volume control that I broke the shaft on a long time ago and some dirty switch contacts. The phono stage was noisier than I'd like but it was that way as far back as I can remember. What finally brought in in for service was a leaky transistor in the FM muting section that was cutting the radio in and out. 47 years with nothing beyond a couple shots of contact cleaner (and a volume control) is pretty fine if you ask me. I probably could have swapped those 3 transistors (or just the one if I'd spent enough time to fully isolate it) and run it for a while more but I thought nearly a half century was long enough to justify some PM work.
     
  19. Blue Shadow

    Blue Shadow I gotta get me a new title

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    Swapping those extra transistors would have been way quicker than finding out exactly which ones were noisy and at less than a couple bits each, cheaper than the time needed, even if it is your unit and time doesn't count. Drag it over and give it a listen. We had it hooked up when Mike was here recently. He liked the sound of the main rig better, though.
     

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