SX-1010 Mods

Discussion in 'Pioneer Audio' started by Twenty20Man, May 12, 2007.

  1. Twenty20Man

    Twenty20Man Is that you Michael?

    Messages:
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    Location:
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    I have bought a SX-1010 that has some issues and I have begun research into it's known problems and it seems an overwhelming amount rests with the P/S regulator board underneath. I have read some interesting mods that have been done to relieve some of the heat buildup in that area, ( additional h/s area). I haven't read whether anyone has drilled vent holes on the bottom cover and whether it would be of any benefit (bear in mind I haven't laid eyes on a 1010 yet). I just trying to get my lil ducks in a row.

    thanks guys
     
  2. EchoWars

    EchoWars Hiding in Honduras

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    I have a problem with drilling holes in the bottom of my own units. You may feel differently about it.
     
  3. Twenty20Man

    Twenty20Man Is that you Michael?

    Messages:
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    Location:
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    not really Glenn, I would always prefer things as original as possible, but I live in Texas which probably has the very worst climate in the US, Its always warm in my Den/office where I do the majority of my listening. I am just thinking of ways to introduce more air flow to the regulator board.
     
  4. jpdylon

    jpdylon non-active member...

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    The best thing to do for the pioneer regulator boards is to re-solder them with decent quality solder that isn't as prone to heat, and replace the caps near heat sources (IE regulator transistors) with something that will stand up to abuse (like caps rated at 105 degrees centigrade or more)

    Considering the regulator board failures have only really started to show up 30+ years down the road, 45 minutes worth of work seems much better than modifying the receiver.

    If its in a cabinet, I have used low-noise DC fans with an external DC power supply to make a quiet cooling solution. I cut a hole at the rear of the cabinet behind where the receiver sits (usually next to wiring hole in the backing) install the fan and let it pull the cool air in and push the hot air out.


    just my two cents.
     
  5. Twenty20Man

    Twenty20Man Is that you Michael?

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    Location:
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    true enough, of course i intend to refurbish the electrolytics in this wonderful piece. i did just wonder if anyone had done this (drill vents) before and if it had any merit. i have quite a few Pioneers that have vent holes on the bottom panel so I was thinking adding some underneath the regulater wasn't much of a stretch ( i'm talking about a quality job, drill press.etc, sanding priming and repainting. you would never know it wasn't original when i was finished.) but most that have vents underneath also have corresponding vents on top so the air flows up over the h/s's and then out the top (heat rises) but on the 1010 the path is impeded and thats probably why pioneer didn't use vents on the bottom, for that reason alone i wouldn't do it unless someone can convince me it would benefit my 1010 and so far it seems that its not going to happen.
     
  6. tarior

    tarior Dirty pool, old man?

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    It made it for over 30 years the way it is. I would (and I do) just re-cap the regulator board with 105 degree caps, and touch up the solder joints. Ventilating the cabinet that it sits in is never a bad idea.
     
  7. CharlieBee

    CharlieBee Well-Known Member

    Messages:
    855
    Location:
    Baton Rouge, Louisiana
    Twenty20man
    I just finished a mod on the cooling the regulator board on my SX-1010. It was lightly charred looking but was working to spec on voltages for now and I wanted to eliminated having to replace all those parts.

    I added heat sink similar to others here on AK. I used piece of 2" x 2" by 1 inch thick heat sink from a junk computer found in the garbage. I sawed it into pieces with a hack saw and drilled holes in the L shaped sx1010 heat sink and bolted them in with heat sink heat transfer paste (SpectraCool one shot polysynthetic). I used a Dremel Moto-tool to trim the heat sink fins to miss all electrical contacts nearby and cut slots for the screws and nuts. It would have been easier to drill and use self tapping screws into the 1/8 inch aluminum bottom of the heat sink but I noted how strongly all the heat sinks are bolted to transistors. The board was worked on while connected to receiver but the six nylon stands were undone to allow board to be pulled out for access.

    A fan and baffle ring will be installed to draw in outside air across the heat sink only in a spot fashion and remove hot air and keep dust out of the receiver tuner and dial area. I next drilled a hundred or so holes in the area of the original and new heat sink with a drill press, primed and painted. Care and time was taken to draw out the hole pattern and center punch each hole for a professional look. I used a Dremel Moto tool with grinding wheels to smooth out the holes rough edges, masked the area off and primed with Walmart gray primer spray paint. Then I hit it with Krylon 1613 Semi Flat Black spray paint, a perfect match. I made a baffle ring (from a plastic butter tub) to surround the heat sink and used double sided tape to hold it to the inside bottom of bottom grill with the new holes ( about 3 1/2 inches in dia worth of holes). I bought a PCI Slot system Exhaust Blower Cooler 92 mm fan from and Ebay dealer. It is only 1 inch thick and ducts the heat away from under the receiver. I mounted the fan under the receiver with its 3 1/2 inch dia intake over the heat sink and aliened it up with the baffle using clear double sided tape. I had to use two layers of tape to get distance to keep the fan blades from tapping the grill. I aimed the discharge to the left front corner of the receiver to keep the duct from obstructing all the air holes to the rear of the unit. This fan is rated at 12 vdc. I used a selectable dc transformer for 3, 6 , or 9 v. 12 v is fairly noisy, 9 quieter, but would not start on 6v only transformer. With this multivolt transformer I start at 9 volts and can run 9, or 6 or 3. It is quiet now.

    I had to make 1/4 inch plywood spacers to install under the plastic feet to raise the receiver 1/4 inch to allow the fan housing to clear the table. I could have used one of the pancake computer fans I had which were 1 inch thick but then would have had to make about another 1 inch thick duct for it ( the fan is 1" plus the 1 " duct) and raise the receiver at least 1 inch higher than the existing feet. The fan I used is 1 inch thick with a side discharge so only 1/4 in was needed.

    This fan and baffle work by pulling ambient air into the bottom grill holes, then up and over the gap between the circuit board and the baffle, past all the new heat sinks that are vertical fins, pull through the grill, then thru the fan and out the duct. It is then directed away from the receiver into the room, away form the receiver and its hot rear power transistor heat sinks and away from the other bottom holes to keep from recycling hot air back.

    I am very pleased with the outcome and think it will remove the trapped heat from the problem area. Drilling a few more needed holes is not an issue with me and I have corrected a design problem with this receiver. This voltage regulator board should never have been put on the bottom of this receiver or some other components or values of components should be changed to keep it from running hot. I could make some measurements and calculations figure out how many BTUs I am removing but feeling the warm air flow is proof enough for me! I picked this sx1010, dead at an estate sale, cheap and only had to replace a fuse near the 110 volt plugs. After setting the DC offset and deoxit it is flawless. It is my only unit with two phono inputs which has come in handy checking out two turntables I picked up at a church sale (Sony PS-X6 and Technics SL-D3). It is running a pair of Optimus 1 speakers in my shop waiting on the Mach 2s to get new surrounds.

    This is no 45 min project. Plan a day or two depending on your tools and workmanship and how fast you work.

    Charlie
     

    Attached Files:

    Last edited: Jan 29, 2015
  8. Twenty20Man

    Twenty20Man Is that you Michael?

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    Location:
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    CharlieBee

    That is really good work and right along the lines of my line of thought, thank you for the pics
     
  9. EchoWars

    EchoWars Hiding in Honduras

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    You don't need to drill and bolt the new heatsink pieces to the old one. Use a thin coat of JB Weld to hold them on...it's good 'n strong, and conducts heat pretty well.
     
  10. Twenty20Man

    Twenty20Man Is that you Michael?

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    Location:
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    Glenn I saw your thread elsewhere on the additional H/S and J B weld and had decided I would go with that.
     
  11. Fred Longworth

    Fred Longworth audio fanatic

    Messages:
    3,473
    Location:
    San Diego
    Twenty20Man,

    If you want to cut holes in the bottom plate, that will aid ventilation, however, you should also make sure that there is good air flow inside the shelf system where the Pioneer is living.

    Make sure that there is at least 3" -- and ideally more -- above the machine. And make sure that the BACK of the shelf system is open. Many popular shelf systems have TINY holes in the back, which impede air flow. Get out your saber saw if needed.

    Also, consider adding a small 120vac whisper fan to PUSH fresh air toward the bottom of the Pioneer. This should be mounted behind the machine by the rear panel. You can run this off it's own outlet strip, so that you'll have a power switch available (a cheapie will do.)

    ONLY use 105 degree caps on the power supply board. (I don't use 85 degree caps for much of anything any more.)

    Enjoy your machine!!!

    Fred Longworth
     
  12. Twenty20Man

    Twenty20Man Is that you Michael?

    Messages:
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    Location:
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    Thx Fred
     
  13. Twenty20Man

    Twenty20Man Is that you Michael?

    Messages:
    3,062
    Location:
    Texas
    well here it is...

    this is the 1010 I just received it. I have ordered the differential trannies for both channels, the the low voltage regulator is a crispy critter but the voltages are all good and stable I have ordered the caps and resistors to rebuild that board and caps for the protection and amp drivers. keep ya posted.
     

    Attached Files:

  14. CharlieBee

    CharlieBee Well-Known Member

    Messages:
    855
    Location:
    Baton Rouge, Louisiana
    It is 10 years after my mod to fix the hot regulator board on my SX-1010 in post 7. I did mine by adding heat sink and a bottom cooling fan and it is still working great.

    Any others fixed their SX-1010 receivers in the last 10 years?

    Charlie
     
  15. john stumpf

    john stumpf AK Subscriber Subscriber

    Messages:
    402
    Location:
    philippines
    i did mine and its hot here too. after a total recap and problematic transistor change i run a fan on the top drawing air up taking advantage of convection. i cut a piece of black naugahyde the same size as the upper grille area with a round hole in it the size of the fan. of course the grille itself is a huge restriction to flow, but i only use this unit in my office with a/c on. so far so good.
     

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