 Posted: Thu Sep 03, 2015 6:10 am Post subject: |
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Just remember, it's a stereo receiver ... NOT a drink coaster.  |
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| Posted: Thu Sep 03, 2015 5:10 am Post subject: |
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| thanks again jts! the DeoxIt worked pretty well... i had to apply it a few times and work the buttons a lot to work it in there, but the sound is pretty consistent now! my dad is gonna be stoked! | |
| Posted: Tue Sep 01, 2015 10:12 pm Post subject: |
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| http://imgur.com/BxrJUTR
You may want to confirm by holding a strong flashlight beam on one side while you look from the other, that with each switch in the OUT position there will be nothing on the inside of the switch at the red dots when you drill. You may want to remove switches from PC board if hard to view. Working the switch while lighted may allow you to see if red dots need relocation. IF all looks well, drill a hole at a red dot (you may only need to drill one on each switch, depending on their construction) the diameter of the extension spray tube that comes with your favorite aerosol chemical contact cleaner (Deoxit, Blue Stuff, Tuner cleaner, etc.). Only drill into the switch the thickness of the plastic wall. It actually looks like once switches are removed from the PC board AND from metal frame by straightening 4 bent metal tabs, that each could be disassembled. Let's only try that IF chemically cleaning doesn't improve. |
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| Posted: Tue Sep 01, 2015 6:57 pm Post subject: |
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| Posted: Tue Sep 01, 2015 6:55 pm Post subject: |
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yep checked the solder joints on the main board weeks ago when i first disassembled it and they looked good... so do the joints on the SP switch ass. (see pics). i've noticed that the optimal placement of the Speaker B button is when the button is out (i.e. the B speakers are off) and then pushed in slightly (maybe just 0.5-1mm), well before the B speaker button engages/turns on the B speakers
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| Posted: Fri Aug 28, 2015 9:29 am Post subject: |
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| Only three possibilities:
1) Either end of J5/J6 connectors or any pin(s) of S570 could have bad solder connections. All of these are on the speaker switch board. The main board ends of J5/J6 hopefully were inspected earlier, plus the having to wedge the button point more towards the switch itself. 2) The contact surfaces inside of S570 are filthy and need cleaning (both the 'fixed' - that mount the switch to the speaker switch board and 'slide' - the metal shorting clip that moves from the outside and center contacts to the center and inside contacts as the plunger is moved forward or back). 3) The contact surfaces inside of S570 are actually worn through (more commonly associated with power switch applications, and normally only repairable by switch replacement). Since the second option is the most likely, can you post a picture of switch so that the best method of getting a chemical cleaning fluid or preferably foam into same can be determined? |
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| Posted: Fri Aug 28, 2015 4:19 am Post subject: |
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| there is one other issue though! maybe its easy to fix... i have a pair of speakers plugged into the A channel, and they will short out depending on the movement of the B speakers button. this is a problem the receiver was having before. we usually have to lodge an object underneath the B button to push it up in order to get both speakers working. same problem happens if i plug the speakers into the B channel... so something is up with this "B speakers" button that is affecting the sound whether the speakers are plugged into the A or B channel. thought i might try fixing that if possible, before i give it back | |
| Posted: Thu Aug 27, 2015 10:14 pm Post subject: |
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 Glad to 'hear' it. |
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| Posted: Thu Aug 27, 2015 8:17 pm Post subject: |
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yes!! it works! it's staying on and i hear music!! 
nearly 2 months later... i'd give you a big hug jts! and i definitely owe you some beers! you are incredibly knowledgeable and an asset to this site, thank you so much!! |
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| Posted: Wed Aug 26, 2015 9:31 pm Post subject: |
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| Collectors of transistors are at plus AND minus ~60 volts - NOT a good idea if they were to be connected to ground.
Insulators can be either plastic or mica and can be removed, and if undamaged reused. Wipe off old compound and apply fresh compound to BOTH sides (or to one side of insulator and also to heat sink. Use and spread enough realizing that pressure from the screw WILL help distribute. Too little compound is the only way to mess up. Too much compound will make a mess, with just right amount somewhere in the middle. |
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