SX-1010 won't Power On...

[D.E.K]

I can get 1-2 bottles of it and send it to you, on me. I'd be happy to. The only problem is the damn Customs.

 

[D.E.K]

This stuff DOES leave some residue and on the foil side the board is quite sticky. You can also see the rosin sort of smudged in some pats of the Foil Side. It might be my fault, I only used cuetips instead of an acid brush, that might make a difference. I will later try cuetips dipped in only water and try to get rid of the sticky stuff on the foil side. On the other hand, it removes dirt and residue in no time at all and as far as cleaning goes, it works wonderful. I don't see any trace of 'Salt Rings' do you?

P.S: The 4th picture is the Before/After shot.

 

[D.E.K]

Nevermind the sticky stuff on the foil side. It's alright now. I just needed to give it some time to completely evaporate. No stickiness left what so ever. I also tried wet cuetips (water) on the board side and the clearly seen residue between Q5 & Q2 and in front of Q1 (that's the only area I tested) is gone, refer to the picture. In other words, this seems to be THE stuff. I smell like a hospital though...

 

[markthefixer]

Now THAT looks GOOD, how did the undersides of the remaining original transistors clean up? That according to Fred is the worst spot. They pick up a bit of humidity and the salt between the transistor leads becomes slightly conductive.

As far as a dim bulb tester, it's always a good idea to bring a unit up on it the first time after work was done. Just long enough in this case to see the light dim back down, with amplifier work, a little longer with a few more checks.

 

[D.E.K]

Undersides as in the area of the board directly under the remaining caps or underside as in the area on the actual body of the capacitor? The areas of the board under the remaining original caps (the areas with the green pinout signs on them) are very clean and free of salt residue. As for the actual underbellies of the caps, I neither can see nor get at them, the leads restrict any cleaning object reaching the bottom side of the caps. I will, however, try to pick some of the cotton off the cuetips, thinning them and then try to get at the underbellies of the caps. It might not be 100% but sure will improve them immensely. I have to work out now, I will be back in an hour or two.

Earlier I asked if you wanted some Isopropyl Alcohol. Let me know and I will gladly send a few bottles down your way.

 

[D.E.K]

I gave both Foil and Board side a final cleaning. I cleaned the undersides of the capacitors (both boad and the actual body of the omponents) the best way I can. Both sides look pretty good to me, especially Foil Side improved dramatically. I am setting up the DBT right now.Mark, if you're around, keep an eye.

Good luck to me.

 

[D.E.K]

Same thing. No change what so ever. Same symptoms before recapping the PP Board. The relay clicks, when I turn the Dimmer OFF, relay clicks out. When Dimmer is ON and relay is engaged, I hit FM and relay clicks out. Sometimes I power up the unit, the relay clicks and then within 1-2 secs clicks back out. That rules out the PP Board.

:gigglemad

 

[markthefixer]

Same thing. No change what so ever. Same symptoms before recapping the PP Board. The relay clicks, when I turn the Dimmer OFF, relay clicks out. When Dimmer is ON and relay is engaged, I hit FM and relay clicks out. Sometimes I power up the unit, the relay clicks and then within 1-2 secs clicks back out. That rules out the PP Board.

:gigglemad

Considering all the salt, that isn't a surprise. Water / moisture drips down, so it concentrates on the bottoms of transistors. Of course the power supply was in the bottom of the chassis upside down and the amp is on it's side vertically.

Then the salt gets moist, conducts and does all sorts of weird things, especially in the more sensitive circuits. Which most are.

This salt soaked 1010 isn't a fair receiver for someone to cut their teeth on, but when it is stable, it will be quite a noteworthy accomplishment.

You can connect the voltmeter between pin 1 (and pin 3) and ground, and watch the amplifier's output voltage, it's probably jumping around on at least one of the channels due to all that salt condensed on the bottoms of the transistors.

Did we ever measure the power supply voltages? You may want to do that first, You need to watch these voltages and as the receiver goes in and out of protection to see if they are doing it, the old garbage in - garbage out principle. The amplifiers can't be expected to be stable when the power supply is jumping all over the place.

The AWR054 power supply board:
pin 14 +56v
pin 13 +35v
pin 10 -56v
pin 8 13.4v

Basically, we're talking about a 100% cleaning job,starting with the power supply and amplifiers, with the other circuits later to quiet them down. We can consider the protection circuit trustworthy now.

 

[D.E.K]

Maybe I oughtta take it apart, recap the WHOLE thing and give it a good scrub. When this is over, if it is ever over, the damn thing will have cost me $500.

 

[ccheath]

....When this is over, if it is ever over, the damn thing will have cost me $500.

And will gain your Pride, Dignity, and Experience. :yes:

 

[D.E.K]

And will gain your Pride, Dignity, and Experience. :yes:

True enough. We know Mark ain't much for 'Pep Talk' as he once put it Someone's gotta do it :thmbsp:

 

[larryderouin]

What a way to get an education in Electronics! You got more patience than I'd ever have. Mine would have either been in the DUMP by now (worse case) or on it's way to MTF or EW!

I just hope it's something simple, now that you've gone damn near thru the whole thing.
Larry

 

[markthefixer]

$500? not in parts costs - the outputs and big caps are the pricey items, shipping parts from mouser can't be THAT expensive to Canada...

Depends upon how you price your labor to yourself.

In fact for example the parts for the Sx-737 and sx-950 phono preamps I posted about here:
http://www.audiokarma.org/forums/showthread.php?t=204726
the price of the caps had gone down quite a bit in 6 months, while the transistors were about a penny more apiece.

You have two channels worth of amplifier transistors, and all but two caps for the amps (sorry-my oversight on them)

Re: pulling it apart for cleaning, I would, just to get it over with - my nightmare would be cleaning the tuner board. THAT was enclosed - I hope that would make a difference.

 

[D.E.K]

Funny you should mention the tuner board. Remember that "chirping" noise while looking for stations? It is still there, alive and loud. Also, when the relay is engaged and stays engaged, as soon as I hit FM button, relay goes off. Might not have to do anything with our primary problem (whatever it is) but it sure as crap is a problem on its own, has to be. Now I don't want to fluff here and act like I know it all but it's just my gut feeling, something that tells me it's something that's not supposed to be. None of the receivers I have (SX-737, SX-680, SX-950) has that chirping sound. It is either normal, which I doubt VERY much, or there really is something wrong with the tuner section.

Another thing, since the "Relay Incident" I probably turned the unit ON/OFF over 200 times. My observation is that, the more the receiver heats up, the less frequently the relay engages. Heat has a role in this whole thing perhaps.

The PA Boards... I don't think I should be concerned with that just yet. I have the parts for both PA Boards right here. I don't think replacing the parts will be a problem, personally the PP or turned out much better than I expected (I literally had some bleak dreams about it) which was a HUGE confidence boost and needless to mention a priceless experience gain. I say the best thing to do at this point would be cleaning the tuner board, Power Supply and taking it from there. We also keep blaming the salt for everything but I just went through the PA boards and a few others, none of them has the slightest trace of salt on them, not anywhere. It amost looks like something was spilled or steamed through the top grille and got to the PP board.

After all that, I am ready to have EVERYTHING removed from EVERY board and rebuild the entire bloody thing, what the hell.

 

[LWB]

Hey, DEK, your protection board looks wonderful. Very, very nice work, indeed. Tough luck that the amp still misbehaves, but you can obviously do what needs to be done to bring it back, with the right advice of course. Don't be discouraged.

I suspect the salt crystals may be a big part of the problem. With the heavy salt deposits I see in your 'before' photos, just normal humidity close to the sea could be causing all manner of electrical havoc.

 

[D.E.K]

Ahem... Gentlemen, I introduce you my RIGHT PA Board:

Mark, I think I've found our PROBLEM...

 

[markthefixer]

There is a VERY FRAGILE part wired from the PA board to the heatsink, there are two transistors and the thermal diode. The wires on the little horse shoe shaped diode LOVE to break - sometimes I think it is their goal in life.

So please be careful to keep the flexing of wires within 1/2 inch of the diode to an absolute minimum.

I didn't expect you to dive into the PA so quickly. And I acknowledge we may have covered the diode before, I would end up kicking myself (figuratively) if something happened after I decided not to say anything.

 

[D.E.K]

I didn't either, I traced the chirping noise, it lead me straight to the PA board and I just wanted to have a look-see. Right off the bat I see 2 spots on the foil side that are peeled off to a point where there is no conductivity. I expected from you something like "HOLY COW" but you don't seem to be much surprised. Should I leave it alone?

 

[markthefixer]

I didn't either, I traced the chirping noise, it lead me straight to the PA board and I just wanted to have a look-see. Right off the bat I see 2 spots on the foil side that are peeled off to a point where there is no conductivity. I expected from you something like "HOLY COW" but you don't seem to be much surprised. Should I leave it alone?

I'm looking, looks like Q8's base connection, the two pads further over are a less used part of the circuit. I will edit this post after I look at the other area. edit: The less used area isn't- there's an anti-oscillation capacitor there that is needed.

Both areas should be repaired after a thorough cleaning of the entire board, there are two ways (well, more but..) to fix the interrupted traces, both involve connecting the solder pads back together, one with insulated wire from pad to pad when there is no chance of the loose copper shifting and shorting out something, and the other uses bare wire, with the green coating scraped off the traces, and the bare wire is soldered along the trace's bare copper to provide mechanical support as well as electrical conductivity.

I'll look for a junk board I can demonstrate on, but I don't have much junk around. Maybe somebody else can contribute on the subject?

 

[D.E.K]

No rush. While we're at it, I might as well replace the parts too, no? Or just fix the broken traces and power her up?