AGH! Why do things keep breaking on me?!
nj pheonix
Lunatic Member
And just to be sure, the second one was working before you started?
It might get confusing trying to troubleshoot both in the same thread at the same time.
It might get confusing trying to troubleshoot both in the same thread at the same time.
I've yet to find any measurements here. You cannot recap a unit without verifying at least the power supply voltages. Before and after. A non-responsive micro (as evidenced by a working display without information) hints to a missing voltage somewhere. Get the manual. It's all in there.
Having said that. If the second unit has exactly the same symptoms as the original one after your recap you must have introduced the exact same fault. Missing plug maybe?
Having said that. If the second unit has exactly the same symptoms as the original one after your recap you must have introduced the exact same fault. Missing plug maybe?
dly66
Addicted Member
Putting in new filter caps with everything else as it should be should result in a functioning unit. Something is not right.
Did you check out the new SX-50 after you received it to make sure it was working properly?
Maybe more pictures of the work would help remote diagnosis. Top side pictures may help.
Did you check out the new SX-50 after you received it to make sure it was working properly?
Maybe more pictures of the work would help remote diagnosis. Top side pictures may help.
cpt_paranoia
Addicted Member
Are there any fuses in the PS section? Could your new caps have blown a fuse due to higher inrush current? Are the new caps the same value as the originals?
The bias wouldn't make the front panel not work. Changing the 2 big power supply caps wouldn't change the bias anyway. There has to be missing voltage somewhere. If you are absolutely certain there was no damage to the "new" unit's board, either those replacement caps are bad or installed wrong. Could have blown a fuse somewhere. I'd put the original caps back in if they were working, and be absolutely certain they are installed in the correct direction. The caps are polarized, so it is possible to install them backwards. That will cause things to not work.
Looked up the SDS on this. Its petrolatum, zinc chloride, and ammonium chloride mostly. There are also trace amounts of tin, bismuth and copper in it.
petrolatum is just petroleum jelly. Vaseline. Not a big deal, just greasy.
zinc chloride is a salt, it will dissolve in water. This is mostly whats doing the work, since it also eats metal oxides. It is corrosive so it needs to be cleaned off, but hey, water soluable.
ammonium chloride is another water-soluable salt that reacts with metal oxides. Its the other active flux ingredient.
the other materials are metal, and would be conductive.
Use q-tips in an 70% rubbing alcohol to clean the area off and you should be fine.
petrolatum is just petroleum jelly. Vaseline. Not a big deal, just greasy.
zinc chloride is a salt, it will dissolve in water. This is mostly whats doing the work, since it also eats metal oxides. It is corrosive so it needs to be cleaned off, but hey, water soluable.
ammonium chloride is another water-soluable salt that reacts with metal oxides. Its the other active flux ingredient.
the other materials are metal, and would be conductive.
Use q-tips in an 70% rubbing alcohol to clean the area off and you should be fine.
The Fuxtor
Addicted Member
that!
OK, this is what you do. The power supply has seven voltages that are relevant. They all come from the same source: those dreaded power caps C106 and C107 which you replaced. I want you to check all of'em. First the voltages across C106/7 (44 V), the emitter of Q104 (+16 V), emitter of Q105 (-16 V), the emitter of Q102 (+16 V), the emitter of Q103 (+5.5 V) and point C2 (+4.9 V). These are all on the "complex" board. Now stop replacing stuff willy nilly and get us some readings.
Unfortunately, it's impossible to find rubbing alcohol anywhere because of COVID. Would acetone work instead?
Because of the flux, do I have to replace any components around the filter caps? (Diodes, resistors, etc.) They all look fine to me, and they weren't really touched by the flux.
Actually, he has three threads going. Not cool.
Okay,
Get one more sx50. Now make a video. We'll see where you go wrong.
All kidding aside, (not making fun of you, or at least no more fun than I make of myself anyway).
I'm not sure your issues are related, though they quite possibly could be
I think I've found my problem here.
The flux I used to solder on these filter caps is actually Oatey No. 95 lead-free tinning flux. It sounds innocent enough, but it's actually PLUMBING FLUX. Upon further research, it's corrosive and contains trace amounts of metal... I'm going to desolder the caps, and scrub all of it off the board before I really have an issue.
I'm also trying to get the voltages, but I don't have a DMM, and my analog multimeter is being an idiot. Yes, yes, I know DMM's are important, I need one for sure.
And yes, the new SX-50 was working as it should, aside from a strange buzz noise every time I changed the inputs. Seemed to be related to the filter caps. The filter caps would also squeal slightly when I shut the unit off. That's what led me to replace them.
One of those threads is from before I had this issue. If there was a "delete thread" button, I would gladly use it.
Understood!