Need to wash a board

[Spork Schivago]

Hey, I'm working on my future mother-in-laws stereo. It just stopped playing, she said. I get output of the speakers when I plug into auxilary. When I switch the tuner to FM, I get nothing. When I switch to AM, I get nothing. No static or anything so I know it isn't the antenna.

Anyway, I decided to rip it apart and much to my dismay, there was a mouse nest inside. I want to start testing various parts but it's real nasty. I vacuumed up most of it but I need to wash it. What's the best way of doing this without damaging the board? My father and I have a part washer for car parts. I was almost tempted to use that, however, I know that's not a smart idea. Is there anything like that for electronics or any liquids that would be safe to use such as rubbing alcohol?

Thanks.

[t.j.]

Re: Need to wash a board

warm slightly soapy water! let soak a bit then use a finger nail brush on it! tooth brush works too!

[Spork Schivago]

Re: Need to wash a board

Thank you T.J.. The minerals in the water won't short out the connections after the water evaporates? We have hard water here because we live in the country and have a well.

[t.j.]

Re: Need to wash a board

rinse with distilled or bottled water after! can take a hair drier to speed up drien process !

[Spork Schivago]

Re: Need to wash a board

Okay, thank you very much. I will do this and go from there. Wish me luck, this thing is disgusting! I still haven't figured out how the mouse got in there!

[ComputerGeek]

Re: Need to wash a board

Yes if you rinse with distilled water you should be fine, I have washed a couple of boards and they have worked. I would not use the hair drier though, I would be concerned with the heat on the board and the Caps.

[Spork Schivago]

Re: Need to wash a board

Okay, just out of curiosity, how much heat does it take to ruin a capacitor, in general? I got a heat gun and was thinking of getting some spare parts off of some broken electronics using it. Up till now, if I needed a part and didn't want to / couldn't order it, I'd just desolder it. I was thinking a heat gun would make it a lot quicker though {:- )

[t.j.]

Re: Need to wash a board

dont over heat the board though! that is why i say hair drier! putting on heater vent with furnace running works too!

[999999999]

Re: Need to wash a board

There's probably no need to wash the board, merely dust off the heatsink unless it is highly visible through the top of the amp case so it looks disgusting.

What exactly does "I get output of the speakers when I plug into auxilary." mean?

It would be very difficult to damage the board, if they are smokers then spray some Mr. Clean or similar ammonia based cleaner on it and let it sit for a minute before rinsing. Otherwise plain warm detergent solution will suffice. No need to rinse with anything exotic, any tap water suitable for drinking is pure enough. No need to speed dry it either, just gently shake off excess water and set it on its side. However, a hair dryer held at a reasonable distance won't heat up the caps enough to matter, although if the amp is pretty old they might be degraded in performance already though if it still sounds good once the failure is repaired I would wait to recap unless it's a high value amp.

Most often an audio amp fails from either a blown fuse, diode, or output transistor. Trace the power and signal, power from the input and signal backwards from the output. Be careful when working with live circuits, do as much as you can before powering it up.

If you want to cannibalize caps off boards with a heat gun, get them off the board by heating the back of the board first, before other components. Otherwise with surface mount caps just be vigilant in pulling the cap off the moment you get the solder melted, not heating it any longer than that. Generally, capacitors are not rare or expensive enough that their reuse is a good idea unless reliability and performance doesn't matter, particularly when they are one of the shorter lived components in consumer electronics if they're electrolytic.

[t.j.]

Re: Need to wash a board

There's probably no need to wash the board, merely dust off the heatsink unless it is highly visible through the top of the amp case so it looks disgusting.

What exactly does "I get output of the speakers when I plug into auxilary." mean?

It would be very difficult to damage the board, if they are smokers then spray some Mr. Clean or similar ammonia based cleaner on it and let it sit for a minute before rinsing. Otherwise plain warm detergent solution will suffice. No need to rinse with anything exotic, any tap water suitable for drinking is pure enough. No need to speed dry it either, just gently shake off excess water and set it on its side. However, a hair dryer held at a reasonable distance won't heat up the caps enough to matter, although if the amp is pretty old they might be degraded in performance already though if it still sounds good once the failure is repaired I would wait to recap unless it's a high value amp.

Most often an audio amp fails from either a blown fuse, diode, or output transistor. Trace the power and signal, power from the input and signal backwards from the output. Be careful when working with live circuits, do as much as you can before powering it up.

If you want to cannibalize caps off boards with a heat gun, get them off the board by heating the back of the board first, before other components. Otherwise with surface mount caps just be vigilant in pulling the cap off the moment you get the solder melted, not heating it any longer than that. Generally, capacitors are not rare or expensive enough that their reuse is a good idea unless reliability and performance doesn't matter, particularly when they are one of the shorter lived components in consumer electronics if they're electrolytic.

has mouse urine an feces on it! needs a wash!

[bluto]

Re: Need to wash a board

The cleaning motherboards thread might be useful here: https://www.badcaps.net/forum/showthread.php?t=1463

[Spork Schivago]

Re: Need to wash a board

There's probably no need to wash the board, merely dust off the heatsink unless it is highly visible through the top of the amp case so it looks disgusting.

It's actually a stereo, not an amp. It's a Panasonic RX-C45 stereo.

What exactly does "I get output of the speakers when I plug into auxilary." mean?

When I have it set to tuner, on either AM or FM, there's no sound out of the speakers. Not even static. On the back of the stereo, there's some RCA plugs for me to hook the stereo up to an external source (like a CD player). When I hook something like a CD player up to the unit, the music comes out of the speakers. Also, I believe the tape deck works as well, but I haven't been able to test it because I have no tapes.

However, a hair dryer held at a reasonable distance won't heat up the caps enough to matter, although if the amp is pretty old they might be degraded in performance already though if it still sounds good once the failure is repaired I would wait to recap unless it's a high value amp.

I will try the hair dryer after washing it.

Most often an audio amp fails from either a blown fuse, diode, or output transistor. Trace the power and signal, power from the input and signal backwards from the output. Be careful when working with live circuits, do as much as you can before powering it up.

Does this still hold true seeing how it isn't an AMP? Just the AM/FM isn't working. I figured it was something with the radio circuitry. I don't know much about this stuff, still learning.

If you want to cannibalize caps off boards with a heat gun, get them off the board by heating the back of the board first, before other components.

Thanks.

Generally, capacitors are not rare or expensive enough that their reuse is a good idea unless reliability and performance doesn't matter, particularly when they are one of the shorter lived components in consumer electronics if they're electrolytic.

Okay, around here, only place to get parts like that is from Radio Shack. They don't have a huge selection of components. I hate ordering them off the net. Can you suggest some of the more important components I might be interested in saving? Thanks.

[Spork Schivago]

Re: Need to wash a board

The cleaning motherboards thread might be useful here: https://www.badcaps.net/forum/showthread.php?t=1463

Thanks Bluto! I had an idea from what others posted on how to do it. I like the fan idea overnight though. I'll do that.

[999999999]

Re: Need to wash a board

I usually save stuff like through-hole ICs, heatsinks, transformers, maybe switches and various hardware... depends on what it is and if I have any of the component and how much it costs.

Digikey is a great place to order online, a wide selection and for orders under 8 ounces, an inexpensive USPS first class shipping option which for some small orders I place, usually comes in between $2 and $3 shipping cost and at least at my location, usually arrives on the 3rd business day after ordering. BIG improvement over years ago when they had a $5 small order fee and shipping started at roughly $7 and went up from there.

Thanks for explaining about the AM/FM, it does seem the tuner is suspect not any of the things I mentioned, although it could still be a power subcircuit going to it.

[Spork Schivago]

Re: Need to wash a board

I just recently ordered a film capacitor off of digikey. A snubber / safety cap on an amp needed replacing. The reason I don't normally order off of digikey is because I'm not 100% certain if the part I'm looking for is the same one on digikey. For example, my snubber cap wasn't on digikey. A forum member helped me find a replacement one on there. If it wasn't for him, I never would of found it. I searched as best I could for one, but some of the values in the filters are beyond my electronic understanding. A friend is supposed to be loaning me a book that explains the theory behind the electronics. I can build a circuit with schematics and replace broken parts, but actually understanding how it works is beyond me, right now. I wish I could find a digital copy of a book that would help me in the department.

[999999999]

Re: Need to wash a board

http://www.google.com/search?q=learn+electronics+PDF

There's definitely a learning curve, start out memorizing things like component function, relevant parameters, and studying basic circuits then eventually it all starts to click into place and you'll want to build stuff and spend a lot of money on a personal component inventory. There are also a lot of online tutorials rather than PDFs.

[Spork Schivago]

Re: Need to wash a board

Hey, I'm getting ready to wash this board but I got a few questions left. There's a part on the board, I'd call it the AM/FM tuner. It has a wheel on it and when you turn the wheel, it changes the frequency for the stations. There's also a volume pot and some slider switches. I can get all of those wet, right? I'm afraid that if I get them wet, water will get inside and stay there when I dry them out.

[999999999]

Re: Need to wash a board

There are a couple of things to keep in mind. One, detergent solution is generally used to wash boards but it may degrade the grease on the mechanical portions of the tuner so they "might" need greased. For that matter the original grease may have hardened years ago and they might benefit from fresh grease either way.

Second, yes you will get water in the little nooks and crannies that won't dry out fast. This is why the final rinse should have something in it to decrease the water surface tension so there aren't any drops sitting around later, that when you shake the board gently most of the water comes off. There are a few options like a drop or two of detergent, dishwasher rinse agent, (more than a couple drops of...) alcohol mixed in. If you have low enough surface tension the water will sheet off instead of forming drops on the board., which also gets it out of nooks and crannies better.

It will need to sit in open air for a while to be sure everything is dry, pointing a fan at the board will reduce drying time. I'd leave a fan on it at least a day or a few days without a fan, but tapwater isn't especially conductive at low voltages so if they were slightly damp inside the remaining concern is corrosion of brass contacts in switches, pot sliders, etc. but being mechanical they should wipe themselves clean enough, brass doesn't corrode very fast/much in tap water. You might also consider spraying those with contact cleaner and turning or sliding them but I mean only the ones user controlled from the outside, do not turn the variable capacitors or other fine tuning that's not normally user accessible.

However, some contact cleaners also displace water so using one that does would be the ideal... but not really necessary.

[Spork Schivago]

Re: Need to wash a board

Thanks. Does Radio Shack sell this contact cleaner? I might of moved the variable capacitor a very little bit the other day. That'll just make the displayed frequency off a little, right? For example, if the stereo shows the station on 95.1 FM, it might actually be on 95.6 FM.