A 500 sound issues (Short maybe) - Resolved
 

Hi again,

Seems I got the one of the worst possible A500s on ebay that was supposed to be working in good order. Provided you don't count the non-responsive (sometimes) left mouse button, the non working Shift key and the non working 0 keypad key. Sheeshk.

I started a thread for the keyboard issue and I'll address the recommended fix. But now a new problem that I thought I fixed:

Sound output not working on the RCAs. I noticed if I pushed down on the RCA where it plugs in to the jack the sound comes back although a tad bit distorted. I took the case off and examined the motherboard and everything looks visually good. I pushed down on the grounding bars(?) on the top of the RCA jacks and bent them a tad bit in and then the sound seemed to work fine for a while. Now it is back to not working/distorted without pressure.

Any advice on how I could possibly fix this?

This is really disappointing. Oh well its a 24 year old computer. :laughing

Thanks

if it is the connectors and pressing down on them makes the sound come back on it could one of two things.

1,the connectors socket has levers inside which press on the plug to make contact and there bent and might need pushing back to make them work.or even needs to replace the sockets completly.
2,the solder joint which holds the socket on the motherboard has developed a dry joint and will need re-soldering.

and this is of course if you have good leads to connect it up with.(which dont have anything wrong with them)

these are the most simple fixes i can come with,but you will still have to have some soldering knowledge.and the tools to take your machine apart down to motherboard to get at the underside for inspection.
youll have to do this anyway,as you know there not getting any younger.

When people pull out the RCA plugs, they often wiggle the plug up and down until it comes out, thus bending the insides and stressing the solder joints. So it is like roy_bates writes one of those two (I'd say 99% sure).

Thanks roy and demolition.

I have no problem taking it apart and adding some solder to the joints. If I hold the cable up or down it seems to work fine so what you say makes sense. I have tried 2 known good cables. I also have a de-solder iron is it a good idea to suck the old out first or just simply heat it and add a blob of solder?

Thank You!

yes, just heat it up and add a little solder to it if needed but not too much.

if you can,use flux paste and clean it off after with ipa.

if there is a problem with the solder joints youll more than likely be able to see it with the naked eye as it will crack check all the solder joints while your at it.it time consuming but worth it.another socket ive seen myself known to go bad is the power socket mouse, joystick ports etc,because there used alot.
while your there check all the underside pins on the dil sockets as well ive seen them go bad a few times.

Alright sounds good. I have a flux pen, does that work? And I have no clean solder, not sure if that makes a difference.

i dont use flux pens for this i use flux paste that you have to brush on.and leaded solder.

you might just get lucky and just simply have to re-melt the solder on the joint with the tip of your iron.

Ok thanks for the tips. I am not an electronics wiz, by any stretch so forgive my ignorance. What advantage does leaded solder have in this situation? I guess I don't know what the difference is in type of solder.
thanks.

Lead-free solder melts at a higher temperature than lead-based solder. The Amiga's 24-year-old motherboard was designed and built in the days before unleaded solder was developed, and so cannot be assumed to be able to withstand the higher temperatures required to work with unleaded solder.

Therefore, to guarantee the integrity of your repaired solder joint, it is recommended that you use lead-based solder aided by a little flux paste, which will remove any tarnish (oxide layer) which may have formed on the original joint and enable the new joint to flow properly.

+1 for leaded solder when working with pre ROHS Compliant circuits.

I personally HATE lead free solder as it's much more difficult to work with, plus you get solder whiskers with lead free which will shorten the life of the circuit.

the phrase "they don't build 'em like they used to" is certainly apt for this thread :D

good luck anyway! not that you'll need it as reflowing a lead joint is a piece of cake :)

All right sounds good. I guess I need to check my solder. I did a repair on a C= 1581 drive with this same solder on the main switch (6 contacts plus 2 frame joints) and it seemed to work fine, don't know if it is leaded though.

It just says MG Chemicals Solder, No Clean Sn60/pb40, 22 gauge 0.032" diameter. Doesn't say lead free or anything like that. It seemed to melt fairly easy with my 25 watt iron...

Pb is the scientific symbol for Lead. you're good to go! :great

Yes, it's lead-based alright -Tin(Sn)60%/Lead(Pb)40%. :great

Does it mention "resin-cored" or something similar? If so, you may not need flux paste.

Edit: "No Clean" may or may not mean that the solder incorporates a flux core.

Does the a brown waxy residue form on the iron bit when the solder melts?

typically flux is sold as "no clean", so i think you maybe right.

another clue is looking for smoke when it touches the iron and listening for a "hiss" or popping bubbling sound. of the non fluxed solders i've used, barely a whisp of smoke is seen when i prime my iron tip, but with the fluxed stuff you cant miss it (or the smell!)

EDIT, either way, fluxed or not flux cored, i always use flux as it pools the solder better for me and my single temperature iron. some thinner guaged flux cores don't have enough in them for my taste

Well, that's pretty conclusive. I would say that Zippy Zap is all set! :D

Yes, of course, those signs will give it away too. :)

Edit:I must admit I've only used flux paste for soldering copper pipe unions when I'm fixing up the plumbing with a blowtorch! :D

I have a good temp-controlled iron for electronics, multi-resin-cored 22 SWG solder and a lot of experience with it, so I have never needed flux paste.

most definitely :agree

time to get your iron on :spin

Cool. Learn something new everyday.

No it doesn't say resin core. I'll get some paste. Oops didn't use any on the C=1581 switch. It seems to work fine though, so hopefully it stays that way. I de-soldered the old switch and put in a new one. This one sounds easier. Now to find the time to do it. haha

Thanks everyone for the help!

Edit: Read the replies after I posted. I think it does smoke a bit. Sounds like I may be ok, so I'll try it out. Hopefully I can't screw it up too bad. LOL!

Good luck! :great

Be sure to report back and let us know how you get on. :)

it'll take you less time to reflow them than the time you'll wait for the iron to heat up, and then cool down again for putting away :laughing

to reflow, i cheat... after tinning my iron tip, i dip the end of the solder (NOT the iron!!!) in my flux... hold my iron to the contact needing reflowing until it melts, and then just touch the iron with the fresh solder for a split second. = total time for all of that, about 3 seconds. and an even shinier joint than before with no bulging of the solder :cool


:great

Hey, that's not cheating. :shocked
It's how you should have been taught to do it if you served an electronics apprenticeship like I did! :cool
Edit: Either that, or you're just a natural! :D