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Author Topic: Need repair advice for C15 on an A500  (Read 7210 times)

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Offline BosonMichaelTopic starter

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Need repair advice for C15 on an A500
« on: April 29, 2011, 05:01:08 PM »
While trying to remove a faulty U15 chip in my Amiga 500, I damaged C15. According to the A500 service manual, it looks like C15 is a 0.1uF capacitor. Does that sound right? I don't know much about component repair... can I use any 0.1uF capacitor, or is there a certain type I should try to get?
 

Offline Franko

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Re: Need repair advice for C15 on an A500
« Reply #1 on: April 29, 2011, 05:18:41 PM »
If it's a 0.1uf Capacitor and the voltage rating on it is say for example 16v then you can easily replace it with any other 0.1uf capacitor as long as the voltage rating is at least 16v... :)

Just remember to get the positive an negative terminals round the right way... ;)

As a general rule when replacing capacitor match the capacitance value ie: if it's 0.1uf then always replace with a 0.1uf but the voltage rating must always be of an equal value of higher & NEVER lower ie: if the voltage is 16v then replace with one that has a 16v rating or higher... :)
 

Offline tone007

Re: Need repair advice for C15 on an A500
« Reply #2 on: April 29, 2011, 05:24:33 PM »
Franko is correct!
3 Commodore file cabinets, 2 Commodore USB turntables, 1 AmigaWorld beer mug
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Offline JimS

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Re: Need repair advice for C15 on an A500
« Reply #3 on: April 29, 2011, 05:58:49 PM »
Actually, it's unlikely that a capacitor that size is polarized. It's just a noise decoupling capacitor. It's good practice to put those from 5v to gnd close to the chips. You'd probably run OK without it anyway.
Obsolescence is futile. You will be emulated. - Amigus of Borg
 

Offline Franko

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Re: Need repair advice for C15 on an A500
« Reply #4 on: April 29, 2011, 06:34:54 PM »
Quote from: JimS;634409
Actually, it's unlikely that a capacitor that size is polarized. It's just a noise decoupling capacitor. It's good practice to put those from 5v to gnd close to the chips. You'd probably run OK without it anyway.


Ooooh... dunno about that, here's a wee pic of one I had to replace in an old Hi Fi about 3 weeks ago... ;) (very rarely do I come across one's that aren't polarised)... :)

 

Offline arttu80

Re: Need repair advice for C15 on an A500
« Reply #5 on: April 29, 2011, 07:11:25 PM »
Sorry for maybe little offtopic question, but may I ask what are most likely symptoms in Amiga if some capacitor go bad?
 

guest7146

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Re: Need repair advice for C15 on an A500
« Reply #6 on: April 29, 2011, 07:17:41 PM »
I only have a copy of the A500+ manual but in there C15 is a 0.01uF (10nF) capacitor, non polarised (please re-check your manual and advise if yours says different.  From here on I will assume C15 is the same in your machine as the A500+).  As JimS has already said, it's a decoupling capacitor and is not critical to the operation of U15.  You could probably get away without fitting a replacement, although obviously this isn't ideal.

I checked the parts list and it looks like we're talking about a through-hole axial component, right?

Please see my info attached.




The capacitor is described as a Z5U device in the parts list.  That means it's designed to operate between +10 to +85 degrees C and has a tolerance of -56% to +22%.

Get yourself a replacement ceramic capacitor (MLC means Multi-Layer Ceramic) that matches those specs (easy peasy) and you'll be just fine!

If you want further help choosing a capacitor let me know and I'll suggest some replacements from Farnell for you.  In this case please photograph the component for me so that I can suggest one that will match the footprint of the original component.  I'd dig out my A500+ and find it myself but I've just moved and my A500 machines are both still at my old house!

Cheers!

AH
 

guest7146

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Re: Need repair advice for C15 on an A500
« Reply #7 on: April 29, 2011, 07:23:09 PM »
Quote from: arttu80;634422
Sorry for maybe little offtopic question, but may I ask what are most likely symptoms in Amiga if some capacitor go bad?

Unfortunately it's not quite as simple as "bad capacitor = symptom x".  The symptom will depend on what the offending capacitor's function in the circuit is, what type of capacitor it is, and the manner in which the capacitor has failed.

That said, there are some common symptoms associated with the failure of certain capacitors.  I've never had any problems like these with my machines so unfortunately I can't elaborate on that for you - although I do seem to remember something about poor sound quality being associated with dud capacitors on some machines.  Other members will be able to elaborate on this I'm sure.

AH
 

Offline Franko

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Re: Need repair advice for C15 on an A500
« Reply #8 on: April 29, 2011, 07:35:51 PM »
Quote from: arttu80;634422
Sorry for maybe little offtopic question, but may I ask what are most likely symptoms in Amiga if some capacitor go bad?

The only problems I've ever came across in the Amiga when it comes to capacitors has been Video problems (eg:wavy lines/patterns on the display) and once on a friend of mines A1200 with poor Audio quality... :)

You can't just generally put down problems on the Amiga to "bad capacitors" as at the end of the day it all depends on what the problem/symptoms are... ;)

Edit: Just noticed what AppleHammer said... That too... :)
« Last Edit: April 29, 2011, 07:37:27 PM by Franko »
 

guest7146

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Re: Need repair advice for C15 on an A500
« Reply #9 on: April 29, 2011, 07:36:51 PM »
Quote from: Franko;634414
Ooooh... dunno about that, here's a wee pic of one I had to replace in an old Hi Fi about 3 weeks ago... ;) (very rarely do I come across one's that aren't polarised)... :)

These days 0.1uF (100nF) capacitors are often non-polarised, ceramic surface-mount devices.

From the A500+ service manual, and assuming this information is the same as the A500 service manual, the component in question is a 0.01uf (10nF) non-polarised, ceramic, through-hole axial component.


PS: .... what in the name of all that is sensible is going on with your signature?!?!?

AH.
 

Offline Franko

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Re: Need repair advice for C15 on an A500
« Reply #10 on: April 29, 2011, 07:42:31 PM »
Quote from: AppleHammer;634429
These days 0.1uF (100nF) capacitors are often non-polarised, ceramic surface-mount devices.

From the A500+ service manual, and assuming this information is the same as the A500 service manual, the component in question is a non-polarised, ceramic, through-hole axial component.

AH.


Been many moons since I last looked inside an A500 or looked up the service sheets on them, but true... even in the A1200 most capacitors are non-polarised... :)

Trouble with Amiga specs sheets is they didn't adhere to them very well during manufacture, for example there are two different REV 1D.4 motherboards that I know of, seemed to depend when and where they were manufactured... ;)
 

guest7146

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Re: Need repair advice for C15 on an A500
« Reply #11 on: April 29, 2011, 07:46:49 PM »
Quote from: Franko;634430
Trouble with Amiga specs sheets is they didn't adhere to them very well during manufacture

Well, a simple photograph from the OP will put the issue to bed once and for all.

But in any case, regardless of what is currently fitted, a replacement 0.01uF ceramic axial component with specs the same or better than a Z5U component will do rather nicely.
Unless there's a difference between C15 in an A500 and C15 in an A500+ of course.  I don't have the A500 info unfortunately.

AH
 

Offline BosonMichaelTopic starter

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Re: Need repair advice for C15 on an A500
« Reply #12 on: April 29, 2011, 10:31:18 PM »
Quote from: Franko;634404
If it's a 0.1uf Capacitor and the voltage rating on it is say for example 16v then you can easily replace it with any other 0.1uf capacitor as long as the voltage rating is at least 16v... :)

Well, that's the problem... I don't know what the voltage rating is.
 

Offline Franko

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Re: Need repair advice for C15 on an A500
« Reply #13 on: April 29, 2011, 10:38:20 PM »
Quote from: BosonMichael;634462
Well, that's the problem... I don't know what the voltage rating is.


I've got the old service manual somewhere, I'll need to try and find it and check for you (been about 12 years since I last saw it) as some of the others have said it's most likely the non-polarised type and these sometimes have no indication of the voltage rating on them... :)

Hopefully I'll get back to you soon with the details or perhaps someone else can supply them in the meantime... :)
 

Offline Franko

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Re: Need repair advice for C15 on an A500
« Reply #14 on: April 29, 2011, 10:45:23 PM »
In the meantime you might like to look through this online Service Manual for the A500+, If I recall correctly though I don't think it contains a part list... :)

A500+ Service Manual...