A500+ Broken Component !

[NikGrey]

Hi All,
Like many I'm reliving My youth with the Amiga.

I recently bought an Amiga 500+ Rev 8a and found the battery had started to leak - not badly, more like corrosion.
So I changed that for a modern equivalent, I tried the machine again and nothing (same as when I bought it) - a black screen and I 'Think' the green LED is dim. so I started to re-seat the chips after cleaning them (IPA and a fibreglass pen).
To be honest I think it must have been Me who damaged the component.

I would like to know what it is and what I can replace it with if this part is no longer available (I just checked the many PCB's I have here and none of these to be found).

NikGrey.

[AndyFC]

Hi and welcome to the forum.

That's a ceramic capacitor. Fortunately they're cheap and easy to buy.

I don't know if chipping off the ceramic casing affects the operation.

[F0LLETT]

I'd replace it. Even if it didn't effect operation. However it is there for a reason.

Its a 101, 100pf (0.1nf). They are easy to get hold of and cheap as AndyFC said.

If its a 500+ board. It will more than likely be damage from leakage. Had one recently and it only started booting, after I changed 3 sockets (curroded) and one ceramic cap by ram (it was short).

[NikGrey]

Thanks for the fast replies, it's lovely to find an active forum in times of trouble

I found that Gary was not seated properly, now I get a white screen and a single Green flash of the caps lock.

I understand it's difficult to help remotely as I'm DysonDoctor.com and I often get people trying to resolve a problem over the phone so I'm super grateful for any input from forum members

My sockets, well - Paula and Gary's do have a certain amount of verdigris inside them and Gary wasn't getting warm (not sure about Gary now/yet as I only discovered he wasn't happy in his socket).

And thanks for identifying that ceramic resistor - I though this was what it was but needed expert clarification.

I'm thinking I should re-seat everything again ?
You will have to forgive me if I ask obvious questions as electronics aren't my thing.

Am I correct in thinking that the only thing I need connected to the board is the keyboard so I can see the lights ? the floppy drive doesn't need to be connected ??
I just have the bare board on a quartz kitchen worktop so there shouldn't be any shorting etc.
I know My PSU is good as I usually have another Amiga permanently set up in the kitchen as I'm obviously single and a big kid

Nik.

[notel98]

This link might be of some use. If sockets are dirty you might want to spray some contact cleaner on them too.

https://ia601203.us.archive.org/13/items/Amiga5002000TroubleShooter/Amiga%20500-2000%20Trouble-shooter.pdf

[Castellen]

I would like to know what it is and what I can replace it with if this part is no longer available (I just checked the many PCB's I have here and none of these to be found).

The damaged component appears to be E632, which is a 100pF feed-through capacitor on the keyboard clock line.  That won't prevent the computer from booting, but if it's open circuit, will prevent the keyboard from working.  There should be close to 0 Ohms between pins 1 and 3, and no connection between pins 1 or 3 to the centre pin (ground).  The component performs decoupling of high frequency noise on the keyboard clock line, and the system will absolutely work fine without it.  If the part is damaged (open circuit between pins 1 and 3), then you can replace it with a wire link between pins 1 and 3.  A standard 100pF capacitor (2 leads) is not a drop-in replacement a feed-through capacitor (3 leads).

A brief read of this thread suggests there are obvious IC socket corrosion issues.  In which case replace them first, clean IC leads as necessary, and look at any remaining faults after that.