A4000 sound problems and AmigaKit

[Castellen]

http://cosmosamiga.blogspot.com/2010/03/preparer-un-colis-ii.html

There's some really good pictures there, been meaning to take some for my packing guide as well, but I never seem to get the time.

I'd strongly recommend using ESD safe packaging.  Bubble wrap and EPS foam chips are certainly not what I'd directly pack static sensitive items in.  Should be placed into an anti-static bag or covered in a layer of aluminiumn foil first to minimise the chance of damage.


As for the additional capacitor replacement time, I'm guessing there are around 12 pieces.  Haven't timed myself, but I'd estimate closer to 30 minutes for the job to be done correctly.  Some of the capacitors are in tricky spots with plastic components nearby which you need to avoid damaging with hot air.  Plus there's the additional $12 in parts, it all adds up.  As I said, if customers request it, I'm more than happy to do it.  However, although the capacitors are aging like every other component on the board, I don't recall the last time I saw an an A4000, A1200, A600 or CD32 with the 100µF, 47µF or 10µf parts failing, so there is less urgency to replace them.  The 4.7µF and 22µF parts are a different story; the electrolyte is far less stable, so it's necessary for all of these parts to be replaced.

[gertsy]

@gertsy:
Do you have access to a spare riser card to narrow down the problem?  Sounds like a possible termination problem on the riser card.  There are resistor networks along the top edge of the card which provide bus termination, one of these may be damaged.  You can measure them using an Ohm meter, keeping in mind they're a network with a resistor to +5V and another resistor on the same line to GND, can't remember the exact vaules, but you'll soon work it out.  All the data and address bus lines should measure the same.  Can scan the schematic for the riser board for you if you want to look further yourself.  Doubt if it's a damaged internal track, I think it's only a 2-layer board to start with.  And a damaged track would usually result in more serious problems such as certain slots not working at all.

Could be a dodgy Zorro card causing issues as well, have you tried other combinations of cards, and combinations with one card removed?

Failing that, I'm happy to have a look for you, just send me an Email.

I'll have a check of the resistors. Don't have a spare riser.  I wish.  I have two display cards that don't work beyond slot 1. One ZII Picasso II+ and one ZIII Retina Z3. Actually I've never tried the Picasso in slot 1.  The Picasso II works Puuurrfectly in my A2000. So I put 2 and 2 together and came up with 5.  The Retina works fine in slot one but after a few hours it can have freeze issues which I am thinking might be caused by the heat from the Lisa which is mms from the Z3 chip in the retina directly in line.  Good design.
I'll put the specs on and get out the trusty digital ohhmmeter. I am guessing as they are resistors I can measure accross each pole passive and I should get the same reading for each if not.. possible problem.  

Thanks for the tip.  I'll let you know how I go.

BTW Sorry about the Test.. (o;


I'm back. !

I checked each of the terminating resistors. From ground?(Pin1) I am getting 135 Ohms to each point except for the last(+5?) Which is 133 Ohms to it's neighbour.  Hope that makes sense.  Anyway the measurements were consistant across each of the resistors on the board, above and below the top zorro slot. (I was kind of hoping they wouldn't be) so I think that takes the resistors out of the equation?  While I was there I checked the other single resistors which are all 100k except for R601 whih I think was 45k or 49k from memory.  the 2 caps look visually fine.

I'm just about to do a track continuity trace from the edge connector to as high as I can go to see if I see anything strange there.  

BTW did I mention that my Buddah IDE works fine in the two top slots.

Might want to drop to PM otherwise this thread is well and truly hijacked.. soz all.

Cheers.  

Gertsy