A1200 Component broken

[Retrofan]

Hi:
I had an accident and a piece got broken in my A1200. It puts F3.00F. Which is it and where can I find it?


http://img821.imageshack.us/img821/2765/abcd0013br.jpg

[prowler]

Hi Retrofan,

The broken component is a ceramic resonator.

See this thread for more information:
http://eab.abime.net/showthread.php?...amic+resonator

[cosmicfrog]

hehehe ho no, My spare one went to Fitzsteve who did exactly the same

[fitzsteve]

Originally Posted by cosmicfrog

hehehe ho no, My spare one went to Fitzsteve who did exactly the same

Yep and thanks again froggy!

This board is now up ad running again even though Royal Mail gave it a good soaking after the repair

Albiet a little hit and miss, I think the water ingress so soon after repair has affected the joins.

@Retrofan what you need is someone with a dead board who can donate you the part, I couldn't find any identical - at least not that you could buy as a single unit.

[8bitbubsy]

This timer is used for the keyboard input, it is very important to change it with a working one!

[Retrofan]

Fitzsteve let me ask you a thing... did you break it installing a fast Ata?

You could have warned... That's what hapenned to me.

[cosmicfrog]

breaking components is just one more step to computer nivina and been an expert

[Retrofan]

I'm searching now a broken mb, and when I'll solder it I will try to leave it the lowest I can.

Wait a moment... what about this?

http://cgi.ebay.es/MURATA-CSA3-00MG-...item53db3eff0b

[8bitbubsy]

Should work. I'm not exactly sure how this component work, but my guess is that it is blocking the current but opening it each X ticks or something.

[Retrofan]

I will ask something else... About the fast ata, I put the ribbon cable upside down (the 4-way buffered ide goes that way) and later I saw that. What happens if you put the Hd ribbon cable upside down? Can I've made any other problem?

[Zetr0]

@thread

The 3Mhz resonator used with the keyboard MPU is just like any other *resonator based* clock - it is essentially a pump.



@retrofan

A great find - these should be drop in replacements - 4 pieces for under $10 is also a good price =D

the 40pin IDE is only SIGNAL theres no voltage going down the wire (well I think pin 20 might have it) but its grounded on the other end so if you get a 40pin cable the wrong way its possible (if the Fast ATA provides Pin 20 power) it may ground out.

Now the 44 pin on the otherhand has a nice juicy +5v : this wll be able to draw out aleast 2-3amps (quite toasty) so dont mess with it - treat the 44pin ide with respect and loving =D

I would suggest at this point you relax... get the board backup and slowly build up again - at that point should we find extra errors we can repair them as we go =)



Note
looking at the A1200 specifications hypothetically you could use a 3MHz crystal (not oscilator module) as a resonator replacement.

to be 100% confirmed I would have to test this on a motherboard - the reason I mention this is that the A1200 uses a PZT based resonators - I believe and contain Lead, thus due to RoHS in europe I believe that it will be difficult finding suitible 3MHz components.

I just checked Farnell and all they stock are 3.58MHz resonators, which is the same as www.futurlec.com - However futurlec do have 3MHz low-profile Crystals


It should be noted that while Crystals are a lot more acurate than a resonator, that are a lot more sensitive - so although the schematics look good enough for me to give a crystal a go within the circuit - remember this is not 100% prooved - besides its late and I am a little sleepy... I may of forgot something lol

I would suggest where you can stick with as close to the original components

[Retrofan]

Thank you very much, Zetr0. Yes, yesterday wasn't a good day for me and perhaps there's something else wrong, but let's go step by step.
Yes, you're true about the crystal and so. In other forum...
(---Here I must give an explanation that Zetr0 knows: I don't use to open the same thread in two forums at the same time, and I don't know if it's right or not, but as my thread here passed without answer some time or I was a little desperated, I tried in A-Org, and now I try to search in both sites.---)

...they told me the same, and Zac67 recomended me:


But one thing I've seen is that it seems taller than the original, and the last thing I want is that, because it has to stay under the Fast Ata board (well, it's true I can put it aside).

So, now I'm asking Tony at Ebay and he has to see if he has any mb left.
If not, I think I will buy the ceramic part of Ebay. I have enough to have the same piece working to start trying Crystals and experiments I don't have an idea.

[pandy71]

Direct replacement quartz instead ceramic can be not possible - usually ceramic ones are a bit different impedance than quartz - generator may not work - but connecting external oscillator should be possible - the best - just replace ceramic for ceramic, on same FDD's 3.0MHz ceramic can be found.

"Resonant Impedance: The net impedance of the ceramic
resonator at resonant frequency. Ceramic resonators have
superior resonant impedance than quartz crystal, which offer
much better start-up time."
www.abracon.com/Support/ceramic-resonators.pdf

[Anemos]

Crystal and Resonator have many differences between them.. > http://www.differencebetween.net/tec...and-resonator/

Personal i have use for 2 same PCB,s resonator (3pins) and crystal (added 2x30pf caps) to other ,that works same,but maybe is difference of this work on your A1200,try to found a same 3.00 ceramic resonator for sure.

[Retrofan]

It's a pity... because yesterday I received a sheilding alone that I bought at Ebay... and now I see this http://cgi.ebay.co.uk/AMIGA-1200-A12...item43a3380743
, but I'm not going to put a shop of sheildings... I have asked Tony at Ebay and he has to see if he has an spare mb. If it's faulty I will use it and if not I will use mine as spare donnor... ( I was appreciating it).

I don't know the tales about A1200 mb. Mine is Revision 1D.1 any quick guide if any are better than others?

[prowler]

Originally Posted by Retrofan

I don't know the tales about A1200 mb. Mine is Revision 1D.1 any quick guide if any are better than others?

Hi Retrofan,

Amiga 1200 motherboard Rev. 1-D-1 is the most stable and compatible version there is. This mothherboard revision needs no timing fixes to use faster (68040 up) accelerators.

[Retrofan]

Thanks. So I will repair mine in case of difference.

About putting the ide cable (I put both, 2.5 for the CF HD and 3.5 for the internal Cd) upside down, for what I've seen in other related thread about a buffered ide:

"Thomas wrote:
Also are you sure that you connect the IDE cable in the right way. Turning it upside down (pin 1 of the cable to pin 40 of the connector) will prevent the computer from booting. "
Other:
"If you do that the cable will fry!!!!! happened to me, lucky I caught it before any damage was made"

I don't think I had fried anything else, much more as it coudn't boot because of the broken ceramic part...

[fitzsteve]

Originally Posted by prowler

Hi Retrofan,

Amiga 1200 motherboard Rev. 1-D-1 is the most stable and compatible version there is. This mothherboard revision needs no timing fixes to use faster (68040 up) accelerators.

I'm sure this is a myth, I've got 3 1D4 Mobo's here (2 without timing fixes) and they all work perfectly with:

Apollo 1240
Blizzard 1260
Blizzard PPC 060/240

[rkauer]

And I also had a 1D1 board that refuses to work with anything but a 030 card.

After making the timing fixes it worked with 040 & 060 accelerators no trouble.

[prowler]

Originally Posted by fitzsteve

I'm sure this is a myth, I've got 3 1D4 Mobo's here (2 without timing fixes) and they all work perfectly with:

Apollo 1240
Blizzard 1260
Blizzard PPC 060/240

Originally Posted by rkauer

And I also had a 1D1 board that refuses to work with anything but a 030 card.

After making the timing fixes it worked with 040 & 060 accelerators no trouble.

Hi guys,

It's certainly not a myth. Details of the reasons for it have been given previously in these forums. However, it should be seen as a general rule only, as there's always a degree of unpredictability regarding individual motherboards due to component tolerances.