My A1200 Rev. 1D4 motherboard doesn't load from floppy drive

[Amiga1983]

Hi everyone,

I'm Laura from San Francisco and I'm new on this forum. I was wondering if you could help me with a problem I’m having at the moment with an Amiga 1200 and, in particular, with a motherboard Rev.1D4 I bought months ago from a UK seller on Ebay.

This A1200 has the following problems:

1) it turns on, boot to OS from my old hard disk, but it takes at least 15-20 seconds in order to do so because it keeps on looking for the floppy drive (for at least 3 times);

2) the FDD light turns on normally, but under OS the famous "tik tik" sound of the drive is missing.

To rule out any kind of problem with floppy drives and cables, I must mention that I tried with 2 different floppy drives, both Chinon, I replaced both power/data cables with new ones, I also checked all the connections but, unluckily, still nothing changed.


This is what happens:

- When I try to insert a floppy disk under OS, a "DF0:Unreadable" icon appears;

- When I try to boot the Amiga directly from a floppy disk, it tries to load it but after other 15 seconds it boots to OS.


I read that some particular Amiga mobos have these kind of problems. Mine is NOT Escom: it’s Commodore and was made in the Philippines in May/June 1993.
Some users of the Facebook group "Commodore Italia” observed my pictures and noticed an INTERRUPTED TRACE (close to C306) that goes from pin 3 of U26 to the through-hole. However, I can't see any interruption, but I'm not an expert. Plus, the defect could also be due to damaged SMD CAPACITORS. Still, this is not my diagnose and I have no idea if it is correct.

Now, talking about my mistakes: I tried to solder a cable from pin 1 of the external FDD to pin 34 of the internal FDD because, as explained in some online forums and guides, other people have the same problem as mine and could fix it thanks to this "mod". In doing so, I lifted a trace but, thankfully, Amiga still boot to the OS. I have no experience in electronics or in soldering electronic things, and the tip of my soldering iron is also too large.

Here's a Google Drive link to a folder containing 4 detailed photos of the floppy drive area of my motherboard (if you need more photos, just let me know). I couldn't upload or attached them here directly because too big: https://drive.google.com/folderview?id=0Bx4kGbpVHsqfSnBfS3d1bnFYcWM&usp=sharing

Despite not being an expert, I noticed some leakage around C591 and over C28A and maybe there's much more.
If you could help me fixing it, I would keep this motherboard: I have no money to purchase another one or another Amiga at the moment, and the prices on Ebay are simply unacceptable for this model. Or, if you have another A1200 motherboard that you could sell me, I’d try to get rid of mine selling it for spare parts first and then I’d purchase yours. I spent so much for it in the past and now that i'm unemployed I need some money back.

Thank you so much to all of you for any help you could give me: it will be highly appreciated!

Have a nice day,

Laura

[paul1981]

A few bad caps just looking at those pics. The board needs a thorough inspection to check traces and vias. Would be a shame to ditch the board...I hope someone on your side of the pond comes forward to help you. Good luck

[QuikSanz]

Hi,

Welcome to AO. There are 2 places I know of for cap replacement, one is in Oxnard, CA. He is Acill who is on this forum or AW forum. The other is this one in Michigan,

" http://maccaps.com/MacCaps/Repair_Service.html "

[Amiga1983]

Hi Paul and QuikSanz, thank you!
I've already contacted MacCaps on Ebay, the problem is that he only replaces the capacitors but doesn't test if the Amiga works after that, plus it seems he has no knowledge about repairing traces and other problems.
I'm interested in contacting Acill, hopefully he can help me keeping this great motherboard because it would be a pity to sell it for spare parts when, after all, it's still working except for this defect.

Thank you again to both of you for your precious advice!

Laura