My new Amiga 4000T - work in progress

[Hanzu]

Don't know about A4000T I just pulled oscillators for3 motherboards and it is this way:

• A4000cr Rev D U104 not socketed, but U154 socketed.
• A4000 Rev B U104 and U154 socketed.
• A4000 Rev B U104 and U154 socketed.

So since Rev D is closer to age of your A4000T, I thing manufacturer decided to not socket 50MHz oscillator anymore to reduce costs and/or because of users were more tempted to experiment with overclocking and breaking something.

None of my 3 Y176 and VC190 are touched by soldering iron and I see no reason why that part should be hand assembled and hand soldered for A4000T.

More on VC190 http://amiga.serveftp.net/RTCrepair.html

I think no A4000 needs those clock circuit parts to be able to boot. Correct me if I'm wrong.

[Hanzu]

I have officially quit Amiga repairs for others for reasons explained (in finnish) here: http://saku.bbs.fi/cgi-bin/discus/show.cgi?3/9250

But if I ever get my last foreign customers A4000 repaired I may take a look but promise me to get it out of my hand if it starts to last. I have bad habit to not give up easily. It would be wrong to delay that A4000 repair I took before quitting with another hard case.

The substance in your picture may be harmless process or flux marks that you still see on the solder side of new PC motherboards. It also looks like water stain that I see often in my real work. Either way clean it with isopropanol tipped cottonstick or what ever it is in english.