TF536 Bad Expansion Diagnostic

[Bmrsred]

Hello
I soldered the Tf536 pcb purchased from Shop Exxos over the weekend. :)
In the Amiga 500 with Kickstart os3.2 tested I got the error as in the picture.
I checked the soldering points again but I can't find anything wrong.
maybe you can help me with my investments

4BE3F0FE-7F37-47AC-A898-581E694D6722.jpeg

[PhilC]

If you have Diagrom then use that and carry out a memory test.

[go0se]

A diagnostic failure on the 536 is almost always a RAM soldering issue.

Check the following:

1. You definitely don't have any bridges or unconnected pins on IC7,IC8 or U1-U4. Use magnification to check. Also check for bridges and unconnected pins on the CPLD side, particularly those pins linking the CPLD to IC7 and IC8.

2. The memory chips you are using are definitely suitable for the TF536. If you got them from somewhere reputable and the part numbers are know to work then they are probably fine. If you got them from AliExpress or UTSource then they are possibly faulty or not what they claim to be.

3. IC7,IC8 as well as U1, U2, U3 and U4 all have correct pin1 orientation i.e. they're not soldered in 180 degrees out of whack.

Upload some clear, well lit photos, without nasty reflections if possible. Viewed from top down and 45 degree angle on soldered edges of the chips listed above.

[Bmrsred]

Thanks for the quick help

i actually bought the rams from alliexpresse.

I took a few photos with my cell phone.
which are not so good, but I'll post the high-resolution ones later.

64C9ED1D-6322-466C-9D48-7292F11A33A0.jpeg

5B0F5EED-3A02-4FA7-A670-DC076E4B73BB.jpeg

4F45494C-149A-4CB0-B8E0-80764F30791C.jpeg

[terriblefire]

The red screen is usually a sign the ram is totally dead. if it was slightly working or partially (areas etc) it would boot loop.

[alenppc]

Buying ram from Aliexpress is a bad idea, I recommend you get it from mouser/digikey instead.

[Danoo]

Buying ram from Aliexpress is a bad idea, I recommend you get it from mouser/digikey instead.

Yea totally agree, have been down this path myself, some work but most are just silicon waste.

[dalek]

Looks like solder bridges on the ram in the second pic - really need high res pics from multiple angles as goOse said.

Look at the bottom right of the top right chip and the top left of the left one in the second pic.

And yeah - chips from Ali is a bad idea - been burned by them a few times too. The time spent troubleshooting is not worth the dirt cheap prices.

[Bmrsred]

Hi
Thank you for the many ideas you are great.
Unfortunately I have problems with my microscope I will upload it at the weekend.

You are right, I will swap the ram.
I will order the ones from Digi-key.
what do you think of these?
MT48LC16M16A2P-6A:G TR

[alenppc]

Hi
Thank you for the many ideas you are great.
Unfortunately I have problems with my microscope I will upload it at the weekend.

You are right, I will swap the ram.
I will order the ones from Digi-key.
what do you think of these?
MT48LC16M16A2P-6A:G TR

That should work fine.