exxos's Atari, Amiga & retro forum

Hello everyone,

I've been working on a TF534 build to get some practice in before the TF536 boards get here.

Things have gone reasonably well and the board boots diagrom now, but I'm trying to track down some memory problems. If I scan $40000000 to $40400000 then I get this:
I think this is telling me that it could read the bottom 16 bits ok, but the top 16 bits are duff. Or have I got that the wrong way round?

I'm thinking it could be:

1) Bad solder job on IC6/7
2) Duff IC6/7 (quite plausible as I've had them on and off a couple of times)
3) Bad solder job on RAMCS2/3 on the RAM CPLD

I've reflowed and inspected a couple of times, so I'm leaning towards 2)...

Neil

I had a lot of problems with soldering RAM chips.
I took needle and checked each leg to be 100% sure that they were soldered.

arkadiusz.makarenko wrote: 20 May 2020 23:11 I took needle and checked each leg to be 100% sure that they were soldered.

Hi Neil,
Built a TF534 a few weeks back, had a few issues with the memory scan on the initial boot.
Found my issues by conducting continuity tests between ram chips on the address lines. If you have Eagle or another software package that will read the board file, you can easily follow the circuit and check your soldering.
As @arkadiusz.makarenko indicated above a couple of fine needles attached to the multi-meter probes, and check each leg is connected will also identify ordinary solder joints.

Hope that helps :)

Thanks for the tips guys. Will give it another shot this evening

Success!
And here's the finished article. Things were getting a bit hairy around memory town there, as you can see :mrgreen:
Well, I've learned a huge amount putting this together. I'm sure the 536 build will go a lot more smoothly.

Thanks for your help, and thanks @terriblefire for creating it! Can't wait for my 3.1.4 ROM to get here so I can really try it out...

BTW, I have a few boards left over. If anyone's interested, shoot me a PM

Neil

Great work Neil, was it just a few flaky solder joints in the end?

Yeah, one on the big CPLD and a few on the RAMs. First time working at this tiny scale, but starting to get a feel for it now.

neilo40 wrote: 22 May 2020 22:16 Yeah, one on the big CPLD and a few on the RAMs. First time working at this tiny scale, but starting to get a feel for it now.

Hi neilo040

Since terriblefire deleted the TF534 Github repositories there aren't any Kicad or Gerber files, I wonder if you could point me in the right direction for these, please.
I know you were selling some PCBs on eBay in 2020, I'd like to make a board or two up and a PCB stencil would save a bit of fuss and bother.

Help appreciated!

:slapface: