exxos's Atari, Amiga & retro forum

The last one in the batch failed :( like before I could not see any shorts or broken connections etc, but it just does not work. So I have plastered it in flux and sent it to the fiery pits of hell for about six minutes...

EDIT:

Nope :( CPU was tested before it was soldered, GAL was verified after programming, can't really find anything wrong with it, but doesn't work.. Very odd... Gonna run it through the US cleaner just in case there is some gunk somewhere causing the issue.. but annoying as yet again have a board which should work but doesn't :roll:

Do the failed ones just not work or not working at 36/40?

just thinking that if it was a speed thing and thy ran fine at 32, sell them at that for a slightly lower price, I'm sure there will be buyers on here.

Forgottenmyname wrote: 23 Nov 2018 15:48 Do the failed ones just not work or not working at 36/40?

just thinking that if it was a speed thing and thy ran fine at 32, sell them at that for a slightly lower price, I'm sure there will be buyers on here.

They don't work even at 8MHz...

On a lot of boards I can see the CPU switching to 8MHz so its not like the GAL isn't working..

I've not checked this board on the scope to see if its got a clock or not, but none of the boards had a missing clock so far.. will check later anyway, its in the US cleaner having another blast currently.

I can't imagine you'd be that unlucky with Cpus. The few I've bought, every one has worked, albeit at 8mhz etc.

Forgottenmyname wrote: 23 Nov 2018 16:25 I can't imagine you'd be that unlucky with Cpus. The few I've bought, every one has worked, albeit at 8mhz etc.

I always test the use before soldering them anyway. Even the boards have failed previously, I have taken CPUs off several times and tested them directly board, and I have not had one CPU fail at any time. I've even swapped out the GAL's in previous boards in case there was something odd going on.

I checked the clocks on this current faulty board, and it is running as expected. Sometimes I get garbage and bombs on screen but that is pretty much it.

I will re-check absolutely everything on this board.. I need to find out what is going wrong.. There can only really be a bad connection somewhere. But I have already played this board and it made no difference and even under the magnifier all joints look okay. I guess it could be possible the PCB itself could be faulty..

Or the machine you are plugging it into?

No doubt you've used and abused it :D

Some progress.. this one does actually boot in 8MHz mode :roll:

So it would seem the CPU can't overclock enough.. *somewhere* I have some 16MHz chips....

EDIT:

Found some 32MHz ones... nope.. Found some 20MHz ones.. nope... though it does show the logo and mostly passes RAM test.. seems OK in 8MHz modes...

So thinking this isn't the "normal" range of issues I been having.. I think I just got a bad CPU :roll: I only tested them at 8MHz before soldering them on :roll:

Out with the iffy CPU...


In with the new...

Now the booster is happy and is currently looping through all tests at 36 MHz :cheer: :cheer: :cheer:

I guess this is what happens when you buy crap from China :(

So back to the plot... I need to build up the remaining 4 green PCBs.. Will have to be next week now..

So far all the green PCBs have worked perfectly other than this last one which had a bad CPU.

Assuming all these work fine, I will then start building up a batch of the red boards again and see the failures start coming back again.. If they do, I will likely just bin the red boards.. There isn't exactly anything wrong with them, just I suspect they are a lot more difficult to assemble than they should be, and it is resulting in high failure rates. So I will have to make the choice if to get another batch of PCBs made or not.

The ones which I have tested so far, mostly the working red ones, will be heading to my store very soon..

Well done. Glad you got to the bottom of the problems.

Good luck in getting the rest working and getting them sold to pay for all the hard work.

4 more now in stock :)

https://www.exxosforum.co.uk/atari/store2/#0147


Likely next week will start to appear the green boards without SIL's.