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Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Fri Jun 08, 2018 7:55 pm
by exxos
Forgottenmyname wrote:
Fri Jun 08, 2018 7:42 pm
Is it possible that the board is warping underneath the cpu after it's been on load and warmed up? thus breaking some of the contacts onto the socket on the MB.?
Its possible a solder connection has broke... I mean the CPU ran direct in the MB... but I did check bus activity before I took it out, and CPU did put /AS low several times and DTACK issued also..

I've been heating up my second board a lot.. but nothings died and its almost smoking now :lol: Even so, the CPU hardly gets warm anyway. The GAL actually gets a lot hotter than the CPU.

I did try pushing down on the CPU pretty hard before I removed the CPU from the board...Though if it was a bad connection on the board, its take like 30+ hours to show up.

Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Fri Jun 08, 2018 8:03 pm
by PhilC
30 hours and a pig to find, especially how that CPU is mounted to the board i bet.

I work in hot boiler houses and component failure due to heat is a big thing for me.

You'll sort it I'm sure....

(Unlike me and the Mega, having a break, lol)

Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Sat Jun 09, 2018 9:53 am
by exxos
I left it running overnight, and will leave it running today also as much as possible. Currently its at loop 261... The previous board got to around loop 120.. Though it had been running several hours for the past week before that...

So I am leaning towards its more PCB related than CPU...

Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Sun Jun 10, 2018 1:15 am
by exxos
Must have been running 30+ hours constantly now and got to loop 461. So must have been a bad solder joint or bad PCB on the previous board.. So looks like all is well in the world again :D

Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Mon Jun 11, 2018 2:34 pm
by exxos
So a bit more chaos today..

I had on the board 2x220R (normal wire ended types ) resistors on the buffer input and this is what was working fine. So I change this for a normal 100R 1206, and it crashed after about 30 seconds :roll: obviously the system should not be that critical over just a few ohms.. So I had a little bit more investigation to do..

Cut a long story short, I think just a tiny bit of noise on the 40MHz line is enough to cause problems.. The input value resistor to the buffer seemed overcritical in all my previous tests and of course this was proven again today. I tried a lot of things, there was seems to work is simply placing a 22pF capacitor on the buffer input. Now I am going via a 33R resistor and it all seems fine again.

I'm using a schmitt buffer, so it should filter out all sorts of noise and glitches. Obviously there is something else going on which it is not filtering out. It's not relating to minimum or maximum voltages as I did a lot of experimenting with that this morning. Even altering DC offset levels etc..

In any case, I will update the PCB design to include this capacitor.. I will leave the board on testing throughout today again to make sure's works.. I'm not too worried about investigating this issue.. If I investigate every tiny little thing the project will never move forward..

In relation to the dualtos boards, where currently I am soldering on the ROM directly onto the PCB.. The problem is that I wanted to keep stock of the ROM's separately in order to keep costs down a lot. It is not really practical to build up 20 of each language.. It's why I put a lot of the current boards (with sockets) built up, so I can keep a large stock of them, I just program low quantity of ROMs as needed. But obviously this would be a huge problem if I went to solder all the ROM's onto the new PCBs...

So I'm going to order a few SMT sockets and see if these are better than the larger through-hole sockets.. I don't have any spare boards, so I will have to order some more, so it could be some time before updating relation to those...

Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Fri Jun 15, 2018 2:47 pm
by exxos
The sockets I investigated in another thread... viewtopic.php?f=23&t=74&p=6567#p6567

And I just on the changes to the DualTOS board.. I also added on the list as previously mentioned...

Will get some prototypes made soon..

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Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Fri Jun 22, 2018 5:09 pm
by exxos
I've ordered 3 of the final revision boards. Which are the new dualtos boards & plug in booster boards and stencils.

If all goes well, they will be 2 sets of boards which will be up for sale once tested out. I don't know what price these will be yet, but likely more expensive than the current boards in my store due to assembly and prototype costs.. But they will likely be still cheaper than the final store price... In any case if anyone wants to call dibs on one then let me know and I will try and remember :)

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Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Fri Jun 22, 2018 5:15 pm
by PhilC
Oh go on then, you twisted my arm....

And hopefully that'd help with the drop in sales too..... but will want some1mb simms too if I'm selected to be the guinea pig, lol.

Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Tue Jul 10, 2018 1:51 pm
by exxos
Updated boards just arrived with stencils :)

I will try and build up the DUALTOS board today and see if I can get the SMT socket on without melting it 8-)

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Re: STE V1.5 32MHz BOOSTER - STATUS

Posted: Tue Jul 10, 2018 2:39 pm
by rubber_jonnie
Niiiiiiiice.

:bravo: