STE V1.5 32MHz BOOSTER - STATUS

[Maeke]

well 36 is still a huge gain from the stock cpu.

[exxos]

The green board has been running almost 3 hours now.. so that seems ok.

Will try building up a couple more tomorrow and see if they work fine...

I may also try (again) to solder the header pins in one go as well. I ended in a mess trying that last time with the pins on the MMU adapter... https://www.exxosforum.co.uk/forum/viewt ... 334&p=2056

[exxos]

Back to the sockets..

So as suspected, the motherboard with integrated blitter has a foxconn where the booster doesn't want to stay in the socket without being forced.

The TZT socket ( external blitter) is the one I designed the booster on, and fits perfectly.

I can't really fix that issue without doing 2 seperate booster revisions for each socket (they maybe more brands!) and even had to do (5 I think ) revisions before I got it to fit that socket correctly.

I think really the booster needs a re-design to look more like the previous V1 layout. Where the CPU is "outside" the PLCC socket, then header pins could be placed in the correct place in the socket.. but then thats going to need a 4 layer board, twice the cost.. the PCB would be twice the size.. twice the cost.. and testing would have to be done all over again..

If I was doing a larger board, I would use a larger PLD and add ROM on there as well.. but thats gone back to designing a whole new booster again. Just not worth the time and costs involved.

So I may do a tweaked revision to fit the foxconn sockets better, but for now, people will just have to put up with it staying in the sockets on its own.

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This was just funny....

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[exxos]

Next test batch of 4 in the oven...

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[sandord]

Next test batch of 4 in the oven...


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Looks like you have some space left for cookies.

[exxos]

Onto close inspection...

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[exxos]

First one is now testing

Despite best efforts on checking, one of the CPU pins was not contacting the PCB. A quick heat up with the soldering iron fixed that.

I could really do with a quicker way of testing that sort of thing. Currently I have to go round all the CPU pins with my multimeter to check for shorts, then go round them all again between the CPU pins and the header pins.

[PhilC]

At least you know the cause. Nothing worse than something that won't work but you don't know why.

[exxos]

At least you know the cause. Nothing worse than something that won't work but you don't know why.

Yeah, I am hoping these new boards all work... though I am now thinking of "junking" the red boards

[exxos]

Number 3 built up and now under test.

I have tweaked the PCB to include the "fast mode" resistor. Also I have made the header pin via's outer diameter small from 1mm to 0.9mm.. It is nightmare enough to solder such small pins, but when they have shored in between them, it's a right bugger to separate!

Also ordered more 36MHz osc's and 2 more soldering iron tips as the one I am using I think is slightly too big for this work.

I have also done a second header template which I think will fit the Foxcon sockets better. But I will not really know until the PCBs made could be a while away yet.

I need to finish building up this batch of about 10 to see if these boards are being more reliable with assembly than the previous red boards.

So far there does not appear to have been any issues with not having the SIL resistors on the booster board. I still need to verify this on some other STE's yet though.