Brett's STE - Repair thread

[rubber_jonnie]

Yep, Blitter tests 100% in my Mega ST, so I have no qualms about the IC itself, so I just need to do some work on the socket, and fingers crossed that will be enough to revive it.

Like the CPU, I am not keen on replacing the socket if I can possibly avoid it.

I'll do the bus resistors whilst I'm at it too, and pop a few spots of hot glue onto the longer bodge wires to keep them from moving around.

Nearly there!!

[rubber_jonnie]

So, I took 15 mins at lunch to reflow the socket for the Blitter and tweak the metal fingers.

I can now turn the Blitter off and on at will with no freezing in TOS 1.62 & 2.06.



So next up I'll swap out the bus resistors for 2.2k and I'll likely add the pull up to the fdd controller while I'm at it.

[exxos]

[stephen_usher]

Excellent! Almost there.

[rubber_jonnie]

Excellent! Almost there.

Soooo close!!

I'll hopefully get the bus resistors done this week before I have to go away, then Brett has requested a mod to add a switch to swap the floppies, which I've said I'll do since I already have the machine.

Should all be done in the next week or so though.

Very pleased with the outcome.

Next on the bench after this is my 600XL.

[rubber_jonnie]

For those who are interested, this is the final rewire job:

IMG_20220131_135715.jpg (534.52 KiB) Viewed 2352 times

All repairs, including those to tracks missing from the top of the PCB, were undertaken on the bottom of the board to keep it looking clean and tidy on top.

Once the remaining jobs are done, I will pop a bit of lacquer over the wire ends to ensure there is no chance of shorts happening on reassembly.

The few wires that look like they have really long copper ends don't, it's just the way they were lit on my bench.

I'll probably also switch out the 'W' jumpers for proper jumpers whilst I'm doing the bus resistors.

[derkom]

So, I took 15 mins at lunch to reflow the socket for the Blitter and tweak the metal fingers.

I can now turn the Blitter off and on at will with no freezing in TOS 1.62 & 2.06.

Makes me wonder if the whole board got flexed at some point and just broke a few iffy factory solder connections on these sockets.

Congratulations on the good work!

[exxos]

For those who are interested, this is the final rewire job:

Bodge wires

[exxos]

Makes me wonder if the whole board got flexed at some point and just broke a few iffy factory solder connections on these sockets.

They are terrible for that. The solder literally disintegrates as soon as you remove the metal shielding from the thing. That was one of the main problems I had with development as I would lift them on and off my shelf and that was enough to break them

[rubber_jonnie]

So, I took 15 mins at lunch to reflow the socket for the Blitter and tweak the metal fingers.

I can now turn the Blitter off and on at will with no freezing in TOS 1.62 & 2.06.

Makes me wonder if the whole board got flexed at some point and just broke a few iffy factory solder connections on these sockets.

Congratulations on the good work!

Cheers

Yeah, I had much the same thought, they are very susceptible to flex, caused me a lot of problems with my Mega 4. This is where new PCBs are sometimes the best way forward.