Looks like I'll be getting a Mega ST4 soon

[rubber_jonnie]

I managed to find a supplier at the reasonable price of £3.49 a chip, and not eBay either, a surplus place on the web.

If they turn out to be decent, I'll share the url.

[rubber_jonnie]

Dammit I missed the postie yesterday, and I'm pretty sure it was my RAM chips!

Should be delivered tomorrow though

[rubber_jonnie]

Good news tonight

I arrived home to find the chips waiting for me, so I got the soldering iron fired up, and without burning myself I removed U69 based on the previous diagnostics, installed a socket, then the replacement RAM chip as below:

IMG_20191106_223051.jpg (347.08 KiB) Viewed 3396 times

I ran both the diag cart RAM test with the following results:

IMG_20191106_221930.jpg (216.91 KiB) Viewed 3396 times

And then ran up Sysinfo and now see all 4MB:

IMG_20191106_222149.jpg (318.23 KiB) Viewed 3396 times

I've left it running YAART, but so far everything looking good.

Apart from reassembly, that is actually the last job!!

The summary of fixes is as follows:

1. Replace missing sound chip and repair nearby traces.
2. Replace faulty RAM chip at location U69.
3. Replace missing Blitter.
4. Upgrade PSU to Meanwell device.
5. Replace floppy connector.
6. Repair freyed and shorting floppy power cable at mainboard.
7. Added Eiffel for PS/2 keyboard compatibility.
8. Fixed bent ROM pin.

Replacement RAM was ordered from here at a cost of £3.49: https://www.mushroom.co.uk/

They seem to have a good selection of stock,and the guy was quick to respond and very helpful. I ended up buying all their stock,7 chips. Well you never know

Big thanks to DoG for all the help re RAM chip vs bit locations, it got me straight to the right chip

I guess reassembly is next with a Gotek in place of a floppy, and I've tested with my CosmosEx and it boots fine and dandy. Since it has an internal ACSI interface, I may get an Ultrasatan and fit it internally, or alternatively fit the spare Beta IDE interface.

I may even go for installing the PAK as I previously mentioned.

Very happy with the result

[rubber_jonnie]

Just checked YAART and its 11 passes in with no errors. I may try leaving it to run for longer over the weekend, but looking good

[exxos]

[PhilC]

Another Mega saved. Welcome to the Mega owners club

[rubber_jonnie]

Another Mega saved. Welcome to the Mega owners club

It had to be saved!

Incidentally, I managed to kick off YAART when I got home, and it completed 40 passes with no errors, so I'm happy with that.

[rubber_jonnie]

IMG_20191109_093306.jpg (205.14 KiB) Viewed 3321 times

I think I can call it fixed from a RAM point of view

Gotek is now installed, Eiffel works lovely, as does my CosmosEx.

Now to start pimping it

[PhilC]

Looks good to me RJ, how you gonna pimp it? Paint it pink?

[rubber_jonnie]

Well, today I picked up a Mega ST 1 to go with the 4 for the princely sum of £45.

Will have a proper play with it this evening, but does boot up and give a picture.

Power supply is suspect, but not really a problem, and TOS is German, so that's going to be out on its ear.

It still has the original case and it's completely uncut which is nice.

Is 9x STs too many or do I need more?

More to report later.