Black screen after tos upgrade

[Groppo91]

I finally got that pin out and fitted actual jumpers and headers. On my old original tos it booted up so I put the new tos upgrade chip in and set the jumpers but only seem to be getting a black screen. Would I be worth ordering another tos chip set to see if they were just bad?

I'd double check your jumpers first.

I think the jumpers are correct they match the ones provided by the seller the only difference was w103 is soldered by factory which I haven't messed with. I still think the chips are to blame.

[rubber_jonnie]

I'd double check your jumpers first.

I think the jumpers are correct they match the ones provided by the seller the only difference was w103 is soldered by factory which I haven't messed with. I still think the chips are to blame.

Have you spoken to the vendor, see if they can provide a replacement set? Jay's is pretty good TBH.

[Groppo91]

I think the jumpers are correct they match the ones provided by the seller the only difference was w103 is soldered by factory which I haven't messed with. I still think the chips are to blame.

Have you spoken to the vendor, see if they can provide a replacement set? Jay's is pretty good TBH.

I have tested continuity of each chip pin to the board and everything seemed fine. I have spoken to the vendor and ordered another set to try.

IMG_20220326_172158.jpg

IMG_20220326_172223.jpg

IMG_20220326_172228.jpg

[derkom]

The soldering work on those jumpers is not good, and there is heat damage to the board. Also I'm curious what has happened to the top of the board just to the left of the W102 marking...

IMG_20220326_172223.jpg

Before blaming the new ROMs, you need to check the continuity of all six of these jumper pins vs the schematic posted earlier in this thread. Check the connections between the relevant pins on the ROM sockets (or installed chips) and the jumper pins, and the appropriate jumper pins and ground. And of course verify that you no longer have any continuity between the jumper pins themselves, barring the ones the schematic shows should have continuity.

[Groppo91]

The soldering work on those jumpers is not good, and there is heat damage to the board. Also I'm curious what has happened to the top of the board just to the left of the W102 marking...


IMG_20220326_172223.jpg


Before blaming the new ROMs, you need to check the continuity of all six of these jumper pins vs the schematic posted earlier in this thread. Check the connections between the relevant pins on the ROM sockets (or installed chips) and the jumper pins, and the appropriate jumper pins and ground. And of course verify that you no longer have any continuity between the jumper pins themselves, barring the ones the schematic shows should have continuity.

Thank you I have ordered another ROM just to double-check as I am starting to think it is the ROM but not sure where the heat damage is you sure that wasn't the flux? I have cleaned most of it off now. Also the 28pin ROM chips work fine. The damage below the jumpers was already on the board not sure where that happened but I can tell that a previous owner has carried out soldering work because I found a lot more flux left on the board. I looked at the schematics but can't see where some of the pins go to as the diagram is cut off and very squashed. Will spend some more time testing them though if I can work out where the jumpers go.

[rubber_jonnie]

The soldering work on those jumpers is not good, and there is heat damage to the board. Also I'm curious what has happened to the top of the board just to the left of the W102 marking...

@Groppo91 I tend to agree with derkom, but specifically the soldering on the underside of the jumpers. I said it before, the solder looks wrong. It is lumpy, dull and looks like it hasn't had enough heat to melt it fully.

As I said previously, correctly done, solder should be fully fluid and smooth and shiny before you remove the iron, and will hold together by surface tension whilst it cools and will be completely smooth. Yours just isn't like that.

BTW I'm not saying this to be spiteful, I'm trying to help you understand why your solder joints may not be properly made, or 'cold' as they are sometimes described.

My other question would be, what solder are you using? Lead free solder does not mix well with leaded solder and can result in poor joints not dissimilar to yours. I'll say it again, don't practise on your STE, these boards are fragile, get some cheap disposable kits on eBay to practise your soldering on, it will help you in the long run.

[derkom]

There is certainly some flux on the underside, but I think also some heat damage, but it's not particularly bad. Just letting you know what's there and could be causing problems. Regardless, you should check the continuity of every pin on those jumpers, not just the ROMs. They should be:

W102:
- 1: GND
- 2: Pin 24 on both ROMs
- 3: Pin 45 on CPU

W103:
- 1: VCC
- 2: Pin 3 on both ROMs
- 3: Pin 44 on CPU

W104:
- 1: Pin 45 on CPU
- 2: Pin 2 on both ROMs
- 3: GND

Verify each of those, and verify (as I believe you say you have already done) that every pin on each ROM socket connects to the correct address and data bus pins on the CPU (have a look at https://console5.com/wiki/File:MC68000- ... Pinout.png for example for a nice diagram of the 68000 pinout). If all of those things verify, it should work. Even if there is a little damage on the board, there is nothing that looks serious.

I agree with @rubber_jonnie that the soldering on your header pins looks like it didn't get hot enough. If you add some flux and maybe a tiny bit more solder on your iron to help with thermal conductivity and heat those up again, they will probably flow into place nicely. But as @rubber_jonnie says, do some practise on junk boards. If you just have some old trash electronics sitting around (I believe having a closet full of junk we can't part with is an entry requirement for this forum), just practise on one. You can build up this skill very quickly with practise.

[Groppo91]

There is certainly some flux on the underside, but I think also some heat damage, but it's not particularly bad. Just letting you know what's there and could be causing problems. Regardless, you should check the continuity of every pin on those jumpers, not just the ROMs. They should be:

W102:
- 1: GND
- 2: Pin 24 on both ROMs
- 3: Pin 45 on CPU

W103:
- 1: VCC
- 2: Pin 3 on both ROMs
- 3: Pin 44 on CPU

W104:
- 1: Pin 45 on CPU
- 2: Pin 2 on both ROMs
- 3: GND

Verify each of those, and verify (as I believe you say you have already done) that every pin on each ROM socket connects to the correct address and data bus pins on the CPU (have a look at https://console5.com/wiki/File:MC68000- ... Pinout.png for example for a nice diagram of the 68000 pinout). If all of those things verify, it should work. Even if there is a little damage on the board, there is nothing that looks serious.

Just tested the headers but finding the pins are going to different pins on CPU.

W104
pin 1 is going to 48 on CPU - wrong?
Pin 2 is going to pin 2 on both ROMs - correct
Pin 3 is going to ground - correct

W102
Pin 1 is going to ground - correct
Pin 2 is going to 24 on both ROMs - correct
Pin 3 is going to 48 on CPU - wrong?

W103
Pin 1 is going to vcc - correct
Pin 2 is going to 3 on both ROMs - correct
Pin 3 is going to 47 on CPU - wrong?

I am going to test each rom pin to CPU next but I take it there is already an issue to which pins the jumpers connect to on the CPU?

[rubber_jonnie]

I'm not sure if already suggested, but take a look at @sporniket's schematic here, it'll help verify what goes where.

https://www.exxosforum.co.uk/forum/viewt ... =31&t=4584

[derkom]

W104
pin 1 is going to 48 on CPU - wrong?

W102
Pin 3 is going to 48 on CPU - wrong?

W103
Pin 3 is going to 47 on CPU - wrong?

My apologies. I should not be reading schematics before coffee. ;) Your connections are correct. My post is wrong.