Help needed urgently!

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BrettRogersUK
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Help needed urgently!

Post by BrettRogersUK » Tue Nov 23, 2021 9:50 pm

Hi Everyone,

I wonder if anyone can tell me what I need to do to repair a track trace on the motherboard of an Atari 1040STE.

I've got the dual tos module from Exxos and I've had to remove the TOS Roms from the board (they weren't in holder's, they were soldered directly to the board). I tried to be as careful as possible. When removing the LO chip a trace came away from the board with one of the pins.

On a full 32 pin chip it is the trace that goes to pin 6. Its come clean away and where the trace goes through pin 6 of the LO and goes to pin 6 of the HI its broke away completely.

The chips I took out are 28 pin chips so on that it would be pin 4 of the chips I took out.

Can anybody help me at all?

Thanks.

Brett

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Icky
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Re: Help needed urgently!

Post by Icky » Tue Nov 23, 2021 10:05 pm

Please post a picture to help with the diagnosis but you will have to solder some wires from the pins now missing the traces back to another point on the board. Tracing the trace and following the STE schematics will help.

Schematics area on the forum viewtopic.php?f=31&t=100

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rubber_jonnie
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Re: Help needed urgently!

Post by rubber_jonnie » Tue Nov 23, 2021 10:09 pm

As well as what @Icky said, get yourself the schematic diagram so you can visually see where the track goes to and simply replace the track with some fine wire. There is no need to repair the track as such as the ST boards are only double sided, so as long as you know where it needs to go to, simple wire is fine.

But photos are always required when you need to get help, it makes the process much faster.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

BrettRogersUK
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Re: Help needed urgently!

Post by BrettRogersUK » Tue Nov 23, 2021 11:11 pm

Hi All

Sorry forgot to post a picture. I'll have a look at the schematic and see what I can find.

Thanks.

20211123_215301.jpg
20211123_215301.jpg (371.04 KiB) Viewed 216 times

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rubber_jonnie
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Re: Help needed urgently!

Post by rubber_jonnie » Tue Nov 23, 2021 11:40 pm

Ok, so you'll need to trace the traces (!!) both up and down as that pic is oriented, because it looks like it's either a data or address line and it's ripped in the middle, so you'll have to bodge wire it both ways.

Follow the trace both directions using a multimeter and work out where the next hop on the trace is and join the points with small pieces of wire.

You may need to check both sides of the board to confirm if there are traces on both sides that need bridging with wire. We refer to this as bodge wiring.

As I said, get a schematic too as it will help to identify the points that are connected together. It's not a hard fix, you just have to be smart and take the time to plan it out.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

BrettRogersUK
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Re: Help needed urgently!

Post by BrettRogersUK » Tue Nov 23, 2021 11:58 pm

Hi,

So I traced it back to part P103. I've put the wire in place but when I turn it on I sometimes get a fizzing sound to which I immediately switch the power off. But when I put it back on and turn it on all i get is a white screen. Nothing on the screen. The keyboard is plugged in but the mouse isn't. I've got my gotek connected too.

I've looked at the schematic and it's on page 2 of the schematic. They both connect to ADDR <23 1> as does P103 which is a resistor array (4.7K x 8).

I've connected wire from the pin that I traced it back to on P103. I've connected the pin on P103 to pin 4 on the 28 pin IC on exxos board on the LO and also connected it through the same pin on the HI side. There aren't any more traces for that that I can see.

Thanks,

Brett

Screenshot from 2021-11-23 23-53-09.png
Screenshot from 2021-11-23 23-53-09.png (379.64 KiB) Viewed 208 times

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rubber_jonnie
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Re: Help needed urgently!

Post by rubber_jonnie » Wed Nov 24, 2021 12:16 am

As I said, you potentially have a break in the middle of that address line, so you need to trace both ways and make appropriate connections. Look closely, you'll see the trace going both ways.

It sounds like you've only connected one side, and given you get a white screen, which is generally a sign of no ROM, so I'd suggest you double check, and make sure you haven't made an incorrect connection and the fizzing noise isn't the sound of another component dying.

If you are really stuck then I'd suggest you stop and have somebody look at it who is confident repairing these sorts of things, as you don't want to cause more damage.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

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Icky
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Re: Help needed urgently!

Post by Icky » Wed Nov 24, 2021 12:19 am

I am not quite sure I follow your explanation.

It is not a case of just taking the pin back to the resistor you need to complete the circuit of the A6 line. That’s the line I think you have the track break on.

Thus trace from the pin where A6 track breaks back to the next solderable point in one direction and find the nearest solderable point in the other direction. You need to do the bodge wire from these two points to complete the original A6 circuit. Then tap off of one of those points to the pin where the trace was.

When you finish soldering the wires in place use a meter to check for shorts between the A8 line and 5V or GND or the nearest address lines A5 and A7. Only when there are no shorts see if it works.

Please share a picture of your handiwork once done so we can check there isn’t anything else needed. Pictures speak louder than words :)

EDIT: corrected address number as read schematic from your pic late last night. It’s the A6 line not A8.

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rubber_jonnie
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Re: Help needed urgently!

Post by rubber_jonnie » Wed Nov 24, 2021 12:22 am

Please post more pictures of what you've done too.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

BrettRogersUK
Posts: 47
Joined: Wed Sep 15, 2021 12:48 am

Re: Help needed urgently!

Post by BrettRogersUK » Wed Nov 24, 2021 12:31 am

Hi,

I've checked. From where I've taken the pic the trace only goes to pin 4 on the HI chip, it goes no further. So Hi pin 4 goes to LO pin 4 and then that trace goes back through a plated through hole (via) in the board at the bottom and then across the board to P103. The track is only damaged between pin 4 LO and Pin4 HI. The track broke half way under the LO chip to the pin 4.

I've remade the connection using thin wire from P103 to pin 4 LO and then Pin 4 LO to pin 4 HI.

Just so I'm clear on things on the exxos board there a SEL and GND I've connected these to a switch one to the middle pin of the switch and SEL to the other so when I switch it it wither stays gnd (off) or when the switch is in the SEL position it toggles the rom?

I'll post more pics tomorrow.

Thanks,

Brett

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