Atari STE v1 BOOSTER ic2 burned

[valfac]

Hello,

I have recently installed the ste booster, it worked fine one week at 8mhz while waiting for the dual rom.

This afternoon the dual rom ic has arrived.

I have changed the jumpers on the w104 and w102 center and right board.

I have turned on the first time and the screen has gone gray.

The second time Ic2 has burned.

Some ideas? Is possible repair it?



Hotlink for forums






I'm going to upload images little by little of all process.

Thanks in advance,

[exxos]

I've never seen that happen before. Its only a clock buffer for the CPU. What voltage is your PSU outputting ??

It should be possible to fix, but with it being tiny, you may want someone else to do it.. ?

[valfac]

Hello,

Without load. I have 11.57v in the 12v rail and 5.19v in the 5v rail.
With load 5.03v and 12.26v.

I have comeback the old roms and the w102 and w104 to the previous position.

The reset appears works well, but the atari screen is black.

I can solder this little ic, I have tools to do it.

I have removed it



Some idea is welcome

[exxos]

I can send you replacement part, but it may be quicker if you order direct or some local supplier to you..

https://uk.farnell.com/diodes-inc/74lvc ... st=1893824

[valfac]

Hello!

I have been searching the Ic2 and not found near me it.

I think that my power supply maybe is not at its best, I'll wait for him to make one of your power supplies.

Can I do some more tests to know that I only damaged the Ic2?

Greetings!

I can send you replacement part, but it may be quicker if you order direct or some local supplier to you..

https://uk.farnell.com/diodes-inc/74lvc ... st=1893824

[exxos]

Can I do some more tests to know that I only damaged the Ic2?

I don't know any reason why it would fail. It is only used as a clock buffer. Same IC used in all STE series boosters and first one I know of that failed. Must be a reason why. Can only really think bad PSU. But don't know why only that IC would fail and nothing else (but possible I guess as your machine isn't booting)

I guess if you wire link from R2 to R5 you might still be able to boot in 8MHz mode, but I haven't tried it.

[Tomswork]

Does the diode clip over voltage. And became a fuse for that or a ground short


Tom

[valfac]

Thank you very much exxos, tomswork

I'm wired R2 with R5 and the STE boots well, only appears noise in the screen, maybe is for the wire..

Greetings,

[valfac]

Hello!

Yesterday I have replaced the ic2:



I do a power on and:



In the Next step, I do all test with the official Atari,s service cartridge.

First pass ok

The second pass says "DMA error" and Blitter error.

I boot the atari and the atari shows:



Next reboot the atari not show any image, and the lcd screen no activity anymore.

I test the IC2 in with the oscilloscope:



And the ic2 out:



This time it,s worse, but the lcd screen goes to standby, the first issue, before I changed the IC2 the system did not start, but the screen received signal.

I have checked voltages and clocks and it works fine.

Someone have an idea on how I could to continue?

Thanks in advance

[exxos]

What do you get on the resistor above the CPU ?