SpeedyTT, black screen of death !!!! HELP

[zfrenchy]

I was in the process of installing the SpeedyTT ...

All was fine, double, triple checked everything before first boot ...

Turn ON ... Atari logo show-up, yeah baby ... memory test in progress ... GOOD !
THEN BLACK SCREEN !!!!

Power down, check all again, but never get back alive !!

Remove SpeedyTT, remove Storm, re-install all original IC, reconnect BG pin ... STILL DEAD !!!

Please help me, what I should checked ?
I have an analog oscilloscope (Tektronix 222), but I am not skilled to use it.

[Steve]

I would email Matthias for support! Hope you get it working again

[zfrenchy]

I would email Matthias for support! Hope you get it working again

Yes I did contact Matthias by email.

[zfrenchy]

here is a short video about how the MEDUSA Scandoubler is acting weird, never saw that when the TT was working.

https://youtu.be/2onps7C67ys

[mikro]

First, don't use Medusa when debugging in issue like this. You want to have as bare setup as possible.

Second, assuming that you didn't do any short circuit and verified that the original restored connection is good (i.e. no shorts/cold joints), make sure that you reverted all three changes, not just /BG:

- /BG line
- W101 jumper (put into 1-2 position for the stock setup)
- R888 patch wire

Apart from then, I can think of only that your CPU and/or FPU got very upset with the higher clock but you should check those three things carefully. I had a trouble with reverting my Speedy, too.

[zfrenchy]

BG line
jumper back

no patch on R888 on my board

[zfrenchy]

BG line
jumper back

no patch on R888 on my board

[zfrenchy]

The CPU got hot rapidly, like 50C in 1 minutes.

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[zfrenchy]

here photos of my soldering, before flux cleaning.

All connection tested, no issues, even if the pin 17 look bad, i got continuity to all other IC on the board.

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[HigashiJun]

@zfrenchy

Looks like the part of your PCB under the resistor (1st picture) is fried...