TT030 Reset Issue

[MacTech05]

stephen_usher,

Yes, agreed, maybe not a good idea to just randomly choose a larger cap value without some engineering done by a qualified/experienced engineer in these types of issues.

Here is the thing. The Reset button works, for the most part. The issue with the Reset button is that it sometimes resets with a quick press, sometimes it takes 2-3 quick presses. Then sometimes it takes 1-2 press and hold for couple of seconds. These are the reason I thought I should replace the Reset Switch.

My main issue started when all of a sudden, for no apparent reason, when I turned on the TT, the PSU fan started and the internal hard drive spun up, but the TT did not boot. I thought maybe there was some sort of glitch, so I pressed the Reset button and the TT booted up normally. The problem is that is when the requirement to press the Reset after turning on the TT to get it to boot up began. That is the main issue I am trying to solve. And it is this issue the caused me to speculate that I need to probably replace the Reset Circuit electrolytic capacitors, as is required in other ST models when it becomes necessary to always press the Reset button for the ST to boot up.

I had a long time Atari support business tell me to live with the reset issue. I was surprised at that suggestion, to just live with a problem. That is not support, that is checked out and not caring about fixing Atari computers going for those who still enjoy them. I am not doing that, just live with a problem with my TT. I need to solve this issue. This is a TT, it should function properly, as I would want from any ST, TT, Falcon computer. This has to be fixable, I just need to determine what to fix. My thought process is to replace the two Reset Circuit caps and probably the Reset Switch as well.

Does that make sense or am I missing something?

Thank you.

Randy

[stephen_usher]

I'd definitely suspect the reset switch. It seems to be either sticking on or not not connecting, depending upon the day. The internals have probably become dislodged.

I'd also only make one change at a time, so go for the most likely (the switch) and only if that doesn't fix it then move on to the next likely target.

Seeing as it's a rather intermittent fault these are the hardest to tie down.

[frank.lukas]

When the Computer do not boot up check if I'm not sure but the first cable should be orange must has high level (+5V) ...

pg_atari_tt.jpg

[MacTech05]

stephen_usher,

I measured the voltage of the orange wire at J100 at startup, would not boot. Initially the voltage was 5 VDC, then drops and settles steady at 4.97 VDC (orange wire at J100).
All of the red wires at J100 were steady at 5.10 VDC. Voltage of the yellow wire at J100 was steady at 12.07 VDC.

Thanks,
Randy

[MacTech05]

frank.lukas,

I am sorry, I meant to address this to you.

I measured the voltage of the orange wire at J100 at startup, would not boot. Initially the voltage was 5 VDC, then drops and settles steady at 4.97 VDC (orange wire at J100).
All of the red wires at J100 were steady at 5.10 VDC. Voltage of the yellow wire at J100 was steady at 12.07 VDC.

Thanks,
Randy

[Steve]

Just replace those caps and the reset switch. No point speculating until the first step is made.

[frank.lukas]

I measured the voltage of the orange wire at J100 at startup, would not boot. Initially the voltage was 5 VDC, then drops and settles steady at 4.97 VDC (orange wire at J100).

So PowerGood is fine.

[MacTech05]

I have ordered the caps from Mouser Electronics. I am trying to order the Reset Switch from Brad a Best Electronics. Hopefully, he will get the switch on the way sometime next week.

Thanks,
Randy

[MacTech05]

I was trying to order the Reset Switch for the TT from Best Electronics in San Jose, California. Brad has been telling me a bunch of different things to do to hopefully, solve my TT030 Reset issue. At one point the advice was to live with the Reset issue. I said I did not want to live with it, I wanted to fix it.

The last thing he had me do was to remove the 3 resistor packs on the failed Quantum SCSI hard drive and place them in the right back of the TT motherboard behind the SCSI port. I advised him that there were already 3 resistor packs installed there. He told me remove them and install the resistor packs removed from the failed Quantum HD. So, I did. It did not solve the problem. I still had to press the Reset button for the TT to boot up.

I removed the 3 resistor packs,I had removed from the failed Quantum HD, and reinstalled the 3 resistor packs that were originally on the TT motherboard.

I turned on the TT and it booted right up, without pressing the Reset button. I tried it a total of 3 times and the TT booted up without pressing the Reset button.

However, on the 4th attempt, I had to press the Reset button for the TT to boot up. I am now back to where I was, having to press the Reset button every time I turn on the TT for it to boot up, as it has been doing. Except now, I have to press the Reset button 3 times for the TT to boot up. Very weird.

I am waiting for the arrival of the capacitors for the Reset Circuit to arrive. Once I get Best Electronics to send the Reset Switch, and the capacitors arrive, I will replace all 3 components and hopefully, that will solve the issue.

Thanks to everyone for all of the help.

Randy

[MacTech05]

Hello Everyone,

Well, I removed my motherboard so I can remove/replace the 2 capacitors in the Reset Circuit.

But I have a question. The wide vertically mounted PCB the two flat cables plug into (I do not know the name for the card, once I removed the metal cover that runs from the card to the back of the case, I noticed the small PCB wobbled a little. It does not appear to be soldered to the motherboard, but just mounted through 2 slots on the motherboard, almost looks like it snaps into the motherboard. It does not look like is soldered to the top of the motherboard either. Is that metal cover just to steady the small PCB? I will include photos to show you what I am talking about. I have a Mega STE that had a bad 30-pin SIMM socket broke and removed the MSTE motherboard to replace all 4 of the SIMM sockets. That same small PCB was also wobbled back and forth a little. Is this behavior for this little PCB normal? If not, what should I do to ensure it is ok when I reinstall the motherboard in both my MSTE and TT030? Photos below.

Thank you!

Randy

My TT030 Motherboard 2.jpg

My TT030 Motherboard.jpg