A3000T takes over 2 min to boot, problem solved.

Caution: Non registered users only see threads and messages in the currently selected language, which is determined by their browser. Please create an account and log in to see all content by default. This is a limitation of the forum software.


Also users that are not logged in can not create new threads. This is a, unfortunately needed, counter measure against spam. Please create an account and log in to start new threads.

Don't Panic. Please wash hands.

    I turned on my A3000T one day and all I got was a grey then black and grey screen and would not boot. I removed the buddha board keyboard mouse floppy and still no boot. I checked PSU voltages an all were ok. I decided to leave it on and after 2 minutes and 20 seconds it rebooted and got the insert disk screen. I installed the buddha board and after the above time it booted to my workbench 3.2.1 screen, and all worked great. I knew it wasn't a major problem with the ROMs, RAMs or the major chips. I knew the clock chip has a _FAIL on pin 2 and it was low. and after 2 minutes and 20 seconds it went high 5.13v and the Amiga booted. I removed the clock chip and the Amiga booted normally. I replaced the chip with a new one and all is well. This will fix the problem on the A3000D/T machines and may fix other Amigas. Hope this helps anyone that has this issue.

    Jens, The _FAIL output pin 2 when it goes LOW it will halt the GARY IC. If you open pin 2 and insert the IC the computer may boot ok but the data going to the data buss will be garbage or all LOW. Since it is a clock IC it may time out and allow the _FAIL line to go HIGH and allows the GARY to continue. I am glad that when I ordered the clock chip I ordered 5 so I have extras and was able to get my 3000T up and running. Let me know if you see the same.

    _FAIL is an input to the RTC (CS) and should disable all inputs and outputs of the RTC in case of missing power supply (battery is used in this case) to block random changes of the RTC.


    The same is valid for Gary and Ramsey.


    If the RTC is bad, it might pull this input low and causes the same effect as the PST518 used in the A3000 for this purpose.


    If it starts to work after 2 minutes and 20 seconds it's more likely a random time the RTC needs to warm up (or any other component, like the PSU) and not draw enough current on the _FAIL line any more.

    I checked the PSU voltages and are all ok, the ac ripple is a fraction of a volt using a recording O-Scope. I also Load tested the PSU for 8 hours (overnight). Since I replaced the RTC I have had no issues. As I stated, when I pulled the RTC the 3000T loaded normally, when I put it back it took over 2 minutes to boot so I replaced it with a new IC. Good thing the RTC is socketed or I would had to unsolder it, I would had to remove the motherboard.

    Quote from A3000T

    the ac ripple is a fraction of a volt using a recording O-Scope.

    It should be, but _what_ fraction? Measured under what conditions and scope settings?


    Quote from A3000T

    I also Load tested the PSU for 8 hours (overnight).

    That's a time (probably 8 hours), but "load test" usually involves a controlled load. How did you do that?



    Don't get me wrong - your finding of the computer being kept from starting by the _fail signal is most likely correct. However, if it comes to PSU testing, many people think they do "Everything", yet their efforts are mostly pseudo-scientific.


    Jens

    Jens

    I tested my power supply and was satisfied that it was ok and not causing any problems.

    I have a resistive load box for each of the voltages and used a recording voltmeter(s) (Fluke) to recording low, high and average voltages.

    The ac ripple was 3mv or less.

    It was NOT connected to the A3000T motherboard as the motherboards generates noise. The O-scope is a Tektronix.

    Quote from A3000T

    The ac ripple was 3mv or less.

    This is most definitely a measurement error. No switchmode power supply that I have heard of - let alone the generation that Commodore has used - was ever in that order of magnitude.


    Also, if you have a Tektronix scope, why use the multimeter? I have a feeling that you like to throw around big names and superlatives. It's nice if you own all that equipment, but for others to replicate your measurements, you need to specify what the setup was, how you've measured (especially what the limits were on all variables), because without that, it just reads like "this is 35-40 times better than any other Amiga power supply around, must be from another world". In other words: You only impress people who can't judge the numbers anyway.


    Jens

    Have you seen an Amiga A1200 with a working eSATA port connected to a CD/DVD running on the A1200 power supply!

    No cables hanging out. I am working on a DB15 video connector to connect to the new monitors, no DB23 adapter sticking out from the video connector.

    Good, so you own all the equipment. Key to power supply measurement is the right measurement method and interpretation of the measured values. If you're quoting 3mV ripple "or less", the message I'm getting is that you've measured the 12V and the 5V rail, where the 5V rail has "less ripple" and the 3mV is your worst case, which is expected on the 12V rail.


    However, with an expected ripple value of 120mV on the 12V rail and about 50mV on the 5V rail (each on a perfectly new PSU), your result is so far off that something in your setup is smoothing out the result. You should identify the source of the error before you continue giving out measurement results.


    Historically, PSU measurements have been made with a 20MHz oscilloscope. All modern scopes have a 20MHz bandwitdh limit switch (these days they're digitally implemented), so you can still make measurements with the same result as you would have gotten in the old days. It's the norm to apply this bandwidth limit, and to mention that you did so. This is the "method" I was looking for.


    As for equipment, this needs to be alibrated on a regular basis, so in addition to mentioning the name, type and method, you'd also quote the last calibration date, or at least mention that it's in calibration.


    Power supply is a touchy subject. A lot of truly bad stuff is on the market that hardly fulfills half of the requirements that Commodore has specified. It's not as bad on the big box Amigas as it is on the compact ones, but the problem exists there as well. In order not to raise the wrong expectations or a wrong interpretation of measurement data, I suggest to apply common standards to publishing measurement values, or just to admit that you didn't want to take that effort because you've had reason to believe it's OK, which I think is the case here.


    Jens

    Jens, you are the one that stated I was putting out equipment names that I didn't own. When I was working at Idaho Power Company, I sent all of our equipment in for calibration and the company paid thousands of dollars. Now that I am retired, I can't do that,s I use the internal calibrator and cross check with the other O-Scopes, that good for my purpose. As for my cat, she can't take measurements as she has no thumbs, but she got too close to a 9 volt battery, once.

    Now getting back to the technical level here are the ac component in comparison My A3000T 30+ year old PSU and a much, much younger used PC ATX PSU. Using my Fluke 187 voltmeter and the PSU's on a resistive load. There is no tag on the Amiga PSU as to the wattage so I can give it a guess of 200 watt, the ATX is a Dell 235 watt. All voltages are good. Here are the O-Scope pictures, as you can see the Amiga has a lower noise than the newer Dell. So that's why the Amiga PSU is in excellent working condition. The voltage range is the same 50mv the sweep is different to get a stable display. Note all pictures taken with my Olympus 4mp camera, no conversion used.


    I see 380mV ripple on the first scope shot (7.6 divs, where the uppermost division is fully used, so ripple may even be higher). To me, this is the perfect example why you shouldn't use an ATX power supply in an Amiga, as that is designed for main boards that use point-of-load regulators for just about anything.


    Also, is AC trigger really what you use for this kind of measurement? Isn't it easier to move the DC offset, set the trigger to a DC level until it barely triggers, then look for the maximum? At least that's what I do on the digital scopes that I use. It gives a nice lower/upper boundary for calculating the ripple range.


    Jens

    -Jens

    I do NOT have a ATX PSU in my Amiga, all of my Amiga A1200, A3000D, A3000T have their original PSUs and they haven't had any capacitors change! I was using this to compare the 32-year-old Amiga 3000T PSU to a newer 4-year-old ATX PSU of similar wattage under a resistive load.

    ALL ATX switching PSUs will put out noise it's just how much noise is harmful to the electronics!

    All this started because I wanted to share my A3000T taking over two minutes to boot and how I found the problem. So, if all of you have a booting problem on A3000D/T just pop out the RTC chip and turn it on, if it boots fine, just replace the RTC! You can still use the Amiga it just won't show the correct time. Note: DigaRom will not boot either so you may think you have a more serious issue.

    I think your still mad because you sold me an intermittent buddha IDE and I named it the lemon buddha! After 3 months trying to work with you, I found the bad solder connections and repaired it, it's working great, so is the one in my A3000D.

    Quote from A3000T

    I think your still mad because you sold me an intermittent buddha IDE and I named it the lemon buddha!

    Nope - I can admit mistakes.


    The one thing that caught my attention here was "3mV ripple or less", which you clearly did not measure.


    Jens