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Just bought an Ace but I don't think it works

Started by RetroMal, September 09, 2019, 10:09:00 am

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RetroMal

Good Morning All,

I'm a collector of retro game consoles and I've wanted an X68000 for a while and thought it out of my reach.  I managed to pick up a "Junk" Ace relatively cheaply from Yahoo Japan - though the shipping was horrendous.  I had been advised that many "junk" items are just untested but I think they may have been correct with this one.

I have a step down transformer which I used but the X68000 wouldn't switch on.  With my limited electronics knowledge I determined that the power supply was dead and I sent to to a local repairer who recapped - and dioded - it for me.

My X68000 now switches on !  But doesn't show anything.  I have a SCART cable on it's way from eBay but I was impatient and built my own VGA cable but I get no picture out of the X68000.  I don't know whether the boot screen is 15 or 31kHz but the screen it's plugged into I use with an Amiga and I believe it displays both. I did remove the motherboard and gave it a clean and while there were some stains on it there didn't appear to be any blown components.

If I switch it on the green light comes on for a short while and then changes to red.  I'm hoping this is standard operation and it's going to sleep because I haven't given it anything to do or answered any questions it might be presenting on the screen.  It came with a copied floppy disk - supposedly with R-Type on it.  While the light is green I can press the eject button and the disk pops out - but I'm assuming that's a function of the drive itself not necessarily the X68000.

I am in Melbourne, Australia and looking for some advice from you fine people.

Any help/advice would be gratefully received.

Thanks

Mal

Jehuty

When you Switch the main power Switch on the back the LED should be red. After pressing the powerbutton on the front the LED Switches to green. Now the X68000 should boot the floppy.
Does your machine boot the disk or eject it ?
When the floppy is not bootable it eject it. If bootable it boots.
The bootscreen is 31khz. But there is a known problem with a 74LS which is often blown when a wrong cable is plugged in. Do a search for this here in Forum.
But this is one of, if not the only issue, my 2 machines not had until now.

Are after the rework of the PSU all voltages OK ? 5V, 12V, -12V and 5VSB ?
I replaced all my PSU with ATX PSU. I´m in Germany and so we have 230V and i don´t Need a stepdown converter any more.

LowDefAl

The X68000 uses soft power on/off and the circuit can sometimes get confused. The system should only go to sleep if you tell it too.

If the system is on it should try to read the discs at boot, this should result in the floppy activity light working and you should hear the disc accessing.

spud

Be careful with these scart cables, they can ruin some chip in your X68000 as well. Don't know the exact details, others here will.

hoshikawa

ACE is the least reliable model, the power supply will definitely need to be replaced, and the nicd battery has most likely eaten the traces away on the bottom board. I have owned 4 and all 4 needed repair. rebuilding the traces is not trivial, you will have to clean up the corrosion from the battery and use a fiberglass pen to remove the solder mask, in some cases you may have to desolder and remove the ribbon connector. repairing the traces and re-flowing the solder on the IOSC should bring it back to life.

LowDefAl

September 10, 2019, 12:08:14 pm #5 Last Edit: September 10, 2019, 12:11:50 pm by LowDefAl
Quote from: spud on September 09, 2019, 11:07:36 pmBe careful with these scart cables, they can ruin some chip in your X68000 as well. Don't know the exact details, others here will.
This is incorrect, scart cables won't damage the console unless you jump the wrong pins and that's not scart specific. You can do the same with vga or any other cable.

Scart is just a connector and separately a wiring specification (they are usually the same because it's a standard but not always!). The problem comes from different video signal types.X68000 outputs TTL sync which is 5v. Consumer TVs are not designed for this so can be damaged. Framemeister too. OSSC accepts it and professional monitors shouldnt have an issue with this either and indeed I've used the scart cables with my BVM (via a bnc adapter) just fine. You can also use a resistor to drop the signal down to 75ohm. You also need to tie the syncs together because the system uses HV to sync, some would argue that this requires a circuit but it could also be argued that this isn't strictly necessary.

Either way, Scart won't damage your x68000 unless another factor is involved, but there is a possibility of damaging the display. But that can happen with any carrier cable on the wrong device.

RetroMal

Firstly can I thank you all for your responses.  I appreciate your help.

I've just tried my Ace again and very little is happening.  I switch it on and the light goes red but then I can't start it with the power button at the bottom.  It was starting late last week with a green light so something else has gone wrong.

hoshikawa - I have had the power supply recapped and I believe it to be perfect now - though it's hard to tell when the Ace won't turn on.  My NiCd does appear to have leaked but I didn't think it was too bad.  I cleaned it up with a toothbrush.  I am concerned about the underside of the board.  If I remember correctly - under the battery are a number of parallel thin tracks dogleging through that area and they look damaged - at least the protective layer seems to have come off.  Perhaps I should take the motherboard out again and take a picture to post here.  You speak of the ribbon cable - I believe they are intact - hopefully just the area around the battery.  Should I remove the battery completely and get in there with my multimeter checking connectivity ?

LowDefAl - Hopefully the VGA cable I made was correct.  I did double check it before I tried it and tested for shorts with a multimeter.  As for sync the cable I made is this one http://pds21.egloos.com/pds/201101/22/28/e0013828_4d3ad13b4bc81.png and it uses a separate horizontal and vertical sync.

Thank you again for your help - any advice is appreciated.  I have limited electronics knowledge - enough to get me into trouble.

Mal

Jehuty

Sometimes a normal Recap didn´t do the Job.
My first try was to recap my PSU - but after that it didn´t work. So i replaced it with the ATX one and all was fine.

Could you post some pics of the Battery area ?

RetroMal

OK I'm even more confused now.  My ACE has been off power completely all day.  I just switched it on and the green light appeared, soon afterwards the floppy was ejected and the green light faded.  I then switched it off and back on again and it started and then went to red light within a few seconds.  I've taken the motherboard out - here are a few pictures:

The first is an overall view of the board so you can gauge it's restoration-ability (if that's a word).

The second is a close up of the top side near the battery and the third the underneath of the battery.

You might also notice the yellow colouration in the bottom right of the last picture.

Your opinion would be appreciated.

Thanks

Mal

LowDefAl

September 11, 2019, 12:49:05 am #9 Last Edit: September 11, 2019, 12:57:34 am by LowDefAl
Technically I would say that's the sub or I/O board. The "motherboard" is actually in the right side of the case with the CPU, video system, ram and expansion riser. Best have a look at that too.

If it is a power control issue then it probably is on the "sub board" but best to check there isn't an obvious issue with the other board.

mattsoft

You have visible corrosion around the battery. Remove it, clean the board, and start checking those traces and vias for continuity. I'll bet the battery has eaten some of that copper.

hoshikawa

your bottom IO board has visible corrosion several inches away from the battery, the traces are most likely destroyed. cut the battery out with some flush cut nippers. the trouble area is most likely the traces and vias beneath the battery.

RetroMal

Thank you everyone.  I have removed the battery and tested the tracks down to the IOSC chip.  There are a few that don't work.  I've organised the guy who repaired the power supply to have a look at it but I can't get it to him until Friday.  He says he has a high powered magnifier and facilities to reflow the solder on surface mounted chips.  We'll see what he comes up with.

Mal

RetroMal

Good Morning - though it isn't really.

I have my IO board back from repair and reassembled but my system won't switch on.  The repairers said they had to repair many tracks that had been damaged by the leaking battery.  They also had to redrill some of the plate through holes and solder a minuscule piece of wire through them to link the front and back of the board.

The SCART cable has arrived so I used that - when I turned on the system the light went green and it ejected the disk I had in 1 but then nothing else seemed to happen.  I think it must have been switched on from the front toggle switch.

I have since pulled it all apart and looked at the main board.  It appears OK but then again I said that for the power supply and the tech told me all the capacitors had leaked from the bottom.  I assume the daughter board in the top left corner is the RAM ?  I removed it and the video board - pushed down on the socketed chips on the main board and then reassembled everything - well not everything - I left the card cage off the back as I thought it wouldn't matter at the moment.

Now when I switch it on from the switch on the back the light goes straight red.  If I press the power button the light goes a faded green, then amber then red and the fan stops almost immediately.

Any advice from you knowledgeable people ?

The repairers are old school and I think they'd like to see it going again.  They charged me $100 for about three hours of work to repair the tracks.  They have said if it doesn't work to take it back to them.  More money that I don't really have but I'm this far down the rabbit hole.

With all these repairs perhaps it would have been cheaper to buy a working unit.

Thanks to you in advance

Mal

ShootTheCore

September 26, 2019, 09:50:44 am #14 Last Edit: September 26, 2019, 09:53:03 am by ShootTheCore
IMHO, I think you should set the Ace aside and look for another computer that already works.

I went through the exact same scenario with my Ace.  Bought it from YAJ as Junk.  Computer arrived, and appeared to be in clean condition internally except for a leaked CMOS battery.  Performed a complete capacitor replacement on all PCBs, replaced the power supply with a PicoPSU, replaced the leaked CMOS battery and repaired the traces that were damaged by the leaked battery.  But even after all that work, I could never get it to boot up - I would always get a black screen. I finally gave up, put the computer on the shelf, and purchased a different model.

I want to get back to my dead Ace one day, and I'm slowly learning more about how to diagnose boot faults at the electronic logic level, so hopefully I'll be able to take it on soon.  I don't want to leave it dead.  But I can assure you from my similar experience that you're definitely out of the realm of easy, inexpensive repairs now.

RetroMal

Not what I wanted to hear but I appreciate the honest opinion.

Thanks

RetroMal

I'm getting different behaviour.

I left the X68000 completely disconnected from power overnight.  I go and try it again and when I flick the switch at the back and the green light came on - the disk drive whirred and it ejected the disk that was in it.  I left it and it stayed with the green light for about a minute and then the light turned amber and then red and the fan stopped.

I then pressed the power button on the front but nothing changed.

Is there hope for this unit yet ?

Mal

ShootTheCore

Your latest symptoms sound to me like a problem with either your power supply or the bridge board at the bottom.

I say power supply, because if the supply isn't supplying power consistently, it could be supplying insufficient power at power on, then the supplied power could be dropping over a minute until the levels reach a point where the system goes to sleep and then shuts down.  That would also explain why you can't power up again - the capacitors have to discharge before the faulty supply can power on again.

I say bridge board because it's responsible for cycling the soft power functions between Power On and Sleep.  A fault there could cause it to be confused on which soft power state it should be operating in.

The power supply is your most likely culprit, so I suggest trying an alternative, modern supply like Mattsoft's Easy Pico PSU that's for sale on this forum.  If you see the same symptoms with a different power supply, you can cross that off your list of potential faults.

Jehuty

Another Point to check is the power plug from your PSU to the subboard.
On mine were the featherontact gambled away.

RetroMal

An update for you.

I took my ACE to the local repairer so they could see how it all fitted together.  They loved the styling of it.

We switched it on and it went straight to sleep with the red light on the front.  When they repaired the power supply there was a diode which they were unable to read because it had blown.  At the time they took a guess and that got it working and it did power on my ACE but not for long.  They decided to replace a diode with another and it seems to stay on now !  We still have no image out but after further checking they think there is a signal on the video connector but the SCART cable doesn't seem to work.

While I was there the B7W SCART monitor I was testing with decided to let out the magic smoke.  It had previously been repaired by one of their colleagues so they replaced the capacitor that had blown but still no picture.

Not having ever seen an X68000 start up I have some silly questions:
Which drive is the boot drive ?  They seem to think that the drive is seeking so that's a start.
Which way should I insert the disk - notch up or down ?
Will it boot without a keyboard or joystick ?
What should we expect to see on the screen if nothing else is attached ?  I don't have a keyboard but I'll have to pick up an adaptor if it works.

Any suggestions as to why we don't have a picture ?

Thank you for your help - I'll keep you informed of any progress though the repairers have said they can't get back to it until next week and I'm taking in the VGA cable I made in the hope that will work.

Jehuty said that the boot screen is 31kHz so I should be able to plug it into a standard VGA monitor ?

Thanks

Mal

leonk

Until you get this thing working, I would focus on testing on a real PC monitor / VGA monitor.  I made my own VGA adapter cable and it works great on standard PC LCD monitor.  Here's the pinout for you:

https://gamesx.com/wiki/doku.php?id=av:japanese_rgb-15

You should see boot screen asking for floppy on screen.  Keyboard/mouse/joystick not required.  Get it to show boot screen and take it from there.

Jehuty

Yes, use a normal VGA Monitor, the Bootscreen is 31khz. The solder a vga adapter with the linked pinout.
The left drive (0) is the bootdrive. The upside from the floppy must show to the left.

RetroMal

Good Afternoon,

I was at the repairers again today with the VGA cable I made but we couldn't get any out of my X68000 regardless of which cable I used to what monitor.  They think it could be a problem with the video board and have asked if I can track down schematics.  I see there are a number of diagrams on this site but nothing that specifically says CZ-601C.

I have more questions:

My ACE has a memory board attached - is that all of it's memory or does the motherboard have 1M and this is an extra 1M ?
Should the ACE make an beeps or buzzes when it is switched on ?
Could this possible RGB problem apply to my ACE - https://gamesx.com/wiki/doku.php?id=x68000:fixing_rgb_output ?
Is the CZ-6BV1 the video board I have in my ACE ?

Sorry for the stupid questions

Mal

ashrion

October 10, 2019, 06:51:02 pm #23 Last Edit: October 10, 2019, 06:53:09 pm by ashrion
The real problem you have is that neither you nor those who repair do more than change parts and have no idea of the operation of the machine, this is  not a amiga or anything.

First look for someone who has one, and learn its operation at normal level, then look for the operation at chip level, both off and on, and then look for a 100% compatible monitor.

Learn what 15, 31 hrz are.

With all this you will stop treating an x68000 as if it were a amiga.

And finally buying the cheapest thing you see on Yahoo is the first thing to buy useless scrap.

First have a base of knowing its operation and how to operate an x68000 and then look for a good unit, everything that is not that you're wasting your time.

NFG

@RetroMal - to answer some of your questions:

1. The base memory cannot be removed.  If your unit has a plug-in RAM card, that's additional.

2. The Ace will activate and load a floppy when it's turned on (if one is inserted).  It does not do anything else until the software tells it to.

3. Dunno.  It's never happened to me, but apparently it happens to other people.  ¯\_(ツ)_/¯

4. The CZ-6BV1 is an extra video board.  For the purposes of troubleshooting, you should remove it and rely on the basic capabilities of the machine.

The X68000 is a super simple machine, in general: plug it in, turn it on, and magic happens.  Pull all the extra cards out, plug in only the power, and turn it on with a floppy inserted.  Does it start to load?  If it's a bad floppy, it'll spit the disk out again.  If it doesn't spin or auto-eject, then the system itself is not running at a fundamental level, and video is a secondary concern.

ShootTheCore

October 12, 2019, 09:01:26 am #25 Last Edit: October 12, 2019, 09:03:04 am by ShootTheCore
Regarding Number 3, I'd say Yes it's very likely that the SN74ALS05AN needs to be replaced on the video board since you tried using a SCART cable earlier.  There are many warnings on these forums about how SCART shouldn't be used with an X68000 - it's very likely to burn out both the SN74ALS05AN chip and the upscaler or display you're plugging into:

https://nfggames.com/forum2/index.php?topic=6459.0

Ask your repairers to either test the outputs of the SN74ALS05AN with a logic probe, or to just replace the chip outright.  They aren't expensive.  And only use VGA connections with the X68000.


LowDefAl

October 12, 2019, 07:11:31 pm #26 Last Edit: October 12, 2019, 10:07:32 pm by LowDefAl
First let's get it straight, the issue with Scart is that people assume that because it's got a Scart connector, it's compatible with any scart device. with our realising that the X68k outputs a TTL signal which most Start devices don't expect. So yes, you could potentially burn out a Scart TV or a Framemeister due to incorrect sync voltage, but on the other hand professional displays and OSSC don't care - I also would hope that many devices have the circuit integrity to be able to tolerate TTL even if they can't display it - at your own risk and all that. However this is a display device issue and has nothing to do with either the X68k or Scart as a connector/wiring standard being connected to it. Just please don't try to hook up to random TV's.

It's still up for debate if displays have caused a "feedback" of sorts, but only a handful of people have ever reported issues despite so many people using them with their machines that it's hard to get accurate data. There may be other factors involved. I've had shocks from VGA cables before, which could equally be a sign of issues.

What can happen is that wires can move under tension and short out other pins in the connector, usually due to bad soldering. This is not exclusive to Scart, I've done it twice and Scart wasn't involved, the most recent example was me changing a vga to bnc cable to use a DB15 instead of vga connector - no signal issues there. It still happened. It's only because fixing the cable didn't fix the image and I tested the cable on my PC98 where it worked fine that I knew it was the Sn74 had blown.

So yes, Scart should only be used if you know what you are doing, but blaming it for breaking systems is misleading and scaremongering even if that was not your intention. And certainly don't say only VGA should be used because BNC is equally valid and ideal for people with professional displays or video switchers. The system doesn't care what you use as long as it is wired properly and the display device can display TTL sync. It's only introducing shorts or 5v where it shouldn't go that will cause issues.

The SN74 should be checked as a matter of course, but even with a blown sync line it should still display something even if its gibberish. , so I'm inclined to think it's not that. The soft power circuitry still seems the most likely suspect to me. Even on my working system is doesn't always behave properly and we are dealing with a lack of user understanding which complicates matters.