X68000 ACE HD Memory Expansion

[X-Col]

Hi Guys,

I'm brand new to X68000 but have been enjoying emulation of the system for a few months. I just had to have the 'real' thing.
I've just read that you can't expand an ACE until it has 2mb internal memory! I didn't know this and have already bought a Basic House KGB-PRKII 8mb expansion board in order to run stuff off HD. Does this mean that this board can't be used to expand the system until I buy some sort of internal expansion?
If so, why is this the case? And is there a way round it?

Sorry if this has already been discussed,

Col

[eidis]

 Hi X-Col !

Every X68000 must have 2MB ram before it can be expanded further with I/O slot expansion cards. Japanese are very nice and kind people. Sometimes the purchased X68000 have various goodies inside which are not listed in the auction description. It could be that your ACE had 1MB internal RAM expansion. If not, you will need to buy one. Compatible models are CZ-6BE1A and PIO-6834-1M

Keep the scene alive !
Eidis

[X-Col]

Oh no!
I can't sell my other kidney to buy one of those! 

Done loads of reading up on the system before buying one, don't know how I missed this important piece of information.
Hopefully there is one in there, but knowing my luck there won't be.

Would you suggest buying a HxC in the meantime so I can at least use it?
I have no way of transferring images to floppy at present, my 5.25 is not reading and writing reliably.

[costa]

Hi X-Col.

I got one spare, can sell you.
Not cheap, but you wont have to sell your kidney.

pm to you.

[eidis]

 Hi X-Col !

No need to sell the kidney Just wait until your X68000 arrives and maybe you will have a secret bonus item inside.

IMHO it would be much wiser to invest in the STRATOS CF AztecMonster and find someone who could write the MasterDisk_V2.xdf to real media. This is the only floppy you will need. There have been reports that SCSI2SD is not compatible with ACE but it is not yet verified.

SxSI V5 with DMA patch Translated by Eidis
http://nfggames.com/X68000/Misc/Drivers/SxSI%20V5%20with%20DMA%20patch%20Translated%20by%20Eidis/MasterDisk_V2.zip

Try cleaning your 5.25" drive heads with medical grade spiritus. It helped me to revive one drive which was otherwise immune to cleaning.

Keep the scene alive !
Eidis

[X-Col]

Cheers Costa & Eidis!

PM'd you back Costa mate 

Eidis,
the drive reads and writes 360kb ok, but really struggles with 1.2mb floppies. Yeh, cleaning didn't help but never tried what you suggest. Will give it a go.
Otherwise, would some kind person send me a predumped floppy? I'll cover the cost of course 
I already have a Yamaha V769970 hanging round somewhere, would I be able to use this in the X68000?

[eidis]

 Hi X-Col !

Yes, the Yamaha V769970 will work. Don't forget to install the SRAM driver before booting from HDD/CF

Keep the scene alive !
Eidis

[X-Col]

YES!!

Thanks Eidis 

Hopefully someone can send me the floppy I need to get the driver to SRAM 

Here is the X68000 I won, has a Midi board attached: https://www.jauce.com/auction/t388655409

X-Col

[eidis]

 Hi X-Col !

That's a very nice bargain. It has a midi board so it could have an internal 1MB ram expansion and I would not be surprised if the closed I/O slot contained another ram expansion.

Keep the scene alive !
Eidis

[X-Col]

Just had to pay customs charges, what a rip off!
Arranged delivery for Saturday 13th September, so will find out if there are any nice surprises inside 

[H68k]

Customs charges in one form or another are unfortunately unavoidable if you live in a country outside of the European union or a country that does not have some sort of trade pact with something relating to the import/export of goods.

In my country, her dear majesty's customs department is in bed with a courier service that at times is capable of a rather comical level of incompetence (it's a commercial division of my country postal service that handles parcels and small freight)

Witch basicly gives them dibs on every parcel that's waiting to clear customs, so every time I have a parcel in retention that's waiting for the fee's to be paid. I get a letter from them stating they will pay the customs fees on my behalf.
The import tax and percentage of value added tax you have to pay is usually quite reasonable... However.. the bastards slap there 'clearance' 'administration' and 'handling' fee's on top of that, witch lands me with an extra £30 (37 euro, 48 usd) on top of what I've had to bleed through the noise already.   

[BlueBMW]

I guess we are spoiled here in the United States as there are no import fees or dutys that we have incur when receiving parcels from outside the country.

[X-Col]

Parcel arrived today, and it has a Sharp CZ-6BE1A inside! 

I note that there is leakage of the battery.

I need to remove it now and clean it up.

How do I take the bottom PCB out without having to dismantle the entire machine?

Looks like it's never been apart, so PSU etc may need a refurb

[X-Col]

Ok, removed the battery and cleaned the pcb.

Tried the machine and it worked for about 4/5 minutes, then turned itself off.

Won't turn back on. No power light at all.

Took the the power supply apart and smells a bit fishy, does this look like the culprit?

[eidis]

 Hi X-Col !

Looks like your PSU is fried and might need some repair. Replace all capacitors in your X68000 before even attempting to power it on. The following link might help.

PSU Schematics
http://nfggames.com/X68000/Schematics/PSU/

Keep the scene alive !
Eidis

[X-Col]

Is there a chance the PSU has taken some components with it, or are these ones in the ACE safer than the originals?

I'm a little worried 

[BlueBMW]

The Ace power supply is jjst like the ones found in the Expert, Super, XVI and 030.  Caps leak then kaboom!   Typically it will need more than just caps though.  Google translate this page to see what other components you should go ahead and replace.  There are several transistors and diodes that like to die.  Ive also seen some resistors blow too.   Also, the ace supply seemed to use slightly lower rated capacitors than the expert and newer but its the same design so you can use the caps show for the expert and newer models.  There should be a chart somewhere in this forum or in the wiki.

http://x68k.net/x68dengen/

The other option id recommend is pico psu conversion. 

[X-Col]

Thanks for the advice 

Should I be worried about the X68000 itself? As I say, it seamed to be working before the PSU died

[eidis]

 Hi X-Col !

Usually the PSU does not take anything with it so there is a very high probability that your ACE is fine.

Keep the scene alive !
Eidis

[X-Col]

Hi Eidis,

Thanks for that, makes me feel a bit better!

I've stripped off the old caps from the psu, they stink, phew!

I'll replace them first before I try anything else. I'll then get cracking on the rest of the caps in the X68000 once I know the PSU is functioning again.

A big job to replace everything, but at least it should last another 20 years once done.

Hope your right and the system is fine 

X-Col

[BlueBMW]

If the power supply stopped working then I would guess at a minimum some of the zener diodes will have failed.  Check for burn marks around them.  Youll probably have to replace them.

[X-Col]

Cheers BlueBMW,

The 3 zener diodes on the list;
RD6,8EB 6.8v
RD4, 3EB 4.3v
RD15EB 15v
Are discontinued
Would any zener diode of the same voltage suffice?

[BlueBMW]

I believe so.  I know Ive found replacements without much trouble.  Ill try and dig out my parts order and get the part numbers for them.

[X-Col]

OK, replaced all caps in PSU
Replaced the 3 zenner diodes listed.

Still no power output from the power supply. No red light, tested output and no voltage registered on multimeter.

Suggestions?

[eidis]

 Hi X-Col !

Check if the values of nearby resistors conform to their specifications. Might as well check voltage regulators too.

Keep the scene alive !
Eidis

[X-Col]

Thanks, will do. Or try with my limited knowledge & skills....

Just noticed that D23 (5DL2CZ) is very green, the other regulators look clean.

Another thing I remember is that when I first fired up the machine it did not have a red light, it went straight to green and the power button had no affect at all.

Don't know if this points to a particular component, but thought it was worth mentioning.

Checked

D27: 0v on all 3 pins
IC22: 0v on all 3 pins
IC23: 0v on all 3 pins
IC31: 0v on all 3 pins (on schematic as IC35)
D23: 0v on all 3 pins
Q1: 1, -2.7v; 2, 140v; 3, -3.7v (the voltages on the 2 outside pins vary by up to 4v)
Q31: 1, -2.2v; 2, 150v, 3, -2.2v (as above 1 & 3 volts vary)
Q32: 1, -5v, 2, -5v; 3, -5v
Q33: 0v on all 3 pins
Q51: 1, -2.6v; 2, -1.6v; 3, -2.3v
Q53: 1, -1.7v; 2, -1.6v; 3, -2.3v
PC51: 1 to 3, 0v; 4, -3.3v
PC52: 1, -1.5v; 2, 0v; 3, 0v; 4 to 6, -3.2v

Resistors: all seem fine

No idea if these mean anything to anyone, maybe I should ditch the old PSU and try the Pico mod (when a link to the mod is available)

Or just buy this: http://www.ebay.co.uk/itm/121345323688?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[eidis]

 Hi X-Col !

Please don't go the short and easy route. It will give you instant results but you will regret it after a while because nothing is as satisfying as looking at a machine which has most of its original parts intact and has not received a "nose job" which went bad.

About the resistors. Have you actually checked them with a multimeter ? I had one stubborn arcade PSU which, after an incident, had two 1/2W resistors with much larger values than their color code suggested. Did you actually desolder one end of the resistors and checked them with a multimeter ? They might look fine to the naked eye but that might not be the case.

Keep the scene alive !
Eidis

[X-Col]

OK Eidis, I won't give up just yet. The expense is just mounting up...

Resistors (checked so far):
R2 - 1m
R6 - 1k (x2)
R5 - 0.7
R31 - 217k
R36 - 470
R4 - 185k
R54 - 62k
R52 - 390
R55 - 624
R35 - 3.8
R56 - 5.65k
R57 - 10

Will update as they are checked....

[eidis]

 Hi X-Col !

Good news ! Judging by your findings, it looks like ACE and EXPERT have identical PSU's. The following schematic should be accurate and aid you in further troubleshooting.

X68000 EXPERT PSU Schematics
http://nfggames.com/X68000/Schematics/PSU/X68000_EXPERT_PSU_Schematics_v1.5.pdf

I checked the resistor values and the only ones which had different values were:

R5 - 0.7 (0.39)
R31 - 217k (220k)
R4 - 185k (180k)
R35 - 3.8 (3.3)

By the way, try testing the bridge rectifier (BD1 RBV-406M) and see if anything comes out of it. AC goes in, DC comes out. Try testing voltage regulators for continuity and make sure that they are not shorted.

Keep the scene alive !
Eidis

[X-Col]

Resistors checked:
R2 - 1m (1m)
R4 - 184.6k (180k)
R5 - 0.7 (0.39)
R6 - 1k x2 (1k)
R22 - 3.6k (2.7k)
R23 - 3.8k (2.7k)
R24 - 473 (470)
R31 - 217k (220k)
R33 - 100.5 (100)
R34 - 99 (100)
R35 - 3.8 (3.3)
R36 - 470 (470)
R37 - 1k (1k)
R38 - 1k (1k)
R39 - 475 (470)
R40 - 2k (2k)
R41 - 10.7 (10)
R51 - 10 (10)
R52 - 390 (390)
R54 - 62k (62k)
R55 - 624 (620)
R56 - 5.65k (5.6k)
R57 - 10 (10)
R58 - 7.45k (7.5k)
R59 - 98.7k (100k)
R95 - 220 (220)
R96 - 329 (330)
R97 - 98k (100k)
R98 - 2.28k (2.2k)
R99 - 319 (314)
R100 - 303 (301)
R102 - 120 (120)

Actual values followed by the schematic values in brackets. Let me know if I've missed any.
Which ones may be causing problems and need changing?

[eidis]

 Hi X-Col !

Replace R22 and R23. Any news about the rectifier and voltage regulators ?

Keep the scene alive !
Eidis

[X-Col]

Hi X-Col !

Replace R22 and R23. Any news about the rectifier and voltage regulators ?

Keep the scene alive !
Eidis

Hi Eidis,

I don't really know how to check them to be honest, can you explain as if taking to a 3 year old? 
I have only a very basic electronics knowledge, but am trying to learn as I go.
Can you list which components, and then what I need to do to check them? That would be a massive help!
I'll order some resistors to replace R22 & R23 as you suggest. They did look a bit high!
Will 1/4w resistors be OK? 1/6w are harder to come by.....

Cheers
X-Col

Note: checked pins of rectifier and one pin outputs a steady 140v DC

[lydux]

Honestly guys, I wouldn't spend my time with checking/changing resistors. Trust me, I've repaired many kind of electronic stuffs (including switching PSU) and never seen a blown resistor...

Assuming you have correctly done measurements of D23 and D27, they both indicates 0v, meaning  that the main transformer doesn't deliver voltage, or does not have current on input.  Transformers rarelly die suddenly, however it happens sometimes that you have a cold solder join on its pads. Check this out.

But the main responsible here for turning on this transformer is the mosfet Q1! After capacitors, the second PSU killer are mosfets and they die  without preventions, sometimes bringing with them diodes or others transistors.
I strongly advice you to remove it, and test it (a mosfet is always  tested out of its circuitry).

Testing guide here : http://www.utm.edu/staff/leeb/mostest.htm

[costa]

R5 seems suspicious too...

Hi X-Col !

Replace R22 and R23. Any news about the rectifier and voltage regulators ?

Keep the scene alive !
Eidis

[X-Col]

Honestly guys, I wouldn't spend my time with checking/changing resistors. Trust me, I've repaired many kind of electronic stuffs (including switching PSU) and never seen a blown resistor...

Assuming you have correctly done measurements of D23 and D27, they both indicates 0v, meaning  that the main transformer doesn't deliver voltage, or does not have current on input.  Transformers rarelly die suddenly, however it happens sometimes that you have a cold solder join on its pads. Check this out.

But the main responsible here for turning on this transformer is the mosfet Q1! After capacitors, the second PSU killer are mosfets and they die  without preventions, sometimes bringing with them diodes or others transistors.
I strongly advice you to remove it, and test it (a mosfet is always  tested out of its circuitry).

Testing guide here : http://www.utm.edu/staff/leeb/mostest.htm

Thanks Lydux!

I have checked all solder pads on the transformers and all are fine. To be sure I de-soldered and re-soldered with new solder. Tried the test on Q1 but wasn't sure if I was doing it right, so ordered a new part anyway.
So once the resistors come and the new MOSFET, I'll try the PSU again.

Am I right in thinking the PSU doesn't output 12v until the power button is pressed on the X68000? And is the PSU always outputting 5v to supply the standby voltage?

[caius]

But the main responsible here for turning on this transformer is the mosfet Q1! After capacitors, the second PSU killer are mosfets and they die  without preventions, sometimes bringing with them diodes or others transistors.
I strongly advice you to remove it, and test it (a mosfet is always  tested out of its circuitry).

Testing guide here : http://www.utm.edu/staff/leeb/mostest.htm

I fully quoted what 'Master' Lydux said, I have repaired many dead PSU (including X68000 ones) and a shorted MOSFET was the culprit most of the times.So, out of circuit, check the resistance between GATE, SOURCE and DRAIN terminals or use some chinese tester.

[X-Col]

Thanks for the tip, I've checked resistance between all the pins with my multimeter and the only reading I get is between Drain & Source. It reads 8.8 milliohms.
So looks like a short between these pins. Hopefully this is the cause of my problems 
Already ordered a replacement part.

I will also change the resistors suggested by Eidis too for good measure 

Thanks for the help guys!

[X-Col]

MOSFET now replaced and the PSU now powers on 

champagne isn't out yet as the transformer now makes a high pitched screeching sound when powered on. Now the fuse has blown.

Any suggestions?

Update: the stepdown transformer has started smoking, so I guess this is the culprit. 
Will replace it and try again....
What wattage rating will I need guys? I'll get a fused one this time!

[lydux]

Ouch... That's not good ! By which reference did you replace the mosfet ? I know the original one to not being easy to find nowadays...

As said in my previous post, dead mosfet also bring other passive components with him to death... You should check near diodes and transistor.

Update: the stepdown transformer has started smoking, so I guess this is the culprit. 

Possible, some users here experienced this ! I guess a minimal of 100W is necessary, I don't really remember... Don't hesitate on quality, this is a very important piece for your X68000 health !

[X-Col]

2SK643 found new on eBay

I noted that the DC voltage from the rectifier was measured in excess of 140v. Maybe because the step down transformer was on the way out?...

Would this cause the noise from the transformer?

I did replace some C1815Y transistors and a few diodes too. The resistors that Eidis mentioned were just about blown (some of the casing come off) so replaced them too.

I've ordered a new 300w step down transformer with fuse protection