Found A3640 Upgrade Service

Taj, you're very welcome mate!

I'm so glad you're pleased with the results. Hopefully I can get Steve's done exactly the same

If you're happy with this and fancy playing with it this week, I can get it sent off on Monday if you wish.

So, you're now free to swap out the crystal for other speeds if you're interested. It may be worth finding people with spares in the 70-80MHz range to try out, as crystals seem to be fairly pricey from where I've looked so far. Who knows, you may find some success at higher speeds...

I reckon that if you get your A4000 going and think you're going to use the A3640 for some time to come, we could revisit the Rev 3.2 GAL upgrade at a later date, perhaps with hikey's help. With it being a Rev 3.1 board, you don't suffer from the worst incompatibilities that were present in the 3.0 - they're to do with Zorro cards. How much the GALs affect a successful 40MHz overclock seems to be just theory at the moment

Also, I'd be happy to look at your A4000 board. If it hasn't been done already, it'd be worth re-capping along with the SIMM sockets I think I'd be up for the challenge.

Woot! PM on the way Dale!

Hi Steve,

Received your A3640 and new 040 this morning in perfect condition - again, excellent packaging

I'm loving these metal, bulletproof heatsinky-type casing things the 040s are arriving in, hehe

I'll be able to do your card tonight, most likely!

Awesome, awesome stuff!

By the way I sent you a PM about the CF adapter at EAB but, let me see if I can get in touch with Mika first

Oh by the way, you may have noticed I forgot to put a fan with it oh:

The one I have here has the wrong adapter anyway so I might grab something from ebay - do you think my heatsink will be ok? I'd like to try for 37mhz if you can make it work?

However would be happy at 33mhz if it just runs with the heatsink and no fan.

Anyway, lets hope the Caps Changes sorts out the boot issues before we get too excited...

Thanks again!

Steve.

Many thanks for the PM, I have read it I'll wait to see the outcome of you contacting him (thankyou!)

I think I have a spare fan you can have I'll have a look around tonight and if so, I'll fit it for you.

I'm sure your heatsink will be fine. Actually, these new 040s you guys have seem to run very cool! You have now got the MC68040 which I've read run cooler than the XC68040 - and during my testing of Taj's card, the heatsink was cold to the touch I reckon 33MHz on your new 040 would be easily safe running fanless, though I'll be checking this.

I see some very early signs of leaking on the caps which are hidden under the sink - no damage - but theyre probably failing and a possible culprit for any instability. I'll also clean out the edge connector as I can see a little bit of dirt in there which may be causing a bad contact.

After I've performed the mod and installed the socket, you are free to try any crystal you wish. I would myself, but I don't have any crystals other than the 66MHz (/2 = 33) crystals I have bought for yourself and Taj - as these are quite pricey new.

I wonder if Zetr0 or anyone else has some crystals in the 70-80MHz range that we can borrow?

This all sounds absolutelty perfect

Really appreciate this and will let you know about the CF adapter, I found his email in an old PM so I've just sent him a quick email.

Hiyas guys,

alas still suffering some nasty bugs at the moment, kinda in and outa consciousness a lot lately, unfortunately the little'un has it now too... which I was expecting.

okay... heres a resource for you.

www.futurelec.com

Good news (\o/ YAY \o/)
Futurlec has no minimum order
A flat rate $5 postage fee
14pin (full can) oscilators from 1.8Mhz to 83Mhz (including 70Mhz, 80Mhz and 83Mhz)
Price for a 14pin 70Mhz Oscilator = $1.20 (80pence aprx)
Price for a 14pin 80Mhz Oscilator = $3.50 (£2.25 aprx)

Bad News
Shipping can take upto 3 weeks.


I have done a lot of business with futurlec over the last few years and I can honestly say that their products are no fakes and of good quality, they also have a pcb prototyping service as well which I have used =)

okay... need to lay bck down again.. catchup with you guys in a bit...

Hey Zetr0,

Thanks for the post mate, I'll defo order some of their oscilators, not too worried about the wait as I'll have the 33mhz boost for now

Steve.

Zetr0:

Nice information - thankyou Good to know!
Take it easy mate, winter flu = not nice

Fitz:

I found (and think I have fixed) the reason your card was unstable.

Again, as I did with Taj's card, I just put it into my 4000 as I received it to see how well it worked as it was, and it took some persuasion to get it to start. Had a few yellow screens and sometimes not booting at all.

So, as before, I removed the oscillator, and removed the capacitors. The last one... uh-oh... what's this:



This capacitor had completely blown and stealthily leaked a puddle of corrosive electrolyte all over the tracks underneath its base, completely hidden from view with the capacitor sitting on top. It had actually damaged a via - notice the leftmost one which only had a "half-moon" of the hole left:



A simple repair with some very thin wire going from one side to the other has fixed this trace:


This via actually led directly to a pin on the 68040, so some signal was definitely very iffy before this fix. It's sorted now, and the other vias around the the leakage area are fine, having checked each one

All other capacitors have been replaced without incident, I scrubbed the edge connector with IPA to clean them up and the machine booted up first time with the 33MHz clock and your new 040! :drinkin:

It still sometimes didn't want to boot after some power cycling and reseating the card, so I inspected it again. The soldering on the edge connector looked a bit suspect - some dry joints very likely.

I have just finished fluxing and resoldering all two hundred pins and it seems to be booting up much more reliably now

I think I would like to hang onto it for a couple of nights just to keep an eye on it, but I think we have a full fix and overclock.

Stay tuned!

Dale, I really can't thank you enough for all your work on this card

As a thank you I have ordered you one of those Angle CF-IDE adapters from Mika, I'll have it sent straight to you.

Again, I really appreciate this

Look forward to more news...

Steve.

OMG Steve!

That's so bloody kind of you, mate - seriously you don't have to!
Thankyou SO much - it will be perfect for the 600!

Cheers man! int:
This does however mean I'll be ready to try and help fix anything else that you may need looking at.

d0pefish said:

OMG Steve!

That's so bloody kind of you, mate - seriously you don't have to!
Thankyou SO much - it will be perfect for the 600!

Cheers man! int:
This does however mean I'll be ready to try and help fix anything else that you may need looking at.

Click to expand...

Its the least I could do after all the work you've done tonight mate, you are a true credit to this community :rainbow:

Cheers!! :beer::drinkin:

still feeling quite rough, but managed to log in tonigh with a hot-toddy and lots of zombie moaning...

I have to admit these pictures sincerely lifted up my spirits today!

some very good work d0pefish!

Thanks very much Zetr0! I do my best - I doubt I'll ever match your level of expertise though my friend

Just an update:

I hit a bit of a rut, the machine kept freezing on me. I had a good look around the card and saw a few joints on the GALs that looked a bit weak.

I've gone around the GALs with flux and the rework tool to warm and melt all the joints to hopefully eliminate any microscopic cracks in the solder.

So far I've gotten through 10 minutes of playing some MODs... wish me luck.

I really want to be 100% sure that the card is in fully working order before I return it to you Steve - so I hope you don't mind me taking my time and testing as much as I can and fixing things that I can see wrong.

Hey d0pefish, I really appreciate the extra work. I know the card is in good hands and as you say best to make sure its 100%

Just as long as you are ok to keep doing all this work for me!

As soon as its 'done' then send it back mate, if it takes some time no worries.

Its not like I dont have any other Amiga's here

Steve.

ps. don't stay up too late

Thanks Steve.

Well, this is quite bizarre. :huh:

The card will will boot the machine first time, every time now, but only at 25MHz. It seems to be reliable at this speed at least.

Put the crystal for 33MHz in though, and it's a struggle to get it to boot at all. This is completely different to Taj's card, which effortlessly boots up and stays at 33MHz all day long.

Your card is the same revision, 3.1, as Taj's, and it has the same code in its GALs (if the stickers tell the truth). I'm starting to wonder if the GALs aren't as tolerant as the ones in Taj's card, like was suggested as a reason for an overclock ceiling by Zetr0, I think.

I'll continue playing tomorrow, but I'm starting to think there's going to be a few possible outcomes here (opinions from fellow techies welcome )

Option 1:
We buy some modern/fast GAL chips, and some sockets for them to sit in, and ask hikey or someone else with a GAL programmer if he will kindly flash them for us. Then I solder in the sockets, and we install the chips - this also nets us a Rev 3.2 A3640. Perhaps then we can get our 33Mhz, and maybe more - worst that happens is we don't, and just end up with a card that's at least repaired and bugfixed.

Option 2:
We relax the clock with another crystal to say, 31MHz (as reported to be a more achievable overclock) and hope it works.

Option 3:
I return the card as-is with new capacitors, repair work done, socketed crystal and spare 66MHz crystal.

I am not a factor in this decision - I'm definately all for giving further component replacements a shot - soldering sockets is not a problem and I'd love a chance to try and make it work We just need the parts - but it depends if you're willing to gamble a few quid on some more components.

It looks like the processor itself isn't the only deciding factor here, and it rests on the rest of the board's ability to cope with higher clocks - and thus is the design of the A3640.

I'm sorry Steve, I thought I'd had two successes in a row tonight I feel bad for getting your hopes up, especially seeing as you've gone and bought me that adaptor... oh:

One thing I've noticed that makes me optimistic about replacing the GAL chips - Taj's card's GAL chips are ALL Lattice brand chips. Your card has a MIXTURE of Texus Instruments and Lattice.

Could the TI chips be its Achilles' heel when it comes to overclocking? I'm going to have a rummage through some datasheets - Zetr0 - please feel free to chime in here

Hey Dale, you've already earned the adapter and item some!

Would be interesting to hear from Zetr0 to see what he thinks but if you are happy to do the work Im happy to get the parts needed and give it a shot.

Would be awesome if we can get the card up to and above 33mhz.

Thanks again for everything.

Steve.
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just knew steve was going let you play with the card a bit longer dopefish

why dose this make me feel happy, because we get to see more p0rn

Good luck and may the ribbits be with you

hiyas guys,

Still struggling here =( - I must admit if it gets much worse I shall be painting a WHITE cross on the door - denoting the plauge and for other to stay away.

Now before you get deep into removing GAL chips etc, there is something we can test and thats U400 (the KS Mapper) - turn map-rom off and try the 33Mhz Overclock again - its possible that U400 is lagging behind, either because its just not quick enough or that the Kickroms are 200ns and not 150ns

try that and see how you fair.


Okay. after reviewing the a3640 schematics I will say that replacing the GAL's for faster latching varients *should* improve its clockablility, however I wont lie, I have not sat down and done the loading/latching/propagation and skew calculations.. as my head hurts too much =(

So this is pretty much and educated guestimate - I will say (even after doing calculations) you are in for a 50/50 chance it will improve anything.

Now, replacing the GAL's for faster vairents shouldn't be hard - I would suggest replacing one at a time, I would start with the folllowing

U208: PAL16AB-7 and then U203: PAL16L8-7

Note:

These two CPLD's are labled as PAL's on the schematics however in the images these are infact GAL's

These two devices tie the LEBUS ( U208 ) to the CPU and the TERM ( U203 ) to BUSTERM ( U205 ) to the CPU as well - so reviwing the schematic these two devices I see as lynch pins to the water wheel as it were.

so try these first one at a time, and then if no success slowly repopulate all the GAL logic in ascending order. obviously remember to test (25mhz and then 33mhz) at each stage.


After looking at many images of the card, I cannot see any hard logic that would need replacing as its at the fastest latching - lowest propagation you can get, but this might not be on the specific card (I only have amiga.resource.cx and amiga-hardware.com to go by)

so if you do have hard-logic on the card that isn't an "F" varient, I would suggest that gets replaced first and foremost.

remember always test after each component replacement.

I hope that lot helps in some way, sorry I couldn't help more I am feeling somewhat boxed =(

Cosmicfrog: Cheers for the moral support, bud! Moar pr0n on teh way.

Hi Zetr0,

Thanks for taking your time to help out here! Really do hope you're feeling better soon.

I'll play with the mapper option again to confirm what I *think* was happening - mapper on = no boot, mapper off = boot, then lockups at random places.

U208 is one of the chips that is a TI model on Steve's card - I'll look into getting some fast Lattice replacements in the 22v and 16v sizes.

I will go over the hard logic and see which ICs differ between Steve and Taj's cards

Many thanks!