Printable View
Hope this is the right place to post :cool:
I'd like somebody to upgrade my A3640 to 33mhz by performing the overclock mod and fit a cooling fan. Would I need a 33mhz CPU or would the 25mhz unit be overclockable?
I'd also like to have the capacitors replaced at the same time as I get random boot issues so think maybe that woud help.
If anyone can give me a quote for this job including tracked postage back to me in UK I'd appreciate it :thumbsup:
Cheers!
Steve.
Hey Steve
Check out my thread here
http://amibay.com/showthread.php?t=8784
It offers advice on how to do it yourself and there is an eBay link to a 33Mhz 040 too.
Taj
Hiya Steve :)
If you would like someone to help, I'd happily do it for cost of parts and shipping.
I will be doing a component order this week and can include crystals and SMD capacitors on my list if you like.
I have a spare unused A3640 as insurance.
If you'd like to give me some time to build a shopping list, I can quote you for parts (will only be a few quid). I'd insure it with Royal Mail up to the value of your choice.
I will stress-test and benchmark the card using a variety of different programs for you.
Would you like my help? :)
@dopefish I'd love your help :D
But I must give you something for your time!
Do you think I should grab the 33mhz CPU as per Tajmaster's post? (Thanks for the link by the way) or should we see if my current CPU is up to the job?
Thanks so much for posting :thumbsup:
PM me all the details and I'll get the parts payment over to you.
Steve.
I think it's probably worth it for a more predictable and safe result :) They're nicely priced!
Otherwise, I have my 25Mhz 040 which I'd be willing to try pushing if your 040 refused to work at 33Mhz. I'm happy keeping my card stock as I'm lucky enough to have the CyberStorm :shhh:
It'd maybe be a bit nicer to have an 040 which was graded for the job.
Heck, with a 33Mhz part, we might be able to go higher (the guide reports some were successful at 37, 40Mhz). I'd be socketing your crystal, of course - so if crystals are cheap, and you fancy it, we'd be able to switch them easily enough and see how far we can take it :) As far as I can see, provided we keep it cool, the worst that can happen is that it'll not boot, or crash, at which point we relax the clock back again.
It's completely up to you, my friend. I'll only do exactly as you ask, and I aim for a high standard of work and communications. :nod:
As for paying me, I'm open to small tips etc, but only when you're completely satisfied with the outcome. Unless you have anything Amiga-related you fancy trading? :) But seriously, I just fancied helping - and I want to make it up to you for wasting your time with that RAM a short while ago. :Doh:
Hiyas guys
this is awesome to read here - I honestly wish I had the time to help.
What I can say is that milage may variy but for the top end results you will need a faster rated CPU and for the best (top end 40Mhz) results the replacement of (FASTER) GAL chips - I believe that the code is online to program your own.
however I believe that a good 33Mhz is definately achievable which is a much welcome 33% boost over the stock CPU!
Good luck on the hackery / upgradery
Hey Zetty, nice to see you back on the Prowl :cool:
Think I'll grab one of those 33mhz CPU's then as it sounds like a good idea.
@d0pefish, I'm sure we'll figure something out, I've got plenty of Amiga bits and pieces if there is anything you need ;)
Once I have that CPU and a decent Fan/Heatsink I'll get it all off to you, if you could PM me your address that would be awesome.
Again thanks for helping me out :thumbsup:
And don't worry about the Ram, nothing is a waste of time for the peeps of this great board!
Steve.
edit just bought the CPU :)
Thanks for the pointer, Zetr0 :D
At the moment, it looks like the crystals themselves are the most expensive piece.
Farnell do just one 14-pin (4 populated) DIL tin-pot crystal @ 66Mhz (that I can see), and it's £5.01 ex VAT. We could look elsewhere - I'm just using Farnell as they have everything else (as well as the rest of my order) and they deliver free. :)
This is assuming you would like to use the 33MHz 040 from eBay, and that you don't want to go any higher for now.
If you'd like to turn this into an experimental project (that carries quite a bit more risk) and aim for 40MHz, you may have to replace/uprate the GAL logic chips as Zetr0 says. I can remove and socket the current GALs (would need sockets) but I don't have a GAL programmer or any chips, although I think Zetr0 might have at least the programmer. Maybe a revisitable thing in the future?
The oscillator socket is £0.59 ex. VAT.
They have my favourite series of capacitor, the Panasonic FP high-temperature, long-life, low-ESR surface-mount range, ideal for computers. Your A3640 needs five of these at 22uF, 16V. I have chosen a 22uF, 25V part (costs no more than the 16V part and is the same size) and these are £0.44 each ex. VAT. (£2.20 total ex. VAT)
These will of course be installed with the polarity correction. :thumbsup: (Many A3640s were built with capacitors in the wrong way round!)
Current total for parts is £9.17 including VAT.
The GAL chip sockets if wanted:
7x 28pin PLCC sockets: £0.47each ex VAT.
3x 20pin PLCC sockets: £0.46each ex VAT.
(add an extra £5.49 which includes VAT)
Oh - forgot to ask - is your A3640's 040 socketed? I haven't looked at my one for some time and can't remember if it is :oops:
If not, we'll need some pin-strip to build a socket for your new 040 if you choose to go with it. :)
So to summarise:
- £9.17 will get you a recapped board with a 33Mhz setup. There is a risk of this not working with the current 040, but better chances of it working if you would like to try the 33MHz eBay 040 :)
- An extra £5.49 lets you socket the GAL chips. This could makes your (or Zetr0's) life easier in future if you'd like to go for the 40MHz goal - perhaps more research on success rates and past experiences would be a very good idea. You'd ideally want a range of oscillators between 74-80MHz to find a working setup... but going by the price of one at £5.00... :(
I'll mirror the same delivery service you use to get it to me, so just let me know which one you used/will use, and cover the cost as appropriate. I'm not sure how much the board is worth, so I'll let you decide mate :)
Any input on the proposal above, Zetr0? :)
---------- Post added at 15:49 ---------- Previous post was at 15:47 ----------
Ah, you got a post in before me :)
For your heatsink, I have Arctic Silver 5 somewhere, I think :thumbsup:
Look out for a PM in a few seconds :)
Hey d0pefish,
The 040 is socketed, so no worries there - I should have mentioned that sorry!
I'll send to you by recorded delivery as that covers it for £40 which is what I paid for the board, on the way back I'd like it special delivery which will be about £6 becuase my post delivery here is shockingly slow and I'll be too excited to wait a week for it ;)
As for the further upgrade, if you think you can do it mate and you're happy to take on the extra work I have the faith that you can do it :thumbsup:
I think the best thing to do though is get the board booting reliably first, so perhaps change the caps and soak test it?
Cheers! :D
Steve.
Firstly, Steve, I hope you dont mind me asking DopeFish if he would be willing to do the same service to my A3640? Please accept my apologies if you do and PM me and Ill edit my post :)
@Dopefish
I was going to attempt the delay line mod (not the caps although I wanted them doing too) but tbh my soldering is VERY poor and would rather someone in the know such as yourself do it. Would you be willing to do mine as per Steves A3640? Its a v3.1 board with socketed CPU as per the pics in my thread and I already have the 33Mhz CPU too :)
Excellent, we're good to go.
As PMed, we'll go for Phase 1 first - service the caps, replace the CPU, install oscillator socket and test for stability.
Then we can slot in the 66MHz crystal (gets halved to 33), do the necessary minor mod as described in the guide, and stress-test again.
At that point we can decide if you'd like to go any further :)
Unless there's anything you'd like to add, I'll probably get the order in in the next day or so :)
Cheers :):beer:
---------- Post added at 16:15 ---------- Previous post was at 16:11 ----------
Of course mate! :)Quote:
Originally Posted by Tajmaster
Actually that helps - capacitors need to be ordered in minimum quantities of 10. Your board can be the other 5 - they'd be in my spares box otherwise! :)
Would you like the same plan as above? (I'm calling it "Phase 1") :)
hi guys,
ive just done the very same mod to my A3640 (v3.1) and its happily running at 33mhz ...
although id like to try for 40mhz ....
Anyway i have fittted a nice heatsink and fan and it is rock solid and stable and is a big improvement over the 030 at 33mhz that was in my A4000....
@fitzsteve
>just bought the CPU
All 68040@25 are working fine at 33 Mhz !
Oh well, wont hurt to have the correct spec part, and a spare CPU :cool:Quote:
Originally Posted by Cosmos
Steve.
I'm glad I managed to get Anthony to upgrade 3 of my A3640s to revisions 3.2 (one included a 30Mhz version) before he disappeared into the deep south for a year
good luck!
Thanks guys :)
@Slayer Anthony is an awesome guy - very knowledgeable and a gentleman. I look up to him in my electronics endeavours :)
He is indeed, I once I asked him what I'd need to get going with soldering etc if money wasn't a concern and he replied with a very detailed email listing all the machinery and gizmos I'd need and loads of advice, maybe I should ask him if I can publish it? :cool: I've kept the email because ONE DAY, I hope to start down that road and of course I do want the right tools for the job! and having over 100 Amigas to tinker with will help :shhh:Quote:
Originally Posted by d0pefish
Sounds like you're well down that road d0pefish, nice work! :nod:
To be fair I would say you have it pretty much covered, all I can say is just dont underestimate the amount of time to do the work (including testing) =)Quote:
Originally Posted by d0pefish
I do indeed have a GAL programmer, I do need to get a PLCC adapter for it though =)Quote:
Originally Posted by d0pefish
good to see another panosonic fanboi on the site :thumbsup:Quote:
Originally Posted by d0pefish
Only thing I can add here it ensure a good quality socket - reduces breakages, improves connectivity, and reduces any slew rates akin to PLCC sockets.Quote:
Originally Posted by d0pefish
All A3640's that I have encounterd are socketed 040's \o/ YAY \o/Quote:
Originally Posted by d0pefish
Although a 25Mhz 040 can clock to 33Mhz there is NO guarantee of it.. the beauty here would be the possibility of clocking the 33mhz further up (37/40)
I have here two XC040@25 that can only run at 25 - they wont go to 33/40 at all (with or without RAM)
Now, where 37 doesn't seem that much more than 33 - let me explain that over another 10% increase in workload - such that a 33mhz 040 would achieve 24MIP's - the 37Mhz would achieve 26MIPS (as well as a good FLOP bonus too =) )
what ever Steve decides to do and what D0pefish can do, I would love to see a how-to with pictures =D
I can reprogram the GALs for you if you want to drop them round at some point D0pefish. Ideally you want U209 at revision -03 and U204 at revision -02 -- this will essentially upgrade the board to 3.2
Naturally - of course, matters can always be complicated by the unexpected. :) We'll start (relatively) simple and work our way forward as per Steve's wishes. :thumbsup:Quote:
Originally Posted by Zetr0
Would you recommend any particular model(s)? I may want to invest in one for future projects. :) I have my trusty Willem for some casual EPROM flashing, but that's all it seems to support.Quote:
Originally Posted by Zetr0
I like the pretty colours some of them come in; black and gold FM series - awesome! Oh, they're alright as capacitors too. :lol:Quote:
Originally Posted by Zetr0
Actually that's a very good point. I've tried Multicomp ones from Farnell recently, and they do the job - not as heat-resilient for reflow as I'd hoped though; ended up hand-soldering them with the 0.12mm tip, which turned out absolutely fine. I might try the 3M ones next, a little pricier but may be more robust.Quote:
Originally Posted by Zetr0
I was thinking that "all 25s will run at 33" is a rather broad statement - has there been any extensive testing? I'd agree with the benefits of having a spare, and a part that has even more potential. :)Quote:
Originally Posted by Zetr0
As I've said to Steve, I'd be glad to write-up the work and take plenty pictures to keep everyone up to date with what's happening :D I'm quite looking forward to it!Quote:
Originally Posted by Zetr0
Now THAT is VERY useful to know as you are on my way home from work! That's much appreciated Hikey :D Forgive me, as I haven't played with GAL/PALs yet, but are you saying that they are erasable and rewritable like EEPROMs?Quote:
Originally Posted by hikey
Cheers! :)
yes - they are reprogrammable in most of the decent modern programmers, but as Zetr0 mentioned - you need a DIP -> PLCC adapter (which I have)
@d0pefish
I use (and whole heartedly recommend a Genius G540 programmer
You can get one from eBay for £29.60 + £15.75 (eBay.co.uk buy it now)
http://images.tupianguanjia.com/bin/5083/g540-1.jpg
Heres a supported device list (lots btw) - unfortunately it wont 16bit EPROMS - so for Amiga Kickroms a trusty willem will do you good!
However the device is capable of a lot of things like programming EPROM, FLASH, GAL, AVR, PIC's etc.
One extra feature is the testing mode thats strictly AWESOME!
you can test 74x IC's as well as a range of 1-8bit memory chips!!!
how awesome is that?! - recently I used this to test the RAM in a spectrum 128k and C64 =D
That looks like a nice programmer Zetr0, thanks for the info! :)
It looks quite similar to the "TOP853" I've seen around - do you know how they compare?
Loving the idea of using it to test 8bit memory chips! :lol: Awesome!
Ooh, also, an update to say that my massive component order has gone from "Processing" to "Complete" and I have a UPS tracking number :) Should be here tomorrow! :nod:
Enough gear to:
- Do these two cards for Steve and Taj :Rockon:
- Recap tokyoracer's A1200 whose IDE header I've just replaced :drinkin:
- Recap my new A600 to preserve it :thumbsup:
- Recap an A1200 I'm trying to fix :coffee:
- Recap two MORE A1200s or 600s (I might sell on these spare capacitor kits :))
- Start Project: Lazarus Mac-SE/30 - a tale of the most horrendous soldering you will ever see in your life! I am going to try and revive tokyoracer's poor abused Mac, which had a cap-replacement by a previous-previous owner go horribly wrong. Wait til you see the PCB traces that are hovering half an inch above the motherboard and hanging on for dear life to grubby 2nd-hand through-hole caps! :overactor:
A busy few weeks ahead of me, but I'm looking forward to seeing these jobs through to completion :) I enjoy helping with projects and repairs :)
Yay :)
http://lh4.ggpht.com/_kRG1wB80tiI/TO...0/IMAG0075.jpg
Rock and roll!
@d0pefish,
33mhz 040 CPU was here as expected when I got in, so just been up and posted the A3640 and CPU :cool:
Thanks again!
Steve.
Thanks Steve! I'll let you know as soon as I've received it mate :)
Well, I'm happy to say guys, Taj's card is finished, and has been successfully upgraded to 33MHz. :drinkin:
Currently running ADoom for a bit of a burn-in test :D
I thought I'd share what I've noticed some of you guys like to refer to as "hardware pr0n". :lol:
I tested the card with SysInfo and AIBB before touching it at all, just to make sure it was working, and to check it was benching at the known speed - which it was:
http://lh5.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0093.jpghttp://lh5.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0094.jpg
After removing the heatsink and carefully extracting the 25MHz 040, the crystal was the first component to come out:
http://lh4.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0100.jpg
Followed by the capacitors - some of which were leaking and had left small traces of gunk. I shielded the 040 socket from the rework tool's heat.
http://lh6.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0101.jpg
The areas they occupied were cleaned up and prepared for the replacements to go in:
http://lh4.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0102.jpg
Now for the bit I'm kinda proud of :oops: - the delay line hack. I have not cut any traces as the guide suggests - I like my mods to be as reversible as possible. So, I removed R101:
http://lh6.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0105.jpg
Insulated the front pad, moved the resistor back, and soldered on a thin wire, but tucked it underneath the chip to keep it out of the way, and to stop it from being caught or tugged when installing/removing the card:
http://lh5.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0107.jpg
Board repopulated and complete:
http://lh4.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0109.jpg
And the benchmarks:
http://lh3.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0110.jpg http://lh4.ggpht.com/_kRG1wB80tiI/TP...4/IMAG0111.jpg
SysInfo: a gain of 5801 Dhrystones.
AIBB: a gain of 9704 Dhrystones per second
I'll continue testing and using it over the weekend to ensure stability - please let me know if there's anything you'd like me to run in particular Taj! :)
I've also put some Arctic Silver on your heatsink for you.
Further photos on my album here: http://picasaweb.google.com/daleyo/T...eat=directlink
Hope you enjoyed the photos - Steve, you're up next! :D
Awesome stuff :bowdown:
Dude this is amazin!! What a fantastic job! And great pics too, Im big fan of hardware pr0n ;)
I cant thank you enough for this Dale, I might just use my A4000 a lot more now! Gotta get those SIMMs fixed soon but will wedge them back in again to have a run around on the upgraded A3640 when it gets back :thumbsup:
@ mods
I know this is Steves thread, but am I able to leave some sort of feedback for Dale? It only seems fair :)
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... :thumbsup:
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!
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? :)
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 :cool:
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:
http://lh3.ggpht.com/_kRG1wB80tiI/TP...0/IMAG0114.jpg
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:
http://lh5.ggpht.com/_kRG1wB80tiI/TP...0/IMAG0118.jpg
A simple repair with some very thin wire going from one side to the other has fixed this trace:
http://lh5.ggpht.com/_kRG1wB80tiI/TP...0/IMAG0120.jpg
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 :D
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! :thumbsup:
Dale, I really can't thank you enough for all your work on this card :bowdown:
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 :thumbsup:
Look forward to more news...
Steve.
OMG Steve!
That's so bloody kind of you, mate - seriously you don't have to! :oops:
Thankyou SO much :D:D - it will be perfect for the 600!
Cheers man! :D :pint:
This does however mean I'll be ready to try and help fix anything else that you may need looking at. :)
Quote:
Originally Posted by d0pefish
Its the least I could do after all the work you've done tonight mate, you are a true credit to this community :thumbsup: :boing::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! :thumbsup:
Thanks very much Zetr0! :) I do my best - I doubt I'll ever match your level of expertise though my friend :bowdown:
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. :unsure:
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 :cool:
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... :Doh:
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.
Mozilla/5.0 (SymbianOS/9.2; U; Series60/3.1 NokiaN95/31.0.017; Profile/MIDP-2.0 Configuration/CLDC-1.1 ) AppleWebKit/413 (KHTML, like Gecko) Safari/413
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! :D 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! :bowdown:
You guys are the best :grouphug:
:bounceBoingBall:
Update:
I found some cheap supplies of 20 and 28 pin PLCC sockets, and have ordered enough sockets to replace every single GAL on two A3640 boards, and still have a few spares :)
I've got my eyes on some cheap 5ns Lattice GALs too.
Quote:
Originally Posted by d0pefish
Awesome stuff, just let me know what I owe you and I'll paypal it over :thumbsup:
Hi Steve :)
Don't worry about it for now mate - let's see if we make some progress first :thumbsup:
If we don't end up using them, I'll definitely have uses for them one day.
I've bought enough for two boards because we might as well get Taj up to a Rev 3.2 aswell while we're at it - rude not to! :thumbsup2:
OH Taj - I've also added some new SIMM sockets to my AmigaKit order for December's (hopefully!) ACA630 delivery :)
That way I'm ready for working on your A4000 next year. :thumbsup:
Nice one dude :thumbsup::thumbsup::thumbsup:
Your doing a great job Dale and I (again) cant tell you how much I appreciate it :)
Thanks for v3.2 upgrade! How much more do I owe you?
For those following the thread but not aware, Dale has offered to replace my knackered A4000 SIMM sockets aswell, this is true community spirit! :grouphug:
:bowdown::bowdown::bowdown: