CPC6128+ repair job

[Spirantho]

Hehe.. I intend to find out. I just bought 10cc (which is funny, as I was listening to 10cc yesterday) of the stuff. Maybe I can try a comparison by doing one ASIC with the paste, and one with flux+solder....

[arnoldemu]

light pen is used by light gun.. 2 games support this, so it's no great loss.
cursor is used by nothing in the cpc?
it's not displayed on the screen and I don't know of any hardware or software that actually uses it.
So don't worry about that either.

[Gryzor]

 

Watching it "melt" under the microscope is really cool

Bryce.

You got a microscope in your room as well? Wtf, does it sit next to the centrifuge?

[Bryce]

Yes, you need a microscope to check SMD solder joints on accassions. You can see it in the picture here beside the oscilloscopes: Interview Bryce - NoRecess {the Amstrad CPC website}

My Centrifuge is in the Garage of course! Beside the particle accellerator

Bryce.

[endangermice]

Great interview, really interesting - thanks for posting the link and enlightening to see the kit you're using! I don't have all of those tools but I certainly have enough to do most of the day to day repair tasks and will grow my toolset over time!


I'm totally with you that you have to be very careful not to allow a hobby to take up too much of your time. I often find myself in danger of getting obsessed when I'm desparately trying to get something to work and it is very important to make sure you spend enough time with the others in you life. I can imagine that having kids recently has totally changed everything. I don't have any yet but they're definitely on the horizon which i think will be a big life changer - but a very worthwhile one!

[ralferoo]

I've found SMD work using my hot air station pretty easy, although when I first used it I did have the blower on too fast and my tiny 0805 resistors blew away!

That said, 0.5mm pitch is tricky. Even with the tiniest syringe I could find (I think it's 0.2mm) it's really hard work getting the paste out thin enough that I don't end up with bridges between the pins. I do have a load of flux in a syringe I bought by mistake (also with no presser!), so i might try mixing that with my solder paste to make it a bit runnier which should allow me to apply the paste more fluidly.

[endangermice]

Yeah the more videos I've watched using hot air guns the more I have been convinced that it is absolutely the right way to go - if I can heat up an IC then just remove it with tweezers when the solder melts it can be removed really easily and with no damage to the board!


What have you guys used in the past to suck the solder that inevitably is left in the holes occupied by the chip? I see you can get vacuum units to compliment the hot air blower - is that the way to go...? If so any recommendations?

[ivarf]

Interview Bryce - NoRecess {the Amstrad CPC website}

Bryce.

Quotes below are from the interesting  Interview Bryce - NoRecess {the Amstrad CPC website}
"I also did freelance design for several companies that made CPC and Spectrum hardware, which is where my 8-bit design really started."
What CPC hardware ( I asume addons?) did you design at the time and for what companies?


"I have actually developed more hardware for the XL/XE, C64 and Spectrum than for the CPC."
How did this happen?


"Other ideas on my list are: ...and a hardware diagnositcs card. "
One for the many dead GX4000s would be great

[Bryce]

@Dame1701: I use desoldering wick most of the time, I find it works better than those pumps, especially if you need to get a very smooth surface to put a new SMD part on the pads.

@ivarf: Yes, I was designing stuff while I was in University for a small electronics company that did out-sourced design for several other companies. Some of the things were end-customer add-ons, but other devices were used to develop other hardware/software like porting data from one 8-bit to another, or to digitise sound / pictures that I believe were being used by a games company. I know that one of the devices was for DKTronics and I think some was for Code Masters, but I was never officially told who the customer was, I was just the student bum who had to do the design

I owned an 800XL and a friend owned a C64, that's why I started developing stuff for them first. I only really started doing CPC stuff when I joined the Wiki (around 2009). So the CPC stuff hasn't caught up with the other 8-bitters yet.

The diagnostic card is still just an idea. There's a few other things I'd like to release before then. But any and all ideas are always welcome.

Bryce.

[ralferoo]

What have you guys used in the past to suck the solder that inevitably is left in the holes occupied by the chip? I see you can get vacuum units to compliment the hot air blower - is that the way to go...? If so any recommendations?

Solder braid/wick. It's absolutely phenomenal, although cleaning solder through holes seems to require an awful lot of the stuff comparatively, although I guess there is a lot more solder! It's not so much that the wick gets full of solder cleaning through holes, but by the time it's all sucked up then a lot of the flux nearby in the wick has been used, so you need to move along by about half an inch for the next hole or it won't really work.

But definitely, the holes end up all nice and clean with an ever so slight tinning...

[Spirantho]

My solder flux came today. Awesome stuff.
The flux I bought was ebay item 230807633527 from "catcrusader". Ordered Saturday, came first class Tuesday morning.


I also have solder flux paste and ChipQuik solder paste coming too, might try them on my GX4000s which are (for some weird reason) without ASICs..... see which method works best!
I have to say though, soldering the entire 200-odd pin QFP in 3 hours isn't bad, really - the flux made it soooo much easier. And having the Aoyue enabled me to get the chip off with no bent pins.

[endangermice]

That's fantastic news!! Looks like it's all up and running too. Did you managed to get the cursor and light pen pins attached, I remember you were having trouble with those?


Looks like all you need to do now is clean up the excess flux and you're done - great job!

[Spirantho]

Yes, everything is connected properly now. Last time the colours would fade in and out, and some of the pins I had to wire up. But with the proper fluxing, every single pin was attached properly, even the ones at the top right I think, which are starting to come off the PCB (not surprisingly given this is about the 10th attempt at soldering the ASIC!).


I'm now trying to work out why my RoboCop II cartridge (which was dead) doesn't work now I've programmed the BR/BASIC cart onto an EPROM (I have an EPROM burner which supports 27C1001 now ).....

[Spirantho]

Just a thought - I was going to throw it away as it's dead, but does someone want a knackered ASIC? I might be useful for practising with if you want to try soldering a working one....

[endangermice]

Very well done - must be an amazing feeling of achievement! From what I understand you didn't use the paste this time but the flux and some normal solder...? How did you melt it over the pins?


From what I've seen using solder paste means you could attach such a chip very quickly - will be interesting to see what results you get!

Out of curiosity, which EPROM burner have you got and where did you get it? Does it work with a PC and if so, over USB or does it require a Parallel port? Does it support Windows 7 (I have both 64 and 32bit) or is it more a DOS item...?


Can it also do EEPROMS and Flash?


I'm on the hunt for a new burner (my old one died a while ago and I'm realising I need one again).


Cheers,


Damien.

[Bryce]

Just a thought - I was going to throw it away as it's dead, but does someone want a knackered ASIC? I might be useful for practising with if you want to try soldering a working one....

There was a discussion a while back about sending custom ICs to a group who file the case off and reverse engineer the IC. Maybe your ASIC can be sent to them?
3 hours for one IC! That's quite a job.

@Dame1701: What kind of money do intend spending on an EPROM burner? How much do you intend using it and what ICs must it support? This is off topic, so send me a PM.

Bryce.

[Spirantho]

3 hours is a lot less than I spent on it the first time round.


My EPROM burner is a Wellon VP-490 - you can find them easily on eBay, and they support truckloads of devices. I've not really put it through any great trials yet, but so far it's been awesome, and very useful, especially with the TTL testing.

[endangermice]

That's great thanks Spirantho, I'll check it out. Bryce, my apologies for the EPROM burner being question being off topic - I was inspired by the one of the posts in the thread. Have PM you!

[Spirantho]

I now have my 6128+ working and booting into BASIC! My VP-490 burned the 27C1001 like a champ, and I was soon struggling with a dodgy keyboard in BASIC. Actually, none of the keys worked at all, but I cleaned the contacts and it's better now - about half the keys work now!


Thanks to AndyCadley on this forum who very generously sent me his EME-157 disk drive, I am this close to a fully working CPC 6128+. Not too bad for less than £20 which is what it cost me....


(I just loaded The Hobbit from disk. Hurrah! )

[dragon]

Just a thought - I was going to throw it away as it's dead, but does someone want a knackered ASIC? I might be useful for practising with if you want to try soldering a working one....

[/size]

"There was a discussion a while back about sending custom ICs to a group who file the case off and reverse engineer the IC. Maybe your ASIC can be sent to them?"




Yeah! please contact them and send the asic.This can be a very good oportuniy to discovers the secrets of the asic.What cause the bugs,how is designed.


Please,please,please!!!.


visual6502.org HW Donation




PD:What the hell.I can't eliminate the \size  to quote .

[Spirantho]

Have just mailed them.... will let you all know the response.

[Spirantho]

For anyone interested in the progress of the original 6128+, by the way, here's a photo.


The keyboard is now fully working after I realised that the problem was the connector on the board, and that the cost-reduced CPC464 used the same mechanism.


All working nicely, cartridges (that's my burned EPROM in there!), disks, keyboard and everything. Yay!

[dragon]

Have just mailed them.... will let you all know the response. 

Thanks!




Your cpc is very white.Wonderful.

[Gryzor]

Indeed, great specimen. And thanks for sending it!

[dragon]

[size=78%]Have just mailed them.... will let you all know the response.[/size][size=78%] [/size]

[size=78%]


Any news?[/size]