Posted By
kopsec
on 2014-04-12
07:44:24
|  C16 Repair
Hello finally I got a working C16, couldn't believe. I was desperate.
I had 2 non working C16 and a friend send me 2 more.
None of them working, just black screen and 1 with strange chars,1 showed startup screen for 1/2 second.
After a lot of chip swapping, could get 1 working.
The results from this 4 are:
2 working PCB, one of them needs replacement of CPU socket
1 working CPU
2 working TED (one of them after sandpaper on pins and cleaning with alcohol)
Some pictures for fun
http://s587.photobucket.com/user/kopsec/slideshow/C16
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Posted By
MIK
on 2014-04-12
12:25:52
 | Re: C16 Repair
Looking at what you've said I'm sure you can see now it's not always TED that causes problems such as a black screen which goes back to what I was saying on Lemon64 if you remember. Many people relate to TED as if it was a VIC II from a C64 but this is not always the case with 264 computers as you have found out.
Looking at your last picture that TED looks like it's come from a Plus/4 with the heat sink paste on the top, you can take that off when being used in a C16, should help a little with cooling if removed on a C16 as your just heating the paste up first...
Nice to hear your finally getting some where with your machines! For a while it felt as if you were all alone, left in the wilderness to sort it out your self which is not nice when you've just bought a new machine that was meant to be working! I hope you get the others working soon enough and with spares at your side your be here to stay for along time. Thanks for sharing your pictures with us! 
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Posted By
Imperious
on 2014-04-12
20:44:53
| Re: C16 Repair
I would be putting heatsinks on the 8501 and TED ASAP if I were You, there is a lot more room
in a c16 case than a plus/4 so I would also heatsink the PLA.
Interesting that the 8501 appears to have no revision number.
http://tinypic.com/r/28hhnwg/8
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Posted By
kopsec
on 2014-04-13
04:47:55
| Re: C16 Repair
Imperious you are right, this will be the next step.
Are you using the small vga RAM heatsinks?
I'm using a 9 VDC 2A stabilized power supply and the 5v 7805 regulator inside run cooler than with original power supply that is giving around 10-11 Volts. A good idea could be replace the 7805 with a switching version that doesnot need heatsink.
I was also thinking about using a small external ac adapter 5v 2A but this will need some mods on PCB.
The 8501 without revision number is the working one, this was on a C16 from Germany that came with the repair note replacing CPU on 1990 and repair seal intact.
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Posted By
Retro76
on 2014-04-13
05:22:21
 | Re: C16 Repair
Great Stuff Kopsec My Man 
Yeah I though we'd lost you & Imperious for a while but you are both back doing what you do best;
Electrical Engineering/Technical Repairs & Electronics Repairs respectively.
Sorry I don't have any new technical info to add but I think you guys with Mik make a terrific all-round plus/4 technical advice crew
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Posted By
Imperious
on 2014-04-13
09:22:47
| Re: C16 Repair
Here is a ebay link to copper ram heatsinks
http://www.ebay.com.au/sch/i.html?_sacat=0&_from=R40&_nkw=8pcs+copper+ram+heatsinks&LH_PrefLoc=2&_sop=15
I used the square ones as You could see.
With respect to my 3 plus/4 consoles, 1 of them boots fine but gives a "break" error upon loading anything from my sd2iec, as well as occasional characters appearing on screen and scrolling as though the enter key is stuck down.
I narrowed this down to a faulty 8501 by sustitution. I am currently working on a hackup of a 8501 replacement that is mentioned here http://www.webalice.it/gratteri/65028501.gif
Might take me a couple more weeks but will post success or failure when finished and tested.
It will look very unprofessional with a double decker board design that fits inside with the case closed.
1st level has 8501 cpu pins and a 6522 and 74ls ics. the top level board will have the 8501 pins and
6502 and other 74ls ics. It's a wiring nightmare but If I do a bit at a time I'll finish it eventually.
Someone over at cbm hackers had a go making one years ago, but could not close the case due to
the size of the board. If it works it could be reproduced with some smd parts and double sided pcb
design which would shrink the size down a bit.
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Posted By
kopsec
on 2014-04-13
16:57:37
| Re: C16 Repair
Someone did the CPU replacement in Spain, he had some problems but finally got it to work:
http://www.retrowiki.es/fororw/viewtopic.php?f=687&t=28683&sid=4e676b64222a2a2556f25bfa306cdc8b&start=10
Read all the post, the CPU is really off-topic because the topic is 64K ram expansion, there are some pictures, in this case the case can be closed. If you need translation pls. tell me. I have found a 8501 CPU at reasonable $ so for the moment is enough for me, but if you have succes it will be a very interesting project.
Retro & Mik nice to hear from you again. I will post more pictures when completed the 2 working C16, one of them is in relly mint condition.
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