Posted By
gmc
on 2018-12-29
12:52:18
|  Another black screen issue - already has heatsink fitted.
Picked up a cheap Plus 4 off eBay and after reading a ton of posts it looks like the TED chip needs replacing due to them getting hot and just dying.
I opened up the Plus4 and to my surprise it already has a copper strip riveted to the metal case. Is this from a mod or were any of them manufactured like this? There are no signs of work done to the board so I don't think its been worked on.
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Posted By
Luca
on 2018-12-30
10:32:39
 | Re: Another black screen issue - already has heatsink fitted.
I've read about the heatsink to be applied into the Plus/4 almost everywhere since years, and my opinion is that heatsinking a TED or a 8501 absolutely doesn't help in any way: Plus/4 is one of the coldest computers of the era, insomuch as you can check the broken IC simply by testing all of them with your fingers — the hottest is the broken one.
Plus/4 TED or CPU easily break up due to bad electric charges on the connections, especially the joystick ones, especially if you attach/detach joysticks with low quality 9pin/round cable adaptors, just because those ports are directly connected to the TED itself with no shielding; if TED heroically keeps, next in the cascade is the CPU, and that's the real reason why these machines easily got damaged.
Nonetheless, you can find tons of forum posts in the Plus/4 discussion groups, about this long running lie.
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Posted By
gmc
on 2018-12-30
12:43:01
| Re: Another black screen issue - already has heatsink fitted.
Thanks, this is interesting.
I managed to order a spare TED chip online. They are almost impossible to find now 
Will do some more reading up to see if there are other ways to protect it.
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Posted By
SVS
on 2018-12-30
14:17:37
 | Re: Another black screen issue - already has heatsink fitted.
You can protect the TED by adding this small additional hardware, if you have the ability to solder and connect wires.
See this page on item #4:
http://solder-synergy.de/plus4/hardware/index.html
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Posted By
gmc
on 2018-12-30
14:39:56
| Re: Another black screen issue - already has heatsink fitted.
Cool, will take a look at that.
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Posted By
MIK
on 2018-12-31
03:04:49
 | Re: Another black screen issue - already has heatsink fitted.
I don't recall seeing any posts here of people having dead TED's or CPU's with modern heatsinks added. When people ask they tend to be untouched Plus/4's having not been used for years or they just bought it and they are dead, again untouched.
gmc,
If your Plus/4 looks a bit like this with the metal casing over one chip then that is standard and how they came from the factory.
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Posted By
gmc
on 2018-12-31
05:10:00
| Re: Another black screen issue - already has heatsink fitted.
This is what mine look like. It has 2 rivet holes in so am not sure it came from the factory like this:
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Posted By
gmc
on 2018-12-31
05:12:50
| Re: Another black screen issue - already has heatsink fitted.
Arrgh, can't edit.
Form says I'm a spammer if I post 3 pics
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Posted By
SVS
on 2018-12-31
08:07:11
| Re: Another black screen issue - already has heatsink fitted.
A tech solution: In the second picture you can see white remains of "conductive fat". This allowed the TED chip to have a good thermal contact with the metallic case. In this way you "could" avoid an external heat-sink.
The conductive fat even if dried works, but until you open the case of course.
Then, you can simply scrape the remains, well clean the copper band and TED (carefully!) and add a new conductive fat (not so much).
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Posted By
gerliczer
on 2018-12-31
13:26:22
| Re: Another black screen issue - already has heatsink fitted.
As a slightly off topic remark, it is usually called thermal paste. Not conductive, because things usually called conductive if they conduct electricity. And not fat, because it is neither a body tissue or foodstuff, nor grease, because it is not used to lubricate machine parts. AFAIK
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Posted By
Lavina
on 2018-12-31
16:30:45
 | Re: Another black screen issue - already has heatsink fitted.
Yeah it's called thermal paste but I guess everyone understood what he meant. 
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Posted By
MIK
on 2018-12-31
20:20:05
| Re: Another black screen issue - already has heatsink fitted.
gmc,
I see what you mean, it gives you the impression it may of been changed at some point. Either that or it could be an early shield design and was updated to what we normally see as a part of cost saving?
BTW. A black screen can mean the CPU has died, and sometimes if the CPU dies it can take the TED out at the same time if your really unlucky. TED machines use the CPU as a video chip, TED tells the CPU what to display...
It's when you see something like jumbled and random text on the screen when you switch on that the TED is normally on it's way out. But yeah spares are always handy so you can at least rule out both.
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Posted By
gmc
on 2019-01-01
07:10:44
| Re: Another black screen issue - already has heatsink fitted.
I think it might be a early design design change as the marks are the rived holes look as old as the rest of the heatsink.
Anyway, I think you are right about the CPU. I got hold of a TED chip from Germany and it didnt make any difference. Looks like the CPU is probably gone. Going to try and source another other but they are proving hard to find.
In the meantime I've ordered one of those 6502 to 8501 mods. At least I can then see if it comes back to live.
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Posted By
MIK
on 2019-01-01
17:28:26
| Re: Another black screen issue - already has heatsink fitted.
Fingers crossed that does the trick when it arrives. Best of luck!
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Posted By
Stinaris
on 2019-01-03
03:36:39
 | Re: Another black screen issue - already has heatsink fitted.
These computers are getting old now. I heat sinked a C16 and the bloody thing still died and it wasn't any of the heatsinked chips!
Just had a couple of C64's die on me too (and it's not the PSU). Luckily I have 5 left!
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Posted By
MIK
on 2019-01-03
06:44:34
| Re: Another black screen issue - already has heatsink fitted.
Even when they are running sweat it's still in the back of your mind that one day they might die. If your serious about messing with the old computers, gathering working spares is the best way to be safe! Just a shame the good times of cheap machines on ebay have long since gone.
Be thankful it's not an Amiga as they are going for crazy prices in comparison!
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Posted By
gmc
on 2019-01-05
12:15:56
| Re: Another black screen issue - already has heatsink fitted.
Got one of those 6510 conversion boards and replaced the CPU. Fixed the issue 
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Posted By
Mad
on 2019-01-05
12:59:25
| Re: Another black screen issue - already has heatsink fitted.
yeah! good to hear!
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Posted By
MMS
on 2019-01-05
13:48:09
 | Re: Another black screen issue - already has heatsink fitted.
But I think you may have troubles with the fastloaders, 6510 is missing few datalines VS 8501.
I am not sure, maybeif it happens only if you have a datasette connected.
Maybe I am wrong, but more and more Krill loader games and demo pops up, so I am not sure, if the 6510 will be a final solution or just a 80% solution?
gmc: could you confirm, if Pet's Rescue, or the latest Larry demo works properly on the 6510 modified Plus/4?
Thank you! (BTW there were some trials with 6502 to, it may have more chance for some overclocking)
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Posted By
MIK
on 2019-01-06
07:34:39
| Re: Another black screen issue - already has heatsink fitted.
Good to hear and hope you find a real CPU at some point.
I'm sure you know but just in case... I did read once that these new CPU's may stop the datasette port from working. Not really a problem if your not using it.
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