Posted By
bubi123bubi
on 2016-04-13
10:35:04
|  Plus/4 not working - Blue Screen
Hi guys,
i've a problem with my Plus/4 and i hope that someone can help me.
I can switch on my Plus/4 and the red led works but I get a black/blue screen. The CPU is very warm but the TED is just a little bit warm. Because of that I've try another TED but it is the same problem. I use a Composite cable and a RF Cable to connect my Plus/4 with my TV.
http://s16.postimg.org/seyx5i29d/DSC_0110.jpg
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Posted By
Chicken
on 2016-04-13
11:49:58
 | Re: Plus/4 not working - Blue Screen
The black screen of death can be caused by various issues. It's not necessarily a defunct TED. More likely (from my experience) is a defunct CPU. It could be a defunct PLA as well.
It's hard/impossible to tell from the screenshot. Usually, the black screen of death is black and not blueish.
Btw, are you in PAL or in NTSC land? And your plus/4 is PAL or NTSC?
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Posted By
SVS
on 2016-04-13
12:29:59
 | Re: Plus/4 not working - Blue Screen
It may be also caused by the cables/contacts (if you are lucky).
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Posted By
bubi123bubi
on 2016-04-13
12:30:58
| Re: Plus/4 not working - Blue Screen
With my other TED I get the black screen.
I am in Germany so in a PAL land. How I can find out if my plus/4 PAL or NTSC?
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Posted By
Chicken
on 2016-04-13
13:14:10
| Re: Plus/4 not working - Blue Screen
It's most likely a PAL machine … NTSC machines (even if some were sold in Germany) are not that common.
It's been a while since I've seen an opened up plus/4 but some chips are PAL specific while others are not. I just had a look at the hardware section here to see which chips we got, so you can compare chip with photo.
Check the inside if you see this PAL specific chip:
http://plus4world.powweb.com/hardware/C318004-05
(Or the -04 revision)
It's weird that you get a black screen with one TED and the blueish screen with the other one. With a defunct CPU, you should get the same black screen, I think.
Have you tried carefully reseating all socketed chips? It helps sometimes. Other than that, it's hard to tell what's wrong. Defunct CPUs and TEDs are a common problem 
Do you just have 2 TEDs or do you have another plus/4 (or C16)?
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Posted By
bubi123bubi
on 2016-04-13
14:08:40
| Re: Plus/4 not working - Blue Screen
Yes I've reseating all socketed chip and I've just 2 TEDs.
I think I should buy another PAL and try again. I hope that works 
Thanks to you guys.
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Posted By
bubi123bubi
on 2016-04-13
14:40:33
| Re: Plus/4 not working - Blue Screen
what do you think about Ultimate PLA. Does anyone test this PLA?
http://www.vintage-computers.it/pla-for-commodore-plus-4-16-116
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Posted By
Chicken
on 2016-04-13
16:09:19
| Re: Plus/4 not working - Blue Screen
I don't know anyone personally who uses the Ultimate PLA. I do know some ppl, though, who used an EPROM instead of a PLA (even if this is considered risky by some ppl).
There's another PLA replacement, called superPLA:
https://icomp.de/shop-icomp/de/shop/product/superpla-v3.html
It might be worth it, if you have several CBM machines or need to test stuff quite often. If that's not the case, I'd rather try to find a working plus/4 or C16.
Where are you from in Germany? What region? Maybe someone with a working machine lives close enough.
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Posted By
Imperious
on 2016-04-14
03:43:23
| Re: Plus/4 not working - Blue Screen
Chances are it's the 8501 cpu, not the TED or PLA. Unfortunately the cpu's are extremely expensive. Both the 8501 and TED get rather hot when working, but if scoldingly hot it's most likely kaput. I bought some TED's from Aliexpress and have got working spares as a result. I tried ordering 8501's but nothing ever arrived, dodgy sellers in both instances, I did get full refunds though. I'm not sure if anyone has had any luck with Aliexpress and 8501's.
Any Plus/4 can be modified NTSC or PAL just by burning a PAL or NTSC kERNEL ROM and changing the oscillator. Their seems to be a few of these boxed always popping up at Ebay USA. The TED is the same Chip PAL or NTSC.
There are some 8501's available at Ebay USA.
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