| C128 and C64 OS [message #422717] |
Sat, 17 August 2024 06:59  |
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Originally posted by: Daniel
Hi folks -
I've been really tempted to jump back into the CBM world after watching
a few demo vids of the c64 OS. Heard an interview on a podcast the other
night and... Well, impressed the guy got a wikipedia app running on the
OS. I actually reached out to the developer asking why he stood up a
propxy to scrape wikipedia vs pulling the data with existing API's. He
simply didn't know about it.
Anyway, tangents aside, I'm considering a purchase of a C128 and would
like to know if the C64 OS supports 80 column mode or does the user have
to switch to C64 mode to make it work?
RIght now, my only access to CBM is on a Mini i purchased at gamestop
some time ago but it's finicky about the sort of image it'll load from a
flash drive.
I bought an actual C64 off ebay a few years ago but haven't had a chance
to recap it. There's alot of residue and cleaning to do yet, and figure
out what else if wrong before I can plug it in.
Thanks.
Daniel
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| Re: C128 and C64 OS [message #422720 is a reply to message #422717] |
Sun, 18 August 2024 18:10  |
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Originally posted by: phigan
On 2024-08-17, Daniel <me@sc1f1dan.com> wrote:
>
> I bought an actual C64 off ebay a few years ago but haven't had a chance
> to recap it. There's alot of residue and cleaning to do yet, and figure
> out what else if wrong before I can plug it in.
Don't have the answer to your C64OS question, but there usually isn't a
reason to recap a C64. Unless of course you actually see the caps
looking bad. One big thing to worry about is the original power supply.
If possible, use a new one, or one of those little adapters that combine
two modern power supplies.
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| Re: C128 and C64 OS [message #422723 is a reply to message #422722] |
Mon, 19 August 2024 08:42 |
Robert Roland
Messages: 89
Registered: July 2012
Karma: 0
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On Sun, 18 Aug 2024 23:15:51 -0000 (UTC), kalevi@kolttonen.fi (Kalevi
Kolttonen) wrote:
> You should
> avoid the old power supply at all costs. If and when
> it fails, it will usually take a lot of C64's chips
> along with it.
Do you have any references for this? I mean, actual facts.
Have you ever seen an overvolting C64 PSU?
I suspect the issue is massively overhyped.
--
RoRo
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| Re: C128 and C64 OS [message #422724 is a reply to message #422723] |
Mon, 19 August 2024 10:24 |
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Originally posted by: kalevi
Robert Roland <fake@ddress.no> wrote:
> On Sun, 18 Aug 2024 23:15:51 -0000 (UTC), kalevi@kolttonen.fi (Kalevi
> Kolttonen) wrote:
>
>> You should
>> avoid the old power supply at all costs. If and when
>> it fails, it will usually take a lot of C64's chips
>> along with it.
>
> Do you have any references for this? I mean, actual facts.
>
> Have you ever seen an overvolting C64 PSU?
>
> I suspect the issue is massively overhyped.
I am not sure.
Commodore Finland has several thousands of members
and I guess it is safe to say that everybody there
always recommends ditching the old power supplies.
I have just believed in those warnings.
br,
KK
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| Re: C128 and C64 OS [message #422727 is a reply to message #422723] |
Mon, 19 August 2024 17:36 |
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Originally posted by: phigan
On 2024-08-19, Robert Roland <fake@ddress.no> wrote:
>
> Do you have any references for this? I mean, actual facts.
>
> Have you ever seen an overvolting C64 PSU?
Just my own experience. And yeah, both of my breadbins have been
affected by bad PSUs. In one, the PLA got half-borked. In the other, one
of the sdram chips got messed up. Actually, the ram one might be a
coincidence of just ram gone bad along with the system's PSU gone bad.
The same thing happened to my Atari PSU that I've had for over 30 years
since NIB. Maybe it's this desert climate.
The PSUs from c64psu.com are worth it, imo.
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| Re: C128 and C64 OS [message #422728 is a reply to message #422723] |
Mon, 19 August 2024 19:38 |
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Originally posted by: Adam Sampson
Robert Roland <fake@ddress.no> writes:
> Do you have any references for this? I mean, actual facts.
> Have you ever seen an overvolting C64 PSU?
I found one earlier this year -- an Ismet-made wedge PSU that came with
a breadbox C64. The output was approaching 5.2V at the C64 end of the
cable under load.
Having dismantled it, the reason was that it uses a 7805 regulator with
a resistor divider to lift its ground reference pin a bit, and the
resistor values had drifted considerably. The PSU runs quite hot (not
helped by the heatsink and 7805 being buried in potting compound), so
this isn't terribly surprising after 40 years.
Initially I just replaced the resistors, which worked fine, but I later
found timperi's replacement PCB that uses a modern switching regulator:
https://github.com/timperi/c64-wedge-psu-pcb
I've built a couple of these now (using boards from an eBay seller) and
they run much cooler than the original.
Thanks,
--
Adam Sampson <ats@offog.org> <http://offog.org/>
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| Re: C128 and C64 OS [message #422841 is a reply to message #422728] |
Tue, 20 August 2024 05:27 |
Anssi Saari
Messages: 329
Registered: January 2012
Karma: 0
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Senior Member |
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Adam Sampson <ats@offog.org> writes:
> Robert Roland <fake@ddress.no> writes:
>
>> Do you have any references for this? I mean, actual facts.
>> Have you ever seen an overvolting C64 PSU?
>
> I found one earlier this year -- an Ismet-made wedge PSU that came with
> a breadbox C64. The output was approaching 5.2V at the C64 end of the
> cable under load.
Does that actually matter though, is 5.2V high enough to cause damage to
anything?
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| Re: C128 and C64 OS [message #422842 is a reply to message #422728] |
Tue, 20 August 2024 06:36 |
Robert Roland
Messages: 89
Registered: July 2012
Karma: 0
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Member |
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On Tue, 20 Aug 2024 00:38:38 +0100, Adam Sampson <ats@offog.org>
wrote:
> Having dismantled it, the reason was that it uses a 7805 regulator with
> a resistor divider to lift its ground reference pin a bit, and the
> resistor values had drifted considerably.
I have been thinking about various failure modes that could possibly
cause an overvoltage condition. This is the only one I have been able
to think up. Thank you for confirming.
Not all versions use these voltage boosting resistors, though, so the
myth that all of them will fail, is still on thin ice as far as I am
concerned.
--
RoRo
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| Re: C128 and C64 OS [message #422843 is a reply to message #422841] |
Tue, 20 August 2024 06:53 |
Robert Roland
Messages: 89
Registered: July 2012
Karma: 0
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On Tue, 20 Aug 2024 12:27:19 +0300, Anssi Saari
<anssi.saari@usenet.mail.kapsi.fi> wrote:
> Does that actually matter though, is 5.2V high enough to cause damage to
> anything?
It is still within the tolerance of both TTL chips and the DRAM chips,
so no damage should occur. Yet.
However: The voltage will not have been this high when the PSU was
new. The fact that it is this high now means that something has
changed. If it has changed, it may continue changing, and one day the
limit is reached.
--
RoRo
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| Re: C128 and C64 OS [message #422844 is a reply to message #422720] |
Thu, 22 August 2024 04:25 |
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Originally posted by: Daniel
phigan <phigan@bbs.penisys.online> writes:
> On 2024-08-17, Daniel <me@sc1f1dan.com> wrote:
>>
>> I bought an actual C64 off ebay a few years ago but haven't had a chance
>> to recap it. There's alot of residue and cleaning to do yet, and figure
>> out what else if wrong before I can plug it in.
>
> Don't have the answer to your C64OS question, but there usually isn't a
> reason to recap a C64. Unless of course you actually see the caps
> looking bad. One big thing to worry about is the original power supply.
> If possible, use a new one, or one of those little adapters that combine
> two modern power supplies.
The breadbin case is in great shape and the keyboard is complete. I had my
neighbor test the PSU when I got it and he said it was junk.
After opening the case, it was obvious that a good number of the
capacitors were misshaped, leaky, and left quite a bit of residue and some
rusty looking traces.. Some of the resistors flaked off too, so I
ordered a few of each type from the BOM online. Didn't cost more than a
few dollars.
It's going to take a ton of work to restore it, then I need to get a
test rig to see if any of the chips need replacing, if any. I don't know
if the previous owner plugged in the power supply it came in but I knew
well enough not to. I really hope the chips are in good shape.
In the meantime, I have a C64 mini that I use for daily driver.
I have a growing interest in getting a C128.
Daniel
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| Re: C128 and C64 OS [message #422845 is a reply to message #422844] |
Fri, 30 August 2024 07:34 |
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Originally posted by: phigan
On 2024-08-22, Daniel <me@sc1f1dan.com> wrote:
>
> ordered a few of each type from the BOM online. Didn't cost more than a
> few dollars.
Ah, ok. Good luck with this.
> It's going to take a ton of work to restore it, then I need to get a
> test rig to see if any of the chips need replacing, if any. I don't know
Are there any C= users groups near you that might have someone with a
test harness? I always want to get one myself, but I just can't bring
myself to spend the money on it :).
> I have a growing interest in getting a C128.
Yeah, I had always wanted a 128 since I was kid, so I finally bought one
from Europe a couple years ago. Definitely wanted PAL so I could watch
all the demos!
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