<div dir="ltr">I'll let you know. I thought it was the entire pi but it could well just be the SD card, they don't seem to do much without an os.<div><br><div>It has pretty much sat doing its' thing in the same position for 10 years, could well be more, with only the occasional power outage. In the early days when I had real vintage hardware in the basement and a UPS I think I got to nearly 2 years up time.</div><div><br></div><div>Regards, Mark.</div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 22 Jan 2021 at 17:43, Johnny Billquist <<a href="mailto:bqt@softjar.se">bqt@softjar.se</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">...despite Peter's experience with a KA10. I can't really comment on the <br>
PDP-10s, since I've never worked much on them. But since I suspect they <br>
might not have had switched power supplies, I'm not surprised if it <br>
worked just fine, even after longer storage.<br>
<br>
The only 10s I have worked a bit more on is KL10. And replacing a power <br>
supply for the MF10 was quite a job, since it was a linear supply with a <br>
big trafo in it. *Very* heavy... :-)<br>
<br>
Johnny<br>
<br>
On 2021-01-22 18:39, Johnny Billquist wrote:<br>
> And speaking of power - the one thing that I have experienced a lot on <br>
> 11/70 machines are the H7440 regulators. They tend to blow up. And <br>
> especially if just kept in storage for longer periods, and then starting <br>
> to be used again...<br>
> <br>
> Don't leave these machines off. That's all I say. That's when you get <br>
> trouble.<br>
> <br>
> Johnny<br>
> <br>
> On 2021-01-22 18:36, Johnny Billquist wrote:<br>
>> Not really trying to claim there is anything particular about DEC <br>
>> equipment here. While they were built properly, I don't think there <br>
>> necessarily is anything exceptional about them.<br>
>><br>
>> But no, I do not believe any components have been replaced. One of the <br>
>> biggest issue is when equipment are left turned off for longer times. <br>
>> That usually seems to be the time when problems appear. These machines <br>
>> are (or were) running 24/7, and have always done so. There might have <br>
>> been one or another card replaced from time to time, since they were <br>
>> on service contracts for a long time. But just by looking into them, <br>
>> if something had been replaced, it was a long time ago. Based just on <br>
>> the general look of the cards.<br>
>><br>
>> By the way, we're talking 11/23 machines here. So BA23 box. Not that <br>
>> much loaded in them, so no big strain on the power supply.<br>
>><br>
>> My experience with 11/70 machines are the same. If they are kept <br>
>> running, they usually just continue to work. If you have them off for <br>
>> a couple of years, you'll have a lot of work before they are stable <br>
>> again.<br>
>><br>
>> But disk drives get into trouble with age, even if continually <br>
>> running. And some are worse than others. The RD53 is sortof infamous <br>
>> here...<br>
>><br>
>> Johnny<br>
>><br>
>> On 2021-01-22 18:15, Dave McGuire wrote:<br>
>>><br>
>>> Sigh, yes, we all know of exceptions. But even then, I doubt it <br>
>>> can be proven that those PDP-11 systems in production since the early <br>
>>> 80s have never had components replaced.<br>
>>><br>
>>> Not everything is built to DEC standards. That said, all my life <br>
>>> I've been replacing chips, diodes, transistors, capacitors, and <br>
>>> sometimes even resistors in DEC gear. It does happen, and it's not <br>
>>> uncommon.<br>
>>><br>
>>> The regulator bricks in the H742/H7420 power supplies tend to blow <br>
>>> Zener diodes. That's fresh in my mind because we just lost another <br>
>>> one at the museum recently. Those are failing with such frequency <br>
>>> now that I've purchased stocks of the components that tend to fail. <br>
>>> (we have a lot of those at the museum) And those ARE built to DEC <br>
>>> standards.<br>
>>><br>
>>> Speaking of not being built to DEC standards, I've got a Heathkit <br>
>>> H8 on the bench right now, I'm repairing it for a new exhibit at the <br>
>>> museum. Four failed (non-moving!) ICs replaced so far, it's very <br>
>>> nearly done.<br>
>>><br>
>>> -Dave<br>
>>><br>
>>> On 1/22/21 12:03 PM, Johnny Billquist wrote:<br>
>>>> Well, I know of PDP-11 systems out in production who have been <br>
>>>> running since the early 80s. The only thing that fails is the damn <br>
>>>> RD53...<br>
>>>> Replaced those about 20 years ago now. The rest of the machine was <br>
>>>> running just fine. At that at a steel mill, so not exactly a <br>
>>>> friendly environment. Last I heard, things were still running, but <br>
>>>> it might have been replaced by now. But anyway, it's the moving <br>
>>>> parts that cause problems. The rest usually just keep running...<br>
>>>><br>
>>>> Johnny<br>
>>>><br>
>>>> On 2021-01-22 17:53, Dave McGuire wrote:<br>
>>>>> On 1/22/21 11:41 AM, Thomas DeBellis wrote:<br>
>>>>>> 10 years used to be nearly unheard of for retail machines with <br>
>>>>>> moving parts. When nothing is moving, then supposedly there is <br>
>>>>>> nothing to burn out.<br>
>>>>><br>
>>>>> I don't know who told you that, but he/she knows jack point <br>
>>>>> squat about electronics.<br>
>>>>><br>
>>>>> Materials migration and diffusion across junctions causes <br>
>>>>> semiconductor components to fail, tin whiskers cause shorts, some <br>
>>>>> types of capacitors dry out and/or have their electrolyte <br>
>>>>> deteriorate or crystallize, resistors drift, heat/cool cycles cause <br>
>>>>> PCB flexure resulting in cracked solder joints, corrosion in air <br>
>>>>> creeps into connector pin interfaces and forces pins apart, the <br>
>>>>> list goes on and on and on.<br>
>>>>><br>
>>>>> To be fair, some of the above-listed failure modes do in fact <br>
>>>>> involve things moving, though imperceptibly so, my point stands.<br>
>>>>><br>
>>>>> -Dave<br>
>>>>><br>
>>>><br>
>>><br>
>>><br>
>><br>
> <br>
<br>
-- <br>
Johnny Billquist || "I'm on a bus<br>
|| on a psychedelic trip<br>
email: <a href="mailto:bqt@softjar.se" target="_blank">bqt@softjar.se</a> || Reading murder books<br>
pdp is alive! || tryin' to stay hip" - B. Idol<br>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><a href="https://www.qrz.com/db/M0NOM/P" target="_blank">https://www.qrz.com/db/M0NOM/P</a><br><div><br></div></div></div>