Re: OpenVMS Alpha V7.3
related question - I was not able to make a bootable/readable image from the ISO I have 7.3, although it might have been a bad source. Is there a best way/ best software to make a usable 7.3 install CD that will work in an Alpha? Just curious as to why I was not able to make it work. I make CD's all of the time from ISO, but maybe I need to do more research on the subject as far as size and set up go for an Alpha-bootable CD, or CDRW type I need to use, etc. I'd offer my ISO, but I don't know if it's good. Bill On Thu, Jul 16, 2015 at 11:28 PM, Sean Caron sca...@umich.edu wrote: Maybe my RRD45 doesn't like the 700 MB CD ... does anyone know if it's possible to bootstrap the installation from my existing CISC VAXcluster with the ALPHA084*.ISO images I got from HP? Cross-platform MOP boot from the VAX with the *.ISO images mounted locally on the VAX, perhaps? I assume it's just a save set that's restored with the BACKUP command once one can actually get to the point of a DCL prompt on the machine? Best, Sean On Thu, Jul 16, 2015 at 7:19 PM, Sean Caron sca...@umich.edu wrote: Anyone got an ISO handy? Trying to get my 3000/400 up; V7.0 firmware; and it does not like the OpenVMS V8.4 ISOs I got from HP ... I do have a valid Hobbyist license ... please chat with me off-list? Thanks, Sean
Re: OpenVMS Alpha V7.3
On Thu, 16 Jul 2015, Sean Caron wrote: Anyone got an ISO handy? Trying to get my 3000/400 up; V7.0 firmware; and it does not like the OpenVMS V8.4 ISOs I got from HP ... I do have a valid Hobbyist license ... please chat with me off-list? I have a 7.2 CDrom and a 7.3-1 CDrom that I can send you if you cannot find an ISO. -- Richard Loken VE6BSV, Unix System Administrator : Anybody can be a father Athabasca University: but you have to earn Athabasca, Alberta Canada : the title of 'daddy' ** richar...@admin.athabascau.ca ** : - Lynn Johnston
Front Panels Sample layout.
Hi Guys! Further to my previous email. If anybody would like to see the artwork I can send you a copy. Its in *.svg format. Regards Rod
PDP8/e front panels A and B
Hi Guys! I now have prototype artwork for the two types of 8/e front panel. They differ only in the switch markings. They do both have the same extra (but cosmetic only) features over the first run. Regards Rod
Re: Reproducing old machines with newer technology
On 07/16/2015 11:45 AM, Mike Stein wrote: Not the same thing of course but remotely on-topic, and I never miss an opportunity to put in a plug for Cromemco: By comparison, Cromemco used semi-autonomous 4MHz Z80A SBCs for their I/O processors, with 16KB of local RAM and up to 32KB of ROM; communication with peripheral cards is via a separate 50-pin 'C-Bus'. That wasn't all that uncommon in the microprocessor world--once the price dropped sufficiently, doing multiuser applications by giving each user their own CPU was practical. Molecular was another outfit that did practically the same thing. Dual-CPU setups, where the weaker of the two CPUs was in control of the stronger one were even more numerous--just consider the number of add in processor cards for the PC archicture. 68K, NS32xxx...you name a CPU, it's probably been on an ISA card. And there's the veneered and generated Radio Shack 68K series (16, 16B, 6000) where it's the Z80 that starts things and controls the show initially, even if you're running Xenix. In pretty much all cases, the system is capable of running without the stronger CPU. --Chuck
Re: OpenVMS Alpha V7.3
On Fri, Jul 17, 2015 at 7:53 AM, william degnan billdeg...@gmail.com wrote: related question - I was not able to make a bootable/readable image from the ISO I have 7.3, although it might have been a bad source. Is there a best way/ best software to make a usable 7.3 install CD that will work in an Alpha? Just curious as to why I was not able to make it work. I make CD's all of the time from ISO, but maybe I need to do more research on the subject as far as size and set up go for an Alpha-bootable CD, or CDRW type I need to use, etc. I'd offer my ISO, but I don't know if it's good. Bill Your Alpha system may not support reading burned CDs at all. I know mine doesn't.
Re: OpenVMS Alpha V7.3
Thanks, Richard! I'll try some of the ISOs I received and failing that I might take you up on your offer. I'm going to get this box running VMS one way or the other :O Best, Sean On Fri, Jul 17, 2015 at 11:25 AM, Richard Loken richar...@admin.athabascau.ca wrote: On Thu, 16 Jul 2015, Sean Caron wrote: Anyone got an ISO handy? Trying to get my 3000/400 up; V7.0 firmware; and it does not like the OpenVMS V8.4 ISOs I got from HP ... I do have a valid Hobbyist license ... please chat with me off-list? I have a 7.2 CDrom and a 7.3-1 CDrom that I can send you if you cannot find an ISO. -- Richard Loken VE6BSV, Unix System Administrator : Anybody can be a father Athabasca University: but you have to earn Athabasca, Alberta Canada : the title of 'daddy' ** richar...@admin.athabascau.ca ** : - Lynn Johnston
Re: OpenVMS Alpha V7.3
Sector size? On Fri, Jul 17, 2015 at 8:25 AM, Richard Loken richar...@admin.athabascau.ca wrote: On Thu, 16 Jul 2015, Sean Caron wrote: Anyone got an ISO handy? Trying to get my 3000/400 up; V7.0 firmware; and it does not like the OpenVMS V8.4 ISOs I got from HP ... I do have a valid Hobbyist license ... please chat with me off-list? I have a 7.2 CDrom and a 7.3-1 CDrom that I can send you if you cannot find an ISO. -- Richard Loken VE6BSV, Unix System Administrator : Anybody can be a father Athabasca University: but you have to earn Athabasca, Alberta Canada : the title of 'daddy' ** richar...@admin.athabascau.ca ** : - Lynn Johnston -- Ian S. King, MSIS, MSCS, Ph.D. Candidate The Information School http://ischool.uw.edu Archivist, Voices From the Rwanda Tribunal http://tribunalvoices.org Value Sensitive Design Research Lab http://vsdesign.org University of Washington There is an old Vulcan saying: Only Nixon could go to China.
Re: OpenVMS Alpha V7.3
I've got a few to try so I'll burn those today and see what happens. For the 8.4 disc I have, I used the same process to burn the disc that I did for OpenVMS VAX V7.3 ... I just copied the *.iso to a Mac and used Disk Utility to burn the *.iso just to a regular CD-R. For V7.3 VAX this produced a perfectly good bootable CD, but on Alpha, when I try to boot the disc, it looks like it'll get started, but it will churn for a little while but eventually come back and say it can't find the file SYSBOOT.EXE. I know the monitor environment variable BOOT_OSFLAGS needs to be set to 0,0 and I've ensured that's done ... I definitely get the sense that my Alpha is a little more finicky than my VAXen are ... seems to be kind of picky about what it will run and what hardware it will work with! I'll try these disc images today and write back with my experiences; I hope I can get at least one of them to come up :O Tru64 and NetBSD boot fine on this machine but I've never been able to get it to run OpenVMS ... I'm trying to rectify that this week :O Best, Sean On Fri, Jul 17, 2015 at 9:53 AM, william degnan billdeg...@gmail.com wrote: related question - I was not able to make a bootable/readable image from the ISO I have 7.3, although it might have been a bad source. Is there a best way/ best software to make a usable 7.3 install CD that will work in an Alpha? Just curious as to why I was not able to make it work. I make CD's all of the time from ISO, but maybe I need to do more research on the subject as far as size and set up go for an Alpha-bootable CD, or CDRW type I need to use, etc. I'd offer my ISO, but I don't know if it's good. Bill On Thu, Jul 16, 2015 at 11:28 PM, Sean Caron sca...@umich.edu wrote: Maybe my RRD45 doesn't like the 700 MB CD ... does anyone know if it's possible to bootstrap the installation from my existing CISC VAXcluster with the ALPHA084*.ISO images I got from HP? Cross-platform MOP boot from the VAX with the *.ISO images mounted locally on the VAX, perhaps? I assume it's just a save set that's restored with the BACKUP command once one can actually get to the point of a DCL prompt on the machine? Best, Sean On Thu, Jul 16, 2015 at 7:19 PM, Sean Caron sca...@umich.edu wrote: Anyone got an ISO handy? Trying to get my 3000/400 up; V7.0 firmware; and it does not like the OpenVMS V8.4 ISOs I got from HP ... I do have a valid Hobbyist license ... please chat with me off-list? Thanks, Sean
Re: OpenVMS Alpha V7.3
I'm all set; thanks to all that responded! I've got a few different *.isos to try and hopefully one of them will be palatable to my old 3000/400 ... I'd rather run VMS on it than Tru64 :O I truly appreciate it! Best, Sean On Thu, Jul 16, 2015 at 7:19 PM, Sean Caron sca...@umich.edu wrote: Anyone got an ISO handy? Trying to get my 3000/400 up; V7.0 firmware; and it does not like the OpenVMS V8.4 ISOs I got from HP ... I do have a valid Hobbyist license ... please chat with me off-list? Thanks, Sean
Re: OpenVMS Alpha V7.3
thanks for the info. The Alpha in question is a 2100 4/275. It works enough to connect to the web but I need to fix one of the drives. On Fri, Jul 17, 2015 at 12:22 PM, John Willis chocolatejolli...@gmail.com wrote: On Fri, Jul 17, 2015 at 7:53 AM, william degnan billdeg...@gmail.com wrote: related question - I was not able to make a bootable/readable image from the ISO I have 7.3, although it might have been a bad source. Is there a best way/ best software to make a usable 7.3 install CD that will work in an Alpha? Just curious as to why I was not able to make it work. I make CD's all of the time from ISO, but maybe I need to do more research on the subject as far as size and set up go for an Alpha-bootable CD, or CDRW type I need to use, etc. I'd offer my ISO, but I don't know if it's good. Bill Your Alpha system may not support reading burned CDs at all. I know mine doesn't.
Re: PDP 11 gear finally moved
I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... Perhaps. But not all of it, certainly. I'm currently four for four fixing dead flatscreens by re-capping their power supplies; I imagine others have similar experiences. It's not a huge stretch to imagine that other power supplies may have similar issues; even if it turns out to not be the case, there is probably at least a little can't hurt anything, right? running around. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: PDP 11 gear finally moved
some are good some are bad. http://www.badcaps.net/ here is all the info you ever need on today's bad caps not so much on yesteryears bad caps On 7/17/2015 11:53 AM, Mouse wrote: I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... Perhaps. But not all of it, certainly. I'm currently four for four fixing dead flatscreens by re-capping their power supplies; I imagine others have similar experiences. It's not a huge stretch to imagine that other power supplies may have similar issues; even if it turns out to not be the case, there is probably at least a little can't hurt anything, right? running around. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B -- The contents of this e-mail and any attachments are intended solely for the use of the named addressee(s) and may contain confidential and/or privileged information. Any unauthorized use, copying, disclosure, or distribution of the contents of this e-mail is strictly prohibited by the sender and may be unlawful. If you are not the intended recipient, please notify the sender immediately and delete this e-mail.
Re: PDP 11 gear finally moved
I suspect part of the swap'em ALL out mentality comes from the 90's when some botched industrial espionage had some of the bottom-tier cap manufacturers using a dodgy electrolytic formula for their caps. These caps would have a frequent failure rate.. While not an issue for pre-90's electronics, it has fostered the mentality of full replacement for 'newer' electronics i.e. arcade/pinball machines Todd Killingsworth On Fri, Jul 17, 2015 at 2:42 PM, tony duell a...@p850ug1.demon.co.uk wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. Could you, please, explain why? And how often should this be done? Every week, every month, every year, or what? FWIW, the number PSU elecrtrolytics I have replaced can be counted on the fingers of one hand -- in unary. Well, perhaps both hands. But it's 1% of all the PSU electrolytic capacitors I own. Only 2 cases spring to mind : The PSU in my 11/44 had a high ESR capacitor on the +36V rail (all other caps in the machine were fine) I changed the 2 mains smoothing capacitors in my HP120 not because they were electrically defective (they tested fine) but because one was bulging a little on top and had it exploded it would have hit the neck of the CRT with all the problems that would be likely to cause. I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... -tony
PDP 11 gear finally moved
Devin here, I had asked for advice on how to move a PDP 11 as well as how to lock the heads on the RL Drives. It was quite a move. Ive never driven in a large city before, dealing with traffic was more trouble than it was to move and load up the equipment. Anyhow, i put a few images of what I got up on a postimage gallery, which can be viewed here : http://postimg.org/gallery/1xuwq2s6y/ It was at least working for a hour or so I was trying to enter a short program at the front panel and there was a clicking sound followed by a burning smell. I cut the power, the front panel is unresponsive now, so I'm going to need to look over the power supply for starters. He did include a second empty PDP 11/34 chassis, perhaps the power supply in that one is in better condition. --Devin
Re: OpenVMS Alpha V7.3
I'm using a genuine DEC RRD45 so no sector size issue and it's worked fine with burned CDs in the past to load my VAX machines ... I've never had too much trouble with burns ... I think I just got a funky image from HP ... other people have reported issues with it ... I could see the RRD45 getting hung up more on it being a 700 MB CD rather than it being a burn ... but the RRD45 is the newest drive I've got. Best, Sean On Fri, Jul 17, 2015 at 12:22 PM, John Willis chocolatejolli...@gmail.com wrote: On Fri, Jul 17, 2015 at 7:53 AM, william degnan billdeg...@gmail.com wrote: related question - I was not able to make a bootable/readable image from the ISO I have 7.3, although it might have been a bad source. Is there a best way/ best software to make a usable 7.3 install CD that will work in an Alpha? Just curious as to why I was not able to make it work. I make CD's all of the time from ISO, but maybe I need to do more research on the subject as far as size and set up go for an Alpha-bootable CD, or CDRW type I need to use, etc. I'd offer my ISO, but I don't know if it's good. Bill Your Alpha system may not support reading burned CDs at all. I know mine doesn't.
RE: PDP 11 gear finally moved
It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. Could you, please, explain why? And how often should this be done? Every week, every month, every year, or what? FWIW, the number PSU elecrtrolytics I have replaced can be counted on the fingers of one hand -- in unary. Well, perhaps both hands. But it's 1% of all the PSU electrolytic capacitors I own. Only 2 cases spring to mind : The PSU in my 11/44 had a high ESR capacitor on the +36V rail (all other caps in the machine were fine) I changed the 2 mains smoothing capacitors in my HP120 not because they were electrically defective (they tested fine) but because one was bulging a little on top and had it exploded it would have hit the neck of the CRT with all the problems that would be likely to cause. I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... -tony
Re: PDP 11 gear finally moved
It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. JRJ On 7/17/2015 11:49 AM, devin davison wrote: Devin here, I had asked for advice on how to move a PDP 11 as well as how to lock the heads on the RL Drives. It was quite a move. Ive never driven in a large city before, dealing with traffic was more trouble than it was to move and load up the equipment. Anyhow, i put a few images of what I got up on a postimage gallery, which can be viewed here : http://postimg.org/gallery/1xuwq2s6y/ It was at least working for a hour or so I was trying to enter a short program at the front panel and there was a clicking sound followed by a burning smell. I cut the power, the front panel is unresponsive now, so I'm going to need to look over the power supply for starters. He did include a second empty PDP 11/34 chassis, perhaps the power supply in that one is in better condition. --Devin
RE: PDP 11 gear finally moved
It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. I am not sure either would have done much good here. The OP said it ran OK for an hour or so, when you test a PSU on dummy load you typically do it for a lot less time than that, Incidentally, DEC PSUs of this type run fine with no load in my experience Also I have found the capacitors in these units to be very reliable. They can fail, of course, but virtually all the DEC bricks I have are on their original capacitors. I think I've replaced more chopper transistors than capacitors in these. -tony
RE: PDP 11 gear finally moved
It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. The rest of the advice is sound. Rich Rich Alderson Vintage Computing Sr. Systems Engineer Living Computer Museum 2245 1st Avenue S Seattle, WA 98134 mailto:ri...@livingcomputermuseum.org http://www.LivingComputerMuseum.org/
RE: PDP 11 gear finally moved
I was trying to enter a short program at the front panel and there was a clicking sound followed by a burning smell. I cut the power, the front panel is unresponsive now, so I'm going to need to look over the power Did you see anything on the panel when it died (was the numeric display still alight) ? You had better hope that the +5V line didn't go high and cook all the ICs in the machine. DEC PSUs of that vintage do have crowbar circuits though. supply for starters. He did include a second empty PDP 11/34 chassis, perhaps the power supply in that one is in better condition. The PSU in this machine is relatively repairer-friendly. There is a big mains transformer in the centre of the PSU chassis (at the back of the CPU). It takes mains in (there are 2 primary windings, each 115V, they are connected in parallel for US mains and series for European mains). It has several secondaries, each of about 20V-30V AC Under the mains transformer is a little unit that contains the mains switching relay and control circuits, and a simple linear PSU for the +15V rail. I think the LTC (line time clock), ACLO and DCLO (power failure signals) come from that too. The main supply rails (+5V and -15V) come from 'bricks' that fit either side of the transformer. These are swtiching regulators that take in the 20V or so from the transformer and bring it down to the desired voltage. Although they are switchers, the maximum voltage inside is just the rectified input (say about 40V DC) and is thus a lot nicer to work on than a mains-operated switcher. The bricks are based round the 723 IC along with some transistors, an inductor, flyback diode, capacitors, etc. What I would do is disconnect the logic backplane power (at the distribution connectors under the PSU) then take the PSU covers off, take out the bottom 2 screws each side and loosen the top on so the PSU can hinge away from the CPU and remove the power bricks. Power up the transformer on its own (maybe with a series light bub) and check that is OK. Then try to debug the bricks. If you have a bench PSU with current limiting run them (one at a time) off that (they will happing run from a DC input) and see what happens. The +5V brick just needs the 20V-30V input, the -15V one _also_ needs a +15V supply. -tony
Re: PDP 11 gear finally moved
On 2015-Jul-17, at 11:42 AM, tony duell wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. Could you, please, explain why? And how often should this be done? Every week, every month, every year, or what? FWIW, the number PSU elecrtrolytics I have replaced can be counted on the fingers of one hand -- in unary. Well, perhaps both hands. But it's 1% of all the PSU electrolytic capacitors I own. Only 2 cases spring to mind : The PSU in my 11/44 had a high ESR capacitor on the +36V rail (all other caps in the machine were fine) I changed the 2 mains smoothing capacitors in my HP120 not because they were electrically defective (they tested fine) but because one was bulging a little on top and had it exploded it would have hit the neck of the CRT with all the problems that would be likely to cause. I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... This is something Tony and I are quite in agreement on. Similar to Tony, (and as mentioned in discussion on this topic a couple of months ago): in the solid-state category, of the many pieces of 1960s 70s and later equipment I have or have serviced, the vast majority are running with their original capacitors. If you're dealing with a 1936 or 1952 tube radio, a knee-jerk replace the capacitors is warranted. If you're dealing with a 1970s computer, it isn't (IMHO). Esp. when they're screw-terminal 'computer-grade' caps. My own perception of the concern is that it has been perpetuated over the years from the vacuum tube / antique radio arena. The issue of capacitors drying out dates from the days (1920s,early 30s) when electrolytics actually were filled with an active liquid which actually did dry up. Dry electrolytics were developed in the 1930s, and while early dry electrolytics also warrant replacement, the chemistry and techniques have seen a few improvements in the many intervening years, and solid-state equipment is not placing the same stresses on caps as tube equipment. In other arenas it's a real issue, in a modern arena it is largely lore. The point of electrolytic caps is to form an oxide to be the dielectric, formed (in part) out of the electrolyte, and while I'm no expert on the chemistry, I will point out the oxidised state is 'the' or 'a' low energy state, and hence relatively stable. Rust doesn't normally undo itself.
Re: PDP 11 gear finally moved
That might be a little different -- much more recent - presumably in the ear of flat screens and PCs where there have been times when manufacturers got fed bad capacitors for their boards - which then failed later. IBM replaced a whole series of motherboards in one organization that I worked at because of that (though those were not power supply capacitors.) On 7/17/2015 1:53 PM, Mouse wrote: I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... Perhaps. But not all of it, certainly. I'm currently four for four fixing dead flatscreens by re-capping their power supplies; I imagine others have similar experiences. It's not a huge stretch to imagine that other power supplies may have similar issues; even if it turns out to not be the case, there is probably at least a little can't hurt anything, right? running around. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: PDP 11 gear finally moved
I tend to agree with your hunch. On 7/17/2015 1:55 PM, Todd Killingsworth wrote: I suspect part of the swap'em ALL out mentality comes from the 90's when some botched industrial espionage had some of the bottom-tier cap manufacturers using a dodgy electrolytic formula for their caps. These caps would have a frequent failure rate.. While not an issue for pre-90's electronics, it has fostered the mentality of full replacement for 'newer' electronics i.e. arcade/pinball machines Todd Killingsworth On Fri, Jul 17, 2015 at 2:42 PM, tony duell a...@p850ug1.demon.co.uk wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. Could you, please, explain why? And how often should this be done? Every week, every month, every year, or what? FWIW, the number PSU elecrtrolytics I have replaced can be counted on the fingers of one hand -- in unary. Well, perhaps both hands. But it's 1% of all the PSU electrolytic capacitors I own. Only 2 cases spring to mind : The PSU in my 11/44 had a high ESR capacitor on the +36V rail (all other caps in the machine were fine) I changed the 2 mains smoothing capacitors in my HP120 not because they were electrically defective (they tested fine) but because one was bulging a little on top and had it exploded it would have hit the neck of the CRT with all the problems that would be likely to cause. I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... -tony
Re: MC68451 datasheet wanted
I have it. I'll postprocess and upload it and email you the pinout page On 7/17/15 4:03 PM, Eric Smith wrote: Looking for an MC68451 datasheet (or scan). Most of the ones that turn up from the usual database sites are actually for the MC68450 DMA controller, which is entirely unrelated. The only one I found that is actually for the MC68451 was Advance Information from a databook, and did not include the pin grid (R or RC suffix) pinout. There was a loose (not in databook) datasheet that is more recent, labeled Preliminary rather than Advance Information, and later versions of that include the pin grid pinout. Does anyone have that?
Re: PDP 11 gear finally moved
Thank you for the detailed information. I need to figure out how im going to get it out of the rack and moved to a place where i can test it over the next couple days where it will not be in the way. Ill find some way to do a dummy load and do an extended test to be sure the supply is working properly. All fingers crossed, god it better not have damaged any of the boards, i do not know where i would get replacements.It took years for me to get the machine, who knows how long it would take to find a specific board that is bad. I did buy an oscillicope and a logic analyzer well in advance in preparation for getting this machine, however short of pressing the power button no clue how to use them or basic troubleshooting procedures. Guess i just have to learn by doing On Fri, Jul 17, 2015 at 3:23 PM, tony duell a...@p850ug1.demon.co.uk wrote: When I repaired my VT100s I had to replace all the electrolytic caps on the monitor control board to cure the screen wobble. Before doing so I had reformed them all and I had tested them all for ESR and they had all tested fine so I was unable to determine which of them was the bad one. Perhaps there is other more professional test equipment I could use that would have helped, I don't know. I did keep all the original caps though (somewhere). Are you saying that if you put any of the original capacitors back (leaving new ones in all other locations) you get screen wobble. If so, I am not sure I believe you. It's been some years since I repaired a VT100, but from what I remember there are plenty of capacitors that simply could not cause screen wobble no matter what they were doing. Or did you recap the board and find that it then worked. In which case (a) perhaps only one of the capacitors was faulty or (b) it was actually a dry joint. -tony
Re: PDP 11 gear finally moved
I was operating the panel when i first got it, now the numbers do not light up, panel is unresponsive, and run light stays lit.(just describing the behavior, i will not start it back up till I work on the power supply) On Fri, Jul 17, 2015 at 3:50 PM, devin davison lyokob...@gmail.com wrote: I had to do some cap replacement on some older Motorola tube radios,I have some basic soldering skills. I was under the impression that the capacitors in computer equipment this big from this year would have been of better quality and it would not be an issue. I have someone scheduled to come out tonight after i get off work and get it out of the rack. On Fri, Jul 17, 2015 at 3:45 PM, Brent Hilpert hilp...@cs.ubc.ca wrote: On 2015-Jul-17, at 11:42 AM, tony duell wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. Could you, please, explain why? And how often should this be done? Every week, every month, every year, or what? FWIW, the number PSU elecrtrolytics I have replaced can be counted on the fingers of one hand -- in unary. Well, perhaps both hands. But it's 1% of all the PSU electrolytic capacitors I own. Only 2 cases spring to mind : The PSU in my 11/44 had a high ESR capacitor on the +36V rail (all other caps in the machine were fine) I changed the 2 mains smoothing capacitors in my HP120 not because they were electrically defective (they tested fine) but because one was bulging a little on top and had it exploded it would have hit the neck of the CRT with all the problems that would be likely to cause. I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... This is something Tony and I are quite in agreement on. Similar to Tony, (and as mentioned in discussion on this topic a couple of months ago): in the solid-state category, of the many pieces of 1960s 70s and later equipment I have or have serviced, the vast majority are running with their original capacitors. If you're dealing with a 1936 or 1952 tube radio, a knee-jerk replace the capacitors is warranted. If you're dealing with a 1970s computer, it isn't (IMHO). Esp. when they're screw-terminal 'computer-grade' caps. My own perception of the concern is that it has been perpetuated over the years from the vacuum tube / antique radio arena. The issue of capacitors drying out dates from the days (1920s,early 30s) when electrolytics actually were filled with an active liquid which actually did dry up. Dry electrolytics were developed in the 1930s, and while early dry electrolytics also warrant replacement, the chemistry and techniques have seen a few improvements in the many intervening years, and solid-state equipment is not placing the same stresses on caps as tube equipment. In other arenas it's a real issue, in a modern arena it is largely lore. The point of electrolytic caps is to form an oxide to be the dielectric, formed (in part) out of the electrolyte, and while I'm no expert on the chemistry, I will point out the oxidised state is 'the' or 'a' low energy state, and hence relatively stable. Rust doesn't normally undo itself.
Re: MC68451 datasheet wanted
On 07/17/2015 04:03 PM, Eric Smith wrote: Looking for an MC68451 datasheet (or scan). Most of the ones that turn up from the usual database sites are actually for the MC68450 DMA controller, which is entirely unrelated. The only one I found that is actually for the MC68451 was Advance Information from a databook, and did not include the pin grid (R or RC suffix) pinout. There was a loose (not in databook) datasheet that is more recent, labeled Preliminary rather than Advance Information, and later versions of that include the pin grid pinout. Does anyone have that? The DIP version datasheet is also in the 1981 Motorola Microprocessors Data Manual, page 4-818 to 4-835, but no PGA pinout, sorry. --Chuck
Re: PDP 11 gear finally moved
On 07/17/2015 11:53 AM, Mouse wrote: I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... Perhaps. But not all of it, certainly. I'm currently four for four fixing dead flatscreens by re-capping their power supplies; I imagine others have similar experiences. It's not a huge stretch to imagine that other power supplies may have similar issues; even if it turns out to not be the case, there is probably at least a little can't hurt anything, right? running around. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B This is not surprising given the vintages of the machines. Modern machines using switching power supplies (15kHz+) must have capacitors with low ESR and high capacity to run properly. Older linear power supplies ran at 50/60hz and as such the capacitors had much less ripple current (and low frequency to boot) to deal with and the engineers typically over designed the values of capacitors to allow for some degradation. The machines you are playing with cost fortunes back in the day - they HAD to be reliable as possible. Modern caps run at or near their rated temperature (105C) last around 1,000 to 5,000 hours. The old linear supplies rarely heated the caps much over 40C and thus the caps would last decades...I put fans on our LCD monitors in our games and they last just fine. No fan? Expect a year or two at most before failure. John :-#)# -- John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames) www.flippers.com Old pinballers never die, they just flip out
MC68451 datasheet wanted
Looking for an MC68451 datasheet (or scan). Most of the ones that turn up from the usual database sites are actually for the MC68450 DMA controller, which is entirely unrelated. The only one I found that is actually for the MC68451 was Advance Information from a databook, and did not include the pin grid (R or RC suffix) pinout. There was a loose (not in databook) datasheet that is more recent, labeled Preliminary rather than Advance Information, and later versions of that include the pin grid pinout. Does anyone have that?
Re: PDP 11 gear finally moved
U - his PDP-11/34 most certainly does use switching power regulators. ;) On 7/17/2015 4:06 PM, John Robertson wrote: On 07/17/2015 11:53 AM, Mouse wrote: I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... Perhaps. But not all of it, certainly. I'm currently four for four fixing dead flatscreens by re-capping their power supplies; I imagine others have similar experiences. It's not a huge stretch to imagine that other power supplies may have similar issues; even if it turns out to not be the case, there is probably at least a little can't hurt anything, right? running around. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B This is not surprising given the vintages of the machines. Modern machines using switching power supplies (15kHz+) must have capacitors with low ESR and high capacity to run properly. Older linear power supplies ran at 50/60hz and as such the capacitors had much less ripple current (and low frequency to boot) to deal with and the engineers typically over designed the values of capacitors to allow for some degradation. The machines you are playing with cost fortunes back in the day - they HAD to be reliable as possible. Modern caps run at or near their rated temperature (105C) last around 1,000 to 5,000 hours. The old linear supplies rarely heated the caps much over 40C and thus the caps would last decades...I put fans on our LCD monitors in our games and they last just fine. No fan? Expect a year or two at most before failure. John :-#)#
Re: Front Panels Sample layout.
Sure On Friday, July 17, 2015, Rod Smallwood rodsmallwoo...@btinternet.com wrote: Hi Guys! Further to my previous email. If anybody would like to see the artwork I can send you a copy. Its in *.svg format. Regards Rod
RE: PDP 11 gear finally moved
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of tony duell Sent: 17 July 2015 20:23 To: General Discussion: On-Topic and Off-Topic Posts Subject: RE: PDP 11 gear finally moved When I repaired my VT100s I had to replace all the electrolytic caps on the monitor control board to cure the screen wobble. Before doing so I had reformed them all and I had tested them all for ESR and they had all tested fine so I was unable to determine which of them was the bad one. Perhaps there is other more professional test equipment I could use that would have helped, I don't know. I did keep all the original caps though (somewhere). Are you saying that if you put any of the original capacitors back (leaving new ones in all other locations) you get screen wobble. If so, I am not sure I believe you. It's been some years since I repaired a VT100, but from what I remember there are plenty of capacitors that simply could not cause screen wobble no matter what they were doing. Or did you recap the board and find that it then worked. In which case (a) perhaps only one of the capacitors was faulty or (b) it was actually a dry joint. -tony = I am saying that I recapped the entire board, so one or more of them must have been bad. I agree it could have been a dry joint, but I am not going to put them all back just to check :-) This happened on *two* of these boards, so either I had two dry joints, or two bad caps. Regards Rob
Re: PDP 11 gear finally moved
Replace - no, I don't agree - especially not for those of us who don't have the kind of budget that your organization has. In my experience, for equipment of this quality and vintage, 95% or more of the time an hour to a few hours of re-forming is all that is necessary - and as Tony has pointed out, even that is not often really necessary. JRJ On 7/17/2015 1:33 PM, Rich Alderson wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. The rest of the advice is sound. Rich Rich Alderson Vintage Computing Sr. Systems Engineer Living Computer Museum 2245 1st Avenue S Seattle, WA 98134 mailto:ri...@livingcomputermuseum.org http://www.LivingComputerMuseum.org/
