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101090 discussions

Reforming capacitors (technical description, not politics)

by radiotest＠juno.com

At 4:10 PM 7/29/2015, drlegendre wrote: >... I have somewhere a document from Mallory ... that describes the evolution of the multi-section aluminum can electrolytic ... And at 09:43 PM 7/29/2015, Eric Smith wrote: >Definitely *very* interested. As am I. I have quite a bit of old Mallory literature in-house but don't recall seeing that. Dale H. Cook, Roanoke/Lynchburg, VA Osborne 1 / Kaypro 4-84 / Kaypro 1 / Amstrad PPC-640 http://plymouthcolony.net/starcity/radios/index.html

10 years, 10 months

DEC M705 vs M7050 in PC05

by j＠ckrubin.us

If you were following Joerg Hoppe's recent PC05 auction on eBay, you might have noticed that his system had an M705 in the backplane where I would have expected an M7050. This is the way he received it and the restored unit works as it should. Clearly the cards are similar but different but are they interchangeable? Would the backplane wiring be different and if so where would this be recorded? My copy of the PC04/05 maintenance manual (DEC-00-PCOA-D(1)) makes no mention of the M705 in this location. The PC04/05 print set on Bitsavers has the M705 on the module utilization list (p45) but crossed out with no reference notes. There is an ECO list on the sheet, showing PC05 ECO's 3, 16 and 30 but no specifics. Is there an available ECO log that would cover these notes? Then there's the K303, but that's another story... Jack

10 years, 10 months

H960 blank panel clips

by Arno_1983＠gmx.de

From: Charles Dickman: Tuesday, July 28, 2015 9:03 AM > If the posts and balls are metal, the panel sockets are going to crack > because there will not be any give in the shaft. If the ball and shaft > is replaced with a solid pin, the panel sockets will get damaged > because the socket will have to flex to conform to the pin. Ah, sorry. I had not payed close attention to how the counterpart works and automatically assumed it was some sort of metal spring fitted into a recess in the plastic panel that clips and holds onto the ball head. As I see now, it is just a tube-shaped outgrowth of the panel plastic itself. Phew... Anyway, thanks for clearing this up. Arno

10 years, 10 months

R: Re: IBM RT memory boards

by supervinx＠libero.it

I own two 7012 and could be interested in, if you can shipping overseas :) -------- Messaggio originale -------- Da: Sean Caron <scaron at umich.edu> Data:25/07/2015 16:17 (GMT+01:00) A: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>,Sean Caron <scaron at umich.edu> Oggetto: Re: IBM RT memory boards If you're going to toss them otherwise, I'd be happy to keep them and give them a good home until someone came along who could use them ... but I'll take a backseat to anyone who's actually got one of those systems. Best, Sean On Sat, Jul 25, 2015 at 9:29 AM, Mike Stein <mhs.stein at gmail.com> wrote: > Hello, > > Thank you for your interest but it looks like my 70-year-old gray cells > have let me down again; it's been a few years since I scrapped this system > but after some discussion it turns out that these boards are actually for > an early RS/6000 (7012/7013). > > My apologies for raising your hopes/wasting your time ;-( > > (Anybody still interested?) > > mike > > ----- Original Message ----- From: "supervinx" <supervinx at libero.it> > To: "General Discussion: On-Topic and Off-Topic Posts" < > cctalk at classiccmp.org> > Sent: Saturday, July 25, 2015 5:54 AM > Subject: R: IBM RT memory boards > > >? I'm interested in, if you can ship overseas >> >> -------- Messaggio originale -------- >> Da: Mike Stein <mhs.stein at gmail.com> >> Data:24/07/2015? 18:21? (GMT+01:00) >> A: "General Discussion: On-Topic and Off-Topic Posts" < >> cctalk at classiccmp.org> >> Oggetto: IBM RT memory boards >> >> I've got 4 4Mx32 memory boards here from an old RT >> (AFAIR) in case anybody has a use for them. >> >> Each board has 8 512Kx40 (32 bits + 8 ECC) modules >> (20 pcs. 4x256). >> >> Edge connector is DS 42+49 >> >> m >> >> >> >

10 years, 10 months

DEC M705 vs M7050 in PC05

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > DEC made improved cards in many cases, where they added a 0 at the end > of the improved card. The other thing one will sometimes find (in PDP-11's at least, not sure about other machines) is that an M7xyz is replaced by the upgraded M8xyz, e.g. M7265, M7266 (11/34) -> M8265, M8266 (11/34A); M7685 (RM02/3) -> M8685; etc. Of course, there are plenty that follow no system at all, e.g. M7700 (RK05) -> M7680. > There are also examples where the zero was added, and the new module > replace a set of modules that combine to implement a device. The classic example, to me, being the M780 (KL11) -> M7800 (DL11). Noel

10 years, 10 months

need help getting a Sun Ultra-10 working

by lists＠y42.org

Hello Folks, I just assembled an Ultra-10 (replaced memory, CPU, NVRAM chip, IDE hard disk, IDE CDROM) and it seems to be hanging somewhere. I don't get anything from the VGA connection on the 1280x1024 LCD monitor that is connected, but on the serial console I see the output pasted below. The system does not respond to any input via the attached sun keyboard/mouse or via ttyA after printing the last line in the output below. Obviously, the NVRAM battery is dead, and I'm working on getting a replacement. Does anyone have a good source in Germany? The chip says "M48T59Y-70PC1U". Could the dead NVRAM battery explain the behavior described? thanks, Rob Urban ----- serial console output BEGIN ----- Hardware Power ON @(#) Sun Ultra 5/10 UPA/PCI 3.31 Version 0 created 2001/07/25 20:36 Probing keyboard Done %o0 = 0000.0000.0055.4001 Executing Power On SelfTest @(#) Sun Ultra 5/10 (Darwin) POST 3.1.0 (Build No. 626) 13:56 on 06/27/00 CPU: UltraSPARC-LC (Clock Frequency: 300MHz, Ecache Size: 512KB) Init POST BSS Init System BSS NVRAM NVRAM Battery Detect Test *********************** STATUS =FAILED TEST =NVRAM Battery Detect SUSPECT=NVRAM U13 MESSAGE=NVRAM Low Battery addr 000001ff.f1001ff0 exp 00 obs 10 Status of this POST run: FAIL manfacturing mode=CHAMBER Time Stamp [hour:min:sec] 28:6a:c1 [month/date year] 0b/2c 2130 Power On Selftest Completed Software Power ON0.0000.0000.0001 ffff.ffff.f00b.31a8 0000.3333.0200.001b @(#) Sun Ultra 5/10 UPA/PCI 3.31 Version 0 created 2001/07/25 20:36 Clearing E$ Tags Done Clearing I/D TLBs Done Probing Memory Done MEM BASE = 0000.0000.2000.0000 MEM SIZE = 0000.0000.1000.0000 11-Column Mode Enabled MMUs ON Copy Done PC = 0000.01ff.f000.201c PC = 0000.0000.0000.2060 Decompressing into Memory Done Size = 0000.0000.0006.eba0 ttya initialized Starting real time clock... Incorrect configuration checksum; Setting NVRAM parameters to default values. Setting diag-switch? NVRAM parameter to true Reset Control: BXIR:0 BPOR:0 SXIR:0 SPOR:1 POR:0 UltraSPARC-IIi 2-2 module Probing Memory Bank #0 256 + 256 : 512 Megabytes Probing Memory Bank #2 0 + 0 : 0 Megabytes Probing UPA Slot at 1e,0 Nothing There Probing /pci at 1f,0/pci at 1,1 at Device 1 pci108e,1000 network Probing /pci at 1f,0/pci at 1,1 at Device 2 SUNW,m64B Probing /pci at 1f,0/pci at 1,1 at Device 3 ide disk cdrom Probing /pci at 1f,0/pci at 1 at Device 1 Nothing there Probing /pci at 1f,0/pci at 1 at Device 2 Nothing there Probing /pci at 1f,0/pci at 1 at Device 3 Nothing there Probing /pci at 1f,0/pci at 1 at Device 4 Nothing there ----- serial console output END -----

10 years, 10 months

H960 blank panel clips

by jnc＠mercury.lcs.mit.edu

Saw this auction for a pair of H960 blank front panel clips: http://www.ebay.com/itm/391207099375 and though I'd pick them up... until they went for $30 (including shipping),at which point I decided I'd go back to my previous plan to fabricate some out of some scrap wood, and a pair of screws. Time to find someone who can do injection molding... (I don't think these could be 3D printed, the necks of the bulb-heads are under a lot of stress when removing panels, they often snap off; will 3D printed parts be that strong?) Noel

10 years, 10 months

Reforming capacitors (technical description, not politics)

by cube1＠charter.net

Better explanation than mine. Eric Smith <spacewar at gmail.com> wrote: >Some people seem to think that "reforming" an aluminum electrolytic >capacitor is some kind of cheat, akin to zapping NiCd cells or >rejuvenating CRTs. Actually reforming is the same electrochemical >process that the manufacturer uses to "form" the capacitor in the >first place, building up the aluminum oxide layer, before the sheet is >rolled into cylindrical form. The manufacturer typically uses a >forming voltage higher than the rated voltage, from 135% to 200%, to >provide margin for shelf life. > >When the capacitor goes unused for an extended time (shelf life), the >oxide layer gradually breaks down, increasing the capacitor's leakage >current and reducing the effective usable voltage of the capacitor, >which is proportional to the minimum oxide thickness. If the oxide has >developed spots that are too thin for the applied voltage, it may be >damaged ("punch-through") when that voltage is applied. Punch-through >tends to be a runaway process, so even a small amount of punch-through >usually completely ruins the capacitor. Reforming the capacitor by >applying current-limited power rebuilds the oxide layer to prevent >this type of damage, and to reduce the leakage current back to within >the specifications. The current limiting is what prevents the >reformation process from causing punch-through and damaging the >capacitor. Many of the capacitor vendors actually publish >recommendations for reforming their capacitors. > >See for example information on manufacture on pages 13-14 and a brief >recommendation of reforming procedure on page of 17 of Kemet >publication F3304 dated June 2009: > http://www.kemet.com/ProductCatalog%20Documents/F3304.pdf >Also pages 2-4 on manufacture and page 16 on "recondition" (reform) of >"CDE Aluminum Electrolytic Capacitor Application Guide": > http://www.cde.com/resources/catalogs/AEappGUIDE.pdf >Also pages 1-5 of Nichicon "General Description of Aluminum >Electrolytic Capacitors": > http://www.nichicon.co.jp/english/products/pdf/aluminum.pdf > >In at least some aluminum electrolytic capacitor manufacturing >processes, there is actually a reforming step done after assembly, in >addition to the initial forming. See page 9 of the Panasonic >"Aluminum Electrolytic Capacitors Technical Guide", dated April 2013: > http://industrial.panasonic.com/lecs/jp/i/29880/TAL_E/TAL_E.pdf > >The reforming process WILL NOT fix other things that may go wrong with >the capacitor, such as failed seals allowing the electrolyte to dry >out, or corrosion, or punch through which can result if the oxide >layer is degraded and voltage is applied without current-limiting. > >The US DoD published a technical handbook detailing their policies and >procedures for reforming aluminum electrolytic capacitors that sit in >inventory for years, MIL-HDBK-1131. As of 1999 this is "for guidance >only and should not be cited as a requirement, but the information in >the handbook may be useful in determining or evaluating requirements." >For non-mil-spec capacitors, it recommends inspection and possible >reformation every 3-6 years of shelf storage. It recommends disposal >after 12 years of shelf storage, but AFAICT they're just being >conservative, possibly due in part to not having enough practical >experience with reforming very old capacitors. > >Shelf storage is of course equivalent to having the capacitor >in-circuit but unpowered. Having the capacitor powered in circuit for >any significant length of time will reform the oxide to some extent >based on the applied voltage, though not up to original factory spec. > >When I reform capacitors myself, I use a reforming voltage of 135% of >the rated voltage. Since I use a suitably low current limit, this has >no significant probability of damaging the capacitor, but as with the >initial factory forming, provides some margin for further shelf life. >In my experience, aluminum electrolytic capacitors in equipment that >has been unpowered for 30 years or more almost always need >reformation, but they almost always meet factory specs (capacitance, >ESR, and leakage at rated voltage) after reformation. Since I don't >tend to restore equipment newer than that, I don't have any empirical >data on how much shelf life they can have without needing reformation. > >I'm not particularly advocating for or against reformation, as >compared to replacement. Anyone restoring equipment with electrolytic >capacitors is advised to to read the references and decide for >themselves. > >Eric

10 years, 10 months

H960 blank panel clips

by jnc＠mercury.lcs.mit.edu

> From: Chuck Guzis > Does anyone have a photo or mechanical drawing of one of these things? There are several kinds. These: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H960FrontPanelClips.jpg are some of the better ones; they are connected to the rack via countersunk screws (go in the holes), and have embdedded nuts for use with the blank panels which have the matching captured bolts. The 'usual' ones don't have the embedded nuts, just the two ball/post things on the ends, and to attach them to the rack, they have (on the back) a pair of prongs with a fishhook-tang-like capture device on them. The back prongs were an even bigger crock than the ball-and-post things. The latter at least worked, even if they did occasionally break; the prongs wouldn't hold for s^*&^(*. I'll look and see if I have any of those, to take a photo of. Noel

10 years, 10 months

Microsoft multiuser Basic for the Altair 8800

by cube1＠charter.net

OK at the risk of restarting a long discussion about the value of reforming or lack thereof.... Reforming a cap means to apply power to the cap at or a little below its rated voltage but limiting the current with a resistor in series with the cap until the voltage drop across the resistor indicates acceptably low leakage current. At the low voltages in use on an Altair I typically use something in the range of 4.7k ohms. I have a dual 1-20v power supply to do this. The idea is that this redeposits some of the aluminum that had migrated into the electrolyte while the cap was idle reducing the leakage current of the capacitor. This procedure done correctly with the correct polariy and voltage will never harm the cap, so it isn't unreasonable to reform all of the filter caps on a linear supply like that on an Altair 8800. The current list!meeting resistor prevents the cap frm drawing too much current and overheating or worse until the reforming is complete or too much time has elapsed without reaching an acceptably low leakage current. Just google it and you will find articles on the procedures. As others have pointed out, this will not help if the cap has unacceptably large effective series resistance (ESR). On a linear supply, That will show up as unacceptably high ripple ac on top of the DC the supply is designed to provide. I would test the supply with at least SOME test Load before using it to supply the machine. When I did this to my Altair a few years back I think rather than disassembling the power supply to unsolder the caps I clipped one lead of each one so that one lead was free, but that then leaves one with the need to splice them back, but does avoid potential damage to the board. I also recently did that with an ALTOS which has switching supplies. Both would probably have done just fine without reforming. I also did in on an IMSAI, same story. I also did it to a pdp12, which had blown out rectifier before I did this. Doing a good job of restoring a machine does often mean disassembling and reassembling. It comes with the territory. It sounds like you !might have pretty limited electronics experience, and if that is the case you might try and find Someone local to help you over the humps. SAFETY FIRST. Kip Koon <computerdoc at sc.rr.com> wrote: >Hi Jay, >Thank you so much for the advice. What is reforming a capacitor? Does that mention the electrolytic capacitors may have to be repolarized? If so, how to you do that? How do you know if a power cap needs to be reformed or not? To get to the transformer, I'll have to take out just about everything including the card guides. Labeling the wires will be paramount too. I don't want to get those rascals mixed up! If remember my linear power supplies correctly, I don't need to put a load on them when I test them, but I will need to test the caps disconnected, correct? I doesn't sound too difficult, just tedious and much detail to consider. I definitely want to baby this thing. :) Thanks again for the restoration advice. I'll need it and more before I'm finished. Take care my friend. > >Kip Koon >computerdoc at sc.rr.com >http://www.cocopedia.com/wiki/index.php/Kip_Koon > > >> -----Original Message----- >> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Jay Jaeger >> Sent: Thursday, July 16, 2015 9:39 AM >> To: cctalk at classiccmp.org >> Subject: Re: Microsoft multiuser Basic for the Altair 8800 >> >> First of all, safety first when working around these power supplies. >> You have mains voltage exposed all over the place, including the front panel switch. >> >> What I typically do is take it all the boards out and disconnect the power supply, and pull it out. I then re-form the capacitors by >> taking them off completely or, more often, unsoldering one lead. In one case recently the power supply was regulated (an Altos >> computer), and the power transistors were inserted through the power supply case and into the board from the backside, making >> removal both a pain and a little risky, so I just clipped one lead of each larger in place to do the re-forming (it turned out that in that >> particular case, they really didn't need it). I'd be pretty surprised if you actually had to replace your capacitors. For reforming I have >> had pretty good luck with a 4.7K ohm resistor in serial with the capacitor, and in more than half the cases, the capacitors really didn't >> need it. >> >> The transformer is either good or not - and it is probably just fine. >> Just measure its output voltages. Do make sure that the transformer is wired for your voltage depending upon where you live. One >> could disconnect it first, but the odds of it putting out too high a voltage are very very slim, so long as it is wired for the mains voltage >> wherever you happen to live. Bad ones either put out nothing for one of the voltages (open winding) or get hot (shorted winding). >> Neither is dangerous to the rest of the power supply. >> >> Then, check all the voltages to make sure they are not way too high, and throw and oscilloscope on it to make sure that there isn't a >> whole lot >> of ripple (typically caused by a bad rectifier). Remember that on the >> original Altair and most S100 machines each board had its own regulator, so this isn't an exact thing. (On my machine, I actually had >> to add a second 8V supply in order to provide power for a backplane completely full of boards.) >> >> For bootstraps, perhaps look for a ROM board on eBay (a Bytesaver or the like), and burn yourself a ROM. >> >> For a serial card, you can find T-UART or IMSAI MIO and the like show up >> on eBay pretty frequently. Be patient so you don't overpay. ;) Real >> MITS Altair cards come up far less frequently. Make sure you research (say, on bitsavers.org/pdf) which ones support current loop if >> you really want to hook up a real teletype. >> >> Not sure where you'd find your multi-user basic, but there is quite a lot of Altair/S100 software available as part of the SimH >> environment, and a separate web site at http://schorn.ch/altair_6.php >> >> JRJ >> >> On 7/15/2015 1:56 PM, Kip Koon wrote: >> > Hi Drlegendre, >> > How did you go about checking things out before you applied power for the first time (again)? :) I think I need to check out the >> electrolytic capacitors and the transformer at least. >> > In my system, the front panel is wired to the backplane along with the power supply wires so when I do power up, how do I protect >> everything? >> > There are screws the power wires come from, but they are difficult to get to. Do I need to consider replacing any other caps? >> > Do you have a write up about your experience? Any help you can give in the hardware department is most appreciated. Thanks in >> advance. Take care my friend. >> > >> > Kip Koon >> > computerdoc at sc.rr.com >> > http://www.cocopedia.com/wiki/index.php/Kip_Koon >> > >> > >> > >> >> -----Original Message----- >> >> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of drlegendre . >> >> Sent: Wednesday, July 15, 2015 1:15 AM >> >> To: General Discussion: On-Topic and Off-Topic Posts >> >> Subject: Re: Microsoft multiuser Basic for the Altair 8800 >> >> >> >> Hey Kip >> >> >> >> I can't help you with the software, but I just finished an Altair >> >> restoration (my first) a few months ago, and am still interested in >> >> getting the machine connected and actually doing something >> >> interesting. The Altair was almost totally below the radar by the time I really started getting up to speed on micros, which would >> have been around 1983-1984 or so. This one was sort-of given to me by a former colleague of mine, around eight years ago. It was a >> total basket case, a real pile.. but it seems to be sorted at this point. >> >> >> >> It would be great if you'd let me follow along, keep in touch and let >> >> me know how you're working to get the Altair linked up to the term, >> >> getting the system bootstrapped, loading software, etc.. that's been a problem here, figuring out the serial I card (or finding one to >> replace it, that does have docs). >> >> >> >> Best, >> >> Bill >> >> >> >> On Tue, Jul 14, 2015 at 11:56 PM, Kip Koon <computerdoc at sc.rr.com> wrote: >> >> >> >>> Hi Guys, >> >>> >> >>> I have finally decided to restore my original Altair 8800 which has >> >>> been in storage for over 30 years. Does anyone have a copy of >> >>> Microsoft's Multiuser Disk Extended Basic for the Altair 8800? When >> >>> I was in college in '79 to '81, in the computer room was an ASR-33 >> >>> Teletype and 3 Learseigler terminals connected to an Altair 8800B. >> >>> An IMSAI was also there connected to one >> >>> ASR-33 Teletype. I'd like to resurrect this multiuser Basic >> >>> software environment on my Altair someday once the restoration is complete. >> >>> Any help in securing a copy of all the necessary software would be >> >>> most appreciated. >> >>> Thanks a bunch in advance. Take care my friends. >> >>> >> >>> >> >>> >> >>> Kip Koon >> >>> >> >>> <mailto:computerdoc at sc.rr.com> computerdoc at sc.rr.com >> >>> >> >>> <http://www.cocopedia.com/wiki/index.php/Kip_Koon> >> >>> http://www.cocopedia.com/wiki/index.php/Kip_Koon >> >>> >> >>> >> >>> >> >>> >> >>> >> >>> >> > >> > >

10 years, 10 months

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